Stereocomplexes, based on biodegradable polymers and bioactive macromolecules

Stereocomplexation between two enantiomeric polymers such as D-PLA and L-PL A have been described in the literature. No reports up till now have been p ublished on the complexation between two non-identical complementary polyme rs. Sterecocomplexes between poly(lactide) enantiomers and a representative peptide, LHRH, was investigated. The complex was shown to be of physical c haracter (NMR, IR, X-ray) without any irriversibility. DSC-scans show an ad ditional signal related to the second (beta-) and thermally less stable for m of isotactic PLA. A linear correlation was found between the amount of pe ptide added to D-PLA and the measured enthalpies. An overall decrease in cr ystallinity was noticed. Less than 5% of the total amount of peptide was fo und free in solution after complexation with PLA. A controlled release of p eptide was measured for about 3 months in-vitro. In-vivo similar results we re obtained as earlier reported for a commercial available controlled relea se device containing LHRH.