The objective of this study was to develop and evaluate a nanosuspension of Abacavir, a poorly water-soluble antiretroviral drug classified under BCS Class II, to enhance its solubility and oral bioavailability. Nanosuspensions were prepared using the quasi-emulsification solvent diffusion method, employing Eudragit RS100 and RL100 polymers in combination with Poloxamer 407 (Pluronic F127) as a stabilizer. A total of eight formulations were developed by varying polymer and stabilizer ratios. The prepared nanosuspensions were characterized for particle size, zeta potential, drug entrapment efficiency, saturation solubility, and in vitro drug release.

Among the tested formulations, ABC-F4 (Drug:Polymer:Stabilizer ratio of 1:2:1 using Eudragit RS100) exhibited optimal characteristics, including a particle size of 92.20 nm, zeta potential of –14.55 mV, and drug entrapment efficiency of 91.21%. In vitro dissolution studies revealed a sustained drug release of 99.87% over 10 hours, indicating effective control of drug release. Saturation solubility of the nanosized Abacavir increased nearly fivefold compared to the pure drug, confirming significant solubility enhancement. Compatibility studies using FTIR and DSC showed no interaction between the drug and excipients.

The study concludes that nanosuspension technology using Eudragit RS100 and Poloxamer 407 is a promising strategy to improve the solubility, stability, and oral bioavailability of Abacavir. Such a formulation could contribute to improved therapeutic outcomes in HIV treatment by enabling better absorption and sustained drug release.