*2.1. Quantitative Determination of Efavirenz*

A reversed-phase high-performance liquid chromatographic (HPLC) method was developed and validated for the quantitation of EFV in solubility, loading capacity and in vitro release studies. The HPLC system consisted of a Waters® Alliance e2695 (Waters® Corporation, Milford, MA, USA) solvent delivery module, autosampler, an online degasser and a Waters® 2489 dual wavelength UV-vis detector (Waters® Corporation, Milford, MA, USA). The HPLC chromatographic separation was achieved using a Phenomenex Luna® C18 (2) 100 A 150 mm <sup>×</sup> 4.6 mm i.d. stationary phase (Separations, Johannesburg, Gauteng, South Africa) and a mobile phase flow rate of 0.8 mL/min at a wavelength of 247 nm. The injection volume was 10 µL and mobile phase was 85:15 *v*/*v* acetonitrile and 0.015-M acetate buffer of pH 4.5. The method was linear over the concentration range 1–350 µg/mL with a R<sup>2</sup> = 0.9958, precise with the % RSD < 0.79% for all samples tested. The LOQ was 0.15 µg/mL and LOD was 0.06 µg/mL.
