Formulation and In vitro Characterization of Hydrochlorothiazide Gastroretentive Floating Drug Delivery System

Abstract

The purpose of the study was to develop and optimize floating bioadhesive gastroretentive drug
delivery system (GRDDS) exhibiting a unique combination of floatation and bioadhesion to prolong residence in the
stomach, using hydrochlorothiazide (HCTZ) as a model drug. Formulated matrix tablets were prepared by direct
compression method with two different rate controlling polymer HPMC K4M and Carbopol 971. The formulated
tablets were evaluated for physical characterization, floating lag time, swelling index and drug content uniformity.
The drug release study was carried out in 0.1N HCl as the medium (pH 1.2) for 8 hours using USP type II dissolution
apparatus and investigated the effects of polymers on the drug release profile. In vitro buoyancy study results found to
be 10–33 sec and >8 h, floating lag time and total floating time respectively. Simulated drug release pattern in
different kinetic models of Korsmeyer-Peppas release suggests that the mechanism controlling of the drug release
from all formulations was the anomalous non-Fickian or anomalous release. Polymer with lower viscosity (HMPC
K4M) was found to be beneficial than higher viscosity polymer (Carbopol 971) in improving the release properties of
gastric floating drug delivery system. Incorporation of Carbopol in formulation also helped in maintaining buoyancy
of system with desirable drug release. Further study is necessary in case of in vitro- in vivo relationship, but this study
will ready to lend a hand to future scientists working in this field to successfully exploit the potential of this drug
delivery system for the advantage of mankind.