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The combination of the tricyclic antidepressant amitriptyline hydrochloride (AMH) and the non-selective beta-adrenergic blocker propranolol hydrochloride (PPH) is used for migraine prophylaxis. Higher doses of AMH trigger cardiac arrhythmias, anxiety, tachycardia, convulsions, hyperglycemia and anticholinergic side effects. The combined dosage formulation of AMH and PPH leads to drug-drug interactions; causes sedation, xerostomia, dysuria, insomnia and bradycardia; and results in patient non-compliance. The quantification of AMH and PPN becomes essential, especially for combination formulations, in addition to regular quality control to avoid clinical issues. Considering these facts into account, the reverse-phase -high-performance liquid chromatography (RP-HPLC) method was developed in accordance with International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use Q2(R1) guidelines for the simultaneous determination of AMH and PPH. The HPLC separation was performed on an HPLC system (Shimadzu, Japan, Prominence I series 2030C) using a Shimadzu Shim-Pack GIST C18 column (100 mm × 4.6 mm, 5 μ), which was equipped with an ultraviolet detector at the isosbestic point 238 nm. The mixture of acetonitrile and orthophosphoric acid (pH 3.5) in a ratio of 35:65 v/v with a flow rate of 0.75 mL/min was used as the mobile phase. The regression coefficients of AMH (r2 > 0.998) and PPH (r2 > 0.999) show good linearity between peak areas and drug concentration ranges. The limits of detection (AMH = 0.67 μg/mL, PPH = 0.67 μg/mL) and limits of quantification (AMH = 2.04 μg/mL, PPH = 2.05 μg/mL) demonstrated the higher detection sensitivity of the proposed method., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

This study presents a novel and efficient method for determining of cyclobenzaprine (CBP) in human plasma and tablets using simple liquid-liquid microextraction and ultra-high performance liquid chromatography-diode-array detector. The developed method was optimized and validated for selectivity, linearity, precision, accuracy, limit of detection (LOD) and limit of quantification (LOQ). The chromatographic separation was achieved using a C18 column with a mobile phase consisting of a mixture of deionized water containing 0.1% TFA and methanol (30:70, v:v) at a flow rate of 1.0 mL/min. The extraction process provided high-efficiency recovery of CBP with a small plasma volume (%94.3). The method showed good linearity within the concentration range of 0.005-10 μg/mL, with a correlation coefficient of 0.999. The LOD and LOQ values were found to be 0.0013 and 0.005 μg/mL, respectively. The intra- and inter-day %RSD were <8%, and %RE were ranged from -0.50 to 0.01%. The proposed method was successfully applied to the analysis of CBP in real human plasma samples and tablets, indicating its applicability in clinical and pharmaceutical research. In conclusion, the simple, low cost, high sensitivity and rapid nature of this method make it an attractive option for the quantification of CBP in human plasma and pharmaceutical dosage forms., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Tricyclic medicine such as amitriptyline (AMT) hydrochloride, initially developed to treat depression, is also used to treat neuropathic pain, anxiety disorder, and migraines. The mechanism of functioning of this type of drugs is ambiguous. Understanding the mechanism is important for designing new drug molecules with higher pharmacological efficiency. Hence, in the present study, biophysical approaches have been taken to shed light on their interactions with a model cellular membrane of brain sphingomyelin in the form of monolayer and multi-lamellar vesicles. The surface pressure-area isotherm infers the partitioning of a drug molecule into the lipid monolayer at the air water interface, providing a higher surface area per molecule and reducing the in-plane elasticity. Further, the surface electrostatic potential of the lipid monolayer is found to increase due to the insertion of drug molecule. The interfacial rheology revealed a reduction of the in-plane viscoelasticity of the lipid film, which, depends on the adsorption of the drug molecule onto the film. Small-angle X-ray scattering (SAXS) measurements on multilamellar vesicles (MLVs) have revealed that the AMT molecules partition into the hydrophobic core of the lipid membrane, modifying the organization of lipids in the membrane. The modified physical state of less rigid membrane and the transformed electrostatics of the membrane could influence its interaction with synaptic vesicles and neurotransmitters making higher availability of the neurotransmitters in the synaptic cleft., Competing Interests: Declaration of Competing Interest The authors have no competing interests to declare, (Copyright © 2024 Elsevier B.V. All rights reserved.)

A nanocomposite of Ce-doped ZnO/r-GO was synthesized using a conventional hydrothermal method. The synthesized nanocomposites were utilized for the purpose of sensitive and selective detection of cyclobenzaprine hydrochloride (CBP). The properties of the composite were extensively analyzed, including its morphology, structure, and electrochemical behavior. This study investigates the application of a modified glassy carbon electrode for the detection of CBP, a muscle relaxant used to treat musculoskeletal diseases that cause muscle spasms. The electrode is modified with Ce-doped ZnO/r-GO. Various detection methods, such as cyclic voltammetric and square wave techniques (SWV), were utilized. The composite material showed high effectiveness as an electron transfer mediator in the oxidation of CBP. The electrode showed a good response for SWV evaluations in CBP identification, with a minimum detection limit of 1.6 × 10 - 8  M and a wide linear range from 10 × 10 - 6 M to 0.6 × 10 - 7 M, under ideal conditions. The rate constant for charge transfer (ks) and the estimation of the electrochemical active surface area were obtained. A developed sensor exhibited desirable selectivity, long-lasting stability, and remarkable reproducibility. A sensor was used to analyze water, human serum, and urine samples, resulting in positive recovery results., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Interest in 3D printing has been growing rapidly especially in pharmaceutical industry due to its multiple advantages such as manufacturing versatility, personalization of medicine, scalability, and cost effectiveness. Inkjet based 3D printing gained special attention after FDA's approval of Spritam® manufactured by Aprecia pharmaceuticals in 2015. The precision and printing efficiency of 3D printing is strongly influenced by the dynamics of ink/binder jetting, which further depends on the ink's fluid properties. In this study, Computational Fluid Dynamics (CFD) has been utilized to study the drop formation process during inkjet-based 3D printing for piezoelectric and thermal printhead geometries using Volume of Fluid (VOF) method. To develop the CFD model commercial software ANSYS-Fluent was used. The developed CFD model was experimentally validated using drop watcher setup to record drop progression and drop velocity. During the study, water, Fujifilm model fluid, and Amitriptyline drug solutions were evaluated as the ink solutions. The drop properties such as drop volume, drop diameter, and drop velocity were examined in detail in response to change ink solution properties such as surface tension, viscosity, and density. A good agreement was observed between the experimental and simulation data for drop properties such as drop volume and drop velocity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hydrophilic interaction liquid chromatography (HILIC) has been widely applied to challenging analysis in biomedical and pharmaceutical fields, bridging the gap between normal-phase high-performance liquid chromatography and reversed-phase high-performance liquid chromatography (RP-HPLC). This paper comprehensively explores the retention mechanisms of amitriptyline and its impurities A, B, C, D, F, and G on amide, amino, diol, and silica columns. Dual HILIC/RP-HPLC retention mechanisms were developed, and transitional points between HILIC and RP-HPLC mechanisms were calculated on amide, diol, and silica columns. Adsorption and partition contributions to overall retention mechanisms were evaluated using Python software in HILIC and RP-HPLC regions. The cation exchange mechanism dominates overall retention for ionized analytes in the silica column (R 2  > 0.995), whereas the retention of ionized analytes increases with pH. Impacts of acetonitrile content, buffer ionic strength, and pH, along with their interactions on the retention of ionized analytes in the silica column, were determined using the chemometric approach. Acetonitrile content showed the most significant impact on the retention mechanisms. These findings highlight that a detailed investigation into retention mechanisms provides notable insights into factors influencing analyte retention and separation, promising valuable guidance for future analysis., (© 2024 Wiley‐VCH GmbH.)

