Optimization of the in vitro oxidative biotransformation of glimepiride as a model substrate for cytochrome p450 using factorial design
Journal Title: DARU Journal of Pharmaceutical Sciences - Year 2012, Vol 20, Issue 0
Abstract
Background and purpose of the study Glimepiride (GLM) was chosen as a model substrate in order to determine the kinetic parameters for in vitro metabolism via human liver micrososmes (HLM). We aimed to optimize the turnover of the substrate by the test system in relation to incubation time and HLM concentration in such a way that it was linearly dependent on time and less than 20% of the substrate was consumed which utilized the lowest amount of the HLM. Further we aimed to report Km and Vmax values for GLM. Methods Linearity of enzyme reactions in microsomal incubations was assessed by monitoring the effect of incubation time (from 5 to 60 min) and HLM concentration (from 0.2 to 0.75 mg/ml) on metabolite formation of GLM. The ideal conditions for turnover of GLM were justified using 3x3 factorial design. F value was calculated to confirm the omission of insignificant terms from the full-model to derive a reduced- model polynomial equation. The regression equation was used to develop a contour plot that showed turnover rate within the limits of this design. The optimized reaction velocity data was extrapolated to carry out the kinetic studies in vitro to generate a saturation curve for the determination of Km and Vmax values. Results The reaction was found to be linear with respect to both incubation time between 24 and 50 min and HLM concentration between 0.3 to 0.65 mg/ml. The Km and Vmax values obtained by nonlinear least squares regression method was found to be 28.9 ± 2.97 μMole and 0.559 ± 0.017 μMole respectively. Lineweaver-Burk plot was also used to estimate Km and Vmax which yield value of 29.411 ± 1.25 μMole and 0.571 ± 0.020 μMole/min/mg protein respectively.
Authors and Affiliations
Dipti B Ruikar, Sadhana J Rajput
Keywords
Related Articles
- EP ID EP130171
- DOI -
- Views 119
- Downloads 0
Financial perspective of private pharmacies in Tehran (Iran); is it a lucrative business?
Background and purpose of the study Pharmacies as direct providers of medicine and pharmaceutical services to patients have an important role in the health status of a society. The assessment of their financial situation...
Positive effect of septimeb™ on mortality rate in severe sepsis: a novel non antibiotic strategy
Background Septimeb is a new herbal-derived remedy, recently approved for its potential immunomodulatory effects. Regarding the key role of immune system in the pathogenesis of severe sepsis and lack of any standard tre...
The effect of 12 weeks Anethum graveolens (dill) on metabolic markers in patients with metabolic syndrome; a randomized double blind controlled trial
The clustering of metabolic abnormalities defined as metabolic syndrome is now both a public health and a clinical problem .While interest in herbal medicine has greatly increased, lack of human evidence to support effic...
Single course of high dose dexamethasone is more effective than conventional prednisolone therapy in the treatment of primary newly diagnosed immune thrombocytopenia
IntroductionImmune thrombocytopenia (ITP) is an immune disorder commonly presents as isolated thrombocytopenia. Generally corticosteroids are the main treatment of ITP. This study was designed to evaluate effectiveness o...
Biochemical tolerance during low dose propylene glycol exposure in neonates: A formulation-controlled evaluation
Background and purpose of the study Propylene glycol (PG) is a frequently co-administered solvent in formulations administered to neonates, but reports on its (in)tolerance are limited. We aimed to report on renal, meta...