Preparation of multiple-unit floating-bioadhesive cooperative minitablets for improving the oral bioavailability of famotidine in rats.

Abstract The aims of this study were to prepare fine famotidine-containing floating-bioadhesive cooperative minitablets and to investigate the possibility of using those minitablets as a delivery system for promoting the oral bioavailability of famotidine. Nine minitablet formulations were designed using hydroxypropylmethylcellulose (HPMC K4M) as release-retarding polymers, Carbopol 971P as bioadhesive materials and sodium bicarbonate (NaHCO3) as gas formers. The prepared 3 ± 0.02 mm minitablets were evaluated in terms of their swelling ability, floating behavior, bioadhesion test and in vitro release. The optimized minitablets (F6) containing HPMC K4M (50.00%, w/w), Carbopol 971P (10.00%, w/w) and NaHCO3 (10.00%, w/w) were found to float in 1 min and remain lastingly buoyant over a period of 8 h in vitro, with excellent bioadhesive properties (20.81 g) and sustained drug release characteristics (T50% = 46.54%) followed one-order model. In addition, plasma concentration-time profiles from pharmacokinetic studies in rats dosed with minitablets showed 1.62-fold (p < 0.05) increased absorption of famotidine, compared to the market tablets XinFaDing®. These studies demonstrated that the multiple-unit floating-bioadhesive cooperative minitablets may be a promising gastro-retentive delivery system for drugs that play a therapeutic role in the stomach.