Polylactic acid microspheres

Juni, K., Ogata, J., Nakano, M., Ichihara, T., Mori, K., and Akagi, M., Preparation and evaluation in vitro and in vivo of polylactic acid microspheres containing doxorubicin, Chem. Pharm. Bull.. 33, 313, 1985. 

M., Modification of the release rate of aclarubicin from polylactic acid microspheres by using additives, Chem. Pharm. 

FIGURE 12 Control of the rate of release of methadone from microspheres by the use of blends of a e-caprolactone-lactic acid copolymer and polylactic acid. (From Ref. 63.)... 

This is one of the earliest methods of microsphere manufacture. The polymer and drug must be soluble in an organic solvent, frequently methylene chloride. The solution containing the polymer and the drug may be dispersed in an aqueous phase to form droplets. Continuous mixing and elevated temperatures may be employed to evaporate the more volatile organic solvent and leave the solid polymer-drug particles suspended in an aqueous medium. The particles are finally filtered from the suspension. Fig. 3 shows polylactic acid particles prepared in this manner. ... 

Fig. 3 Scanning electron micrograph of polylactic acid microspheres containing phenolphthalein prepared by the solvent evaporation method. Magnification x4000. (From Ref. . )...

Polymeric micropsheres, particularly those prepared from the biodegradable polylactide/ polyglycolide polymers, have been widely investigated as a means to achieve sustained parenteral drug delivery. The advantage of formulating the polymeric matrix as microspheres is the ability to administer them via a conventional needle and syringe as a suspension formulation, rather than as an implant (see below). Lupron depot formulations are available which can provide therapeutic blood levels of leuprolide acetate for up to four months. These products are presented as lyophilized polylactic acid microspheres which are reconstituted to form a suspension prior to administration. 

Other attempts have focused on intravitreal injections of a suspension of polylactic acid (PLA) microspheres. Moritera et al. (70) showed that in vitro PLA microspheres containing 1% adriamycin (doxorubicin) can give sustained, first-order release for approximately two weeks. 

Ogawa Y, Okada H, Yamamoto M, Shimamoto T. In vivo release profiles of leuprolide acetate from microsphere prepared with polylactic acids or copoly(lactic/glycolic) acids and in vivo degradation of these polymers. Chem Pharm Bull 1988 36 2576-2581. 

In addition to its use as an effective antineoplastic agent, several studies have demonstrated that Taxol is highly effective in preventing restenosis after angioplasty or vascular injury. . The encapsulation of Taxol in polylactic acid microspheres within heparin-chitosan spheres has been shown to provide controlled release of Taxol and... 

Bodmeier R, McGinity JW. Polylactic acid microspheres containing quinidine base and quinidine sulphate prepared by the solvent evaporation technique. I. Methods and morphology. Journal of Microencapsulation. October-December 1987 4(4) 279-288. PubMed PMID 3504509. 

Gen S, Muranishi S, Ikada Y, Yoshikawa H. Polylactic acid microspheres and process for producing the same. US patent 4994281, 1991. 

Hyon SH, Ikada Y. Polylactic acid type microspheres containing physiologically active substance and process for preparing the same. US patent 5100669, 1992. 

Niu, X., Feng, Q., Wang, M., Guo, X., Zheng, Q. 2009. In vitro degradation and release behavior of porous polylactic acid scaffolds containing chitosan microspheres as a carrier for BMP-2-derived synthetic peptide. Polymer Degradation and Stability 94 176—182. 

No.2, Feb.2002, p. 127-36 PHOSPHOLIPID COATED POLYLACTIC ACID MICROSPHERES FOR THE DELIVERY OF LHRH ANALOGUES... 

Journal of Microencapsulation 17, No.5, Sept.-0ct.2000, p.625-38 5-FLUOROURACIL-LOADED CHITOSAN COATED POLYLACTIC ACID MICROSPHERES AS BIODEGRADABLE DRUG CARRIERS FOR CEREBRAL TUMOURS Chandy T Das G S Rao G H R Minnesota,University... 

Chandy, T., Das, G.S. and Rao, G. (2000) 5-Fluorouracil-loaded chitosan coated polylactic acid microspheres as biodegradable drug carriers for cerebral tumors, J. Microencap. 17,625-38. 

Ionic liquids, Polylactic acid. Plasticizers, Lubricants, Microspheres... 

Lupron Depot Injection is lyophilized microspheres of gelatin and glycolic-lactic acid for intramuscular (IM) injection. Nutropin Depot consists of polylactate-glycolate microspheres. 

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