Microspheres, Microcapsules, and Thin Coatings

One application of PLLA in the form of injectable microspheres is temporary fillings in facial reconstructive surgery. Since the introduction of highly active antiretroviral therapy in 1996, the mortality of human immunodeficiency virus (HIV)/AIDS patients has decreased significantly. However, this treatment is associated with side effects such as fat loss (lipoatrophy) in peripheral regions (upper and lower limbs and the face). In 2004, the FDA approved PLLA (Sculptra Dermik Laboratories, Berwyn, PA) for the restoration and correction of facial fat loss in people with HIV. Large clinical trials have been conducted in Europe and the United States and showed successful results [82-84], with no acute inflammation, abscess formation, or cytotoxicity at or remote from the implantation site. 

PLLA microspheres have also been used as an embolic material in transcatheter arterial embolization, which is an effective method to manage arteriovenous fistula and malformations, massive hemorrhage, and tumors. Yamamoto et al. [88] clinically assessed PLLA microspheres (with 

Liang et al. [90, 91] investigated controlled release of methotrexate using a PLLA microsphere delivery system, which was prepared by a solvent evaporation method, in synovial joints for the treatment of inflammation in rheumatoid arthritis. Methotrexate solution or methotrexate loaded microspheres were injected into the joint of healthy rabbits. The microsphere system showed an initial rapid burst of the drug followed by a slow release phase. In comparison to the solution, the microsphere system retained methotrexate in the joint cavity for a longer time. 

Poly(lactic acid) (Japanese), Yoneda Shuppan, Chiba, 2008. 

Yoshino, S. Takai, Y. Watanabe, K. Kamata, Y. Hirasawa, Foot Ankle Int. 1998,19, 634-637. 

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