A Single-Dose, Three-Period, Six-Sequence Crossover Study Comparing the Bioavailability Study of Dextromethorphan Hydrobromide Sustained Release (SR) Tablet and the Immediate Release (IR) Tablet in Healthy Volunteers Under Fasting Condition

Abstract

Objective was to compare pharmacokinetic characteristics of Sustained-Release (SR) and Immediate-Release (IR) formulations of dextromethorphan hydrobromide following a single oral administration of test and reference formulations in fasting healthy male volunteers. A randomized, 3-way, crossover, bioequivalence study was conducted in 6 healthy male volunteers to compare dextromethorphan hydrobromide Sustained Release (SR) tablet as test and the Immediate Release (IR) as reference product. Blood samples were collected and plasma samples were determined by using validated HPLC method involving a solid phase extraction method. Pharmacokinetic parameters were calculated by non-compartmental analysis. C max of the sustained-release formulation was significantly lower than that of the marketed immediate-release. The T max of sustained-release formulation was significantly long-lasting than that of immediate release. These results are in line with the profile of a sustained-release drug. This was also evident by the lower elimination rate and higher t½ values. However, the bioavailability of sustained-release tablets remained the identical as that of immediate release tablets.