Design, formulation and evaluation of Azithromycin binary solid dispersions using Kolliphor series for the solubility and in vitro dissolution rate enhancement

Abstract

The main purpose of this investigation is increasing of the solubility and dissolution rate of Azithromycin by solid dispersion technique using Kolliphor P 237, Kolliphor P 338 and Kolliphor P 407. Kolliphor (P 237, P 338 and P 407) in various properties by weight {(1:0.5), (1:1), (1:1.5) and (1:2)}, utilizing solvent evaporation method. Dissolution studies carried out in phosphate buffer with pH 6.0 according to US pharmacopoeia method. The drug release profiles were studied, so we found that the dissolution rate of the drug (by calculating the dissolution parameters) was significantly increase compared to pure drug, also solubility of physical mixtures as well as solid dispersions increased compared to the intact drug. For example solubility of the drug increased from 85–753 μg mL−1 (for Kolliphor P 237; 8 times more). The best results were as follows: Kolliphor P 237 > Kolliphor P 338 > Kolliphor P 407. IR spectra revealed no chemical incompatibility between drug and polymer. Drug-polymer interactions were investigated using differential scanning calorimetry, powder X-ray diffraction and scanning election microscopy. The dissolution rate and solubility of Azithromycin solid dispersions was improved significantly using Kolliphor. In addition, the simplicity of this method is very effective and have been met the project objectives.