Formulation and Evaluation of Carbamazepine 200 mg Controlled Release Tablets Using Different HPMC Grades.

Possible interaction between carbamazepine and different HPMC grades was done using DSC thermal analysis. The results indicated that the drug was compatible with these grades. Seven preparations of carbamazepine 200 mg controlled release tablets were prepared by wet granulation method and one preparation was prepared by direct compression method where different HPMC grades with different ratios were used. Concerning uniformity of weight, hardness and assay; all tablets conformed to pharmacopeal limits. Dissolution of the prepared tablets was done using basket method for 24 hours and paddle method for 4 hours. Tablets prepared by 30.0, 35.0 and 40.0% w/w HPMC K 100, 25.0% HPMC K 100 in combination with 5.0% HPMC K 4M and 15.0% w/w HPMC K 4M were conforming to USP limits, while tablets prepared by 15% K4M are not conforming to these limits. Tablets prepared by 12.5% HPMC K 15M by direct compression technique showed similar dissolution values to the innovator in five different media: distilled water, distilled water containing 1.0% SLS, buffer pH 1.2, acetate buffer pH 4.5 and phosphate buffer pH 6.8. The difference and similarity factors were found very acceptable. Scaling up of carbamazepine 200 mg controlled release tablets formulation from lab scale (500 tablets) to full production scale (500,000 tablets) was done. All the results of the scaling up were conforming to specifications and indicated that scaling up process has been done successfully and drug release kinetics indicated that the drug dissolution was zero order.

Development and Characterization of Controlled Release Ketoprofen Microspheres.

Microspheres ketoprofen (KP) were prepared by o/w emulsion solvent evaporation technique using Eudragit®RS100 as a polymeric material. The effect of process variables such as drug: polymer ratio, stirring rate, emulsifier concentration, internal organic solvent and dispersing medium volumes were examined. The prepared formulations were characterized for particle size distribution, percent yield, entrapment efficiency, in vitro release and in vivo studies behavior. The study revealed that the mean particle size ranged from 293.06 to 438.63 μm, the KP loading efficiency varied from 60.19-87.63% of the theoretical amount incorporated, all microspheres patches exhibited a prolonged release for almost 24 hrs and the release pattern was diffusion model. The pharmacokinetic parameters, Cmax, Tmax, AUC0-24 and AUC0-∞ were calculated from the plasma drug concentration-time data. Plasma KP concentrations and pharmacokinetics parameters were statistically analyzed. The test formulation exhibited controlled and prolonged absorption (Tmax) of 6.79 ± 0.0.39 vs. 2.03 ± 0.08 and 3.32 ± 0.24 hs; Cmax of 14.42 ± 0.50 vs. 18.78 ± 0.95 and 16.58 ± 1.02 μg/ml) when compared to the plain drug and marketed product, respectively. In-vivo studies revealed that the relative bioavailability of the KP increased by more than 1.3 times by formulating it into microspheres compared to plain drug.