Polyethylene Oxide Based pH-independent Drug Delivery System: Formulation and Optimization by Central Composite Design

Present study deals with formulation and optimization of mucoadhesive alginate beads. Due to pH dependent solubility behavior observed for majority weakly basic drugs, stomach was selected as preffered site for delivery. Gastroretentive dosage form of model drug quetiapine fumarate was developed owing to its high solubility at low pH and polyethylene oxide as mucoadhesive polymer. Ionotropic gelation technique was utilized to prepare beads by applying a central composite design. Two independent factors sodium alginate (X1) and Polyox®303WSR (X2) were studied to derive beads possessing desirable and optimized characteristics. Physicochemical and performance based characterization was performed for developed formulation. Percentage yield of all the batches was above 85%. Despite of a constant fall in adhering percent with time, accetable adherance of beads was found upto 10 h. Derived optimized mucoadhesive beads were having spherical shape and average diameter of 773.7 µm. Percentage yield, % drug entrapment and adhering percentage at 10 h of optimized batch were found to be 91.7%, 85%, and 41%, respectively. Drug release kinetics of optimized batch met the set criteria and followed Hixon-Crowell model. The Fourier transform infrared spectroscopy illustrated stable nature of drug in the beads and proved the absence of any drug-excipient interactions. Beads were found stable throughout the accelerated stability testing period of three months. Gastroretentive beads can be a platform for drug delivery of weakly basic drugs having pH dependent solubility.