Stereocomplexes based on poly(lactic acid) and insulin: formulation and release studies

Diastereoisomeric complexes of insulin with d-poly(lactic acid) ( d-PLA) or stereocomplexes of d- and l-PLA entrapping insulin were discovered. The complexes were spontaneously formed when insulin and d-PLA were mixed together in acetonitrile solution. Complexes of insulin– d-PLA formed a microparti...

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Bibliographic Details
Published in:Biomaterials 2002-11, Vol.23 (22), p.4389-4396
Main Authors: Slager, J, Domb, A.J
Format: Article
Language:English
Subjects:
Acetonitriles - pharmacology
Biocompatible Materials - chemistry
Calorimetry, Differential Scanning
Diastereoisomers
Ethanol - pharmacology
Freezing
Hexanes - chemistry
Hydrogen-Ion Concentration
Insulin - chemistry
Insulin - pharmacokinetics
Insulin release
Lactic Acid - chemistry
Lactic Acid - pharmacokinetics
Methylene Chloride - chemistry
Microscopy, Electron, Scanning
Peptides - chemistry
Polyesters
Polylactide
Polymers - chemistry
Polymers - pharmacokinetics
Solvents - pharmacology
Stereocomplex
Stereoisomerism
Temperature
Time Factors
Water - chemistry
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Summary:Diastereoisomeric complexes of insulin with d-poly(lactic acid) ( d-PLA) or stereocomplexes of d- and l-PLA entrapping insulin were discovered. The complexes were spontaneously formed when insulin and d-PLA were mixed together in acetonitrile solution. Complexes of insulin– d-PLA formed a microparticulate precipitate after a few hours in the solution. The porous 1–3 μm precipitate, which contained both insulin and d-PLA, was insoluble in solvents that dissolve isotactic PLA, and had an additional transition temperature at 169°C. When suspending these particles in buffer solution of pH 7.4, 37°C, insulin was constantly released for a few weeks. l-PLA or d, l-PLA did not form a precipitate with insulin, which indicates stereospecificity to the complex formation. Microparticulates were also obtained when l-PLA was added to the d-PLA–insulin solution. In this case two types of complexes, d-PLA–insulin and d-PLA– l-PLA complexes, were formed. These macromolecular stereocomplexes may form the onset of the development of a new generation of controlled release systems for peptides and proteins, by molecular complexation with enantiomeric polymers.
ISSN:0142-9612
1878-5905
DOI:10.1016/S0142-9612(02)00179-5