RESUMO
Omeprazole [OMP] a proton pump inhibitor is widely used to suppress gastric acid secretions of parietal cells of stomach and metabolized predominantly by CYP2C19. The objective of the present study was to investigate the pharmacokinetics and dosage regimen of OMP, after its single oral administration in eight healthy adult female subjects. Blood samples were collected at different time intervals after oral administration and their pH was measured. Plasma concentration of OMP was determined by high performance liquid chromatography [HPLC] system equipped with UVvisible Detector. The concentration versus time data was used to compute the pharmacokinetic parameters with the help of computer software programme MW/PHRAM APO version 3.02.Peak plasma concentration was [Cmax] 0.38 +/- 0.04 microg/ml achieved at 2.07 +/- 0.22 hrs. The elimination half-life [t1/2beta] was1.82 +/- 0.42 hrs. Volume of distribution [Vd] in the present study was 0.40 +/- 0.07 l/kg with total body clearance [ClB] 0.19 +/- 0.02 l/hr/kg and area under the curve [AUC] 1.89 +/- 0.23 microg.hr/ml. The pharmacokinetic properties which are different from the literature after oral administration of 20 mg OMP in eight healthy female volunteers may be due to the variations of environment and genetic variation between Pakistan and drug manufacturing of foreign countries
RESUMO
Omeprazole is a widely prescribed proton pump inhibitor to treat various gastric acid hyper secretion disorders. The present study was designed to evaluate the renal clearance and urinary excretion of omeprazole in eight healthy female volunteers to increase the understanding of the contributing factors such as demographics variability in the renal clearance and urinary excretion of omeprazole under indigenous conditions. The urine and blood samples were collected 0.5, 1, 1.5, 2, 3, 4, 6, 8 hours after oral administration of enteric coated omeprazole [20 mg] and drug concentration in the samples was determined by High Performance Liquid Chromatography [HPLC] with C18 column and UV detector. Urinary excretion and renal clearance of omeprazole was calculated and data was statistically analyzed by using regression/correlation technique. Endogenous creatinine was also measured by reagent kit available in the market. The results indicate that mean diuresis was 0.0172+/-0.0029 ml/min/kg. While the mean values of renal clearance of creatinine and omeprazole were 1.315+/-0.103 and 0.066+/-0.0042 ml/min. kg, respectively. Whereas, clearance ratio was 0.055+/-0.007 which indicates back diffusion. The cumulative percentage of dose excreted was 6.71+/-0.358. A significant [p<0.05] negative correlation [r= -0.457] between clearance ratio and urine pH of omeprazole reflecting glomerular filtration reabsorption of drug at kidney tubular level while significant [p<0.05] negative correlation [r= - 0.681] between clearance ratio and plasma concentration of omeprazole indicates the involvement of active tubular secretion of drug. It can be concluded that during glomerular filtration, omeprazole diffuse back/reabsorption. Therefore, Urinary excretion of omeprazole in indigenous healthy female subjects was observed to be lower than given in the literature values