PMID- 8126012
OWN - NLM
STAT- MEDLINE
DCOM- 19940408
LR  - 20220331
IS  - 0021-9304 (Print)
IS  - 0021-9304 (Linking)
VI  - 27
IP  - 9
DP  - 1993 Sep
TI  - Tissue response and in vivo degradation of selected polyhydroxyacids: 
      polylactides (PLA), poly(3-hydroxybutyrate) (PHB), and 
      poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB/VA).
PG  - 1135-48
AB  - The tissue response and in vivo molecular stability of injection-molded 
      polyhydroxyacids--polylactides (PLA), poly(3-hydroxybutyrate) (PHB), and 
      poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB/VA, 5-22% VA content)--were 
      studied. Polymers were implanted subcutaneously in mice and extirpated at 1, 3, 
      and 6 months in order to study tissue response and polymer degradation. All 
      polymers were well tolerated by the tissue. No acute inflammation, abscess 
      formation, or tissue necrosis was observed in tissues adjacent to the implanted 
      materials. Furthermore, no tissue reactivity or cellular mobilization was evident 
      remote from the implant site. Mononuclear macrophages, proliferating fibroblasts, 
      and mature vascularized fibrous capsules were typical of the tissue response. 
      Degradation of the polymers was accompanied by an increase in collagen 
      deposition. For the polylactide series, the inflammatory response after 1 month 
      of implantation was less for materials containing the D-unit in the polymer 
      chain, whereas in the case of the polyhydroxybutyrate/valerates, the number of 
      inflammatory cells increased with increasing content of the valerate unit in the 
      polymer chain. Between 1-3 months, there was slightly more tissue response to the 
      PHB and PHB/VA polymers than to PLA. This response is attributed to the presence 
      of leachable impurities and a low molecular weight soluble component in the 
      polyhydroxybutyrate/valerates. At 6 months, the extent of tissue reaction was 
      similar for both types of polymers. All polylactides degraded significantly 
      (56-99%) by 6 months. For a poly(L-lactide) series, degradation rate in vivo 
      decreased with increasing initial molecular weight of the injection-molded 
      polymer. Several samples showed pronounced bimodal molecular weight distributions 
      (MWD), which may be due to differences in degradation rate, resulting from 
      variability in distribution of crystalline and amorphous regions within the 
      samples. This may also be the result of two different mechanisms, i.e., 
      nonenzymatic and enzymatic, which are involved in the degradation process, the 
      latter being more extensive at the later stage of partially hydrolyzed polymer. 
      The PHB and PHB/VA polymers degraded less (15-43%) than the polylactides 
      following 6 months of implantation. Generally, the polymer with higher valerate 
      content (19%, 22%) degraded most. The decrease in molecular weight was 
      accompanied by a narrowing of the MWD for PHB and copolymers; there was no 
      evidence of a bimodal MWD, possibly indicating that the critical molecular weight 
      that would permit enzyme/polymer interaction had not been reached. Weight loss 
      during implantation ranged from 0-50% for the polylactides, whereas for the PHB 
      polymers weight loss ranged from 0-1.6%.
FAU - Gogolewski, S
AU  - Gogolewski S
AD  - Department of Polymers, AO/ASIF Research Institute, Davos, Switzerland.
FAU - Jovanovic, M
AU  - Jovanovic M
FAU - Perren, S M
AU  - Perren SM
FAU - Dillon, J G
AU  - Dillon JG
FAU - Hughes, M K
AU  - Hughes MK
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Biomed Mater Res
JT  - Journal of biomedical materials research
JID - 0112726
RN  - 0 (Hydroxy Acids)
RN  - 0 (Hydroxybutyrates)
RN  - 0 (Lactates)
RN  - 0 (Polyesters)
RN  - 0 (Polymers)
RN  - 0 (poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate))
RN  - 26063-00-3 (poly-beta-hydroxybutyrate)
RN  - 459TN2L5F5 (poly(lactide))
SB  - IM
MH  - Absorption
MH  - Animals
MH  - Crystallography
MH  - Hydroxy Acids/*adverse effects/chemistry/*pharmacokinetics
MH  - Hydroxybutyrates/adverse effects/chemistry/pharmacokinetics
MH  - Lactates
MH  - Mice
MH  - Mice, Inbred ICR
MH  - Molecular Weight
MH  - Polyesters/adverse effects/chemistry/pharmacokinetics
MH  - Polymers/adverse effects/chemistry/pharmacokinetics
MH  - Prostheses and Implants/*adverse effects
MH  - Tissue Distribution
EDAT- 1993/09/01 00:00
MHDA- 1993/09/01 00:01
CRDT- 1993/09/01 00:00
PHST- 1993/09/01 00:00 [pubmed]
PHST- 1993/09/01 00:01 [medline]
PHST- 1993/09/01 00:00 [entrez]
AID - 10.1002/jbm.820270904 [doi]
PST - ppublish
SO  - J Biomed Mater Res. 1993 Sep;27(9):1135-48. doi: 10.1002/jbm.820270904.