Faculty Collaboration Database

Thermoresponsive gelatin/monomethoxy poly(ethylene glycol)-poly(D,L-lactide) hydrogels: formulation, characterization, and antibacterial drug delivery. Pharm Res 2006 Jan;23(1):205-14

Date

11/05/2005

Pubmed ID

16270162

DOI

10.1007/s11095-005-8417-z

Scopus ID

2-s2.0-32244448545 (requires institutional sign-in at Scopus site)   47 Citations

Abstract

PURPOSE: The primary objective of this study was to prepare novel thermoresponsive binary component hydrogels composed of gelatin and monomethoxy poly(ethylene glycol)-poly(D,L-lactide) (MPEG-PDLLA) diblock copolymer and to obtain optimal formulations capable of forming gels upon a narrow temperature range between body temperature and room temperature.

METHODS: MPEG-PDLLA diblock copolymers with a lower critical solution temperature (LCST) feature were synthesized by using a ring-opening polymerization method. The starting weight ratio of MPEG/DLLA was varied to obtain a series of copolymers with a wide range of molecular weight and hydrophilicity. The copolymers were characterized by 1H nuclear magnetic resonance (1H NMR) and thermogravimetric analysis. MPEG (2K)-PDLLA (1:4) was chosen to construct hydrogels with gelatin. To obtain optimal thermoresponsive formulation, various hydrogels were formulated and quantified in terms of sol-gel phase transition kinetics and rheological properties. Selected hydrogels were studied as drug carrier for gentamicin sulfate.

RESULTS: Gelatin/MPEG-PDLLA hydrogels underwent gelation in less than 15 min when 30 wt.% MPEG (2K)-PDLLA (1:4) was mixed with 10, 50, or 100 mg/mL gelatin. Hydrogels showed rapid gelation when 100 mg/mL gelatin was mixed with 15, 20, or 25 wt.% MPEG-PDLLA as temperature fell from 37 degrees C to room temperature. The viscosity of hydrogels depended on the frequency applied in the rheological tests, the environment temperature, and the concentration of both polymer components. The time needed for 50% gentamicin sulfate release was 5 days or longer at room temperature, and the release lasted up to 40 days. 1H NMR confirmed that MPEG-PDLLA hydrolyzed under in vitro situations.

CONCLUSIONS: The incorporation of a second polymer component MPEG-PDLLA into the gelatin hydrogel could modify the thermal characteristic of gelatin and the resulting binary component hydrogels obtained different thermal characteristics from the individual polymer components. Formulation of gelatin/MPEG-PDLLA hydrogels could be varied for obtaining such gels that can undergo gelation promptly upon a narrow temperature change.

Author List

Yang H, Kao WJ

Author

Hu Yang PhD Chair, Professor in the Biomedical Engineering department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Anti-Bacterial Agents
Cell Differentiation
Cell Proliferation
Chemistry, Pharmaceutical
Drug Stability
Gelatin
Hydrogels
Kinetics
Molecular Weight
Polyesters
Polyethylene Glycols
Polyglactin 910
Solubility
Temperature