Development and Evaluation of a Solid Self-Microemulsifying Drug Delivery System Containing Cilostazol Using the Spray Drying Technique

ABSTRACT: A robust self-emulsifying formulation containing cilostazol was produced by mixing hydrophilic surfactants with oil. Considering cilostazol's limited solubility and bioavailability, it was crucial to employ suitable formulation ingredients and methods to enhance the solubility and rate of dissolution of drug. The self-emulsifying system was developed using Tween 80, Polyethylene glycol 400, and Oleic acid, as determined by preliminary study. The microemulsion zone was identified by constructing pseudoternary phase diagrams. The spray drying process employed a liquid system comprising of an adsorbent (Aerosil 200) in a 1:1 ratio. The system was evaluated for in-vitro dissolution, % drug content, and emulsification time. Characterization of prepared system was done by Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), Scanning electron microscopy (SEM), Particle size, Zeta potential, and X-ray diffraction (XRD). The improved formulation had a particle size of 243.8 nm, with 96.52% of the drug being entrapped. Moreover, after one hour, it demonstrated a drug release of 98.01%, exceeding that of the pure drug, potentially attributable to the enhanced surfactant content that reduces both dispersion time and particle size. The drug was successfully converted from crystalline state to an amorphous form and was confirmed by XRD. The spray-dried particles exhibited a smoother surface and confirmed by SEM. The DSC thermogram indicated the absence of a melting endotherm in the system, suggesting that the drug was in an amorphous state and evenly dispersed.