Biopolymers, liposomes, and nanofibers as modified peroral drug release formulants

Abstract Oral drug delivery is the most commonly accepted route for drug administration due to its flexibility in dosage form design and ease of administration. Drug products designed to reduce the dose frequency by modifying the rate of drug absorption have many advantages over immediate release systems. The use of mathematical equations that describe the drug release in function of time is very important when designing a pharmaceutical formulation or evaluating the drug release process either in vitro or in vivo. The main model-dependent methods that describe the release kinetics are the zero-order, first-order, Higuchi, Hixson–Crowell, Korsmeyer–Peppas, and the Weibull equations. Other parameters used to characterize the drug release are the time taken for a given proportion of the active drug to be released into solution (i.e., t20%, t50%, and t90%), the fraction of drug in solution after a specified time, the dissolution efficiency, and the mean dissolution time. Statistical methods are also used, and the comparison of the dissolution profiles in both graphical and numerical form is considered a useful tool. An independent mathematical model for comparing the solubility profiles is the use of the difference factor (f1) and the similarity factor (f2). Over the past decades, excipient development has become a very interesting research area in drug delivery, as it plays an important role in the drug release process especially in modified release formulations. Among various excipients, biopolymers, and nanomaterials are an attractive choice due to their stability and biodegrability. Various ways in developing modified release peroral dosage forms have emerged, nanofibers and liposomes being among the most attractive. Electrospun nanofibers have been successfully used for the modified release of various incorporated drugs, achieving desirable release profiles. Liposomal drug-delivery systems have been used widely in the recent years for treating various diseases ranging from cancer treatment to pain management with control over the pharmacokinetic and pharmacodynamic drug properties.