Properties of lactic acid based polymers and their correlation with composition

Preparation of biodegradable polymeric nanoparticles for pharmaceutical applications using glass capillary microfluidics

“…Both polymers have been approved by FDA for drug delivery (Jain et al, 1998;Södergård and Stolt, 2002;Panyam and Labhasetwar, 2003) and widely used as excipients in nanoprecipitation processes (Jain, 2000;Lu and Chen, 2004). The main objectives of this study were: (i) to make appropriate choice of good and poor solvent of the polymers, (ii) to observe the mixing process in situ using a microscope video system, and (iii) to investigate the effect of operating parameters, system geometry, and surfactants on the final particle size distribution.…”

Crystallization and hydrolytic/thermal degradation of a novel stereocomplexationable blend of poly(L-2-hydroxybutyrate) and poly(D-2-hydroxybutyrate)

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Stereocomplexation between PLLA and its enantiomer poly(D-lactide) (that is, poly(D-lactic acid) or PDLA) can yield biodegradable materials having superior mechanical performance and resistance to hydrolytic and thermal degradation relative to pure PLLA and PDLA. [16][17][18][19][20] Poly(2-hydroxybutyrate) (that is, poly(2-hydroxybutanoic acid) or P(2HB)) is a biodegradable polymer with the structure of a poly(lactide) (that is, poly(lactic acid) or PLA) in which methyl groups are substituted with ethyl groups.…”

Thermal Aging Study of Biodegradable Polymer Materials by Dielectric Thermal Analysis

“…PGA sutures in the period of two weeks loss 50% of their strength, 100% in the period of four weeks, and after 6 months they are completely absorbed [6]. The homopolymer of L-lactic acid (PLLA) is also a semi-crystalline polymer with large tensile, flexure strengths, and modulus of elasticity, and small values of tensile strains, enable the poly(Llactic-co-glycolic acid) (PLLA) as suitable for the application at places with high loads [9]. On the other hand, poly(DL-lactic acid) (PDLLA) is an amorphous polymer with a random distribution of the two isomers of poly(lactic acid).…”

“…It was shown that the thermal stability of aliphatic polyesters is small regarding: (1) a hydrolysis as a result of small amount of water existing; (2) zipper-like de-polymerization catalyzed by the residual catalyst; (3) oxidative degradation leading to the random scission of the main backbone; (4) intramolecular transesterification of monomers and oligomers; and (5) intermolecular transesterification creating small molecular weight compounds (monomers and oligomers) [9]. The application of polyesters for biomedical purposes requires the fundamental knowledge of their stability in biomedical environment, but still there is poor information available regarding this type of hydrolysis [11].…”

“…The time of the hydrolytic degradation of PLLA ranges between several months up to 60 years for the highly oriented fibers [9], depending on the molecular weight, molecular weight distribution, crystallinity and the chains' orientation. On the other hand, poly(glycolic acid) is very hydrophilic, so that it can degrade in a week [14].…”