Sample preparation and extraction techniques for evaluation of semisolid formulations

There are many pharmaceutical formulations available in semisolid form such as cream, ointment, paste, gel, and suppository. The qualitative and quantitative estimation of the semisolid formulation can be carried out using sophisticated instruments/techniques. Sample preparation is an important step to extract the main ingredient which needs to be analyzed in a medium suitable for a specific analytical technique/instrument. Sample preparation can directly affect the final result of analysis and thus sample preparation for the semisolid formulation is challenging. Extraction techniques used to carry out the extraction from semisolid formulation are Liquid–Liquid Extraction, Solid-Phase Extraction, Supercritical Fluid Extraction, Liquid-Phase Microextraction Techniques, Pressurized Fluid Extraction/Accelerated Solvent Extraction, Microwave Assisted Extraction, Pressurized Hot Water Extraction or superheated water extraction, Ultrasound-Assisted Extraction, Matrix solid-phase dispersion, QuEChERs, Solid-Phase Microextraction, Stir Bar Sorptive Extraction, Microextraction in Packed Syringe. A brief introduction along with the principle and application of all techniques is explained to demonstrate the application of specific extraction technique for specific semisolid sample preparation.