Some tricyclic antidepressants (TCAs), including amitriptyline (ATL), clomipramine (CLO), and desipramine (DES), are known to be effective for management of neuropathic pain. It was previously determined that ATL, CLO, and DES are capable of voltage-dependent blocking of NMDA receptors of glutamate (NMDAR), which play a key role in pathogenesis of neuropathic pain. Despite the similar structure of ATL, CLO, and DES, efficacy of their interaction with NMDAR varies significantly. In the study presented here, we applied molecular modeling methods to investigate the mechanism of binding of ATL, CLO, and DES to NMDAR and to identify structural features of the drugs that determine their inhibitory activity against NMDAR. Molecular docking of the studied TCAs into the NMDAR channel was performed. Conformational behavior of the obtained complexes in the lipid bilayer was simulated by the method of molecular dynamics (MD). A single binding site (upper) for the tertiary amines ATL and CLO and two binding sites (upper and lower) for the secondary amine DES were identified inside the NMDAR channel. The upper and lower binding sites are located along the channel axis at different distances from the extracellular side of the plasma membrane. MD simulation revealed that the position of DES in the lower site is stabilized only in the presence of sodium cation inside the NMDAR channel. DES binds more strongly to NMDAR compared to ATL and CLO due to simultaneous interaction of two hydrogen atoms of its cationic group with the asparagine residues of the ion pore of the receptor. This feature may be responsible for the stronger side effects of DES. It has been hypothesized that ATL binds to NMDAR less efficiently compared to DES and CLO due to its lower conformational mobility. The identified features of the structure- and cation-dependent mechanism of interaction between TCAs and NMDAR will help in the further development of effective and safe analgesic therapy.

Aim: Amitriptyline (AMI) has been used to treat neuropathic pain. However, the clinical outcomes remain unsatisfactory, presumably due to a limited understanding of the underlying molecular mechanisms. Here, we investigated a drug repositioning strategy using a low-dose of AMI encapsulated in poly (D, L lactic-co-glycolic acid) (PLGA) nanoparticles (AMI NPs) for neuropathic pain, since PLGA nanoparticles are known to enhance delivery to microglia. Methods: We evaluated the anti-allodynic effects of AMI and AMI NPs on neuropathic pain by assessing behaviors and inflammatory responses in a rat model of spinal nerve ligation (SNL). While the anti-allodynic effect of AMI (30 μg) drug injection on SNL-induced neuropathic pain persisted for 12 h, AMI NPs significantly alleviated mechanical allodynia for 3 days. Results: Histological and cytokine analyses showed AMI NPs facilitated the reduction of microglial activation and pro-inflammatory mediators in the spinal dorsal horn. This study suggests that AMI NPs can provide a sustained anti-allodynic effect by enhancing the targeting of microglia and regulating the release of pro-inflammatory cytokines from activated microglia. Conclusion: Our findings suggest that the use of microglial-targeted NPs continuously releasing AMI (2 μg) as a drug repositioning strategy offers long-term anti-allodynic effects.

The hydrophobic subtraction model (HSM) for characterizing the selectivity of reversed-phase liquid chromatography (LC) columns has been used extensively by the LC community since it was first developed in 2002. Continuing interest in the model is due in part to the large, publicly available set of column descriptors that has been assembled over the past 18 years. In the work described in this report, we sought to refine the HSM with the goal of improving the predictive accuracy of the model without compromising its physico-chemical interpretability. The approach taken here has the following facets. A set of retention measurements for 635 columns and the 16 probe solutes used to characterize new columns using the HSM was assembled. Principal components analysis (PCA) was used as a guide for the development of a refined version of the HSM. Several outlying columns (84) were eliminated from the analysis because they were either inconsistent with the PCA model or were outliers from the original HSM model. With the retention dataset for the 16 probe solutes on the remaining 551 columns, we determined that a six-component model is the most sophisticated form of the model that can be used without overfitting the data. In our refined version of the HSM, the S*σ term has been removed. Two new terms have been added, which more accurately account for the molecular volume of the solute (Vv), and the solute dipolarity (Dd), and the remaining terms have been adjusted to accommodate these changes. The refined model described here provides improved prediction of retention factors, with the model standard error being reduced from 1.0 for the original HSM to 0.35 for the refined model (16 solutes, 551 columns). Furthermore, the number of retention factors with errors greater than 10% are reduced from 231 to 25. A revised metric for column similarity, F, is also proposed as a part of this work., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

Herein, the interaction among the antidepressant drug amitriptyline hydrochloride (AMT) and a green gemini surfactant, ethane-1, 2-diyl bis(N,N-dimethyl-N-tetradecylammoniumacetoxy) dichloride (14-E2-14), via numerous techniques such as tensiometry, fluorimetry, FT-IR and UV-visible spectroscopy in three different media (aqueous 0.050 mol·kg-1 NaCl, 0.50 and 1.0 mol·kg-1 urea) were investigated. AMT is used to treat mental illness or mood problems, such as depression. The aggregation of biologically active ingredients can enhance the bioavailability of hydrophobic drugs. A significant interaction between AMT and 14-E2-14 was detected by tensiometric study as the critical micelle concentration (cmc) of AMT+14-E2-14 is reduced upon an increase of mole fraction (α1) of 14-E2-14. The decrease in cmc indicates the nonideality of studied mixtures of different compositions. Although, employed drug AMT is freely soluble in the aqueous and non-aqueous system but is not hydrophobic enough to act as its carrier. Instead, gemini surfactant formed spherical micelles in an aqueous system and their high solubilization capability, as well as their relatively lower cmc value, makes them highly stable in vivo. The cmc values of AMT+14-E-14 mixtures in all cases were further decreased and increased in NaCl and urea solutions respectively as compared with the aqueous system. Numerous micellar, interfacial, and thermodynamic parameters have been measured by applying various theoretical models. The obtained changes in the physicochemical assets of AMT upon adding of 14-E2-14 are likely to enhance the industrial and pharmaceutical applications of gemini surfactants. The negative interaction parameters (βm and βσ), indicate synergistic attraction is occurring in the mixed systems. The aggregation number (Nagg), Stern-Volmer constant (Ksv), etc. are attained through the fluorescence method, also supporting the attractive interaction behavior of AMT+14-E2-14 mixtures in all solvents. The Nagg was found to increase in the salt solution and decrease in the urea system compared with the aqueous solution. FT-IR and UV-visible analysis also depict the interaction between the constituent alike tensiometry and fluorimetry methods. The results suggested that gemini surfactants may serve as a capable drug delivery agent for antidepressants, improving their bioavailability., Competing Interests: The authors have declared that no competing interests exist.

Water pollution arising from pharmaceuticals has raised great concerns about the potential risks for biosphere and human health. However, rapid and efficient removal of pharmaceutical contaminants from water remains challenging. Wood sawdust, a byproduct of the wood-processing industry, is an abundant, cost-effective, and sustainable material with a unique hierarchically porous microstructure. These features make wood sawdust quite interesting as a filtration material. Here, we report a novel cross-flow filtration composite based on β-cyclodextrin-polymer-functionalized wood sawdust (β-CD/WS) in which the pharmaceutical contaminant water flows through the sawn-off vessel channels and the micropores on the surface of the cell walls, generating the turbulence. Such water flow characteristics ensure full contact between pharmaceutical pollutants and β-CD grafted on the cellulose backbone of wood sawdust, thereby enhancing the water treatment efficiency. Consequently, the β-CD/WS filter device shows a high removal efficiency of over 97.5% within 90 s for various pharmaceutical contaminants including propranolol, amitriptyline, chlortetracycline, diclofenac, and levofloxacin, and a high saturation uptake capacity of 170, 156, 257, 159, and 185 mg g -1 , respectively. The high-performance wood-sawdust-based cross-flow filtration opens new avenues for solving the global water pollution issues, especially those caused by pharmaceutical contaminants.

