Formulation of gastroretentive microballoons of metoprolol succinate using acetylated cocoyam (Xanthosoma sagittifolium) starch as a sustained release polymer

Abstract

Gastroretentive microballoons of metoprolol succinate (an adrenergic beta receptor blocker) were formulated using acetylated starch from cocoyam (Xanthosoma sagittifolium) in order to release the drug at a controlled rate and increase bioavailability. Acetylated cocoyam starch (DS 1.106 ± 0.054) was characterized and used in various combinations with Eudragit S100 to produce microballoons of metoprolol succinate at varying polymer:drug ratios. The microballoons were characterized for morphology, entrapment efficiency, in vitro buoyancy and dissolution time (t₅₀). Metoprolol microballoons containing acetylated starch had higher entrapment efficiency and in vitro buoyancy ( >12 h) than those containing Eudragit S100 alone. The dissolution time (t₅₀) increased with polymer: drug ratio with formulation of starch: Eudragit S100 1:3 showing sustained drug release (t₅₀ = 185.50 min) at polymer:drug ratio 6:1 which was comparable to dissolution time of Eudragit S alone at a similar polymer: drug ratio. Acetylated cocoyam starch showed potential as a cheaper, alternative polymer in gastroretentive drug delivery systems for high entrapment, prolonged buoyancy and sustained drug release.