Solubility Enhancement of Raltegravir by Solid Dispersion Technique

The aim of the study is to formulate Raltegravir tablets, enhancing its solubility by solid dispersion technique. Raltegravir is an anti retroviral drug belongs to BCS Class II. Phase solubility studies of Raltegravir are conducted in presence of Beta cyclodextrin according to the method described by Higuchi and Connors. The value of stability constants indicated that the complex formed between Raltegravir-β-CD are stable in all cases. In distilled water, the solubility of a solid dispersion was determined and compared to the solubility of a pure drug. The solubility of Raltegravir has increased with increasing the concentration of cyclodextrin and maximum amount of solubility was observed at a ratio of 1:3. Among all the methods, solubility of Raltegravir was found to have increased value in physical trituration method (80%) and maximum solubility was observed by solvent evaporation method (93%). Among all the methods, percentage drug release of Raltegravir was found to have increased value in physical trituration method (91%) and maximum drug release was observed in solvent evaporation method (96%).Disintegration time for all the formulation blend of Raltegravir was conducted, the results in ranged from 25 ± 0.04to 130 ±0.04 sec. F3&F6 formulation, formulated using the combination of excipients i.e., 5% cross carmellose exhibited disintegration time of 25±0.03&40 ± 0.03 sec .out of which F3 formulation disintegrated the drug in less period of time .Thus F3 formulation was found to be an Optimized formulation. Pre-compression parameters were studied and the results were within limits. The result indicates all the granules were observed to have good flow and good compressibility properties. Post compression result indicates that all the tablets in the batch were observed to have uniform weight variation and mechanical strength, the drug release data of the F3 formulation fits well into the Zero - order kinetics, which states that the system is concentration independent. Even after three months, the optimised formulation (F3) was determined to be stable with no change in physical properties.