Development and in vitro appraisal of Soluplus® and/or Carbopol® 971 buccoadhesive patches releasing atorvastatin

Abstract

ABSTRACT Atorvastatin (ATR) is frequently prescribed to lower plasma cholesterol levels. However, features such as marginal aqueous solubility, high protein binding (>95%), and low bioavailability (12–14%) have opposed its oral use. Therefore, unidirectional controlled-release mucoadhesive patches of ATR, using Carbopol® (CP) as a mucoadhesive polymer, Soluplus® (SL) as a novel water-solubilizer carrier, and ethylene/vinyl acetate as a backing layer, were proposed as a potential strategy for buccal delivery. Various ratios of CP to SL were employed to prepare eight patches. Physicochemical properties, viscosity, mucoadhesion, and drug permeation were investigated. Patch A1 (3:1, CP:SL) emerged as the most promising system, with appropriate flexibility and uniform thickness, weight, and drug content. Additionally, the appropriate surface pH, positive mucoadhesion properties, and swelling level were observed. Flow curves of the polymer mixtures were fitted perfectly to the Carreau-Yasuda and Casson models. The amount of drug diffused, and flux were 51.57% and 0.82 mg/cm2/h, respectively, with a four-fold increase in permeability across the cellulose membrane (P = 1.80 cm/h) when compared with the reference patch composed of 0% SL. It can be postulated that micellar structures of SL were able to solubilize the poorly soluble ATR and control its release across the uncoiled buccoadhesive CP network.