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Tetracyclines family is considered as the first-line antibiotic drugs for food animals. Formulating bromhexine (BR) with oxytetracycline (OTC) improved the antibacterial activity of OTC, besides it is considered as a mucolytic agent. Four precise, rapid, and simple spectrophotometric methods were successfully developed for resolution of the overlapped spectra of OTC and BR in their pure form and in their pharmaceutical formulation. The proposed methods are absorption correction (AC), dual wavelength (DW), induced dual wavelength (IDW), and spectrum subtraction (SS) spectrophotometric methods. The developed methods were used for the determination of OTC and BR in the ranges of 2–50 µg/mL and 1–30 µg/mL, respectively for all methods. For (AC) and (SS) methods, OTC and BR were determined at 380 nm and 245.6 nm, respectively after spectral resolution steps. While for (DW) method, the absorbance difference between λ (271.8 –287.6 nm) and λ (245.6 –283.2 nm) were used for the determination of OTC and BR, in order. For IDW, it depended on using the absorbance difference between 271.8 nm and 245.6 nm as well as the equality factor (F) calculated for each drug at the selected wavelengths. In all methods, HCl was used as a solvent and they are validated according to ICH guidelines. Several green metric tools have been developed to evaluate the greenness of the analytical methods like National Environmental Methods Index (NEMI), Modified NEMI, Analytical Eco-scale, Green Analytical Procedure Index (GAPI) and Analytical GREEnness calculator (AGREE), and all ensured the low impact of the suggested approaches on health and environment. The proposed methods are highly selective, robust and precise. Additionally they are time and money effective and can be used in any analytical laboratory. [ABSTRACT FROM AUTHOR]

Layered double hydroxide (LDH)/conductive polymer nanocomposites combine the promising adsorption capabilities of 2D layered nanomaterials and the electric properties of conductive polymers, resulting in multifunctional adsorbents for wastewater treatment. In this work, a simple in situ polymerization of aniline was conducted in the presence of Zn-Fe LDH to synthesize a Zn-Fe LDH/PANI nanocomposite, which was characterized by XRD, FTIR, SEM, and BET. The composite showed a particle-like morphology with a size of 30–60 nm and a BET surface area of 23.27 m2/g and was used as an adsorbent for carbamazepine (CBZ). Zn-Fe LDH/PANI removed 98% of CBZ at pH 7, 0.2 g/L, and 40 mg/L CBZ. For biocompatibility, acute toxicity was assessed in vivo for ten days using male albino rats, and probit analysis (after 2, 6, and 24 hours) was used to determine the LD0, LD20, LD50, LD90, and LD100 values, which were calculated to be 890, 1051, 3188, 6371, and 11,300, respectively. During this time, the rats were weighed, and other observations were made, including mortality, behavior, injuries, and any symptoms of toxicity or side effects. Histopathological examination of organs such as the liver, kidney, brain, skin, intestine, and cecum for any pathological alterations was performed. Two green metrics were applied, the Analytical Eco-scale and the Analytical GREEness Calculator (AGREE). [ABSTRACT FROM AUTHOR]

Bromhexine (BR), guaiafenesin (GUF) and salbutamol (SAL) are formulated as Ventocough syrup® (with and without sugar), labeled to contain propyl paraben and sodium benzoate as inactive ingredients. They are used to make coughing more productive and easier. A crucial element and a major issue in the pharmaceutical industry is the control of organic related impurities to obtain safe and effective treatment. Guaiacol (GUL) is reported to be GUF related impurity that was proved to be extremely toxic (toxic rating class 5), and its use should be banned. In this work, In-Silico study and ADMET estimation were conducted to predict GUL pharmacokinetic properties and its toxicity profile. Additionally, two chromatographic methods were conducted to analyze the studied components along with GUF impurity in the presence of the labeled dosage form excipients. The In-Silico study assured that GUL has oral rat acute toxicity and it is considered to be skin sensitizer. On the other hand, the developed TLC- densitometeric method depended on using a mobile phase mixture of hexane: methylene chloride: triethylamine (5.0:6.0:0.3, by volume) as a developing system. UV-Scanning was performed immediately at 275 nm for SAL, GUF and GUL, while scanning at 310 nm was used for scanning BR. Linearity was established in the ranges of 0.25–4.0, 0.25–4.0, 0.5–8.0 and 0.1–1.6 µg/band for BR, SAL, GUF and GUL, respectively. In the developed HPLC method, separation was performed on X-Bridge® C18 column (250 × 4.6 mm, 5 μm) using a solvent mixture of 0.05M disodium hydrogen phosphate pH 3 with aqueous phosphoric acid: methanol (containing 0.3%, v/v triethylamine) (40:60, v/v). Detection was done at 225 nm and separation was achieved within 10 min. Linearity was proved in the range of 2–50 µg/mL for the proposed drugs. Validation of the developed methods was done and all the calculated parameters were within the acceptable limits recommended by ICH guidelines. After that, methods were used to examine the potency of the selected marketed dosage forms and concentrations of all drugs were within the acceptable limits. Additionally, complete separation between the studied drugs and the additives were observed. The developed methods can be used during routine quality control analysis of the proposed drugs when the required issues concern on sensitivity, selectivity and analysis time. [ABSTRACT FROM AUTHOR]

