Stress degradation of Lisinopril as per ICH Guidelines & Characterisation

Lisinopril an antihypertensive drug was subjected to stress degradation, since the drug is photosensitive undergo hydrolysis and oxidized in presence of oxygen. Hence the objective of the study was to stress degrade Lisinopril and to find out the pathway for stress degradation of Lisinopril. Stress testing methods are screening methods to be used to understand the degradation chemistry of a drug. Lisinopril was subjected to stress degradation under different conditions recommended by International Conference on Harmonization (ICH). The chromatographic separation of Lisinopril and its degradation products was done on C18 column and mobile phase was mixture of Methanol and Water in ratio 80:20, pH 3.5 adjusted with orthophosphoric acid at a flow rate of 1ml/min using UV detector with ?max 220nm. The quantification and characterizations of degraded products were carried out by UV, IR spectroscopy and HPLC. The mechanism of degradation was confirmed by GC-MS fragmentation pattern

Hydrogenation of butynediol to cis-butenediol catalyzed by pd-zn-caco3: reaction kinetics and modeling of a batch slurry reactor

An experimental study of the kinetics of hydrogenation of butynediol has been reported using Pd-Zn-Ca3 catalyst in a slurry reactor. The effects of catalyst loading, butynediol concentration, H2 partial pressure, butenediol (product concentration, temperature, and agitation speed on the rate of hydrogenation have been studied using a stirred pressure reactor). The initial rate data shwoed that the rate is proportional to the square root of H2 pressure, while increase in butynediol concentration inhibited the reaction. A Langmuir-Hinshelwood-type rate model has been proposed based on these data and the kinetic parameters evaluated. The values of the activation energy E and the heat of adsorption of butynediol (-ΔH) evaluated were 38.30 kJ/mol and -9.87 kJ/mol, respectively. Batch reactor models were derived based on the rate expression obtained from the initial rate data for variable pressure as well as constant pressure conditions. The prediction of the model were compared with experimental data obtained over a wide range of conditions. The predictions of the model were compared with experimental data obtained over a wide range of conditions. The results agreed well within 5-7% error. Use of the pressure vs. time data for evaluation of kinetic and mass transfer parameters is also demonstrated