title: In situ gelling hydrogels incorporating microparticles as drug delivery carriers for regenerative medicine.
abstract: Aqueous solutions of blends of biodegradable triblock copolymers, composed of poly(D,L-lactide-co-glycolide) (PLGA) and poly(ethylene glycol) (PEG) with varied D,L-lactide to glycolide ratios, displayed thermosensitivity and formed a gel at body temperature. The gel window of the blend solutions could be tuned by varying the blending ratio between the two components. Furthermore, the storage modulus of the resultant hydrogel from the copolymer blends at body temperature was higher than that of each individual component. Incorporation of poly(D,L-lactide) (PDLLA) microparticles (0.5-40% w/v) within the in situ gelling hydrogel did not change the sol-gel transition temperatures of the polymer solutions, while the mechanical strength of the resultant hydrogels was enhanced when the content of the microparticles was increased up to 30% and 40%. Incorporation of proteins into both the gel and microparticle components resulted in composites that controlled the kinetics of protein release. Protein within the gel phase was released over a 10-day period whilst protein in the microparticles was released over a period of months. This system can be used to deliver two drugs with differing release kinetics and could be used to orchestrate tissue regeneration responses over differing timescales.
authors.affiliation: Division of Advanced Drug Delivery and Tissue Engineering, School of Pharmacy, Centre for Biomolecular Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
authors.forename: Qingpu
authors.initials: Q
authors.lastname: Hou
authors.forename: David Y S
authors.initials: DY
authors.lastname: Chau
authors.forename: Chayanin
authors.initials: C
authors.lastname: Pratoomsoot
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Tighe
authors.forename: Harminder S
authors.initials: HS
authors.lastname: Dua
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Shakesheff
authors.forename: Felicity R A J
authors.initials: FR
authors.lastname: Rose
mesh_terms: D004337:Drug Carriers; D020100:Hydrogels; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D011506:Proteins / Q000737:chemistry; D044968:Regenerative Medicine; D012212:Rheology
chemical_list: D004337:Drug Carriers; D020100:Hydrogels; D011506:Proteins