Preserving the environment, reducing the amount of waste resulting from chemical trials, and reducing the amount of energy consumed have currently become a pivotal global trend. An analytical quality by design (AQbD) based eco-friendly TLC-densitometric method was implemented for quantifying two antihypertensive agents, captopril (CPL) and hydrochlorothiazide (HCZ), along with their impurities; captopril disulphide (CDS), chlorothiazide (CTZ) and salamide (SMD). The analytical target profile (ATP) was first identified, followed by selecting the critical analytical attributes (CAAs), such as retardation factors and resolution between the separated peaks. Critical method parameters (CMPs) that may have a crucial influence on CAAs were identified and emanated through the quality risk assessment phase. A literature survey-based preliminary studies were performed, followed by optimization of the selected CMPs through a custom experimental design to attain the highest resolution with optimum retardation factors. Moreover, method robustness was also tested by testing the design space. Complete separation of the drugs and their impurities was achieved using ethyl acetate: glacial acetic acid (6: 0.6, v/v) as a developing system applied to a 12 cm length TLC plate at room temperature with UV scanning at 215 nm. Calibration graphs were found to be linear in the ranges of (0.70–6.00), (0.10–2.00), (0.20–1.00), (0.07–1.50) and (0.05–1.00) µg/band corresponding to CPL, HCZ, CDS, CTZ, and SMD, respectively. Four different green metric tools were used to evaluate the greenness profile of the proposed method, and results showed that it is greener than the reported HPLC method. Method whiteness assessment was also conducted. Moreover, the method performance was evaluated following the ICH guidelines, and the outcomes fell within the acceptable limits. The developed method could be approved for routine assay of the cited components in their pharmaceutical formulations and bulk powder without interference from the reported impurities. The issue of concern is saving money, especially in developing countries. Highlights: A combination of hydrochlorothiazide and captopril is used in treating patients not adequately controlled with monotherapy. The AQbD approach was used to develop the TLC- densitometric method to reduce the number of trials, solvent consumption, and waste production. Increasing global attention for considering GAC principles in developing analytical methods; therefore, different green metric tools were implemented for the assessment of the greenness profile of the proposed and reported methods. Integration between the AQbD and GAC principles was performed to develop a greener, more time- and money-saving method. Whiteness assessment was conducted to evaluate method performance and perform a comparative study between the developed method and the reported ones. [ABSTRACT FROM AUTHOR]

Hypertension is described by the world health organization (WHO) as a serious medical problem that significantly affects the heart, brain and kidneys. It is a major cause of premature death worldwide. The present study aims to quantify the combination of captopril (CPL), hydrochlorothiazide (HCZ) and their harmful impurities; captopril disulphide (CDS), chlorothiaizde (CTZ) and salamide (SMD). In-silico study was conducted for estimation of pharmacokinetic parameters (ADMET) as well as toxicity profile of the proposed impurities. The results showed that the three impurities under investigation had poor permeability to CNS and cannot pass the blood–brain barrier (BBB), reducing the likelihood of causing side effects in the brain. On the other hand, all studied impurities were found to be hepatotoxic. In consequence, a highly sensitive and green ultra-performance liquid chromatography- tandem mass spectrometric (UPLC/MS/MS) method was developed and validated for separation of the cited drugs in the presence of their harmful impurities; methanol and 0.1% formic acid (90:10, v/v) mixture was used as a mobile phase, eluted at a constant flow rate of 0.7 mL/min at room temperature. Detection was adopted using a tandem mass spectrometer in a positive mode only for CPL and negative mode for HCZ, CDS, CTZ and SMD. Separation was performed within 1 min. Calibration graphs were found to be linear in the ranges of (50.0–500.0 ng mL−1), (20.0–500.0 ng mL−1), (10.0–250.0 ng mL−1), (5.0–250.0 ng mL−1) and (20.0–400.0 ng mL−1) corresponding to CPL, HCZ, CDS, CTZ and SMD, respectively. Additionally, comparative study of greenness profile was established for the proposed and reported methods using five green metric tools. The proposed method was found to be greener than the reported HPLC method. The developed (UPLC/MS/MS) method was validated according to (ICH) guidelines and it was found to has greater sensitivity, shorter analysis time and lower environmental impact compared to the reported methods. [ABSTRACT FROM AUTHOR]

Erythromycin (ERY) is one of the macrolides used abundantly in veterinary medicines to treat various infections including respiratory, skin and bones. Combination of sulfadiazine (SFD) and trimethoprim (TMP) has proven efficacy and is widely used in the treatment of many infectious diseases, due to the efficiency of SFD as a bactericidal and TMP as a bacteriostatic. On the other hand, those residues of antibiotics like ERY, SFD and TMP in animal tissues may pose health hazards to humans. A simple and cost effective TLC densitometeric method has been developed to analyze the above mentioned drugs in their dosage form and in spiked chicken muscle and liver samples. A mixture of chloroform: methanol: ammonia hydroxide solution (33%, v/v) (8.5:1.5:0.1, by volume) was the developing system. In order to obtain the highest possible sensitivity, the separated bands were exposed to iodine vapors in well closed container for 15 min and then detection was immediately done at 220 nm. Linearity was achieved in the ranges of 0.5–10, 0.1–2 µg/band for ERY and SFD, respectively in both spiked muscle and liver samples while for TMP, linearity was proved over the ranges of 0.1–1.8 µg/band for spiked muscle samples and 0.1–1.6 for spiked liver samples. [ABSTRACT FROM AUTHOR]

Type 2 diabetes mellitus (T2D) is a world wild health care issue marked by insulin resistance, a risk factor for the metabolic disorder that exaggerates endothelial dysfunction, increasing the risk of cardiovascular complications. Peroxisome proliferator-activated receptor PPAR) agonists have therapeutically mitigated hyperlipidemia and hyperglycemia in T2D patients. Therefore, we aimed to experimentally investigate the efficacy of newly designed synthetic PPARα/Ƴ partial agonists on a High-Fat Diet (HFD)/streptozotocin (STZ)-induced T2D. Female Wistar rats (200 ± 25 g body weight) were divided into four groups. The experimental groups were fed the HFD for three consecutive weeks before STZ injection (45 mg/kg/i.p) to induce T2D. Standard reference PPARƳ agonist pioglitazone and the partial synthetic PPARƳ (PIO; 20 mg/kg/BW, orally) were administered orally for 2 weeks after 72 h of STZ injection. The aorta tissue was isolated for biological ELISA, qRT-PCR, and Western blotting investigations for vascular inflammatory endothelial mediators endothelin-1 (ET-1), intracellular adhesion molecule 1 (ICAM-1), E-selectin, and anti-inflammatory vasoactive intestinal polypeptide (VIP), as well as microRNA126-5p and p-AKT/p-Pi3k/p-PDK-1/p-mTOR, endothelial Nitric Oxide Synthase (eNOS) immunohistochemical staining all are coupled with and histopathological examination. Our results revealed that HFD/STZ-induced T2D increased fasting blood glucose, ET-1, ICAM-1, E-selectin, and VIP levels, while decreasing the expression of both microRNA126-5p and p-AKT/p-Pi3k/p-PDK-1/p-mTOR phosphorylation. In contrast, the partial synthetic PPARƳ derivative evidenced a vascular alteration significantly more than reference PIO via decreasing (ET-1), ICAM-1, E-selectin, and VIP, along with increased expression of microRNA126-5p and p-AKT/p-Pi3k/p-PDK-1/p-mTOR. In conclusion, the partial synthetic PPARƳ derivative significantly affected HFD/STZ-induced T2D with vascular complications in the rat aorta. [ABSTRACT FROM AUTHOR]