The drug loading efficiency was evaluated using a binder-jet 3D printing process by incorporating an active pharmaceutical ingredient (API) in ink, and quantifying the printability property of ink solutions. A dimensionless parameter Ohnesorge was calculated to understand the printability property of the ink solutions. A pre-formulation study was also carried out for the raw materials and printed tablets using thermal analysis and compendial tests. The compendial characterization of the printed tablets was evaluated with respect to weight variation, hardness, disintegration, and size; Amitriptyline Hydrochloride was considered as the model API in this study. Four concentrations of the API ink solutions (5, 10, 20, 40 mg/mL) were used to print four printed tablet batches using the same tablet design file. The excipient mixture used in the study was kept the same and consists of Lactose monohydrate, Polyvinyl pyrrolidone K30, and Di-Calcium phosphate Anhydrate. The minimum drug loading achieved was 30 μg with a minimal variation (RSD) of <0.26%. The distribution of the API on the tablet surface and throughout the printed tablets were observed using SEM-EDS. In contrast, the micro-CT images of the printed tablets indicated the porous surface structure of the tablets. The immediate release properties of the printed tablets were determined using a dissolution study in a modified USP apparatus II., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The extensive use of organic molecules (Rhodamine B and Amitriptyline) also has contributed to environmental pollution; adsorption is a relevant method for removal of these contaminants in aqueous media. In this context, the objective of this study was to modify the surface of cellulose (Cel) with phosphoric acid and sodium tripolyphosphate to obtain a biopolymer with incorporated phosphate groups (PCel). The modification was confirmed by X-ray dispersive energy spectroscopy, solid state nuclear magnetic resonance, X-ray diffraction, and thermal analysis. The obtained material (PCel) was used as a Rhodamine B (RhB) or Amitriptyline (AmTP) adsorbent, and the highest adsorption capacity of this material was obtained at pH 3.0 (RhB) and 7.0 (AmTP) and the equilibrium time was achieved at 65 (RhB) and 150 min (AmTP). Moreover, the pseudo-first-order model best describes the kinetics of this adsorption. The experimental adsorption isotherms were adjusted to the Langmuir model, indicating that monolayer adsorption occurred and the highest experimental adsorption capacity obtained was 47.58 (RhB) and 45.52 mg g - 1 (AmTP) in PCel. The thermodynamic parameters showed that the adsorption process is exothermic and non-spontaneous, with increase of non-spontaneity with enhance of the temperature. However, PCel was efficient in removing the contaminant (RhB or AmTP) in an aqueous solution., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The β-CD encapsulation of two tricyclic antidepressants (TCAs), nortriptyline (NRT) HCl and amitriptyline (AMT) HCl (most widely used TCA), has been thoroughly investigated by single-crystal X-ray diffraction and DFT calculation for insights into the inclusion complexation. X-ray analysis reveals that both drugs insert the A-ring moiety vertically from the β-CD O2H/O3H-side and are kept in position by C5H⋯π interactions, yielding thermodynamically favorable complexes. In the β-CD cavity, NRT and AMT are less open as their butterfly angles are ~10° smaller than those in free HCl salt forms and in complex with proteins. The effect of HCl salt on both complexes is evaluated by DFT full-geometry optimization. When Cl - is directly linked with the NRT NH 2 Me + group, the inclusion complex formed gains stability by 3.65 kcal mol -1 through N5'H⋯Cl⋯HO26 H-bond chain, compared to the complex of NRT base. The addition of HCl to N5' of the side chain marginally affects the structures of β-CD-TCA complexes. This study provides a rigorous crystallographic evidence for the β-CD-TCA complexation and a theoretical view on the improved stability of TCA in the CD cavity, supporting the pharmacological benefit of CD encapsulation in reducing the TCA side effects., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

This paper presents integration of Quality by Design concept in the development of hydrophilic interactions liquid chromatographic methods for analysis of amitriptyline and its impurities (A, B, C, and F). This is the first time that HILIC method for amitriptyline and its impurities is developed. Using QbD concept, it is possible to design a robust method and incorporate quality directly into its development. QbD concept in combination of Design of Experiments methodology (DoE) enables creation of well-defined design space. In this study, for method optimization a Box-Behnken design was used to test the effect of acetonitrile content, buffer concentration and pH of water phase on critical system responses such as retention factor of impurity A, resolution between impurity B and impurity C, amitriptyline peak asymmetry factor and retention time of last eluted impurity F. The defined mathematical models and Monte Carlo simulations were used to identify the design space. For robustness testing, fractional factorial design was applied. Optimal chromatographic conditions were the analytical column ZORBAX NH2 (250 mm x 4.6 mm, 5 μm particle size); mobile phase consisted of acetonitrile-water phase (60 mM ammonium acetate, pH adjusted to 4.5 with glacial acetic acid) (92.5:7.5 v/v); column temperature 30 °C, mobile phase flow rate 1 mL min -1 , wavelength of detection 254 nm. Finally, method was fully validated and applicability of the method in tablet analysis was confirmed., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Aim: To investigate the enhancement of bioavailability by the usage of drug nanoparticles for increasing the efficacy of antidepressant therapeutic value. Materials & methods: Nano-amitriptyline HCI (AMT·HCl) particles were successfully prepared via a simple spray freeze drying (SFD) method. Results: The as-prepared nanoparticles are amorphous instead of crystalline. The mean size of AMT·HCl nanoparticles is 90 nm. In in vitro evaluation, AMT·HCl nanoparticles have greatly improved the dissolution compared with pure bulk materials, which have potential for enhancing human bioavailability and diminishing toxic effect. A nanoparticle formation mechanism was also proposed. Conclusion: These findings promote the development of antidepressant therapeutic evaluation based on the usage of AMT·HCl nanoparticles by SFD method and indicate that SFD is an alternative for a range of nanoparticle preparation in industrial pharmacy.

In the current study, we have examined the interaction amongst an antidepressant drug amitriptyline hydrochloride (AMH) and ethane-1, 2-diyl bis(N,N-dimethyl-N-cetylammoniumacetoxy) dichloride (16-E2-16, a green gemini surfactant) through tensiometric and fluorimetric techniques in aqueous/electrolyte/urea solutions. Significant variations are observed in the various evaluated parameters in the present study. Gemini 16-E2-16 has outstanding surface properties along with a much lower cmc value, demonstrating very little toxicity as well as considerable antimicrobial activity. The cmc values of mixtures decrease through increase in mole fraction (α1) of 16-E2-16, which specifies the nonideality of the solution mixtures, along with demonstrating the occurrence of mixed micellization too. Negative βRub values signify on the whole attractive force of interaction between constituents of mixed micelles. Owing to the incidence of electrolyte NaCl (50 mmol.kg-1), lowering of the micelles' surface charge happens, resulting in aggregation taking place at lower concentration while the presence of urea (NH2CONH2) halts micellization taking place, which means the cmc value increases in the attendance of urea. The [Formula: see text] values for all systems were negative along with the presence of electrolyte/urea. The excess free energy (Gex) of studied mixed systems was also estimated and found to be negative for all the systems. Using the fluorescence quenching method, the micelle aggregation number (Nagg) was evaluated and it was found that the contribution of gemini surfactant was always more than that of the AMH and their value enhances in the existence of electrolyte while decreasing in the attendance of NH2CONH2 in the system. In addition, other fluorescence parameters such as micropolarity (I1/I3), dielectric constant (Dexp) as well as Stern-Volmer binding constants (Ksv) of mixed systems were evaluated and the results showed the synergistic performance of the AMH + 16-E2-16 mixtures. Along with tensiometric and fluorimetric techniques, FT-IR spectroscopy was also engaged to reveal the interaction among constituents., Competing Interests: The authors have declared that no competing interests exist.

