Optimization and evaluation of bioactive drug-loaded polymeric nanoparticles for drug delivery

The premise of the present study was to suitably select or modify the constitution of the polymer matrix to achieve significantly high entrapment of hydrophilic drugs within polymeric nanoparticles (NPs). Glycyrrhizin (GL), the bioactive drug was selected as a representative hydrophilic drug. Ionotropic gelation technique was used for the preparation of glycyrrhizin-loaded NPs. Concentration of polymers were optimized by 3-level factorial design which affected the particle size and encapsulation efficiency. The formulation was subjected to morphological, physiochemical and in vitro drug release studies. Mean particle size of nanoparticles was around 181 nm as estimated with particle size analyzer. TEM observations revealed spherical shape and size in the range of 140-200 nm. Fourier transform-infrared analysis did not reveal any chemical interaction among the drug and polymers used for the nano-formulation. A release study conducted in vitro over a period of 24 h indicated primarily burst release after that controlled release of glycyrrhizin from the formulation. Antibacterial activities of glycyrrhizin, blank chitosan-gum arabic NPs and glycyrrhizin-loaded chitosan-gum arabic NPs were tested against two Gram negative and two Gram positive bacteria. The study demonstrates the benefit of excipient screening techniques in improving entrapment efficiency of a hydrophilic drug.