Cyclizine (CYZ); an antiemetic compound; is widely misused for its euphoric or hallucinatory effects, either by oral or intravenous routes. The concomitant abuse of CYZ among addicted adolescents contributes to neuromuscular disorders that are life-threatening. Consequently, with the company of 1-Methylpiperazine (MPZ) and diphenylmethanol (DPM, Benzhydrol) as pharmacopoeia-reported CYZ impurities, a novel spectrofluorimetric assay for the detection of CYZ, has been established either in human plasma samples or in its parenteral formulation. The native fluorescence of CYZ has been investigated under various conditions. Different parameters affecting relative fluorescence intensity of CYZ including diluting solvent, surfactant, plasma protein solvent, and pH were studied and optimized. The linearity obtained between the fluorescence intensity at emission wavelength 350 nm after excitation at 244 nm and the corresponding CYZ concentrations was in the range 10–1000 ng/mL for measurement of CYZ either in pure form or in human plasma samples, with a appropriate correlation coefficient (r = 0.9999) and 3.10 ng/mL as the limit of detection and 9.41 ng/mL as the limit of quantitation. The suggested procedure was created and validated in accordance with ICH guidelines for quantification of CYZ either in its pure form or its dosage form, and FDA guidelines for the assay of CYZ in human plasma. Finally, in silico study and ADMET predictions were conducted for the studied drug impurities to estimate their pharmacokinetic behaviors. The results showed that both CYZ impurities have higher cellular permeability and maximum tolerated doses, DPM has higher BBB and CNS permeability than MPZ, while MPZ exceeds DPM in total clearance and volume of distribution. [ABSTRACT FROM AUTHOR]

The renin angiotensin aldosterone system has a localized key regulatory action, especially in liver and body circulation. Furthermore, it accomplishes a significant role in the downregulation of the PI3K/AKT/mTOR signaling pathway that is involved in type II diabetes mellitus pathogenesis. The current study aimed to evaluate the effect of a synthetic pioglitazone analogue (benzenesulfonamide derivative) compared to the standard pioglitazone hypoglycemic drug on enhancing liver insulin sensitivity via ACE 2/Ang (1–7)/PI3K/AKT/mTOR in experimental STZ-induced diabetes. After the model was established, rats were distributed into the normal control group, diabetic group, pioglitazone group (20 mg/kg), and a benzenesulfonamide derivative group (20 mg/kg), with the last 2 groups receiving oral treatment for 14 consecutive days. Our results suggested enhancing liver insulin sensitivity against the ACE2/Ang (1–7)/PI3K/AKT/mTOR pathway. Moreover, the synthetic compound produced a reduction in blood glucose levels, restored hyperinsulinemia back to normal, and enhanced liver glycogen deposition. In addition, it up regulated the ACE2/Ang (1–7)/PI3K/AKT/mTOR signaling pathway via increasing insulin receptor substrate 1 and 2 sensitivity to insulin, while it increased glucose transporter 2 expression in the rat pancreas. The study findings imply that the hypoglycemic effect of the benzenesulfonamide derivative is due to enhancing liver sensitivity to regulate blood glucose level via the ACE2/Ang (1–7)/PI3K/AKT/mTOR pathway. [ABSTRACT FROM AUTHOR]

Two simple, sensitive and validated chromatographic methods were developed for quantitative determination of bromhexine hydrochloride (BHX) in presence of its major impurities, impurity B (IMB) and impurity C (IMC), as specified by British Pharmacopoeia. First method (I) was high-performance thin layer chromatography-densitometry at which the chromatographic separation was performed using silica gel plates and developing system consisted of hexane:acetone:ammonia solution (9:0.5:0.08, by volume) with ultraviolet scanning at 240 nm and linearity was achieved in the ranges of 0.40–10.00, 0.20–2.00 and 0.20–2.00 μg/band of BHX, IMB and IMC, respectively. Also, second chromatographic method (II) was high-performance liquid chromatography (HPLC) where the separation was carried out on C18 column at isocratic mode at flow rate 1.5 mL/min. The mobile phase consisted of methanol:water (90:10, v/v) adjusted to pH 2.5 with O -phosphoric acid and temperature was adjusted to 40°C. The scanning wavelength was 240 nm. The chromatographic run time was 6 min. Linearity of this method was achieved in the ranges of 4.00–40.00, 0.20–10.00 and 0.50–10.00 μg/mL for BHX, IMB and IMC, respectively. The validation of these chromatographic methods was made according to International Conference on Harmonization guidelines. These methods were successfully applied for determination of BHX in its pharmaceutical formulation. Also, statistical comparison was attained between the developed methods and the reported HPLC method using Student's t -test and F -test, and the obtained results showed that there was not any significant difference between them concerning with accuracy and precision. [ABSTRACT FROM AUTHOR]

Cyclizine (CYZ) abuse is commonly reported, either through oral or intravenous routes, for its euphoric or hallucinatory effects. The concomitant misuse of CYZ among addicted teenagers leads to life-threatening neuromuscular disorders. Consequently, two green and validated chromatographic methods were developed for the determination of CYZ, an antiemetic drug, in its parenteral formulation in the presence of 1-methyl piperazine and diphenylmethanol (benzhydrol) as the pharmacopeial stated impurities of CYZ. The first method was TLC-densitometry that relied on using a mixture consisting of ethyl acetate:isopropanol:ammonia (9.5:1:0.5, by volume) as a developing system, TLC 60 F254 silica gel plates as a stationary phase and detection of the scanned bands was performed at 210.0 nm. On the other hand, the second method was UPLC which based on the separation of CYZ and its impurities using a mobile phase consisting of ethanol and acidic water at pH 5 adjusted by phosphoric acid in the ratio of (60:40, %v/v) at flow rate 0.2 mL min−1 and UV detection were carried out at 210.0 nm. The greenness profile of the established methods was evaluated and calculated for the first time for CYZ and its toxic impurities through different assessment tools like analytical eco-scale, analytical method volume intensity and greenness profile methods. Validation of the developed methods was carried out in accordance with the guidelines of the International Conference on Harmonization. The suggested methods were accurate, reliable, time and cost-saving. Therefore, they could be used in quantification of CYZ abuse and its toxic impurities in parenteral formulation for routine quality control. The results achieved by applying the suggested methods were statistically analyzed and compared with those given by reported one and no significant differences were obtained regarding both precision and accuracy. [ABSTRACT FROM AUTHOR]

