Transmucosal Delivery of Duloxetine Hydrochloride for Prolonged Release: Preparation, in vitro, ex vivo Characteri-zation and in vitro-ex vivo Correlation

Abstract

Duloxetine hydrochloride is a selective serotonin and nor adrenaline reuptake inhibitor. It is used in the treatment of depression, diabetic peripheral neuropathic pain and in moderate to severe stress urinary incontinence in women. However, it undergoes extensive hepatic first-pass metabolism and susceptible to undergo degradation in acidic environment of stomach, which results in the poor bioavailability. The objective of the present study was to develop and evaluate the mucoadhesive buccal tablets (transmucosal delivery) of duloxetine hydrochloride with a goal of to increase the bioavailability and improve the patient compliance. Mucoadhesive buccal tablets were prepared by a wet granulation technique using mucoadhesive polymers like HPMC K4M, Carbopol 934P and PEO WSR 303. The tablets were evaluated for weight variation, thickness, hardness, friability, surface pH, swelling index, drug content uniformity, in vitro drug release, in vitro bioadhesion and ex vivo permeation studies. The physicochemical properties of all the formulations were shown to be within the limits. The optimized buccal tablets AA1, AB3 and AC1 showed prolonged drug release for a period of 6 h with the Higuchi model release profile. Further, ex vivo permeation studies for optimized tablets were conducted and shown enhanced drug permeation. Therefore, these results demonstrated that the optimized buccal formulation of duloxetine hydrochloride enhances the oral bioavailability by delivered through the buccal route.