A comparative study of doxycycline and tetracycline polymeric microspheres

Abstract

Solvent evaporation technique is used for the preparation of Polylactic acid microspheres loaded with two antibiotics, Doxycycline and Tetracycline, by introducing different masses for each drug. They are characterized by calculation of drug encapsulation and drug loading, measuring the particle size, examining microspheres morphology, and performing FT-IR, stability and in vitro drug release studies. Moderate drug encapsulation values (38% and 24%) are observed for Doxycycline and Tetracycline respectively. Microspheres of both drugs show homogeneous size distribution varying between 80 and 110 µm. the FT-IR study has helped in verifying that both Doxycycline and the polymer are intact after microencapsulation. In the case of Tetracycline, it hasnt revealed any significant results due to the low loading values. After 6 months of storage at different conditions, no appreciable difference is observed concerning the degradation of microspheres. In vitro release of drugs from encapsulated Polylactic acid microspheres shows that Tetracycline release is slightly faster and reaches 98% in less than 5 hours, in comparison with Doxycycline which attains the same percentage after 7 hours.