Liposomes, Facilitating the Encapsulation and Improved Solubility of Zidovudine Antiretroviral Drug

The treatment of children with HIV has become increasingly difficult due to the disagreeable taste, large size of the drug, poor aqueous solubility, short half-life, and poor palatability. The work aims at developing a liposome delivery system (LDS) of zidovudine (AZT) using a natural sweetener inulin to further improve its solubility and oral bioavailability and potentially mask the unpleasant taste. Modified thin film hydration approach was adopted in the formulation while the orbital shaking method was used for 24 h in various pH media for an equilibrium solubility study of pure AZT, AZT-liposomes (AZT-L), and the physical mixture. Different analytical methods were used in measuring the AZT-L particle size (PS), zeta potential (ZP), and polydispersity index (PDI) as well as assessing the physicochemical properties of the formulation, while dissolution studies for pure AZT and AZT-L were carried out in different pH media (1.2, 4.5, and 6.8). The results depicted enhanced solubility of AZT in liposomes in all pH ranges and water. AZT-L revealed reduced PS sizes, lower PDI with significant surface charge, and homogenized and dispersed AZT formulation. The physicochemical characterization of AZT-L confirmed an amorphous preparation whereas the dissolution experiment revealed the release of the drug from the formulation while indicating potential delayed release in some pH media. Results suggest complete encapsulation and enhanced solubility and dissolution rate of AZT in liposome formulation with possible futuristic dose reduction in HIV paediatric formulations.