[Possibilities of influencing the drug content and encapsulation efficiency of chitosan microspheres prepared by ionic gelation process]. / Moznosti ovlivnení obsahu léciva a enkapsulacní úcinnosti chitosanových mikrosfér pripravených procesem iontové gelace.

ABSTRACT

UNLABELLED This study aimed to prepare high molecular weight chitosan blank and drug-loaded microparticles using 5-aminosalicylic acid (5-ASA) as the model active substance by an external ionic gelation. Formulation and process variables included the chitosan concentration and presence of drug in the polymer solution, and/or in hardening solution during the microparticles preparation. The effect of different preparation conditions on the properties of the microparticles was observed with a view to increase drug content in microparticles. For both types of microparticles (with and without the drug), it was found that their sphericity and equivalent diameter increased with increasing chitosan concentration. The drug content of drug-loaded microparticles was the highest in the case of the sample prepared from 1.75% chitosan dispersion, when the drug was present both in the chitosan dispersion and the hardening solution. Maximum six times higher drug content was achieved by change of the placement of 5-ASA during preparation (1.25% chitosan concentration). KEYWORDS microparticles external ionotropic gelation chitosan 5-ASA encapsulation efficiency.