Biodegradable poly(lactic acid) polymers

Abstract

SummaryThe synthesis of poly(1actic acids) from the cyclic lactides and properties of the polymem prepared have been described. Degradation rates in vitro under homogeneous and heterogeneous conditions have been meaqured. The kinetics of deesterification under homogeneous conditions is second order and an activation energy of 11 Kcal/mol has been calculated. This is comparable to the value found for the hydrolysis of alkyl acetates. A biological in vilro method for determining the degradation of poly(1actic acids) has been described. The method indicates, in accordance with expectations, that poly (dl-lactic acid) degrades at a faster rate than L(+) lactic acid. Initial results of medical evaluation of the polymers in suture, rod, and film form are presented.

Synthesis of Poly(Lactoylglycolate): An Alternating Copolymer of Lactic and Glycolic Acids

“…15 After the isolation of the product by vacuum distillation, an odor was noted which was similar to that observed at the same step in the synthesis of lactide or glycolide. Yield was low, and the compound was hygroscopic.…”

Cell colonization in degradable 3D porous matrices

“…), [62][63][64][65][66][67][68][69][70][71] and poly (caprolactone) (PCL) 72,73 have generated immense interest as tissue engineering materials. 74 Further information on specific 3D matrices can be found in a variety of review articles. [75][76][77] Various fabrication techniques such as free-form printing, 78 controlled rate freezing and lyophilization, 33 porogen-leaching, 62 gas-foaming 79 and microfabrication 80 are available.…”

Comparison of Sm complexes with Sn compounds for syntheses of copolymers composed of lactide and cyclic carbonates and their biodegradabilities

“…Poly(L-lactide) (PLLA), produced at industrial scale from starch by Cargill-Dow, is one of the most promising biocompatible and biodegradable semicrystalline polymers [1][2][3][4][5]. PLLA has been widely studied for biomedical applications, particularly those that demand good mechanical properties for surgical sutures and devices for internal bone fixation [6][7][8][9][10].…”

“…We have also reported random, diblock, and triblock copolymers of L-and D,L-LA with achiral cyclic carbonates such as trimethylene carbonate (TMC) and 2,2-dimethyltrimethylene carbonate (DTC) polymerized by using Sm1 or a bifunctional initiator (C 5 Me 5 ) 2 Sm(PhC=C=C= CPh)Sm(C 5 Me 5 ) 2 (Sm2) [24,25]. On the other hand, high molecular weight poly(LA)s were prepared using tin compounds such as Sn(2-ethylhexanoate) 2 and Bu 2 Sn(OR) 2 [5,15,[26][27][28][29][30][31]. This paper describes the comparison of the activities between Sm complexes and Sn compounds for random and diblock copolymerization of LA and cyclic carbonates together with the triblock copolymerization, and their biodegradabilities with a compost and with proteinase K.…”