Cyclobenzaprine hydrochloride (CBH) is a well-known muscle relaxant that is widely used to relieve muscle spasms and other pain associated with acute musculoskeletal conditions. In this study, we elucidated the binding characteristics of this muscle relaxant to human serum albumin (HSA). From a pharmaceutical and biochemical viewpoint, insight into the structure, functions, dynamics, and features of HSA-CBH complex holds great importance. The binding of CBH with this major circulatory transport protein was studied using a combination of biophysical approaches such as UV-VIS absorption, fluorescence quenching, and circular dichroism (CD) spectroscopy. Various in silico techniques, molecular docking and molecular dynamics, were also used to gain deeper insight into the binding. A reduction in the fluorescence intensities of HSA-CBH complex with a constant increase in temperature, revealed the static mode of protein fluorescence quenching upon CBH addition, which confirmed the formation of the HSA-CBH ground state complex. The alteration in the UV-VIS and far-UV CD spectrum indicated changes in both secondary and tertiary structures of HSA upon binding of CBH, further proving CBH binding to HSA. The analysis of thermodynamic parameters ∆H° and ∆S° showed that binding of CBH to HSA was dominated by intermolecular hydrophobic forces. The results of the molecular docking and molecular dynamics simulation studies also confirmed the stability of the complex and supported the experimental results.

In this work, a rapid and simple method is applied using a newly synthesized nanoadsorbent for the extraction and preconcentration of the drugs Amitriptyline (AMT) and Nortriptyline (NRT), which are then determined using high performance liquid chromatography. We focus on the facile synthesis of Fe 3 O 4 @SiO 2 @N 3 , as a new and effective adsorbent, and the effervescent salt-assisted dispersive magnetic micro solid-phase extraction method. The applied method and modification of the surface of Fe 3 O 4 @SiO 2 with the nitrogen-rich group lead to an increase in the interaction between the nanoadsorbent used and the analytes, and increase the extraction recovery. The accuracy of the synthesized nanoadsorbent is confirmed by the FT-IR, FE-SEM, XRD, and VSM analytical techniques. In order to obtain the best experimental conditions, optimization of the main variables involved is carried out using the central composite design method. Under the optimum experimental conditions, the limits of detection (LODs), linear dynamic ranges (LDRs), and relative standard deviations (RSDs for n = 5) for NRT and AMT were found to be as follow: LODs, 0.03 and 0.05 ng/mL; RSDs, 2.04 and 1.1 for NRT and AMT, respectively; and LDRs, 0.07-2000 ng/mL. Furthermore, the results obtained show that the nanoadsorbent can be used for five times with an extraction recovery more than 80% and 70% for AMT and NRT, respectively., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Extemporaneous topical compounds for neuropathic pain offers an alternative or adjunct approach to existing therapies for patients. Assigning evidence-based beyond-use dating prior to dispensing topical medications is a legal requirement by pharmacy governing bodies. The purpose of this study was to utilize a validated stability-indicating high-performance liquid chromatography assay to determine beyond-use dating of topical amitriptyline in three different bases (Lipoderm Base, PLO Gel Mediflo 30, Emollient Cream) at three different temperatures [room temperature (25°C), refrigeration (4°C), and high temperature (40°C)]. Amitriptyline was stable after 90 days at room temperature in both Lipoderm Base and PLO Gel Mediflo 30. However, it was not stable at 40°C in Emollient Cream, irrespective of storage conditions., (Copyright© by International Journal of Pharmaceutical Compounding, Inc.)

Aim: Removal of a toxin from the body once absorbed is usually not possible. We describe the use of magnetite containing pH gradient 'MagnepH' liposomes to overcome limitations preventing removal., Methods: MagnepH liposomes were added to albumin solution containing amitriptyline and dosed intravenously in rats prior to amitriptyline injection. Albumin solution or drawn blood was exposed to a magnet and sampled., Results: One third of amitriptyline was extracted in vitro. In vivo amitriptyline concentrations were 1830 nmol/l (controls) and 10870 nmol/l (MagnepH; n = 2). Amitriptyline extraction increased from 0.6% (control) to 10.4% (MagnepH; 95% CI for difference 2.0-17.6%)., Conclusion: MagnepH liposomes sequestered amitriptyline and could then be extracted. This method has potential to ameliorate limitations to extracorporeal removal of toxins in poisoning.

Five modified multivariate calibration models based on classical least squares (CLS) in addition to traditional CLS model are developed and validated for assaying cyclobenzaprine HCl (CZ) with its major degradants; dibenzocycloheptatrienone (DZ) and anthraquinone (AQ), whether in its pure form or in pharmaceutical dosage form. The five models are net analyte processing CLS (NAP-CLS), orthogonal signal correction CLS (OSC-CLS), direct orthogonal signal correction CLS (DOSC-CLS) and hybrid linear analysis following the strategy of Xu and Schechter (HLA-XS) or Goicoechea et al. (HLA-GO). The five modified CLS models in addition to traditional CLS were subjected to a comparative study through manipulation of ultra-violet absorption data in the region of 220-350 nm. Three factor four level experimental design was adopted which results in 16 mixtures calibration set covering various concentrations of CZ, DZ and AQ. An extra validation set, composed of nine mixtures, was prepared for validation of the prediction power of the presented models. Experimental results showed high capability of the proposed modified CLS models for assaying CZ successfully without any interference from the co-existing degradation products (DZ and AQ). A statistical comparison between the results of CZ analysis in its dosage form by the six CLS based models and the reported HPLC method was carried out presenting no significant difference in regards to precision and accuracy. Significance of CLS based models is a consequent of their high quantitative and qualitative power for assaying multi-components mixtures., (Copyright © 2018. Published by Elsevier B.V.)

