Role of Fine Silica as Amorphous Solid Dispersion Carriers for Enhancing Drug Load and Preventing Recrystallization- A Comprehensive Review.

Amorphous solid dispersion (ASD) is a popular concept for improving the dissolution and oral bioavailability of poorly water-soluble drugs. ASD faces two primary challenges of low drug loading and recrystallization upon storage. Several polymeric carriers are used to fabricate a stable ASD formulation with a high drug load. The role of silica in this context has been proven significant. Different types of silica, porous and nonporous, have been used to develop ASD. Amorphous drugs get entrapped into silica pores or adsorbed on their surface. Due to high porosity and wide surface area, silica provides better drug dissolution and high drug loading. Recrystallization of amorphous drugs is inhibited by limited molecular ability inside the delicate pores due to hydrogen bonding with the surface silanol groups. A handful of researches have been published on silica-based ASD, where versatile types of silica have been used. However, the effect of different kinds of silica on product stability and drug loading has been rarely addressed. The present study analyzes multiple porous and nonporous silica types and their distinct role in developing a stable ASD. Emphasis has been given to various types of silica which are commonly used in the pharmaceutical industry.

Self-emulsifying Drug Delivery System for Oral Anticancer Therapy: Constraints and Recent Development.

Oral anticancer therapy faces several drawbacks: low aqueous solubility, poor and irregular absorption from gastrointestinal sites, high first-pass metabolism, food-influenced absorption, non-targeted delivery, severe systemic and local adverse effects, etc. Enhancement of oral bioavailability could reduce the drug load and associated adverse effects. Self-emulsifying drug delivery systems (SEDDS) can enhance in-vivo solubility and drug absorption from the gastrointestinal tract, bypass liver metabolism by lymphatic absorption and inhibit efflux transport. All these phenomena ultimately result in improved oral bioavailability. Anticancer drug delivery using the SEDDS has shown promising results for bioavailability and pharmacodynamic response. A handful of research studies have produced evidence of the successful loading of anticancer agents in SEDDS-based formulations. Various potent and established chemotherapeutic agents such as docetaxel, paclitaxel, etoposide, 5 Fluorouracil, doxorubicin etc., have been successfully formulated and evaluated. Improved bioavailability and reduction of dose might be possible by SEDDS. It could be effective for low-dose drugs. But, excessive surfactant- cosurfactant concentration, lacking predictive in-vitro models and adequate IVIVC, and unavailability of toxicity data are certain challenges for future researchers. No clinical trials have been recorded with anticancer drug-loaded SEDDS. Overcoming the challenges and further progression to clinical studies are required to avail the benefits of anticancer SEDDS.