Citicoline and piracetam were subjected separately to different stress conditions as recommended by the international conference on harmonization. In addition, new stability indicating thin layer chromatographic and ultra high performance liquid chromatographic methods have been developed and validated for simultaneous determination of citicoline and piracetam in presence of their degradation products. Separation on the proposed thin layer chromatographic method was carried out using a developing system containing methanol:chloroform:ammonium chloride buffer (9:1:2, v/v/v) on silica gel plates at 230 nm. On the other hand, the mobile phase in the ultra high performance liquid chromatographic method was composed of water (containing 0.1% triethylamine):ethanol (92:8, v/v). The flow rate was 1 mL/min and ultraviolet detection was at 230 nm. Moreover, results of the developed methods were statistically compared to those obtained by the reported high‐performance liquid chromatography method and no significant difference between them was found. The greenness profile of ultra high performance liquid chromatographic method was assessed and compared with those of the previously published high‐performance liquid chromatography methods, it was noticed that the proposed ultra high performance liquid chromatographic method more environmentally friendly and greener than other methods. [ABSTRACT FROM AUTHOR]

Three simple, sensitive, and validated methods were developed for the quantitative determination of fosinopril sodium (FOS) and hydrochlorothiazide (HCZ) in the presence of an HCZ impurity, chlorothiazide (CZ). The first method (I) was the ratio difference spectrophotometric method (RD), in which a standard spectrum of 8 µg mL-1 HCZ was used as a divisor, and the difference in amplitude values at 204.6 and 231.2 nm and 290 and 302.6 nm was used for the determination of FOS and CZ, respectively. Meanwhile, for the determination of HCZ, a standard spectrum of 6 µg mL-1 CZ was the chosen divisor, and the amplitude difference at 275 nm and 293.6 nm was selected for the calculation of its concentrations. The second method (II) was mean centering of ratio spectra spectrophotometric method (MCR), which depended on the implementation of the mean-centered ratio spectra in two successive steps and the measurement of the amplitudes of the mean-centered second ratio spectra at 243.4 nm for CZ and peak-to-peak amplitudes at 215.6 and 215.8 nm for FOS and at 223.8 and 224 nm for HCZ. On the other hand, the third method (III) was thin-layer chromatography (TLC)-densitometry at which the chromatographic separation of this ternary mixture was performed using pre-activated silica gel 60 F254 TLC plates and a developing system mixture consisting of ethyl acetate-chloroform-methanol-formic acid (60:40:5:0.5, by volume) with ultraviolet (UV) scanning at 215 nm. The developed methods were validated according to the International Conference of Harmonization (ICH) guidelines and were successfully used for the determination of FOS and HCZ in their pharmaceutical formulations. Also, a statistical comparison between the developed methods and the reported HPLC method was attained. Using Student's t-test and F-test, the results confirmed that there was not any significant difference between them regarding accuracy and precision. [ABSTRACT FROM AUTHOR]

Two validated, simple, and precise chromatographic methods were described for the determination of vildagliptin (VIL) and metformin (MET) in the presence of metformin toxic impurity, melamine (MEL). Method 1 is thin-layer chromatography (TLC)- densitometric method, at which methanol-chloroform-formic acid (7:3:0.3, by volume) was used as the developing system, and separation was carried out on Merck TLC silica gel 60 F254 aluminum sheets. The developed plates were air-dried and scanned at 215 nm. Linearity was constructed in the range of 0.2-2.6, 0.4-4.5, and 0.05-1.4 µg per band of VIL, MET, and MEL, respectively. Method 2 is reversed-phase ultra-performance liquid chromatography (RP-UPLC), where the separation was performed on a C18 column using methanol-acetonitrile-0.01 M sodium dihydrogen phosphate solution containing 50% 0.01 M sodium lauryl sulfate, pH = 5 with H3PO4 as the mobile phase at a flow rate of 1 mL min-1 at 205 nm. The calibration curves showed good linear relationships in the concentration ranges of 1-50, 2-70, and 0.5-30 µg mL-1 of VIL, MET, and MEL, respectively. The developed methods were applied to Galvus Met® tablets, and no interference from excipients was observed. The methods were validated as per the International Conference on Harmonisation (ICH) guidelines, and they compared favorably with the reported one. [ABSTRACT FROM AUTHOR]

Ascorbic acid (ASC), paracetamol (PAR) and guaifenesin (GUF) are co-formulated together as analgesic and expectorant effervescent powder. This work describes a selective stability indicating HPTLC-densitometric method which is the first developed stability indicating one for chromatographic separation of the three studied drugs in presence of paracetamol toxic impurity [4-aminophenol (4-AP)] and guaifenesin related substance [impurity, (guaiacol) (GUC)]. The chromatographic separation was carried out on HPTLC 60F254 plates using chloroform–acetone–trifluoroacetic acid (6.5:3.5:0.30, by volume) as a developing system with UV detection at 254 nm. Factors affecting chromatographic separation have been optimized and good separation was obtained between the studied components where (ASC R f = 0.05, 4-AP R f = 0.12, GUF R f = 0.24, PAR R f = 0.41 and GUC R f = 0.56). Method validation has been performed according to ICH guidelines and linearity was achieved in the range of 0.4–2.4, 0.4–2.8 and 4–15 μg/band for ASC, PAR and GUF, respectively. In order to evaluate the developed method it was applied for determination of the cited drugs in G.C.Mol® effervescent powder and the obtained results were statistically compared with those obtained by applying the reported HPLC method using Student's t - and F -tests where no significant difference was observed. The developed method has the advantages over the reported HPLC one of being more sensitive and selective which permit its application in quality control analysis of the cited their in presence of drug impurities. [ABSTRACT FROM AUTHOR]