Fe(III) and carboxylic acids are ubiquitous in surface water and atmospheric water droplets. Numerous documents have reported the photochemistry of Fe(III)-carboxylate complexes, typically including Fe(III)-oxalate and Fe(III)-citrate. Our previous study preliminarily showed that oxalate enhances the photoreactivity of Fe(III)-citrate system. Here, we further investigate the synergistic effect of Fe(III)-citrate-oxalate binary system at different conditions with pharmaceutical amitriptyline (AMT) as the model pollutant. In the Fe(III)-oxalate system, the photodegradation of AMT decreased with increasing pH from 3.0 to 8.0. In the Fe(III)-citrate system, the optimal pH for AMT degradation is around 5.0 in the same pH range. For the Fe(III)-citrate-oxalate system, the photodegradation of AMT decreased with increasing pH, indicating the combined effect of both oxalate and citrate on the photoreactivity. The addition of oxalate to the Fe(III)-citrate system markedly accelerated the photodegradation of AMT. The Fe(III)-carboxylate binary system exhibited excellent photoreactivity and up to 90% AMT was removed after 30 min at pH 6.0 with Fe(III)/citrate/oxalate ratio of 10:150:500 (μM). Synergistic effect was observed in Fe(III)-citrate-oxalate binary system in the pH range of 5.0-8.0. The presence of oxalate promoted the depletion of citrate in the Fe(III)-citrate system. The higher concentration ratios of oxalate to citrate facilitated the synergistic effect in the Fe(III)-citrate-oxalate system. By LC-MS analyses, a possible pathway of AMT degradation was proposed based on hydroxyl radicals (OH) mechanism. This finding could be helpful for the better understanding of synergistic mechanism of Fe(III)-citrate-oxalate binary complexes, which will be of great potential application in environmental photocatalysis at near neutral pH., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The reversed-phase chromatographic behaviour of six tricyclic antidepressants (amitryptiline, clomipramine, doxepin, imipramine, nortryptiline and maprotiline) was examined in this work with acetonitrile-water mobile phases, in the absence and presence of the ionic liquids 1-hexyl-3-methylimidazolium chloride and 1-hexyl-3-methylimidazolium tetrafluoroborate, which have interesting features for the separation of basic compounds, in terms of peak shape combined with reduced retention. Tricyclic antidepressants are low polarity drugs that strongly associate to the alkyl chains of conventional stationary phases. They are also positively charged in the usual working pH range (2-8) in reversed-phase liquid chromatography, due to their strong basic character. In consequence, they may interact with the residual ionised silanols present in conventional silica-based stationary phases, which is translated in stronger retention, and tailed and broad peaks. A simple chromatographic procedure for the control of tricyclic antidepressants in pharmaceutical formulations was developed using a C8 column and a mobile phase containing 30% acetonitrile/10 mM 1-hexyl-3-methylimidazolium chloride at pH 3, with UV detection. Intra- and inter-day precisions were usually below +1.0%, and intra- and inter-day bias (trueness) ranged between ‒2.1% and +2.4%, and between ‒3.0% and +2.3%, respectively. Sample preparation was simple and only required solubilisation and filtration previous to injection., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Amitriptyline (AMIT) is a compound widely prescribed for psychiatric and non-psychiatric conditions including depression, migraine, chronic pain, and anorexia. However, AMIT has been associated with risks of cardiac arrhythmia and sudden death since it can induce prolongation of the QT interval on the surface electrocardiogram and torsade de pointes ventricular arrhythmia. These complications have been attributed to the inhibition of the rapid delayed rectifier potassium current (I Kr ). The slow delayed rectifier potassium current (I Ks ) is the main repolarizing cardiac current when I Kr is compromised and it has an important role in cardiac repolarization at fast heart rates induced by an elevated sympathetic tone. Therefore, we sought to characterize the effects of AMIT on Kv7.1/KCNE1 and homomeric Kv7.1 channels expressed in HEK-293H cells. Homomeric Kv7.1 and Kv7.1/KCNE1 channels were inhibited by AMIT in a concentration-dependent manner with IC50 values of 8.8 ± 2.1 μM and 2.5 ± 0.8 μM, respectively. This effect was voltage-independent for both homomeric Kv7.1 and Kv7.1/KCNE1 channels. Moreover, mutation of residues located on the P-loop and S6 domain along with molecular docking, suggest that T312, I337 and F340 are the most important molecular determinants for AMIT-Kv7.1 channel interaction. Our experimental findings and modeling suggest that AMIT preferentially blocks the open state of Kv7.1/KCNE1 channels by interacting with specific residues that were previously reported to be important for binding of other compounds, such as chromanol 293B and the benzodiazepine L7., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Cellulose derivatives have been widely used as adsorbents for the removal of micropollutants such as drugs, dyes, and metals, due to their abundance, low cost and non-contaminating nature. In this context, several studies have been performed searching for new adsorbents (cellulose derivatives) efficient at contaminant removal from aqueous solutions. Thus, a new adsorbent was synthesized by chemical modification of cellulose with ethylenediamine in the absence of solvent and applied to the adsorption of amitriptyline (AMI) in aqueous solution. The modification reaction was confirmed by X-ray Diffraction (XRD), elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry/Differential Scanning Calorimeter (TG/DSC), solid state Nuclear Magnetic Resonance of ¹H and 13 C (¹H-NMR and 13 C-NMR). Moreover, the effectiveness of reaction was confirmed by computational calculations using Density Functional Theory (DFT) at level B3LYP/6-31G(d). This adsorption process was influenced by pH, time, concentration, temperature and did not show significant changes due to the ionic strength variation. Through these experiments, it was observed that the maximum adsorption capacity of AMI by CN polymer at 298 K, 300 min, and pH 7 was 87.66 ± 0.60 mg·g -1 ., Competing Interests: The authors declare no conflict of interest.

Antidepressants are among the most commonly detected pharmaceuticals in aqueous systems, and, as emerging organic pollutants, may exert negative effects on non-target aquatic organisms. Previously, it has been revealed that antidepressant exposure significantly inhibits the growth and development of fish during their early developmental stages. Thus, in the present study, we aimed to identify and compare the underlying mechanisms of action of different antidepressants at the transcriptional level using zebrafish (Danio rerio) embryos. Through high-throughput RNA sequencing (RNA-Seq) data analysis, 32, 34, and 130 differentially expressed genes (DEGs) were obtained from zebrafish larvae after 120h of embryonic exposure to sublethal concentrations of amitriptyline, fluoxetine, and mianserin, respectively. The expression profiles of the identified DEGs showed similar trends in response to the three antidepressant treatments, suggesting consistent toxic effects of low concentrations of these three drugs on the regulation of gene expression in fish. Several metabolic and signaling pathways, including glycolysis/gluconeogenesis and the insulin pathway, were affected in the exposed fish larvae. The expression profiles of selected DEGs were then verified by the qRT-PCR method, which indicated significant positive correlations with the RNA-Seq results. Next, we determined the concentration-dependent expression patterns of 6 selected DEGs in fish larvae exposed to three antidepressants at a series of environmentally relevant concentrations. The results revealed a significant concentration-dependent reduction in the levels of dual-specificity phosphatase 5 (dusp5) mRNA, as well as a non-concentration-dependent gene expression inhibition of prostaglandin D2 synthase b (ptgdsb); the circadian rhythm-related genes, i.e. those encoding nuclear receptor subfamily 1, group D, member 1 (nr1d1) and period 2 (per2); and genes encoding early growth response factors (egr1 and egr4), in the antidepressant-treated fish larvae. In summary, to our knowledge, our findings demonstrate, for the first time, that the three different categories of antidepressants have common effects on the gene expression involved in multiple biological processes and signaling pathways during the early development of fish and thus provide information for characterizing the adverse outcome pathways and on the ecological risk assessment of these pharmaceutical pollutants in the aquatic environment., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Three emerging contaminants (amitriptyline hydrochloride (AH), methyl salicylate (MS) and 2-phenoxyethanol (PE)) frequently found in wastewaters were selected to be individually degraded in ultra-pure water by the advanced oxidation process (AOP) constituted by the combination of UV radiation and chlorine. The influence of pH, initial chlorine concentration and nature of the contaminants was firstly explored. The trend for the reactivity of the selected compounds was deduced: AH > MS > PE. A later kinetic study was carried out focused on the evaluation of the first-order rate constants and the determination of the partial contribution to the global reaction of the direct photochemical pathway and the radical pathway. In a second stage, the simultaneous oxidation of mixtures of the selected contaminants in several types of water was also performed by the same combination UV/Cl 2 . The efficiency of this combined system UV/Cl 2 was compared to other oxidants such as the UV/[Formula: see text] and UV/H 2 O 2 AOPs, and the influence of the operating variables was discussed. Results confirmed that the UV/Cl 2 system provides higher elimination efficiencies among the AOPs tested. The presence of dissolved organic matter and bicarbonate ions in the water matrix caused a decrease in the treatment efficiency.

