Abstract

FORMULATION AND EVALUATION OF STABLE NANOSUSPENSION OF SELECTIVE POOR LY SOLUBLE DRUG RITONAVIR

Adilakshmi Challa*, P. Sreevidya, S. Manoharbabu, V. Mohan Varma and Shaik Aakhil

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Abstract

Ritonavir is a commonly used antiretroviral agent, which is used in the treatment of HIV. The solubility of this compound in biological fluids limits its bioavailability to less than 5%. In light of its physicochemical and biopharmaceutical properties, Ritonavir was selected as a drug candidate for evaluating Nanosuspension-based formulations to enhance solubility and bioavailability. Materials and methods: An analytical method was developed and the particle size distribution was reported. Initial preformulation studies were done. Nanomill (Netzsch) media milling was used for the size reduction of drug particles. The physicochemical properties of the nanosuspension were evaluated using standard procedures. Results: The study was found to exhibit the highest solubility in 1.2pH HCl (for Ritonavir). In the preformulation studies data, it was inferred that Ritonavir has passable flow properties. From the stability studies by DSC analysis, it was reasonable to believe that there was no interaction between drug and excipients used in the Nanonisation process used in Ritonavir Nanosuspension preparation. The results of drug excipients compatibility studies suggest that there was no significant change in the physical appearance of premixture blends when stored at 400C/75% RH for a period of 4 weeks when compared to the initial sample. The average particle size of the Ritonavir optimized Nanosuspension thus produced was found to be about 400nm with PDI of 0.268 indicating good physical stability of Nanosuspension. The zeta potential of -25.4mV for optimized Ritonavir Nanosuspension indicates the good physical stability of Nanosuspension produced. The Dissolution of Ritonavir Nanosuspension found to be 87% in selected dissolution media when compared to the dissolution of 41.6 and 56% corresponding to Ritonavir plain drug and Ritonavir suspension. Conclusion: According to the present research, preparation of Nanosuspensions using the Media Milling method (top-down approach) significantly enhanced the solubility and dissolution rate of Ritonavir, a poorly soluble drug.

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