Calcium Phosphate Based Micro and Nanoparticles in Oral Drug Delivery: Formulation Approaches, Intestinal Fate, and Bioavailability Enhancement: A Review

The emergence of calcium phosphate (CaP) based micro and nanoparticles has been of much interest as a novel approach to solving the inherent problems associated with the oral delivery of drugs, namely low solubility, instability, and bioavailability of most therapeutic agents. The paper is a review that gives a complete discussion on the use of CaP as a biocompatible, biodegradable and pH-responsive carrier during oral delivery. The physicochemical versatility of CaP provides the opportunity to make drug delivery systems able to deliver controlled release, targeted absorption in the intestine, and a greater bioavailability. The different synthesis strategies, including wet precipitation, sol-gel processes, spray drying, and biomimetic mineralization, allow a solid control of morphology and drug encapsulation capacity of particles. Moreover, the intestinal fate of CaP systems indicates their capacity to protect drugs in acidic gastric conditions and release and uptake site-specifically in the intestine. Their practical potential is noted in case studies, such as the solubility of compounds with low solubility (such as curcumin, paclitaxel, and raloxifene deliveries). Although there are current shortcomings like aggregation and scale-up biases, new hybrid and surface-modified CaP systems are resolving them. Altogether, CaP-based carriers can be discussed as an effective, safe, and scalable platform for delivering oral medication in the next generation, at the same time, effective for pharmaceuticals and biologically compatible.