Amitriptyline is a frequently prescribed tricyclic antidepressant. Although amitriptyline and its active metabolite, nortriptyline, have been widely detected in natural waters, their environmental fate due to photodegradation is poorly understood. Here we describe a study conducted to investigate the photodegradation of amitriptyline and its active metabolite under simulated sunlight. Neither amitriptyline nor nortriptyline underwent direct photodegradation, but rapid photosensitized degradation did occur in fulvic acid (FA) solutions. The photodegradation of amitriptyline and nortriptyline followed pseudo-first-order kinetics with rate constants 0.24 and 0.16 h, respectively, at pH 8.0 in air-saturated FA solutions. The photodegradation of the substrates increased markedly with pH. The deprotonation of amitriptyline and nortriptyline facilitated the availability of nonbonding electrons on nitrogen (N-electrons). The excited triplet state of FA (FA*) was verified as the main reactive species responsible for the photosensitized degradation. An electron transfer mechanism for the interaction between substrates and FA* was proposed on the basis of a series of quenching experiments, kinetic model and photoproducts determination. Demethylation at the α-carbon of amine and hydroxylation were two primary photochemical processes initiated by the electron transfer reaction in the air-saturated FA solution; these were followed by generation of demethyl amine and mono-hydroxylation isomers. Our results suggest that indirect photodegradation is an important elimination process for amitriptyline and its active metabolite in natural waters., (Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.)

The removal of three emerging contaminants (ECs) (amitriptyline hydrochloride (AH), methyl salicylate (MS) and 2-phenoxyethanol (PE)) dissolved in several water matrices by means of their adsorption onto powdered activated carbon (PAC) and granular activated carbon (GAC) has been investigated. When dissolved in ultrapure water, adsorption of the ECs followed the trend of AH > MS > PE, with a positive effect of the adsorbent dose. According to the analysis of the adsorption isotherms and adsorption kinetics, PAC showed strongly higher adsorption efficiency in both capacity and velocity of the adsorption, in agreement with its higher mesoporosity. Equilibrium isotherm data were fitted by Langmuir and Freundlich models. Pseudo-second order kinetics modeled very successfully the adsorption process. Finally, the effect of the presence of dissolved organic matter (DOM) in the water matrices (ultrapure water, surface water and two effluents from wastewater treatment plants) on the adsorption of the selected ECs onto PAC was established, as well as its performance on the removal of water quality parameters. Results show a negative effect of the DOM content on the adsorption efficiency. Over 50% of organic matter was removed with high PAC doses, revealing that adsorption onto PAC is an effective technology to remove both micro-pollutants and DOM from water matrices.

Herein, we have explored the interaction between amitriptyline hydrochloride (AMT) and hemoglobin (Hb), using steady-state and time-resolved fluorescence spectroscopy, UV-visible spectroscopy, and circular dichroism spectroscopy, in combination with molecular docking and molecular dynamic (MD) simulation methods. The steady-state fluorescence reveals the static quenching mechanism in the interaction system, which was further confirmed by UV-visible and time-resolved fluorescence spectroscopy. The binding constant, number of binding sites, and thermodynamic parameters viz. ΔG, ΔH, ΔS are also considered; result confirms that the binding of the AMT with Hb is a spontaneous process, involving hydrogen bonding and van der Waals interactions with a single binding site, as also confirmed by molecular docking study. Synchronous fluorescence, CD data, and MD simulation results contribute toward understanding the effect of AMT on Hb to interpret the conformational change in Hb upon binding in aqueous solution.

Topical gels compounded by pharmacists are important clinical tools for the management of pain. Nevertheless, there is often a dearth of information about the chemical stability of drugs included in these topical formulations, complicating the assignment of beyond-use dating. The purpose of this study was to develop a high-performance liquid chromatography photodiode array-based stability-indicating assay that could simultaneously resolve six drugs (amitriptyline, baclofen, clonidine, gabapentin, ketoprofen, lidocaine) commonly included in topical gels for pain management and their potential degradation products. Furthermore, this method was applied to the determination of beyond-use dating of combinations of these drugs prepared in commonly utilized bases (Lipobase, Lipoderm, Pluronic organogel). Gabapentin was determined to be the least stable component in all formulations tested. Measured stability ranged between 7 to 49 days depending on the base and other active drugs present in the formulation. In the absence of gabapentin, baclofen was the next least stable component, lasting for 120 days, regardless of the type of formulating base used., (Copyright© by International Journal of Pharmaceutical Compounding, Inc.)

Association of cyclobenzaprine hydrochloride, piroxicam and lidocaine in a topical formulation is one of the newest innovations in the pharmaceutical formulary field. In this study, a reversed-phase liquid chromatographic method was developed for the establishment of the impurities of cyclobenzaprine hydrochloride, lidocaine and piroxicam in the semisolid topical formulation. In this study, we not only determined 2,6-dimethylaniline, 2-pyrydilamine but also specified impurities of cyclobenzaprine hydrochloride (dibenzosuberenone, amitriptyline, carbinole, cyclobenzaprine N-oxide and anthrachinone). The target compounds were determined using a mobile phase that consisted of a mixture of phosphate buffer (0.025 M; pH 6.2)-acetonitrile-methanol (60 : 13 : 27, v/v/v). A minimum of three supplementary possible degradation products were determined. Using mass spectrometry, the unspecified impurities were identified and the use of correlation matrices permitted the association with the possible source compounds. The chromatographic conditions were qualified and validated according to ICH guideline requirements to confirm specificity, linearity, accuracy and precision., (© The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

With the increased detections of commonly used pharmaceuticals in surface water and wastewater, extensive attentions were paid recently to the fate and transport of these pharmaceuticals in the environment. Amitriptyline (AMI) is a tricyclic antidepressant widely applied to treat patients with anxiety and depression. In this study, the removal of AMI with palygorskite clay (PFl-1) was investigated under different physico-chemical conditions and supplemented by instrumental analyses. The uptake of AMI on PFl-1 was well fitted by the Langmuir isotherm with an adsorption capacity of 0.168 mmol g(-1) at pH 6-7. The AMI uptake was fast and reached equilibrium in 15 min. The X-ray diffraction patterns showed no shift of the (110) peak position of palygorskite after AMI uptake. However, the (001) peak position of the minor component smectite (about 10%) shifted to lower angle as the amounts of AMI input increased. These results suggested surface uptake of AMI on palygorskite and interlayer uptake of AMI in smectite. As smectite is a common component of palygorskite clays, its role in assessing the properties and performances of palygorskite clays for the uptake and removal of contaminants should not be neglected. Overall, the high affinity of AMI for PFl-1 and strong retention of AMI on PFl-1 suggested that it could be a good adsorbent to remove AMI from wastewater. Palygorskite clays can also be a sink for many cationic pharmaceuticals in the environmental of the arid regions., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In the last years has increased the study about the using of natural biopolymers and theirs derivatives in the removal (adsorption/incorporation) of contaminats of medium aqueous, and theirs utilization in the desorption (release) de drugs. However, there not in the literature studies about the utilization of the cellulose and cellulose phosphate in the adsorption (incorporation)/desorption (release) of the drug amitriptyline (AMI). Therefore, in this study was accomplished the synthesized of the phosphated cellulose (PC) through the reaction of pure cellulose (C) with sodium trimetaphosphate (P) under-reflux, for 4h and at 393K. The efficiency of the reaction was observed by XRD, TG/DTG, (31)P NMR and EDS. The adsorption study for the AMI in aqueous medium was carried out by varying the time, pH, concentration, temperature and ionic strength. The results showed that the PC showed a greater adsorption capacity of AMI than pure cellulose, presenting an increase of about 102.72% in the adsorption capacity of the drug by cellulose after the phosphating reaction. In desorption of drug from the surface of biomaterials was performed by varying the pH and time, where it was observed that PC showed a maximum release of 40.98% ± 0.31% at pH 7., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The lack of commercially available liquid dosage forms for pediatric patients prompted this study. The objectives of our study were to determine the stability of zonisamide, amitriptyline, and glycopyrrolate in extemporaneously prepared oral suspensions in plastic prescription bottles. One group of suspensions was prepared in OraPlus:OraSweet (1:1) for each drug and stored either under refrigeration (4°C) or at room temperature (25°C). A second group of suspensions were compounded in 1% methylcellulose:simple syrup at a 1:10 proportion for zonisamide, amitriptyline, and glycopyrrolate; these suspensions were stored at either under refrigeration (4°C) or at room temperature (25°C). The drug concentrations were measured by the stability-indicating high-performance liquid chromatographic methods. The mean concentration of zonisamide (10 mg/mL) remained above 95% of the original concentration for 91 days in each group of suspensions at both 4°C and 25°C. The mean concentration of amitriptyline (20 mg/mL) was above 95% for 91 days in the suspensions containing OraPlus/ OraSweet at both 4°C and 25°C. However, in the suspensions containing methylcellulose:simple syrup, the mean concentration of amitriptyline was about 95% for 42 days at 4°C and 28 days at 25°C. The mean concentration of glycopyrrolate (0.2 mg/mL) was above 95% in each group of suspensions during the 14-day study period. These data indicate that zonisamide, amitriptyline, and glycopyrrolate can be prepared extemporaneously as suspensions and stored in plastic prescription bottles for varying periods at 4°C and 25°C for use in pediatric patients.

