Bioequivalence Study of Pantoprazole Sodium-HPBCD and Conventional Pantoprazole Sodium Enteric-Coated Tablet Formulations

The objective of this study was to investigate the bioequivalence of two formulations of 40？mg pantoprazole sodium enteric-coated tablets: Tripepsa as the test and Pantocid as the reference. The two products were administered as a single oral dose according to a randomized two-phase crossover with a 1-month washout period in 25 healthy Indian volunteers. After drug administration, serial blood samples were collected over a period of 30 hours. Plasma pantoprazole concentrations were measured by high-performance liquid chromatography with UV detection. Pharmacokinetic parameters were analyzed based on noncompartmental analysis. The logarithmically transformed data of and were analyzed for 90% confidence intervals (CI) using ANOVA. The mean (90% CI) values for the ratio of and values of the test product over those of the reference product were 90.21 (83.69–97.24) and 108.68 (100.21–117.86), respectively (within the bioequivalence range of 80–125%). On the basis of pharmacokinetic parameters including , , and values, both the formulations were bioequivalent. 1. Introduction Pantoprazole, a proton pump inhibitor (PPI), is indicated for the treatment of erosive esophagitis associated with gastroesophageal reflux disease (GERD). Pantoprazole is one of the highly prescribed PPI in the management of peptic ulcer diseases. It shows high specificity for the relevant binding sites on activated proton pumps with little propensity to cause unwanted systemic effects [1, 2]. Pantoprazole sodium, administered as a 40？mg enteric-coated tablet, is quantitatively absorbed. Its absolute bioavailability is 77% and does not change upon multiple dosing. Following a single oral dose of 40？mg, is approximately 2.5？mg/L with a of 2-3？h. Pantoprazole is extensively metabolized in the liver and has a total serum clearance of 0.1？l/h/kg, a serum elimination half-life of about 1.1？h, and an apparent volume of distribution of 0.15？L/kg. 98% of pantoprazole is bound to serum proteins. Elimination half-life, clearance, and volume of distribution are independent of the dose. Almost 80% of an oral or intravenous dose is excreted as metabolites in urine; the remainder is found in feces and originates from biliary secretion. The clearance of pantoprazole is only slightly affected by age, with its half-life being approximately 1.25？h in the elderly [3]. Pantoprazole is an acid labile drug that requires protection from degradation in acidic media [4]. Hence, oral formulations of pantoprazole are available as enteric-coated tablets. Cyclodextrins are nonreducing cyclic oligosaccharides,