Volume :
1
Issue :
4
Abstract :
Type-2 diabetes is a metabolic disorder, resulting in hyperglycemia because the pancreatic β-cell does not produce enough insulin. Nateglinide is a meglitinide short-acting non-sulfonylurea, pancreatic, beta-cell-selective that improves overall glycemic control in type-2 diabetes, but nateglinide has short biological half-life of 1.5-2.5 h and therefore a controlled release medication is required to get prolonged effect with reduced fluctuations in drug plasma concentration levels. Microencapsulation and mucoadhesion techniques were found acceptable to achieve controlled release and drug targeting for many years. Mucoadhesion facilitates the intimate contact of the dosage form with the underlying absorption surface for improved bioavailability of drugs to prolong intestinal residence time. Nateglinide microcapsules were prepared by following orifice-ionic gelation technique (OIGT) and emulsion ionic gelation techniques (EIGT) employing SA (sodium alginate) as the coat material in combination with some mucoadhesive polymers such as (hydroxypropyl methylcellulose) HPMC, (sodium carboxy methylcellulose) Sod. CMC, carbopol and (methyl cellulose) MC (drug:SA:polymer at ratios 2:2:1, 2:3:1 and 2:4:1). Infrared spectroscopy, differential scanning calorimetry and X-ray diffraction studies proved the compositions were compatible without interaction between the drug and excepients. The prepared microcapsules were evaluated for various physical and release parameters. The resulted microcapsules were found to be discrete and spherical in scanning electron microscopy studies and free flowing in rheological studies. Particle size of microcapsules was found larger with OIGT around 756.54 ± 19.276 µm to 802.74 ± 29.325 µm and smaller with EIGT around 490.16 ± 12.124 µm to 531.61 ± 6.109 µm. The microencapsulation efficiency and swelling index was found to be higher in HPMC containing formulations with OIGT and in carbopol containing formulations with EIGT but, swelling index was found more in HPMC containing formulations. With both techniques microcapsules containing carbopol exhibited good mucoadhesive property in the in vitro wash-off test. In vitro drug release studies were carried out up to 24 h and they followed zero-order release kinetics with Case II and Super case II mechanisms. The drug release from the microcapsules was sustained over a prolonged period with greater retardation in drug:SA:HPMC (2:4:1) containing microcapsules prepared by OIGT technique, and this proved to be the best formulation.