Preparation and characterization of poly microspheres having encapsulated tetracycline

• Published in: Journal of thermal analysis and calorimetry Vol. 106; no. 3; pp. 671 - 677
• Main Authors: Mothe, C.G, Azevedo, A.D, Drumond, W.S, Wang, s.H, Sinisterra, R.D
• Format: Journal Article
• Language: English
• Published: Springer 01-12-2011
• Subjects: Analysis; Chemical properties; Drug delivery systems; Drugs; Ethylene glycol; Thermal properties; Vehicles
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-011-1655-x

Amphiphilic triblock copolymers, based on hydrophilic poly(ethylene glycol) (PEG) blocks and hydrophobic poly(L,L-lactide) (PLLA) blocks, were used as the matrix material for the preparation of tetracycline-loaded microspheres. The morphology and thermal properties of the biodegradable microspheres were evaluated. SEM showed the predominance of the spherical shape, however, it was possible to distinguish three patterns: rough or smooth surface or uneven collapsed volume. The FTIR analysis indicated good mechanical stability and structural integrity of the PLLA-PEG-PLLA copolymer's microspheres enclosing tetracycline. By thermal analysis it was possible to see the marginal influence of tetracycline on the glass transition and melting temperatures of the PLLAPEG-PLLA triblock copolymer, while the results by TG indicated the presence of tetracycline in the inner structure of the microspheres, which thermal decomposition leading to char formation was triggered by the drug's presence.