DEVELOPMENT OF A MICROENCAPSULATED FORM OF CEFUROXIME AXETIL USING PH-SENSITIVE ACRYLIC POLYMERS

Cefuroxime axetil (CA) was encapsulated in pH-sensitive acrylic micros pheres in order to formulate a suspension dosage form. Using this micr oencapsulated form it was expected to prevent leaching of the drug fro m the microspheres into the suspension medium and to assure the releas e of the drug in the first part of the intestine, thus avoiding change s to its bioavailability. For this purpose, CA was microencapsulated w ithin several types of acrylic polymers by the solvent evaporation and the solvent extraction techniques. The acrylic polymers selected were : Eudragit E (positively charged and soluble at pH 5), Eudragit L-55 ( negatively charged and soluble at pH > 5.5) and Eudragit RL (neutral, insoluble, but readily permeable). The influence of the polymer electr ical charge on the stability and in vitro release of CA was investigat ed. Though Eudragit E microspheres presented good morphological charac teristics and dissolution behaviour, the analysis of the stability of CA in the presence of Eudragit E by HPLC, indicated, a negative intera ction between both compounds. However, formulations made of Eudragit L -55 and. RL in the ratios 100:0 and 90:10 were adequate in terms of th e stability of the encapsulated CA. The dissolution studies showed a c ritical pH between 52 and 6.0, which allowed the complete release of C A in a short period. Furthermore, these polymer microspheres were show n to be efficient in masking the taste of CA.