Two validated chromatographic methods have been developed for the simultaneous determination of thalidomide (THD) and dexamethasone (DEX) in rat plasma using paracetamol (PAR) as an internal standard (IS). Chromatographic analysis was achieved firstly by HPLC method on C18 column (150 × 4.6 mm2 i.d. 5 μm) and a mobile phase composed of ethanol:water (containing 0.1% acetic acid) (70:30, v/v) at the flow rate of 0.6 mL min−1. The second method was HPTLC method which depended on using a developing system of methylene chloride:acetone:ethyl acetate (7:4:1, by volume). In both methods, PAR was used as an IS. The developed methods have been validated as per FDA guidelines. All parameters were tested using quality control samples (LQC, MQC and HQC). All the obtained parameters were within the acceptance criteria. In the same way, the two methods were successfully used to study the pharmacokinetic parameters of both THD and DEX after their intra-peritoneal administration. Moreover, results obtained after administration of each drug alone were compared to those obtained after their administration together. The drugs showed drug–drug interactions when administered in combination, meaning that monitoring of such combination is very important. [ABSTRACT FROM AUTHOR]

Abstract: Carbamazepine (CBZ) and oxcarbazepine (OX) are highly effective anti-psychotic drugs. In USP, it is stated that CBZ has several impurities including, iminodibenzyl (IDB), iminostilbene (IMS), and 9-methylacridine (MA). While, for OX, it is reported to have impurities like, CBZ, IMS and 9-methylacridine (MA). Presence of such impurities in various forms may reduce the efficacy and increase the side effects. It is declared that CBZ (Tegretol®) and OX (Trileptal®) oral suspensions contain methylparaben, propylparaben, and sorbic acid as preservatives. For the first time, CBZ and OX were determined with their impurities and formulation excipients with a highly selective and sensitive ecofriendly LC/MS/MS method using methanol: water containing 0.1% formic acid (95:5, v/v) as a mobile phase. Mass spectrometric quantitation was carried out in positive and negative ion modes. Application of the proposed method to quantify CBZ and OX in their tablets and oral suspensions was successfully done. The results obtained by the suggested method and the reported methods for both drugs agreed well with each other. The developed method has the advantage of being ecofriendly using the simple green mobile phase. Unlike other published methods, it is successfully applied to quantify the impurities and excipients along with parent drugs within limits recommended by USP guidelines.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Three accurate, sensitive, simple, and precise spectrophotometric methods along with thin-layer chromatography (TLC)--densitometric method were developed, optimized, and validated for the determination of folic acid in the presence of its two impurities (photodegradation products), namely, pteroic acid and para-aminobenzoic acid. Method A is the ratio diff erence spectrophotometric method (RDSM) which depends on measuring the diff erence value in the ratio spectrum, where the diff erence between 291 and 313 nm was used for the determination of folic acid, while the difference between 305 and 319 nm was selected for the estimation of para-aminobenzoic acid; on the other hand, pteroic acid can be determined using the fi rst derivative of ratio spectra spectrophotometric method at 262 nm. Method B is the double-divisor spectrophotometric method (DDSM); this method is based on using the ratio spectrum obtained by the division of the spectrum of ternary mixture by the spectrum of binary mixture containing two of the three mentioned components, and in this method, folic acid, para-aminobenzoic acid, and pteroic acid were measured at 242, 313, and 258 nm, respectively. Method C is the mean-centering of ratio spectra spectrophotometric method (MCR); in this method, folic acid, para-aminobenzoic acid, and pteroic acid can be measured using the mean-centered second ratio spectra amplitudes at 317-318 (peak to peak), 264-265 (peak to peak), and 232 nm, respectively. Lastly, method D is a TLC-densitometric one that depends on the separation and quantifi cation of the mentioned components on TLC silica gel 60 F254 plates, using methanol- iso-propanol-water-acetic acid (9:0.5:0.5:0.2, by volume) as the developing system, followed by densitometric measurement of the separated bands at 280 nm. Method validation was carried out according to the International Conference on Harmonisation (ICH) guidelines, and the proposed methods were successfully applied to the analysis of folic acid in pharmaceutical formulations, where no interference from additives has been found. The results obtained by the proposed methods were statistically compared with those obtained by the offi cial reversed-phase high-performance liquid chromatography (RP-HPLC) method, in which no signifi cant diff erence was observed. [ABSTRACT FROM AUTHOR]

Flutamide is a potential antineoplastic drug classified as an anti-androgen. It is a therapy for men with advanced prostate cancer, administered orally after which it undergoes extensively first pass metabolism in the liver with the production of several metabolites. These metabolites are predominantly excreted in urine. One of the important metabolites in plasma is 4-nitro-3-(trifluoromethyl)phenylamine (Flu-1), while the main metabolite in urine is 2-amino-5-nitro-4-(trifluoromethyl)phenol (Flu-3). In this work the two metabolites, Flu-1 and Flu-3, have been synthesized, and then structural confirmation has been carried out by HNMR analysis. Efforts were exerted to develop chromatographic methods for resolving Flutamide and its metabolites with the use of acceptable solvents without affecting the efficiency of the methods. The drug along with its metabolites were quantitatively analyzed in pure form, human urine, and plasma samples using two chromatographic methods, HPTLC and HPLC-DAD methods. FDA guidelines for bio-analytical method validation were followed and USP recommendations were used for analytical method validation. Interference from excipients has been tested by application of the methods to pharmaceutical tablets. No significant difference was found between the proposed methods and the official one when they were statistically compared at p value of 0.05%. [ABSTRACT FROM AUTHOR]

Gliquidone (GQ) is an oral hypoglycemic agent, belonging to second-generation sulfonylurea derivatives. New high-performance thin-layer chromatography (HPTLC) and ultra-performance liquid chromatography (UPLC) methods have been developed and validated and used for complete stability study of GQ following International Conference on Harmonization guidelines. GQ was subjected to stress and forced degradation under hydrolytic, oxidative and photolytic conditions. The drug was found to be unstable under acidic, alkaline and oxidative conditions with the formation of gliquidone sulfonamide (GQS), while a marked stability was confirmed under thermal and photolytic stress conditions. GQS is the British pharmacopeial impurity A of GQ and also considered as its synthesis intermediate. The developed chromatographic methods have been utilized for anticipating the degradation behavior of GQ under the studied conditions and then used for quantitation of GQ and GQS either in their pure forms or in laboratory prepared mixtures. The methods were successfully applied to GQ in pharmaceutical formulation. The methods have the advantages of being sensitive and less time consuming compared with the reported methods. The obtained results were statistically compared with a reported HPLC method showing no significant difference regarding both accuracy and precision. [ABSTRACT FROM AUTHOR]