Data always have an experimental uncertainty, i.e. error limits within which the value is very likely to be found. Although the use of statistics is common as is the use of least squares it remains uncommon to see reported the covariance between parameters for an equation to which data have been fitted. This means that a reader cannot properly calculate the error in an extrapolated or interpolated value. Even when the uncertainties in the least squares parameters are reported, errors calculated without the covariance are often too large and almost always different from the correct values calculated using the full formula. This report will demonstrate the importance of covariance in several examples. Systematic errors are also touched on; solubilities of highly hydrophobic and highly insoluble compounds are very difficult to measure for reasons not widely enough appreciated. Aggregation leading to suspended nanodroplets or nanocrystals can lead to spuriously high apparent solubilities. Another class of systematic errors comes from using an equation which is too simple for a desired extrapolation to a value of interest. The magnitude of this possible error is presented for a number of cases. Extrapolation can lead to a value of some use even though it is very uncertain, but expected uncertainty should be pointed out. Recommendations for good publishing practice are proposed for both authors and editors.

Levels of autophagy markers rise upon treatment of cells with antidepressants. However, it was not known whether this phenomenon might be linked to other antidepressant pathways or to any physiological effect. In this punctum, we summarize and discuss our recent findings that provide evidence for a role of the cochaperone FKBP5/FKBP51 (FK506 binding protein 5) in autophagy as a prerequisite for antidepressant action in cells, mice, and humans. FKBP5 associates with BECN1, changes its phosphorylation and protein levels and enhances markers of autophagy and autophagic flux. The effects of antidepressants on autophagy as well as their physiological effects in mice and human depend on FKBP5.

Cytochrome P450 reductase (CPR) is an important redox partner of microsomal CYPs. CPR is composed of a membrane anchor and a catalytic domain that contains FAD and flavin mononucleotide (FMN) as redox centers and mediates electron transfer to CYP. Although the CPR membrane anchor is believed to be requisite for interaction with CYP, its physiological role is still controversial. To clarify the role of the anchor, we constructed a mutant (Δ60-CPR) in which the N-terminal membrane anchor was truncated, and studied its effect on binding properties, electron transfer to CYP2C19, and drug metabolism. We found that Δ60-CPR could bind to and transfer electrons to CYP2C19 as efficiently as WT-CPR, even in the absence of lipid membrane. In accordance with this, Δ60-CPR could mediate metabolism of amitriptyline (AMT) and imipramine (IMP) in the absence of lipids, although activity was diminished. However, Δ60-CPR failed to metabolize omeprazole (OPZ) and lansoprazole (LPZ). To clarify the reason for this discrepancy in drug metabolism, we investigated the uncoupling reaction of the CYP catalytic cycle. By measuring the amount of H2O2 by-product, we found that shunt pathways were markedly activated in the presence of OPZ/LPZ in the Δ60-CPR mutant. Because H2O2 levels varied among the drugs, we conclude that the proton network in the distal pocket of CYP2C19 is perturbed differently by different drugs, and activated oxygen is degraded to become H2O2. Therefore, we propose a novel role for the membrane anchor as a suppressor of the uncoupling reaction in drug metabolism by CYP.

Tandem mass spectrometry (MS/MS) plays an essential role in modern chemical analysis. It is used for differentiating isomers and isobars and suppressing chemical noise, which allows high precision quantitation. The MS/MS analysis has been typically applied by isolating the target precursor ions, while disregarding other ions, followed by a fragmentation process that produces the product ions. In this study, configurations of dual linear ion traps were explored to develop high efficiency MS/MS analysis. The ions trapped in the first linear ion trap were axially, mass-selectively transferred to the second linear ion trap for MS/MS analysis. Ions from multiple compounds simultaneously introduced into the mass spectrometer could be sequentially analyzed. This development enables highly efficient use of the sample. For miniature ion trap mass spectrometers with discontinuous atmospheric pressure interfaces, the analysis speed and the quantitation precision can be significantly improved.

The present paper describes a novel, simple and reliable differential pulse voltammetric method for determining amitriptyline (AMT) in pharmaceutical formulations. It has been described for many authors that this antidepressant is electrochemically inactive at carbon electrodes. However, the procedure proposed herein consisted in electrochemically oxidizing AMT at an unmodified carbon nanotube paste electrode in the presence of 0.1 mol L(-1) sulfuric acid used as electrolyte. At such concentration, the acid facilitated the AMT electroxidation through one-electron transfer at 1.33 V vs. Ag/AgCl, as observed by the augmentation of peak current. Concerning optimized conditions (modulation time 5 ms, scan rate 90 mV s(-1), and pulse amplitude 120 mV) a linear calibration curve was constructed in the range of 0.0-30.0 μmol L(-1), with a correlation coefficient of 0.9991 and a limit of detection of 1.61 μmol L(-1). The procedure was successfully validated for intra- and inter-day precision and accuracy. Moreover, its feasibility was assessed through analysis of commercial pharmaceutical formulations and it has been compared to the UV-vis spectrophotometric method used as standard analytical technique recommended by the Brazilian Pharmacopoeia., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The uptake of amitriptyline (AMI) from aqueous environment by Ca-montmorillonite (SAz-2) was studied in a batch system under different physicochemical conditions. The adsorbent was characterized by X-ray diffraction and Fourier transform infrared (FTIR) analyses. The AMI adsorption on SAz-2 obeyed the Langmuir isotherm with a capacity of 330mg/g (1.05mmol/g) at pH 6-7. The adsorption kinetics was fast, almost reaching equilibrium in 2h, and followed a pseudo-second-order kinetic model. Desorption of exchangeable cations correlated with the AMI adsorption well, indicating that cation exchange was the major mechanism. X-ray diffraction patterns showing significant expansions of the d001 spacing and characteristic FTIR band shifts toward higher frequencies after AMI adsorption onto SAz-2 indicated that the adsorbed AMI molecules were intercalated into the interlayers of the mineral. Thermodynamic parameters based on partitioning coefficients suggested that the AMI adsorption was an endothermic physisorption at high adsorption levels. At low and higher AMI adsorption levels, the intercalated AMI molecules take a horizontal monolayer and bilayer conformation, respectively. The higher adsorption capacity suggested that SAz-2 could be a good candidate to remove AMI from wastewater and would be an important environmental sink for the fate and transport of AMI in soils and groundwater., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The (+)-isomer of indeloxazine AS1069562 exerts multiple pharmacological actions including the inhibition of serotonin (5-HT) and norepinephrine reuptake and analgesia in experimental animal pain models. Here, we evaluated the antinociceptive effects of AS1069562 and the antidepressants duloxetine and amitriptyline in mouse models of prostaglandin-induced spinal hypersensitivity. Prostaglandin E2 (PGE2) and F2α (PGF2α) were intrathecally administered to induce spinal hypersensitivity, causing tactile allodynia in mice. Allodynia induced by PGF2α but not by PGE2 was suppressed by desensitization of C-fibers with systemic pretreatment with resiniferatoxin. C-fiber hyperexcitability might therefore play a role in allodynia induced by PGF2α but not PGE2. In the PGE2-induced allodynia model, AS1069562 and duloxetine significantly suppressed allodynia, whereas amitriptyline did not. In the PGF2α-induced allodynia model, AS1069562 and amitriptyline significantly ameliorated allodynia, whereas duloxetine did not. To demonstrate the broad effects of AS1069562 compared to duloxetine, additional studies were conducted to elucidate other target mechanisms of AS1069562 beyond 5-HT and norepinephrine reuptake inhibition. AS1069562 exhibited affinity for both 5-HT1A and 5-HT3 receptors, and the analgesic effect of AS1069562 on PGF2α-induced allodynia was significantly blocked by the 5-HT1A receptor antagonist (S)-WAY100135 and the 5-HT3 receptor agonist SR57227. Taken together, these results indicate that AS1069562 inhibits both C-fiber- and non-C-fiber-dependent prostaglandin-induced allodynia, while duloxetine inhibits only non-C-fiber-triggered allodynia, and amitriptyline inhibits only C-fiber-triggered allodynia. These broad antinociceptive effects of AS1069562 may be due not only to 5-HT and norepinephrine reuptake inhibition but also to its effects on 5-HT receptors such as 5-HT1A and 5-HT3 receptors., (Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.)

