Optimization of HPMC and carbopol concentrations in non-effervescent floating tablet through factorial design.

This study was to optimize HPMC K4M and carbopol 934 concentration in the development of non-effervescent floating tablets (NEFTs) of glipizide as model drug using 3(2) factorial design. The time required for releasing drug of 50% and 80% and similarity factor were the target responses. HPMC K4M and carbopol 934 concentrations were the variables. The response surface methodology and optimized polynomial equations were used to select the optimal formulation with desired responses. The excipients used in tablets were compatible with glipizide as per the results of isothermal stress testing and DSC study. The drug release of entire NEFTs followed zero order kinetics and non-Fickian diffusion mechanism. Validation of the optimization technique demonstrated the reliability of the model. The optimized formulation containing 124.33 mg HPMC K4M and 25.76 mg carbopol 934 was prepared according to the software determined levels. The stability study of the optimized formulation proved the integrity of the developed formulation.

Development and validation of RP-HPLC method for quantification of glipizide in biological macromolecules.

Glipizide (GPZ) has been widely used in the treatment of type-2 diabetics as insulin secretogague. Multiunit chitosan based GPZ floating microspheres was prepared by ionotropic gelation method for gastroretentive delivery using sodiumtripolyphosphate as cross-linking agent. Pharmacokinetic study of microspheres was done in rabbit and plasma samples were analyzed by a newly developed and validated high-performance liquid chromatographic method. Method was developed on Hypersil ODS-18 column using a mobile phase of 10mM phosphate buffer (pH, 3.5) and methanol (25:75, v/v). Elute was monitored at 230 nm with a flow rate of 1 mL/min. Calibration curve was linear over the concentration range of 25.38-2046.45 ng/mL. Retention times of GPZ and internal standard (gliclazide) were 7.32 and 9.02 min respectively. Maximum plasma drug concentration, area under the plasma drug concentration-time curve and elimination half life for GPZ floating microspheres were 2.88±0.29 µg mL(-1), 38.46±2.26 µg h mL(-1) and 13.55±1.36 h respectively. When the fraction of drug dissolved from microspheres in pH 7.4 was plotted against the fraction of drug absorbed, a linear correlation (R(2)=0.991) was obtained in in vitro and in vivo correlation study.

Taste masking of Etoricoxib by using ion-exchange resin.

The present study was carried out in order to mask the bitter taste of the Etoricoxib by complexation with cation-exchange resin, Indion 204. The drug resin complexes (DRC) were prepared by batch process and efficient drug loading was obtained by using inactivated form of resin in the drug-resin ratio 1:3.3 with 30 min swelling time of resin in 25 mL of water with 5 min stirring time. Drug-resin complexes were characterized for dissolution studies and spectral studies. Drug release from drug-resin complex in salivary pH was insufficient to impart bitter taste. Volunteers rated the drug resin complex as tasteless and agreeable.