Two accurate, precise and highly selective stability-indicating methods were adopted for simultaneous determination of benztropine mesylate (BNZ) in presence of its hepatotoxic and carcinogenic degradation product, benzophenone (BPH) either in pure form or in the pharmaceutical formulation without any preliminary separation steps. The first method is a thin layer chromatography (TLC)-densitometric method that depended on separation of BNZ from its degradate on TLC aluminum plates precoated with silica gel 60 F254 as the stationary phase using a developing system consisted of hexane: methylene chloride:triethylamine (5:5:0.6, by volume) and scanning the separated bands at 235 nm. Linear regression analysis data for the calibration plots of BNZ and BPH showed perfect linear relationships over the concentration range of 1.5-10 and 1-10 μg band-1, respectively. The second method is (UPLC) method, at which the mixture was separated on a reversed phase C8 analytical column (1.9 μm ps, 50 mm x 2.1 i.d.) using a mobile phase of acetonitrile: aqueous sodium dodecyl sulfate (50:50, v/v) Adjusted to pH = 3 with phosphoric acid, at a flow rate of 0.5 mL min-1. Quantification was achieved at 210 nm based on peak area and linear calibration curves over the concentration ranges of (20-200 μg mL-1) and (5-50 μg mL-1) for BNZ and BPH, respectively, were obtained. The investigated methods were successfully applied to available dosage form and method validation has been carried out. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by reported one and no significant differences were obtained regarding both accuracy and precision. [ABSTRACT FROM AUTHOR]

Two sensitive, accurate and precise chromatographic methods mentioned as TLC-densitometric method and RP-HPLC-DAD method, were developed and validated for the simultaneous determination of mefenamic acid (MEF) and its two toxic impurities, benzoic acid (BA) and 2,3-dimethylaniline (DMA). In the proposed TLC-densitometric method a developing system consisting of chloroform: acetone:acetic acid:ammonia solution(70:30:2:2, v/v/v/v) was used, TLC aluminum plates 60 F254 was used as a stationary phase and the separated bands were UV-scanned at 225 nm. While the proposed RP-HPLC-DAD method depended on chromatographic separation on C18 column using 0.05M KH2PO4 buffer: acetonitrile (40:60, v/v) as a mobile phase at constant flow rate of 1 mL/min with UV detection at 225 nm. Linear relationships were obtained in the ranges of 0.3-2, 0.3-2 and 0.3-1.8 µg/band (for TLC-densitometric method) and in the ranges of 7-50, 10-50 and 7-50 µg/mL (for HPLC-DAD method) for MEF, BA and DMA, respectively. Factors affecting the developed methods have been studied and optimized. Moreover, the proposed methods were successfully applied for determination of the studied drug in its pharmaceutical dosage form. The methods showed no significance difference when compared with the reported method using F-test and Student's-t test. The low of detection and quantization limits of the proposed methods get them suitable for quality control and stability studies of MEF in pharmaceutical formulation. The developed methods have advantages of being more selective and sensitive than the published methods. [ABSTRACT FROM AUTHOR]

Three simple, accurate, sensitive and selective spectrophotometric stability-indicating methods for determination of Benztropine Mesylate (BNZ) in the presence of its hepatotoxic and carcinogenic degradation product; Benzophenone (BPH); were developed and validated without preliminary separation. The developed spectrophotometric methods are; first derivative, first derivative of ratio spectra and ratio difference were developed for the determination of BNZ in the presence of BPH in pure form and in pharmaceutical formulation. The most important advantage of this work is that it is the first time to develop spectrophotometric methods for determination of BNZ and its carcinogenic degradation product. BNZ was subjected to stress degradation conditions (acid, alkaline and oxidation) and the obtained degradate was confirmed to be BPH. Calibration curves of these methods are linear over the concentration ranges of 5-20 and 3-20 μg mL-1 for BNZ and BPH, respectively. Method (I); first derivative spectrophotometric method where BNZ was measured at 228.2 nm. Method (II); first derivative of ratio spectra spectrophotometric one where the overlapping spectra of BNZ and BPH were well resolved and BNZ was measured at peak amplitude 228.8 nm. Method (III); ratio difference spectrophotometric method which depends on measuring difference in peak amplitude values between two different wavelengths of the ratio spectrum at 224 and 234 nm for determination of BNZ. While BPH was determined by the first derivative at 245 NM without interference from BNZ. The proposed methods were successfully applied for determination of the studied drug in its pharmaceutical formulation. These methods were validated according to ICH guidelines. Results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by reported one using F and student's t-tests showed no significant difference was obtained regarding both accuracy and precision. [ABSTRACT FROM AUTHOR]

Sofosbuvir (SOF) and ledipasvir (LED) are recently approved and coformulated as directly acting antiviral agents used for treatment of hepatitis C virus (HCV). A reversed phase high performance liquid chromatography - diode array detector (RP-HPLC/DAD) method was developed and validated for the first time for the analysis of newly formulated anti-HCV combination, in pure form, pharmaceutical formulation and in human plasma. In the developed method, separation was performed on Zorbax® Eclipse C18 column using a gradient mixture of acetonitrile–water as a mobile phase and scanning was performed at 260 nm (for SOF) and 330 nm (for LED). The two drugs were completely separated from each other and from plasma, where plasma peak appeared at 2.76 ± 0.05 min, SOF at 4.25 ± 0.05, and LED at 7.35 ± 0.05. The developed method showed high sensitivity, the drugs showed linearity in the range of 1–45 µg/mL for both pure form and spiked human plasma. Three freeze–thaw cycles were performed separately at two different temperatures, −8 and −20°C. No significant loss of the studied drugs were observed during repeated thawing and freezing. Validation parameters such as accuracy, precision, robustness, and ruggedness were tested in compliance with USP recommendations, where acceptable results were obtained. Applying to pharmaceutical formulation showed no interference from tablet excipients. [ABSTRACT FROM PUBLISHER]