Introduction: Intravenous lipid emulsion (ILE) resuscitation is now frequently being used for severe overdoses due to lipophilic drugs. However, the optimal dose, duration, and safety are still unclear., Case Report: A patient with refractory cardiovascular collapse following an amitriptyline overdose was treated with ILE with initial improvement. Instability recurred after ILE discontinuation and lipid therapy was restarted, but high-dose treatment was complicated by severe lipemia. A low-dose infusion was instead used, and the patient did not experience further toxicity despite amitriptyline levels in the toxic range for 21 days. He survived to discharge without long-term sequelae., Discussion: A low-dose infusion of ILE was well tolerated and may have successfully prevented recurrent toxicity in a case of severe tricyclic antidepressant overdose.

The repeatability and extraction recoveries of parallel electromembrane extraction (Pa-EME) was thoroughly investigated in the present project. Amitriptyline, fluoxetine, and haloperidol were isolated from eight samples of pure water, undiluted human plasma, and undiluted human urine, respectively; in total 24 samples were processed in parallel. The repeatability was found to be independent of the different sample matrices (pure water samples, human plasma, and water) processed in parallel, although the respective samples contained different matrix components. In another experiment seven of the 24 wells were perforated. Even though the perforation caused the total current level in the Pa-EME setup to increase, the intact circuits were unaffected by the collapse in seven of the circuits. In another approach, exhaustive extraction of amitriptyline, fluoxetine, and haloperidol was demonstrated from pure water samples. Amitriptyline and haloperidol were also isolated exhaustively from undiluted human plasma samples; the extraction recovery of fluoxetine from undiluted human plasma was 81%. Finally, the sample throughput was increased with the Pa-EME configuration. The extraction recoveries were investigated by processing 1, 8, 68, or 96 samples in parallel in 10min; neither the extraction recoveries nor the repeatability was affected by the total numbers of samples. Eventually, the Pa-EME was combined with ultra performance liquid chromatography (UPLC) to combine high-throughput sample preparation with high-throughput analytical instrumentation. The aim of the present investigation was to demonstrate the potential of electromembrane extraction as a high throughput sample preparation platform; and hopefully to increase the interest for EME in the bioanalytical field to solve exisiting and novel analytical challenges., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The mixed micellization behaviour of amitriptyline hydrochloride (AMT) with ionic liquid (IL) 1-methyl-3-octylimidazolium hydrochloride, [C8mim][Cl], have been investigated using electrical conductivity, at different temperatures. The non-ideal behaviour (i.e., synergistic interaction) of AMT-[C8mim][Cl] binary mixtures, explained by the deviations in critical micelle concentration (cmc) from ideal critical micelle concentration (cmc*) and micellar mole fraction (X(m)) from ideal micellar mole fraction (X(ideal)) values. The values of interaction parameter (β) and activity coefficients (f1 and f2), also confirm the synergistic interaction. The excess free energy (ΔGex) for the AMT-[C8mim][Cl] binary mixtures explains, stability of mixed micelles in comparison to micelles of pure, AMT and [C8mim][Cl]. The calculated thermodynamic parameters (viz., the standard Gibbs energy change, ΔGm(∘), the standard enthalpy change, ΔHm(∘), the standard entropy change, ΔSm(∘)), suggest the dehydration of hydrophobic part of the drug at higher temperatures (>313K), not only in case of AMT but also in the presence of [C8mim][Cl]., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Drug release from hydrophilic matrices is regulated mainly by polymeric erosion, disentanglement, dissolution, swelling front movement, drug dissolution and diffusion through the polymeric matrix. These processes depend upon the interaction between the dissolution media, polymeric matrix and drug molecules, which can be significantly influenced by formulation variables and excipients. This study utilized mathematical parameters to evaluate the impacts of selected formulation variables and various excipients on the release performance of hydrophilic polyamide 6,10 (PA 6,10) monolithic matrix. Amitriptyline HCl and theophylline were employed as the high and low solubility model drugs, respectively. The incorporation of different excipient concentrations and changes in formulation components influenced the drug release dynamics as evidenced by computed mathematical quantities (t x%, MDT x%, f 1, f 2, k 1, k 2, and К F). The effects of excipients on drug release from the PA 6,10 monolithic matrix was further elucidated using static lattice atomistic simulations wherein the component energy refinements corroborates the in vitro and in silico experimental data. Consequently, the feasibility of modulating release kinetics of drug molecules from the novel PA 6,10 monolithic matrix was well suggested.

As the most commonly prescribed tricyclic antidepressant, amitriptyline (AT) is frequently detected in wastewater, surface runoff, and effluents from sewage treatment plants, and could potentially reach agriculture land through the application of municipal biosolids or reclaimed water. Kaolinite is one of the most important soil components under warm and humid climate conditions. In this study, the uptake and retention of AT by kaolinite from aqueous solution were investigated by batch tests, XRD, and FTIR analyses. The uptake of AT on kaolinite was instantaneous, attributed to surface adsorption as confirmed by XRD analyses. Quantitative correlation between desorption of exchangeable cations and AT adsorption confirmed experimentally that cation exchange was the dominant mechanism of AT uptake on kaolinite. The values for free energy of adsorption also suggested physi-sorption such as cation exchange. Solution pH had minimal influence at pH 5-11 even though the pKa value of AT was 9.4 and the surface charge of kaolinite was pH-dependent., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Shuttle-drug: Self-assembled vesicles of a pharmaceutically active ionic liquid are shown to be an efficient drug delivery system, which realizes the controlled release of its pharmaceutically active component directly., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)