The polymorphism of statins and its effect on their physicochemical properties

Polymorphism of pharmaceutical substances has a significant impact on their physicochemical properties, durability, bioavailability and consequently on their pharmacological activity. Solid dosage forms may exist in both crystalline and amorphous forms. Amorphous varieties are characterized by higher solubility and dissolution rates, while crystalline forms show greater purity and storage stability. The choice between the crystalline or amorphous form of a drug is extremely important to ensure effective and safe pharmacotherapy. Statins - the most commonly used group of drugs in the treatment of lipid disorders - are an example of drugs that occur in many crystalline and amorphous forms. Statins belong to class II in the biopharmaceutical classification system (BCS), which means that they are poorly soluble, but permeate biological membranes well. The bioavailability of statins shows considerable variation, which is associated with the first-pass effect in the liver and the accumulation of the drug in the hepatocytes. The improvement of bioavailability after oral administration of poorly soluble medicinal substances remains one of the most challenging aspects of the drug development process. A specific polymorphic form is obtained by applying appropriate conditions during the process of its preparation under industrial conditions, including the use of a suitable solvent, a specific temperature or rate of crystallization. The article provides a comprehensive update on the current knowledge of the influence of polymorphic form on statin solubility and bioavailability. Research is still being carried out to obtain new polymorphic varieties of statins that are characterized by better physicochemical and pharmacokinetic parameters.