Aher Nitin Sanjay, Dattaraya Manohar, Saudagar Ravindra Bhanudas

Abstract

Cocrystals as defined by the FDA are, “Solids that are crystalline materials composed of two or more molecules in the same crystal lattice”. Pharmaceutical cocrystals represent a subset of cocrystals. Pharmaceutical cocrystals have quickly evolved from relative obscurity to a widely studied class of crystal forms in the context of pharmaceutical science and engineering. Cocrystals, like salts, represent solid forms that if novel can be patented and they are known to modulate important physicochemical properties such as solubility, stability, or bioavailability. They can therefore be applicable for use as an API in either immediate release or extended release formulations. The diversity of API crystal forms makes it difficult to classify solid forms into three categories that are mutually exclusive: Polymorphs, Salts, and Co-crystals. However, a classification of cocrystals has been attempted in this review. There is an extensive amount of literature available on cocrystals. However, there is a lack of an exhaustive review on methods of preparation of cocrystals. This review has made an attempt of bridge this gap. This review covers all methods of literature such as grinding method (Neat and Solvent drop grinding methods), Cocrystallization from Solution, Sonocrystallization Method, Hot melt extrusion, etc. A brief on characterisation techniques routinely used for cocrystals has also been incorporated here. Advantages of adopting the cocrystal approach have also been mentioned. Reported work on cocrystals was reviewed and has been briefly outlined herewith.