Synthesis, spectral and thermal degradation kinetics of divalent cadmium complexes of dothiepine and diphenhydramine

Cadmium(II) complexes with 3-(6H-dibenzob,e thiepin-11-ylidene) propyl dimethyl amine chloride (dot) and 2-diphenyl methoxy-N,N-dimethylamine hydrochloride (dp) were synthesised and characterised by reflectance, IR, 1H NMR, magnetic moments and conductivity measurements. The new complexes studied for kinetics of thermal degradation by thermogravimetric analyses (TGA) and derivative thermogravimetrie studies (DTG) in a static nitrogen atmosphere at a heating rate of 10°C min-1. The kinetic and thermodynamic parameters such as energy of activation (Ea), frequency factor (InA), enthalpy (ÎH), free energy (ÎH), and entropy (ÎS) evaluated. The energy of activation values for the degradation of (dot) and (dp) complexes were found to be in the range 22.3-125.4 kJ mol-1

Spectrophotometric determination of some antidepressant drugs using 3-methylbenzothiazolin-2-one hydrazone

A sensitive spectrophotometric method for the determination of amitriptyline hydrochloride, nortriptyline hydrochloride and doxepin hydrochloride in pure and dosage forms, is described. The method is based on the oxidative coupling of the drugs with 3-methylbenzothiazolin-2-one hydrazone in the presence of iron(III) chloride in 1 M hydrochloric acid. The commonly encountered excipients and additives do not interfere with the determinations. Results of the present method are comparable with those of official methods. The new method offers the advantage of simplicity and rapidity. (C) 1999 Published by Elsevier Science B.V. All rights reserved

Spectrophotometric method for the determination of ritodrine hydrochloride and amoxicillin

A rapid and sensitive spectrophotometric method is described for the determination of ritodrine hydrochloride (RTH) and amoxicillin (AMX) in both pure and dosage forms. The proposed method uses 3-methyl benzothiazolin-2-one hydrazone as a chromogenic reagent. A mixture of aqueous solutions of the drug and reagent is treated with ammonium cerium(IV) sulfate in an acidic medium to yield pink-colored species. These species exhibit maximum absorption at 520 nm for RTH and at 490 nm for AMX with a molar absorptivity of 2.35x10(4) and 1.27x10(4) l mol(-1) cm(-1) for Pim and AMX, respectively. The optimum reaction conditions and other analytical parameters are evaluated. The influence of the substrates commonly employed as excipients with these drugs have been studied. The proposed method was applied to the determination of these drugs in pharmaceutical formulations. The results have demonstrated that the method is equally accurate and reproducible as the official methods

Spectrophotometric determinations of some phenothiazine drugs

A rapid and sensitive spectrophotometric method has been developed for the quantitative determination of some phenothiazine derivatives as the pure substances and in different dosage forms. The method is based on the formation of red coloured products with 1% iodic acid in sulphuric or phosphoric acid medium. The reaction involves oxidation of the phenothiazine nucleus into a semiquinonoid radical. The optimum reaction conditions and other analytical parameters are evaluated. The influence of the substrates commonly employed as excipients with phenothiazine drugs has been studied. Statistical comparison of the results with those of an official method shows excellent agreement and indicates no significant difference in precision

Complexes of divalent cadmium with N,N-dimethyl-3-dibenzob,e-oxepin-11-(6H)-ylidine-1-propanamine)chloride: Synthesis and evaluation of thermal degradation kinetics

A tricyclic antidepressant drug doxepin (C19H21NO), abbreviated as DOX, forms complex with divalent cadmium metal of the type Cd(DOX)2X2 (X = Cl-, Br-, NO 3 -, I-, 1/2SO4 2- or CH3COO-). In all the complexes, DOX coordinates through side-chain nitrogen atom. The TG data of degradation of the complex have been analyzed for kinetic and thermodynamic parameters employing Briodo's method

Permanganometric determination of etamsylate in bulk drug and in tablets

One titrimetric and two spectrophotometric methods which are simple, selective, sensitive, accurate, precise and economical for the determination of etamsylate (ETM) In bulk drug and In tablets employing permanganate as the oxidimetric reagent are described. In titrimetry, ETM is titrated directly with permanganate in sulphuric acid medium. A direct spectrophotometry (method A) involves treating the aqueous solution of the drug with permanganate in alkaline medium and measuring the bluish green product at 6 10 nm. In indirect spectrophotometry (method 8), the drug solution was treated with a fixed concentration of permanganate in H2SO4 medium, and after a specified time the unreacted permanganate was measured at 545 nm. The molar combining ratio in titrimetry and the optimum assay conditions were studied. Titrimetry is applicable over 1-10 mg range and the calculations are based on a 1:4 (ETM:KMnO4) molar ratio. In spectrophotometry, Beer's law is obeyed over 0.5- 5.0 and 1.5- -15 mu g ml(-1) for method A and B, respectively. The molar absorptivity values are calculated to be 2.79x10(4) and 4.17x10(4) / mol(-1) cm(-1) for method A and B, respectively and the corresponding sandell sensitivity values are 0 0094 and 0.0063 mu g cm(-2). The limits of detection (LOD) and quantification (LOQ) are also reported for spectrophotometric methods. The applicability of the developed methods was demonstrated by the determination of etamsylate in pure drug as well as in commercial dosage forms

Structural, electronic, vibrational and pharmacological investigations of highly functionalized Diarylmethane molecules using DFT calculations, molecular dynamics and molecular docking

Present work describes the UV–Visible and FT-IR spectral behavior of highly functionalized diarylmethanes via theoretical investigations. Analyses of both theoretical and experimental UV data were in good agreement with the assigned bands. In addition, calculations pertaining to natural bond orbitals (NBOs) and mapped molecular electrostatic potential surface (MEPS) were also performed, revealing that the strongest hyperconjugative intramolecular interactions involves the p ⟶ p*, LP⟶ r* and n ⟶ p* transitions in the D and A rings. Further, the theoretical vibrational analysis revealed several characteristic vibrations that may be used as a diagnostic tool for other diarylmethanes and also indicated that the experimental bands related to the nitrile group occur in regions lower than usual, which confirms high conjugation of the triple bond with the aromatic system. Molecular dynamics (MD) and molecular docking calculations were performed in order to evaluate the behavior of such molecules in aqueous medium and the pharmacological potential. Another interesting observation in this study is the HOMO–LUMO analysis, which showed that the global reactivity values changed according to the type of substituent groups