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A number of new 1,2,4-thiadiazole linked 1,3,4-thiadiazole-carbazole derivatives has been designed, synthesized and evaluated for cytotoxic activity against four cancer cell lines such as MCF-7 (breast cancer), Colo-205 (colon carcinoma), A549 (lung cancer), and A2780 (ovarian carcinoma) by using MTT assay and etoposide as a reference. According to the preliminary screening, most of the tested compounds have exhibited significant cytotoxicity against four cancer cell lines. One of the compounds is determined to be potent against all tested cell lines.

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.

Kinetics of PEG-200 oxidation by potassium periodatewas studied in alkaline medium. First-order dependence of reaction on periodate was observed. Rate of the reaction was found to be independent of substrate concentration. An inverse fractional order with respect to alkaliwas shown. Arrhenius parameters were calculated. Rate law was postulated taking into consideration of experimental results.

LC-MS compatible stability indicating RP-UPLC method for the estimation of ester prodrug of mycophenolic acid in injection formulation

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.

Two simple, sensitive, selective, accurate and economical spectrophotometric methods (A and B) have been described in the present work for the determination of Nicergoline in bulk drug and pharmaceutical formulations (tablets). Methods - A/B are based on the formation of orange red / yellow colored ion-association complexes between Nicergoline and Tropaeolin ooo (TPooo) / Alizarine Red S (ARS) in acid medium followed by their extraction with chloroform, exhibiting absorption maxima at 490nm / 430nm, and obeying Beer's law in the concentration range of 2.5- 12.5µg/ml. Statistical analysis of the results of the proposed methods reveals high accuracy and good precision. The proposed methods could be successfully extended to the commercial pharmaceutical formulations containing Nicergoline.