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Roflumilast is a selective enzyme inhibitor of phosphodiesterase-4. This drug is recommended for treatment of patients suffering from chronic-obstructive-pulmonary-disease with chronic-bronchitis. Roflumilast is not official in pharmacopoeia and the reported methods are having high chromatographic run times. A short run time HPLC method was developed for assay and content uniformity testing to determine the roflumilast in blend and tablets. The mobile phase consists of 10 mM sodium dihydrogen phosphate monohydrate buffer and acetonitrile in the ratio of 45:55 v/v. The HPLC method was developed using accucore-C18 150 × 4.6 mm, 4 μm column with a flow rate of 1.0 mL min-1, 215 nm wavelength and 10 μL injection volume with run time of 5 min. The method linearity was proved between 5.02-40.17 μg mL-1 and obtained correlation-coefficient value is 1.0000. The mean recovery of roflumilast was 100.6%. The stability indicating nature was established and performed the validation by considering ICH Q2 (R1) recommendations.

Ruthenium(III) catalyzed oxidation of propane-1,3-diol by potassium periodate was studied in aqueous perchloric acid medium. Orders of reaction with respect to concentrations of oxidant, substrate, acid and catalyst were determined. First order in oxidant and catalyst concentrations, and inverse fractional order in acid medium were observed. In addition, substrate inhibition (i.e. a decrease in reaction rate with an increase in substrate concentration) was observed. Effect of addition of salt and solvent was studied. Based on the studies of temperature variation, Arrhenius parameters were calculated. Plausible mechanism was also proposed based on observed kinetics.

A simple, sensitive, precise, accurate, highly reproducible and economical, visible spectrophotometric method for the determination lurasidone in bulk form was developed and validated. The method is based on the formation of an oxidative coupling product by the reaction of lurasidone with 3-methylbenzothiazolin-2-one hydrazone as a chromogenic reagent in presence of ferric chloride. The linear regression analysis data for the calibration plot showed good linear relationship within the concentration range of 0–100 μg/mL with a correlation coefficient (r) value of 0.9997. The limits of detection and quantitation are 0.6 and 1.7 µg/mL, respectively. The method was tested and validated according to ICH guidelines. The results demonstrated that the procedure is accurate, precise and reproducible (RSD < 2%).

A simple, selective, accurate and low-cost spectrophotometric method has been described for determination of satranidazole in bulk and pharmaceutical formulations. The developed method involves the formation of chloroform extractable colored ion-association complex of satranidazole with Tropaeolin OOO (TPooo). The extracted colored complex showed absorbance maximum at wavelength 484 nm and obeying Beer′s law in the concentration 4-20 μg mL-1 with the correlation coeffiecent of 0.9998. The results of statistical analysis of the proposed method reveals high accuracy and good precession. Thus, the proposed method can be used commercially for the determination of satranidazole in bulk and pharmaceutical formulations.

2,4 disubstitiuted furan derivatives (8Aâ8M) were prepared from furan-4-carboxylic acid ethyl ester (1). Antibacterial activity of new 2,4 di substituted furan derivatives was studied against Gram (+) and Gram (â) bacteria. 8F, 8E, 8D and 8J were found to be effective against Gram (â) bacteria whereas, 8A and 8L were effective against Gram (+) bacteria. Least MIC value was found as 100 µg/ml against Escherichia coli (for 8D and 8F), and Proteus vulgaris (for 8E and 8F). Antibacterial activity is correlated with different substituents. Products exhibited better antibacterial activities especially towards Streptococcus pyogenes, Proteus vulgaris, and Escherichia coli. Keywords: Pathogens, Antibacterial activity, Structure-activity relationship, Disubstitiuted furans, Synthesis

In the present study, two cancer therapeutic drugs (docetaxel and bortezomib) were separated from their potential impurities on a chromatographic platform by utilizing CO2 gas (supercritical state) and quantified. The chromatographic separations were achieved on two short columns BEH-2EP (100 mm × 3 mm, 1.7 μm) and CHIRALPAK AD-3 (100 mm × 4.6 mm, 3 μm) for docetaxel and bortezomib, respectively. The present work describes the role of organic modifiers in the separation of polar compounds by supercritical fluid chromatography. The two new methods were fully validated in accordance with the current ICH (International Council for Harmonization of technical requirements for pharmaceuticals for human use) guidelines. The stability indicating power of the methods was demonstrated from the stress studies conducted on the injection formulations of the two compounds. The methods are precise with % RSD of 0.4, linear with the correlation coefficient of r2 ≥ 0.999 and accurate in the range of 50–150% of the target assay concentration. The two methods can be equally employed for the assay determination of docetaxel and bortezomib APIs as well.