Ledipasvir (LED) and Sofosbuvir (SOF) are newly approved antiviral agents co-formulated for treatment of hepatitis C virus (HCV). Up till now, no analytical methods have been published for determination of this pharmaceutically important combination. In this work novel spectrophotometric methods were developed for resolving the partially overlapped spectra of LED and SOF with simple data manipulation and without preliminary separation steps. In method (I), LED was directly determined using its extended spectra at 325 nm where no interference from the co-formulated SOF while the absorption at the isoabsorptive point (λ= 262.4 nm) was used for measuring concentrations of both. By subtraction, concentration of SOF could be obtained. Method (II) is the absorbance subtraction method (AS) at which a mathematically estimated factor representing the absorbance ratio (A262.4/A325) for pure LED was used for simultaneous quantitation of LED and SOF using a unique equation computed at λiso(262.4 n m). Method (III) depended on using ratio spectra and then measuring the amplitude of the constant at 325 nm for LED while using ratio subtraction spectrophotometric method to quantify SOF at 262 nm. Finally, method (IV) was area under the curve correction method (AUCC) at which the areas from 245-265 and 315-335 nm and a mathematically calculated factor for pure LED were used. The methods were validated in compliance to USP guidelines and were successfully applied to available dosage form. [ABSTRACT FROM AUTHOR]

Simple, precise and economic spectrophotometric and multivariate calibration methods were developed for determination of Paracetamol (PAR), Ascorbic acid (ASC) and Pseudoephedrine hydrochloride (PSH). In method (I) ASC and PSH were determined by applying1DD spectrophotometric method at 266 and 280 nm for ASC and 218 nm for PSH while PAR was determined by using 1D spectrophotometric method at 257 nm where the linearity ranges are 2-16, 3-40 and 2-28 μg/mL for ASC, PSH and PAR, respectively. While in the developed MCR method the absorption spectra of PAR, ASC and PSH were recorded over 200-400 nm and divided by the spectrum of suitable divisor of PAR, ASC and PSH then the obtained ratio spectra were mean centered. The amplitudes at 287, 286 and 290 nm for PAR, ASC and PSH, respectively were determined where the linearity ranges are 4-20, 3-40 and 2-28 μg/mL for ASC, PSH and PAR, respectively. In method (III) the developed PCR and PLS models were built using a calibration set consisting of seventeen mixtures while the validation set consisted of different eight mixtures in the range of 206-290 nm. The accuracy and precision of the developed methods were proved while their selectivity has been tested by their application for determination of the studied components in different synthetic mixtures. Statistical comparison of the suggested methods with the reported HPLC one using F-and student’s t-tests showed no significant difference. [ABSTRACT FROM AUTHOR]

Two selective, accurate, precise and validated spectrophotometric methods were developed for determination of mefenamic acid (MEF) and its two toxic impurities, benzoic acid (BA) and 2, 3 dimethylaniline (DMA) without preliminary separation. The developed methods are direct spectrophotometric method {0D} {Method I}, area under the curve {AUC} {Method II}. In method {I} Mefenamic determine directly by measured absorbance at 350 nm in the range of 2-15 μg/mL. In method {II} the drug was determined by measuring AUC in the wavelength range of 330-370 nm while the impurities could be determined by dividing by of 10 μg/mL MEF then interference from MEF was eliminated by subtracting the amplitude of the constant at 350 nm and then multiplying by the divisor. Then by using AUC at the range 220-230 nm and 235245 nm and by applying in Cramer’s rule, concentrations of BA and DMA could be calculated. The work introduces a low cost and does not need sophisticated steps for determination of MEF, BA and DMA in their powders and in pharmaceutical preparations. The validation of methods was performed according to ICH guidelines regarding accuracy, precision and selectivity. No significance difference was found when these methods were compared to the reported one. [ABSTRACT FROM AUTHOR]

Stability indicating spectrophotometric methods have been developed and validated for determination of Vitamin E (VIT E) and Vinpocetine (VINP) in presence of alkaline induced degradation product of Vinpocetine (DEG) without prior separation. In method (A), two wavelengths were selected for each drug in such a way that the difference in absorbance was zero for the other drugs. Absorbance difference between 217.4 and 234.4 nm were used to determine VIT E while difference between 250.4 and 314.0 nm were selected for VINP determination and the difference between 258.6 and 312.0 nm were selected to determine DEG. In method (B), area under the curve method (AUC) was used for measuring VINP concentration by direct measuring AUC in the range of 330-350 nm, at which no interference from other components. While for determination of VIT E and DEG, the ternary mixture was divided by standard spectrum of 6 μg/mL VINP, in the obtained ratio spectra VIT E and DEG has been directly determined at 210.0 and 230.0 nm, respectively. In method (C), VIT E and DEG were determined by second derivative of ratio spectra (2DD) method by measuring their peak amplitudes at 215.2 and 237.2 nm, respectively, using 6 μg/mL standard spectrum of VINP as a divisor, while the absorbance at isoabsorptive point (λiso=264.4 nm) was used to determine the total concentration of VINP and DEG (where no contribution from VIT E) in the mixture and then by subtraction, VINP concentration could be obtained. The developed methods were validated according to ICH guidelines revealing good accuracy and precision. The results obtained by the proposed methods were statistically compared with those obtained by the reported HPLC methods and no significant difference was obtained. These methods are the first developed SIAM ones for analysis of the studied components. [ABSTRACT FROM PUBLISHER]

