Preparation, characterization andin vitrorelease properties of ibuprofen-loaded microspheres based on polylactide, poly(϶-caprolactone) and their copolymers

Abstract

In this paper, ibuprofen was encapsulated into microspheres by oil-in-water (o/w) emulsion solvent evaporation method. Biodegradable polymers with certain compositions and characteristics such as polylactide (PLA), poly(epsilon-caprolactone) (PCL) and their block copolymer were used to prepare the microspheres. The results indicate that, under the same processing conditions, the drug entrapment efficiency was similar (approximately 80%) for microspheres prepared with PLA and P(LA-b-CL) (78.7/21.3 by mole), but it was only 25.4% for PCL microspheres. The in vitro drug release rate decreased in the order of PCL, P(LA-b-CL) (78.7/21.3 by mole) and PLA microspheres. PCL microspheres showed more serious burst release during the first day (almost 80%) than P(LA-b-CL) (50%) and PLA microspheres (18%). The complete ibuprofen release duration from the last two kinds of microspheres exceeded 1 month. Characterization of the microspheres by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and polarized optical microscope (POM) revealed that ibuprofen was amorphous in PCL microspheres and partially crystalline in P(LA-b-CL) and PLA microspheres. The different release behaviour of ibuprofen from the three kinds of microspheres could be attributed to the different crystallinity of the studied polymers and drug dispersion state in polymer matrices. All the above results suggest that the copolymer with a certain ratio of lactide to -caprolactone could have potential applications for long-term ibuprofen release.

Electrospun fiber mats containing shikonin and derivatives with potential biomedical applications

“…10). This indicated that shikonin was no longer present as a crystalline material but has been converted into an amorphous state (Yu et al, 2009b) and was uniformly dispersed in the CA matrix (Zhu et al, 2005). PLLA indicated an endothermic peak at 190 • C corresponding to its melting point.…”

Synthesis and Evaluation of Novel Polyester-Ibuprofen Conjugates for Modified Drug Release

“…However, these systems have tended to produce initial burst release of drug, and control of the level of drug loading can be difficult (Bodmeier & Chen, 1989;Flandroy, Grandfils, & Jerome, 1993;Jain, 2000;Oh, Nam, Lee, & Park, 1999;Zhu et al, 2005). In these delivery systems, the rate of release tends to be controlled by the level of drug loading, as well as a combination of the aqueous solubility and molecular weight of the drug, system morphology, and, to a lesser extent, the rate of polymer degradation (Fu, Shyu, Su, & Yu, 2002;Perumal, Dangor, Alcock, Hurbans, & Moopanar, 1999;Tice & Cowsar, 1984).…”

Preparation of self-solidifying polymeric depots from PLEC-PEG-PLEC triblock copolymers as an injectable drug delivery system

“…4c). For microspheres, it was also reported the rougher surface area and numerous interconnecting networks of semicrystalline polymers while amorphous polymers showed smoother surface areas [26]. Moreover, PCL blend with P(DL)LA was reported to have less interconnecting network, smoother surface areas and denser polymer matrix than PCL homopolymers [27].…”