Kinetics of uncatalyzed and ruthenium(III) catalyzed oxidation of monoethanolamine by N-bromosuccinimide (NBS) has been studied in an aqueous acetic acid medium in the presence of sodium acetate and perchloric acid, respectively. In the uncatalyzed oxidation the kinetic orders are: the first order in NBS, a fractional order in the substrate. The rate of the reaction increased with an increase in the sodium acetate concentration and decreased with an increase in the perchloric acid concentration. This indicates that free amine molecules are the reactive species. Addition of halide ions results in a decrease in the kinetic rate, which is noteworthy. Both in absence and presence of a catalyst, a decrease in the dielectric constant of the medium decreases the kinetic rate pointing out that these are dipole—dipole reactions. A relatively higher oxidation state of ruthenium i.e., Ru(V) was found to be the active species in Ru(III) catalyzed reactions. A suitable mechanism consistent with the observations has been proposed and a rate law has been derived to explain the kinetic orders.

In the present study 12 impurities of bisoprolol fumarate (BISO) and hydrochlorothiazide (HCTZ) were separated simultaneously in a single HPLC method. Out of these 12 impurities, five are potential degradants, which are validated as per The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines. As the two active drug substances BISO and HCTZ have different solubilities and polarities, the most critical parameters in resolving the components from each other are pH, temperature, and solvents. The method is precise (RSD 0.999), robust, and stability indicating in the range of limit of quantification (LOQ) to 150%. The HPLC method is then migrated to ultra-performance liquid chromatography (UPLC) to further reduce the run time and solvent consumption, and increase the sample throughput.

Role of added chloride ions on the shift of reaction pathway of oxidation of aromatic ketones (acetophenone, desoxybenzoin) by dichloroisocyanuric acid (DCICA) was studied in aqueous acetic acid—perchloric acid medium. Participation of enolic and protonated forms of ketones in the rate determining steps is manifested from zero and first orders with respect to the oxidant in absence and presence of added chloride ions, respectively. Positive and negative effects of acid and dielectric constant on the reaction rate were observed. The observations deduce plausible mechanisms involving (i) rate-determining formation of enol from the conjugate acid of the ketone (SH+) in the absence of added chloride ions and (ii) rapid formation of molecular chlorine species from HOCl (hydrolytic species of DCICA) in the presence of added chloride ions, which then interacts with SH+ in a rate-determining step prior to the rapid steps of product formation. The order of Arrhenius parameters substantiate the proposed plausible mechanisms based on order of reactants both in presence and absence of added chloride ions.

Kinetics of ruthenium(III) catalyzed oxidation of biologically important sugar alcohols (myo-inositol, D-sorbitol, and D-mannitol) by dichloroisocyanuric acid was carried out in aqueous acetic acid—perchloric medium. The reactions were found to be first order in case of oxidant and ruthenium(III). Zero order was observed with the concentrations of sorbitol and mannitol whereas, a positive fractional order was found in the case of inositol concentration. An inverse fractional order was observed with perchloric acid in oxidation of three substrates. Arrhenius parameters were calculated and a plausible mechanism was proposed.

Polyethylene glycol-400 (PEG-400) has a spectrum of applications in pharmaceutical field. PEG-400 oxidation was carried out in alkaline medium by using potassium periodate as an oxidant. Rate of the reaction was found to be first order dependence on the oxidant concentration. In the studied range, substrate concentration didn't change the reaction rate. Increase of alkali concentration decreased the reaction rate and order of the reaction with respect to alkali was inverse fractional. Effect of temperature on reaction rate was studied and then Arrhenius parameters were calculated. A suitable rate law was proposed based on the observed experimental results.