Solubility Enhancement of a BCS Class II Drug Using Granulated Fumed Silica as an Adsorbent

Aim: The aim of this study was to improve solubility and dissolution characteristics of Ibuprofen using granulated fumed silica (Aeroperl®300) as a carrier.

Methods: Ibuprofen-silica complex was prepared by solvent evaporation technique using ethanol as the solvent. Formulation I and II consisted of polymers hydroxypropyl methylcellulose (HPMC E5) and Polyvinyl Pyrrolidone (PVP K-30) respectively. Each formulation was prepared using 1:1:1 and 1:1:2 ratio of drug, polymer and silica. Dried powder obtained was characterized using Differential Scanning Calorimetry (DSC), Powder X-Ray Diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR) and Polarized Light Microscopy (PLM). In-vitro dissolution studies were carried out using three different media including Phosphate buffer (pH 6.8), 0.1N Hydrochloric Acid (pH 1.2) and de-ionized water.

Results: Drug loading up to 30% w/w was successfully achieved with 1:1:1 ratio formulations. Physical characterization data confirmed change of crystalline Ibuprofen into amorphous form after processing. Maximum solubility increment of 33-37% was achieved in Phosphate buffer with formulations II A and II B within the first 5 minutes of dissolution as compared to the control (pure drug).

Conclusion: Enhancement in drug solubility and subsequent dissolution rate can be attributed to adsorption of amorphous drug molecules onto porous silica that readily desorb on contact with dissolution media. High porosity and huge surface area of silica makes it a potential candidate for improving delivery of poorly soluble drugs.