Polylactic acid preparation

Polylactic acid, also known as polylactide, is prepared from the cycHc diester of lactic acid (lactide) by ring-opening addition polymerization, as shown below ... 

Al-Mulla, E.A.J. 2011. Polylactic acid/epoxidized palm oil/fatty nitrogen compounds modified clay nanocomposites Preparation and characterization. Korean Journal of... 

A method of the preparation of polylactic acid microcapsules of controlled particle size and drug loading, J. Microencapsul.,... 

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. 

Composites made with carbon nanostructures have demonstrated their high performance as biomaterials, basically applied in the field of tissue regeneration with excellent results. For example, P.R. Supronowicz et al. demonstrated that nanocomposites fabricated with polylactic acid and CNTs can be used to expose cells to electrical stimulation, thus promoting osteoblast functions that are responsible for the chemical composition of the organic and inorganic phases of bone [277]. MacDonald et al. prepared composites containing a collagen matrix CNTs and found that CNTs do not affect the cell viability or cell proliferation [278]. 

Research Focus Method for preparing polylactic acid derivatives through the polymerization of o-carboxy anhydrides including (l,3-dioxolane-2,4-diones) using of 4-diaminomethylpyridine as catalyst. 

Assay for Acylated Monolactic Acid, Acylated Polylactic Acid, and Free Fatty Acids Transfer about 100 mg of sample into a small, conical flask fitted with a suitable reflux condenser. Add 5.0 mL of a solution prepared by dissolving 14 g of boron trifluoride in methanol to make 100 mL (a commercial reagent, 14% w/v, may be used Applied Science, or equivalent). Swirl to mix, and reflux for 15 min. Cool, transfer the reaction mixture with the aid of 10 mL of chromatographic-grade hexane to a 60-mL separator, and add 10 mL of water and 10 mL of saturated sodium chloride solution. Shake, allow the mixture to separate, then drain and discard the lower, aqueous layer. Pass the hexane layer through 6 g of anhydrous sodium sulfate into a suitable flask. Inject 0.5... 

Block copolymers, (IV), consisting of succinic acid coupled with propylene glycol and then capped with hexamethylene diisocyanate and reacted with polylactic acid were prepared by Imamura [5] and used as biodegradable containers. 

Amphiphilic block copolymers consisting of polylactic acid or poly(lactic acid-h-glycolic acid) terminated with tocopherol or cholesterol were prepared by Seo [1] and used as drug delivery agents for Paclitaxel . 

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. . )...

Povidone can also be used as a hydrophilic component or pore former in preparations that contain sustained-release auxiliaries like polyvinyl acetate, cellulose derivatives like HPMC [490, 509, 660], alginate [461], cetylacohol [600], polylactic acid [5o6],Gelucire [510],polyvinyl alcohol [522],ceresine wax [523], stearic acid [606] or methacrylate copolymers [491] to control or regulate the release of active substances, as binders and/or sometimes as plasticizers. They can also be extruded together with the active substance in melted stearyl alcohol and filled into hard gelatin capsules to achieve the same effect [471]. Ocular delivery systems are also described [598]. 

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. 

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. 

Interest in polymeric materials prepared from renewable natural resources, such as soybean oil, has grown over the past decade. The advantages of these polymeric materials are their low cost, availability, and possible biodegradability (Kaplan, 1998). Among agricultural resources (starch, cellulose, fibers, polylactic acid, cashew nut... 

Anionic polymerization proceeds by nucleophilic reaction of the anion with the carbonyl and the subsequent acyl-oxygen cleavage. This reaction produces an alkoxide end group, which continuously propagate to prepare polylactic acid (Figure 7.5) [12]. 

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. 

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

Tsai DC, Howard SA, Hogan TF, Malanga CJ, Kandzari SJ, Ma JK. Preparation and in vitro evaluation of polylactic acid-mitomycin C microcapsules. Journal of Microencapsulation. July-September 1986 3(3) 181-193. PubMed PMID 3149671. 

Dasari, A., Quiros, J., Herrero, B., Boltes, K., Garda-Calvo, E., Rosal, R. Antifouling membranes prepared by electrospinning polylactic acid containing biocidal nanoparticles. / Memb. Sci., 2012, 405-406, 134-140. 

A large number of natural polymers could be easily prepared from animals and plants. These include cellulose, chitin, starch, soy protein, casein, hemicelluloses alginates, polylactic acid, polyhydroxyalkanoates etc. They have many attractive... 

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