To evaluate the effect of addition of an anionic surfactant on solid dispersion using model drug indomethacin.

Formation of solid dispersion also known as high energy solids is one of the most successful concepts to improve dissolution profile of poorly water-soluble drugs. Use of surfactants in formulation is one of the methods to increase solubility profile. In this research, we have used model drug, a weak acid (indomethacin) together with polymer (PVP) and anionic surfactant (sodium lauryl sulfate (SLS)) in different concentrations to study the effect of incorporation of SLS in solid dispersion. Three ratios and control were prepared. Physical characterization was performed using modulated differential scanning calorimetry (MDSC), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Critical micelle concentration (CMC) measurements were conducted to see the effect of SLS on dissolution media. Dissolution studies were performed in hydrochloric acid buffer (pH 1.2 buffer), purified water and phosphate buffer (pH 7.4), respectively. Interestingly, depending upon addition of SLS into the system, release profiles were changed. SLS incorporated internally in a solid dispersion gave the highest release.