Biowaiver study of oral tabletted ethylcellulose microcapsules of a BCS class I drug

Abstract

This article describes the preparation and characterization (in vitro and in vivo) of three different sustained-release salbutamol sulfate-ethylcellulose tabletted microparticles (T1, T2 and T3) and reference sustained release tablet (Ventolin 8 mg SR, GSK). In vitro characterization included dissolution study, scanning electron microscopy, UV and FTIR spectroscopy, X-ray diffractometry and thermal analysis. A validated HPLCfluorescent
detection method was adopted to conduct bioavailability studies in young healthy human volunteers. The microparticles exhibited an irregular and slightly aggregated morphology with fine rheological properties. No
strong chemical interaction was found between drug and polymer. A good linear correlation (R2 = 0.9224, 0.945, 0.9363 and 0.9694 for T1, T2, T3 and reference formulations, respectively) was obtained between the percent cumulative drug released (in vitro) and the percent cumulative drug absorbed (in vivo) data of these formulations at specific time points to develop level A in vitro-in vivo correlation. However, T2 was found closer to the reference formulation that shows a reliable prediction of the plasma concentrations obtained following a single dose of salbutamol sulfate modified release formulations.