Design of a novel crosslinked HEC-PAA porous hydrogel composite for dissolution rate and solubility enhancement of efavirenz

The purpose of this research was to synthesize, characterize and evaluate a Crosslinked Hydrogel Composite (CHC) as a new carrier for improving the solubility of the anti-HIV drug, efavirenz. The CHC was prepared by physical blending of hydroxyethylcellulose (HEC) with poly(acrylic acid) (PAA) (1:1) in the presence of poly(vinyl alcohol) (PVA) (as a crosslinker) (1:5) under lyophilization. Efavirenz was loaded in situ into the CHC in varying proportions (200–600 mg). The CHC demonstrated impressive rheological properties (dynamic viscosity = 6053 mPa; 500 s−1) and tensile strength (2.5 mPa) compared with the native polymers (HEC and PAA). The physicochemical and thermal behavior also confirmed that the CHC was compatible with efavirenz. The incorporation of efavirenz in the CHC increased the surface area (4.4489–8.4948 m2/g) and pore volume (469.547–776.916 Å) of the hydrogel system which was confirmed by SEM imagery and BET surface area measurements. The solubility of efavirenz was significantly enhanced (150 times) in a sustained release manner over 24 h as affirmed by the in vitro drug release studies. The hydration medium provided by the CHC network played a pivotal role in improving the efavirenz solubility via increasing hydrogen bonding as proved by the zeta potential measurements (−18.0 to +0.10). The CHC may be a promising alternative as an oral formulation for the delivery of efavirenz with enhanced solubility.

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