Development and in vivo evaluation of functionalized ritonavir proliposomes for lymphatic targeting.

AIMS: The aim of the present work was to prepare, characterize, and evaluate proliposomes containing lipophilic prodrug ritonavir for targeting towards CD4+ T cells in the lymphatic system.

MATERIALS AND METHODS: The liposomes were prepared by lipid thin film hydration method and lyophilized in the presence of cryoprotectant mannitol to obtain proliposomes. The optimized proliposomes by Central Composite Design, were surface modified with biotin. The proliposomes were evaluated for particle size, zeta potential, polydispersity index (PDI), entrapment efficiency, in vitro drug release, in vivo pharmacokinetics and biodistribution studies.

KEY FINDINGS: The mean particle size was found to be in the range of 126.6 to 306.2nm with PDI of 0.340-1.00. The entrapment efficiency was found to be in the range of 18.9 to 86.2%. The formulations showed a zeta potential in the range of -18.1 to -20.2mv. Biotinylated proliposomes (LIP-5B) were in the size of 149.8±6.8nm with entrapment efficiency 61.6%. The % CDR of pure drug, conventional, biotinylated proliposome in 3h was found to be 58.3, 82.04, and 95.9% respectively. In vitro drug release and in vivo pharmacokinetics of the pure drug, optimized conventional proliposomes (LIP-5) and biotin proliposomes (LIP-5B) were executed.

SIGNIFICANCE: The AUC for the liposomes were found to be much higher in the spleen and thymus compared to that in the plasma which indicated that the developed formulations enhance the bioavailability and target specificity compared to that of the pure drug thereby enhancing bioavailability at target site.