Doxazosin mesylate is a selective α1-adrenergic receptor antagonist with low oral bioavailability due to poor aqueous solubility and extensive first-pass hepatic metabolism. This study aimed to design and optimize a doxazosin mucoadhesive buccal film to overcome hepatic metabolism and enable rapid drug onset. The buccal films were prepared by solvent casting, using a Plackett–Burman design to screen formulation variables affecting ex vivo mucoadhesive force, followed by a 2 2 full factorial design to optimize in vitro drug release by varying the concentrations of HPMC, the main film-forming polymer, and glycerin, a plasticizer. The prepared films were characterized for physico-mechanical properties, surface pH, mucoadhesive force, swelling properties, and drug release. In addition, the optimized formula was further characterized by scanning electron microscopy and ex vivo permeation study. The screening study showed that mucoadhesive strength ranged from 28 to 41 g, with the polymer type, polymer concentration, plasticizer type, and plasticizer concentration identified as the most influential variables. The optimized formula (FF3), containing 66 w/w% HPMC K15M and 21 w/w% glycerin, achieved 100% drug release within 15 min with acceptable film properties, in addition, SEM analysis showed a relatively uniform and compact surface with slight undulations, furthermore the ex vivo permeation reached 91% within 15 min, corresponding to a cumulative permeated amount of 1820 µg, a cumulative amount per unit area of 2275 µg/cm 2 , and an estimated steady-state flux of 12750 µg/cm 2 /h. It was concluded that the developed buccal film is a promising system for improving doxazosin bioavailability and providing rapid therapeutic onset.
Maraie et al. (Mon,) studied this question.