Formulation and Evaluation of Mucoadhesive Microspheres of Pioglitazone Hydrochloride Prepared by Ionotropic External Gelation Technique

Microspheres containing Pioglitazone hydrochloride were prepared by the ionotropic external gelation method, using sodium alginate with four mucoadhesive polymers namely sodium carboxy methyl cellulose, hydroxy propyl methyl cellulose, carbopol 934 P and cellulose acetate phthalate as coat materials. Ionotropic gelation is a method to prepare microspheres using combination of Ca²⁺ as cationic components and alginate as anion. The practical yield of prepared microspheres using the ionotropic gelation technique was between 172 mg and 604 mg. The result of the Chi-squared test carried out between the actual (practical) and expected (theoretical) yields showed no significant difference (P < 0.05) which indicated that the ionotropic gelation technique could be successfully employed to prepare pioglitazone microspheres using sodium alginate, sodium carboxy methyl cellulose, carbopol 934 P, HPMC, cellulose acetate butyrate polymers. The drug entrapment efficiency of prepared microspheres showed between 56.12% ± 3.86% to 84.68% ± 2.93% which was significantly higher for ionotropic gelation technique. The highest drug entrapment was found in formulation PMI 8. Swelling index is the capability of a polymer to swell before the drug is released which influences the rate and mechanism of drug release from the polymer matrix. The swelling index of prepared microspheres was in the range of 68% ± 4.52% to 87% ± 0.98%. Pioglitazone HCl microspheres showed controlled release of drug without initial peak level achieving. This type of properties in Pioglitazone HCl microspheres used to decrease side effects, reduce dosing frequency and improve patient compliances. From the all batches PMI 8 is considered the best formulation, because among all other formulations, it shows better extent of drug release up to 82.12% (18 h), good entrapment efficiency (84.68%) and the ex-vivo wash-off test shows the best mucoadhesive property. The in vitro drug release studies do up to 18 h. As observed from the various plots, most of the formulations followed the Korsmeyer-Peppas model.