Development, characterization of Glipizide spherical agglomerates by direct compression method

Abstract

The objective of the research is to prepare glipizide spherical agglomerates with increased solubility, flow and com- pression properties by novel crystallization technique. Glipizide was dissolved in 30ml dichloromethane (good solvent) and stirred. 100ml of water (poor solvent) was added and continued stirring. 5ml of chloroform (bridging liquid) was added and stirred at 1000rpm for 40minutes to precipitate glipizide. The agglomeration method was optimized for parameters like speed and agitation time and amount of bridging liquid added. The precipitated particles were filtered and dried at 40°C. Spherical agglomerates were characterized by IR spectroscopy, X-ray diffraction studies, DSC and SEM and its results showed that no physical or chemical interaction existed in the prepared agglomerates. Spherical agglomerates exhibited decreased crystallinity and improved micromeritic properties (bulk density, tapped density, compressibility index, angle of repose). The prepared agglomerates of glipizide were spherical in shape and dissolution profile was faster and exhibited improved solubility along with proper micromeritic properties than pure drug. The agglomerates can be made directly into tablets because of their excellent flowability. Directly compressed tablets of the glipizide agglomerates exhibited hardness, friability and weight variation appropriately along with improved drug release characteristics. Among the different control release polymers Caesalpinia spinosa (natural mucoadhesive polymer) showed increased drug release retarding capacity. F2 showed the satisfactory results and have better sustainability. A zero order release rate kinetics is exhibited for the best formulation i.e. because it shows correlation coefficient value of zero order is more when compared to first order. F2 formulation diffusion exponent (n) value is 0.45< n >0.89 so they follow Anomalous (Non- Fickian) diffusion. Pharmacokinetic evaluation parameters are used for determination of bioavailability, like maximum Cmax, Tmax, AUC, Volume of distribution, half-life (t1/2), clearance(ClT) and mean residence time (MRT). Cmax of Glipizide market and test formulations were 1.285 ± 0.1 µg/mL and 01.48 ± 0.02 µg/mL respectively having significantly no difference (P<0.05). Tmax values of Glipizide market and test were 4.65 ± 0.25 Hours, 10.05 ± 0.80 Hours respectively with significant variance (P<0.05) and a P value 0.0005. ETOVA and test t½ values were 3.77 ± 0.645 hrs, 4.56 ± 1.71hrs respectively, with significant variance (P<0.05) and a P value is 0.0002. AUC0-∞ values were 118.3± 20.04 µg-hr/mL, 536.5 ± 49.44 µg- hr/mL respectively. Elimination rate constant of reference and test were0.83 ± 0.44 hr-1, 6.36 ± 1.586 hr-1 respectively with significantly variant and P value is 0.0001.