Sulbutiamine (SUL) is an ester of thiazides with neurotropic action. A new stability indicating HPTLC method has been developed and validated for the determination of SUL in the presence of different degradation products. The drug was subjected to different stress conditions following ICH strategy such as hydrolytic degradation (neutral, alkaline and acidic hydrolysis), oxidation, photodegradation and dry heat degradation. The drug demonstrated degradation under all decomposition conditions except neutral hydrolysis and dry heat, where the drug was completely degraded with 0.1 N NaOH, 1 N HCl and 30% H2O2 while it was partially degradaed by 0.1 N HCl, 3% H2O2 and UV light. Structure elucidation of the resulting degradation products was performed using ESI-Q-MS-MS. A welldefined peak for SUL was obtained at Rf = 0.46 and was completely separated from all obtained degradation products. Chromatographic separation was carried out on HPTLC aluminum plates precoated with silica gel 60 F254 using acetone-methylene chloride-ammonia buffer (pH 8.5 ± 0.2) (7:3:0.5, v/v) as a developing system. Densitometric scanning of the separated peaks was performed at 254 nm. System suitability testing parameters were calculated to ascertain the quality performance of the developed method. The method was validated with respect to USP guidelines regarding accuracy, precision, specificity, robustness and ruggedness. Good correlation coefficients were achieved in the range of 0.4-5.0 μg/band, and the limit of detection and limit of quantitation were found to be 0.11 and 0.33 μg/band, respectively. The utility of the suggested method was verified by application to Arcalion forte® tablets where no interference from additives was found. [ABSTRACT FROM AUTHOR]

This work was concerned with development, optimization, application and validation of reversed phase high performance liquid chromatography (RP-HPLC) and thin layer chromatography (TLC)-densitometric methods for analysis of cetylpyridinium chloride, chlorocresol and lidocaine in Canyon® gel. The first developed RP-HPLC method depended on chromatographic separation on a ZORBAX Eclipse Plus C8 column, with elution with a mobile phase consisting of 0.05% phosphoric acid solution : acetonitrile : methanol (15 : 24 : 61, by volume), pumping the mobile phase at a flow rate of 1.00 mL min-1, with ultraviolet detection at 220 nm. While in the subsequently developed method, the TLC-densitometric method, complete separation of the studied mixture was achieved using methanol : acetone : acetic acid (7 : 3 : 0.2, by volume) as a mobile phase, aluminum plates precoated with silica gel 60 F254 as a stationary phase and 215 nm as the scanning wavelength. Factors affecting the developed methods were studied and optimized; moreover, methods had been validated as per the International Conference of Harmonization guideline and the results indicated that the suggested methods were reproducible, reliable and applicable for rapid routine analysis. Statistical comparison of the two developed methods with the reported HPLC ones using F- and Student's t tests showed no significant difference. [ABSTRACT FROM AUTHOR]

Two accurate, selective and precise chromatographic methods, namely thin-layer chromatography (TLC)-densitometric method and reversed phase high-performance liquid chromatography (RP-HPLC) method, were developed and validated for the simultaneous determination of tolfenamic acid (TOL) and its two major impurities, 2-chlorobenzoic acid (CBA) and 3-chloro-2-methylaniline (CMA), which are also reported to be its related substances. The developed TLC-densitometric method depended on separation and quantitation of the studied drugs on silica gel 60F254 TLC plates. Hexane:chloroform:acetone:acetic acid (75:25:20:0.1, v/v/v/v) was used as a developing system and the separated bands were UV-scanned at 240 nm. Linear relationships were obtained in the range of 10-100 μg band-1 for the drug and in the range of 0.1-1 μg band-1 for the studied impurities. The developed RP-HPLC depended on chromatographic separation of the studied drugs on a C18 column using 0.05 M KH2PO4 buffer (pH 3):acetonitrile (45:55, v/v) as a mobile phase delivered at constant flow rate of 1 mL min-1 with UV detection at 230 nm. Calibration curves for TOL and the two impurities were constructed over the concentration ranges of 10-100 μg mL-1 for TOL and 0.01-0.1 μg mL-1 for both CBA and CMA. Factors affecting the developed methods have been studied and optimized. Further, methods validation has been carried out according to International Conference on Harmonization guidelines. The proposed methods were successfully applied for determination of the studied drug in its bulk powder and in pharmaceutical formulation. The methods showed no significant difference when compared with the reported RP-HPLC one. The developed methods have advantages of being more sensitive and specific than the published methods. [ABSTRACT FROM AUTHOR]

This work presents an accurate, sensitive and selective thin-layer chromatography–densitometry method for the simultaneous determination of diacerein in the presence of rhein, the active metabolite and hydrolytic degradation product of diacerein, and emodin, the diacerein impurity, in bulk powder and different pharmaceutical formulations. Chromatographic separation was performed on aluminum plates precoated with 60 F254 silica gel using hexane–ethyl acetate–acetic acid (60:40:0.8, by volume) as a developing system and with detection at 230 nm. The retention factor values of diacerein, rhein and emodin were 0.12, 0.44 and 0.6, respectively. The method was successfully applied for the determination of these compounds with high sensitivity; the linearity ranges were found to be 0.5–10 µg/band (for diacerein and rhein) and 0.5–7 µg/band (for emodin). The developed method was validated according to International Conference on Harmonization guidelines and was applied for the determination of diacerein in different pharmaceutical formulations. Moreover, a statistical comparison between the results of the developed method and those of the reported reversed-phase high-performance liquid chromatography method showed no significant differences. This method can be used for the routine analysis of diacerein, rhein and emodin in quality control laboratories. [ABSTRACT FROM PUBLISHER]

A highly sensitive, selective and accurate thin-layer chromatographic (TLC)–densitometric method has been developed and validated for the simultaneous determination of paracetamol (PAR) and chlorzoxazone (CZ) and their toxic impurities, 4-amino phenol (4AP) and 2-amino-4-chlorophenol (2ACP), respectively, which are also considered to be the hydrolytic degradation products and related substances of the studied drugs. A developing system consisting of chloroform–methanol–glacial acetic acid (9.5:0.5:0.25, by volume) was found to be sufficient for chromatographic separation among the four studied components using pre-activated silica gel 60 F254 TLC plates with ultraviolet detection at 225 nm. Calibration curves were constructed in the ranges of 0.3–3, 1–10, 0.06–3 and 0.04–3 µg/band for PAR, CZ, 4AP and 2ACP, respectively, using polynomial equations. The developed method was validated according to International Conference on Harmonization guidelines and demonstrated good accuracy and precision. Moreover, the method was successfully applied for the determination of PAR and CZ in different marketed samples and the results were statistically compared to those obtained by the reported reversed-phase high-performance liquid chromatography method using F-test and Student's-t test. The low detection and quantitation limits of the developed method make it suitable for quality control and stability studies of PAR and CZ in different pharmaceutical formulations. [ABSTRACT FROM AUTHOR]