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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.

Studies show that tricyclic antidepressants prescribed for migraines, anxiety, and child enuresis have numerous adverse effects in living cells. One of the undesired outcomes observed under treatment with these drugs is DNA damage. However, the mechanisms underlying damage have yet to be elucidated. We performed in vitro studies of the DNA damage caused by four tricyclic antidepressants: imipramine, amitriptyline, opipramol, and protriptyline. We focused particularly on the DNA damage aided by peroxidases. As a model of a peroxidase, we used horseradish peroxidase (HRP). At pH 7, reactions of HRP with excess hydrogen peroxide and imipramine yielded an intense purple color and a broad absorption spectrum with the maximum intensity at 522 nm. Reactions performed between DNA and imipramine in the presence of H(2)O(2) and HRP resulted in the disappearance of the DNA band. In the case of the other three drugs, this effect was not observed. Extraction of the DNA from the reaction mixture indicated that DNA is degraded in the reaction between imipramine and H(2)O(2) catalyzed by HRP. The final product of imipramine oxidation was identified as iminodibenzyl. We hypothesize that the damage to DNA was caused by an imipramine reactive intermediate.

The micellization of amphiphilic drug amitriptyline hydrochloride (AMT, an antidepressant) and conventional as well as gemini surfactants has been studied conductometrically in pure and mixed states in aqueous solutions at different temperatures to derive various physicochemical properties such as critical micelle concentration (cmc), ideal cmc (cmc(id)), counterion dissociation (g), standard Gibbs free energy (DeltaG(m)(0)), enthalpy (DeltaH(m)(0)), and entropy of micellization (DeltaS(m)(0)), micellar mole fractions of surfactant (X1, X1(m)), mole fraction of surfactant in ideal state (X1(id)), interaction parameter (beta), activity coefficients (f1, f2), and excess free energy of mixing (DeltaG(ex)). All the results indicate synergism and attractive interactions in the mixed systems.

We propose that one can deduce very insightful information regarding the drug and fatty acid binding capacity of microemulsions through simple turbidity experiments. Pluronic F127-based oil-in-water microemulsions of various compositions were synthesized and titrated to turbidity with concentrated amitriptyline, an antidepressant drug. We observed that, above certain Pluronic F127 concentrations, turbidity was never observed, irrespective of how much amitriptyline was added to the microemulsion. We also observed that whenever sodium caprylate fatty acid was not included in the microemulsion formulation, turbidity never occurred. On the basis of these findings, we were able to determine the point at which all sodium caprylate present in the microemulsion formulation was bound to the F127 in the microemulsion (i.e., no fatty acid was free in the bulk in monomer form). By the same logic we were also able to determine how much amitriptyline was binding to the microemulsions. We also measured the dynamic surface tension, foamability, and fabric wetting time of the microemulsion formulations to further prove the hypothesis that all fatty acid is bound to the F127 in the microemulsion above a critical Pluronic F127 concentration. On the basis of this research, we have concluded that there are approximately 11 molecules of sodium caprylate fatty acid bound per molecule of Pluronic F127 and approximately 12 molecules of amitriptyline bound per molecule of Pluronic F127 in the optimal microemulsion formulation. These findings give us valuable information about the charge density at the oil/water interface and about the mechanism of binding of the drug to the microemulsion.

Binding of the drugs naproxen (which is an anti-inflammatory) and amitriptyline (which is an anti-depressant) to bovine serum albumin (BSA) has been studied using isothermal titration calorimetry (ITC), in combination with fluorescence and circular dichroism spectroscopies. Naproxen is observed to bind more strongly to BSA than amitriptyline. The temperature-dependent ITC results indicate the interaction of one molecule of naproxen with more than one protein molecule. On the other hand, amitriptyline binds to BSA with a reaction stoichiometry that varies from 1:1.2 to 1:2.9. The van't Hoff enthalpy, which is calculated from the temperature dependence of the binding constant, agrees well with the calorimetric enthalpy in the case of naproxen binding to BSA, indicating adherence to a two-state binding process. However, their disagreement in the case of amitriptyline indicates conformational changes in the protein upon ligand binding, as well as with the rise in temperature. The spectroscopic results did not suggest appreciable conformational changes as a result of binding; hence, the discrepancy could be attributed to the temperature-induced conformational changes. With increases in the ionic strength, a reduction in the binding affinity of naproxen to BSA is observed. This suggests the prevailing electrostatic interactions in the complexation process. The preponderance of the hydrophobic interactions in the binding of amitriptyline to BSA is indicated by the absence of any dependence of the ionic strength. A predominance of electrostatic interactions in the case of naproxen binding to BSA and that of hydrophobic interactions in the case of amitriptyline binding to BSA is further strengthened by the results of the binding experiments performed in the presence of ionic and nonionic surfactants. The binding parameters indicate that Triton X-100 blocks the hydrophobic binding sites on BSA, thereby altering the binding affinity of amitriptyline toward BSA. A partial overlap of the binding sites for these drugs is indicated by the binding parameters obtained in the titration of naproxen to the amitriptyline-BSA complex and vice versa. Thus, the results provide a quantitative understanding of the binding of naproxen and amitriptyline to BSA, which is important in understanding their effect as therapeutic agents individually and in combination therapy.

The objective of this work is the synthesis of water-soluble oligochitosan derivatives with electron deficient aromatic rings for selective and rapid adsorption of amitriptyline through pi-pi complexation. Oligochitosan was chemically modified under homogeneous conditions in dimethyl sulfoxide (DMSO). (1)H NMR, FT-IR, and MALDI-TOF were employed in characterization, confirming that the electron deficient aromatic rings were chemically attached to the backbone of oligochitosan. Thromboelastography (TEG) revealed functionalized oligochitosan derivatives did not affect blood clotting. (1)H NMR was also utilized to observe the aromatic-aromatic interaction between electron deficient aromatic rings on oligochitosan and electron rich aromatic rings in amitriptyline. The chemical shift variation of aromatic protons in oligochitosan derivatives was followed to monitor the aromatic-aromatic interaction. Upfield shift of aromatic protons on benzenesulfonyl and dinitrobenzenesulfonyl groups was observed upon the addition of amitriptyline, supporting the formation of pi-pi complexes through aromatic-aromatic interactions. Dinitrobenzenesulfonyl rings show a larger variation in chemical shift due to the presence of the electron deficient nitro groups.