Long acting injectable formulations: the state of the arts and challenges of poly(lactic-co-glycolic acid) microsphere, hydrogel, organogel and liquid crystal

Background Long-acting injectable formulations (LAIFs) have received substantial attention recently due to their advantages over conventional formulations, including easy administration, continuous and controlled release of drug over months, and the ability to maintain drug concentrations within the therapeutic range. The constant advances in biotechnology produce complex active pharmaceuticals that might be difficult to administer by conventional means. In particular, peptides, proteins, and antibodies are hard to administer orally given their physicochemical instability in the gastrointestinal tract and short half lives in blood. Therefore, LAIFs are a good candidate delivery system for such drugs. LAIFs reduce the frequency of application and improve patient compliance. For instance, LAIF-based antipsychotics can be more effective in patients with bipolar disorder and schizoaffective disorder. Area covered This review provides an overview of the various drug delivery technologies using LAIFs. Poly (lactic-co-glycolic acid) microspheres, hydrogels, organogels, and liquid crystals were chosen as representative LAIFs, and their preparation methods, advantages, limitations, challenges, and prospects are discussed. Expert opinion LAIFs are an attractive delivery system for bio-macromolecules that might participate in the new drug paradigm in the future. While each LAIF-based delivery technology has its own unique advantages, there are still some limitations that need to be overcome, and studies are being performed to understand and address these limitations.