No abstract

Two sensitive and reproducible methods are described for the quantitative determination of itopride hydrochloride (IH) in the presence of its degradation products. The first method is based on HPLC separation on a reversed phase Kromasil column [C18 (5-microm, 25 cm x 4.6 mm, ID)] at ambient temperature using a mobile phase consisting of methanol and water (70:30, v/v) adjusted to pH 4.0 with orthophosphoric acid with UV detection at 258 nm. The flow rate was 1.0 mL per min with an average operating pressure of 180 kg/cm2. The second method is based on HPTLC separation on silica gel 60 F254 using toluene:methanol:chloroform:10% ammonia (5.0:3.0:6.0:0.1, v/v/v/v) as mobile phase at 270 nm. The analysis of variance (ANOVA) and Student's t-test were applied to correlate the results of IH determination in dosage form by means of HPLC and HPTLC methods. The drug was subjected to acid and alkali hydrolysis, oxidation, dry heat, wet heat treatment, UV, and photodegradation. The proposed HPLC method was utilized to investigate the kinetics of the acidic, alkaline, and oxidative degradation processes at different temperatures and the apparent pseudo-first-order rate constant, half-life, and activation energy were calculated. In addition the pH-rate profile of degradation of IH in constant ionic strength buffer solutions in the pH range 2-11 was studied.

A stability-indicating HPLC method was developed and validated for the quantitative determination of diacerein in capsule dosage forms. An isocratic separation was achieved using a perfectsil target ODS-3, 250×4.6 mm i.d., 5 µm particle size columns with a flow rate of 1 ml/min and using a UV detector to monitor the eluate at 254 nm. The mobile phase consisted of phosphate buffer:acetonitrile (40:60, v/v) with pH 4.0 adjusted with phosphoric acid. The drug was subjected to oxidation, hydrolysis, photolysis and thermal degradation. Diacerein was found to degrade in acidic, basic, and oxidative stress and also under neutral condition. Complete separation of degraded products was achieved from the parent compound. All degradation products in an overall analytical run time of approximately 10 min with the parent compound diacerein eluting at approximately 4.9 min. The method was linear over the concentration range of 1-10 µg/ml (r2 = 0.9996) with a limit of detection and quantitation of 0.01 and 0.05 µg/ml respectively. The method has the requisite accuracy, selectivity, sensitivity, precision and robustness to assay diacerein in capsules. Degradation products resulting from the stress studies did not interfere with the detection of diacerein and the assay is thus stability-indicating.

The substrate kinetic parameters of hexokinase (HK) and phosphofructokinase (PFK)—the key irreversible enzymes of glycolysis—in erythrocytes from type 2 diabetic subjects were examined in comparison with control subjects. It was observed that the kinetic parameters such as Km, Vmax, Apparent Kcat, Kcat/Km, and substrate (ATP) inhibition kinetic and substrate binding characteristics are significantly altered in the diabetic group. The observed changes are suggestive of compositional changes in the subunit makeup of HK and PFK. The implication of these findings in relation to energy status of the diabetic erythrocyte and its interrelationship with loss of cell deformability are discussed here.

HPTLC stability indicating method has been developed for determination of anti-psoriasis drug, flurandrenolide in API and its formulation. The method was constructed on high performance thin layer chromatography separation of the drug followed by densitometric measurements of their spots at 238 nm. The separation was carried out on Merck TLC aluminium sheets of silica gel 60F254 using toluene: acetone in the ratio of 6: 4 v/v as a mobile phase. The method was validated in accordance with the requirements of ICH guidelines. Calibration curves were linear in range of 200-1200 ng/µl for flurandrenolide and correlation coefficient of calibration curve was found to be 0.9997 respectively. Limit of detection and limit of quantification were found to be 29.7ng/µl and 90.0ng/µl. Method had an accuracy of 100.09% for flurandrenolide in lotion. The developed simple, accurate, precise, specific and reproducible HPTLC method is successively applied to determine flurandrenolide in its lotion formulation.