title: In vitro degradation and release characteristics of spin coated thin films of PLGA with a "breath figure" morphology.
abstract: Poly (lactic-co-glycolic acid) (PLGA) coatings on implant materials are widely used in controlled drug delivery applications. Typically, such coatings are made with non-porous films. Here, we have synthesized a thin PLGA film coating with a highly ordered microporous structure using a simple and inexpensive water templating "breath figure" technique. A single stage process combining spin coating and breath figure process was used to obtain drug incorporated porous thin films. The films were characterized by scanning electron microscope (SEM) to observe the surface and bulk features of porosity and also, degradation pattern of the films. Moreover, the effect of addition of small amount of poly (ethylene glycol) (PEG) into PLGA was characterized. SEM analysis revealed an ordered array of ~2 µm sized pores on the surface with the average film thickness measured to be 20 µm. The incorporation of hydrophilic poly (ethylene glycol) (PEG) enhances pore structure uniformity and facilitates ingress of water into the structure. A five week in vitro degradation study showed a gradual deterioration of the breath figure pores. During the course of degradation, the surface pore structure deteriorates to initially flatten the surface. This is followed by the formation of new pinprick pores that eventually grow into a macroporous film prior to film breakup. Salicylic acid (highly water soluble) and Ibuprofen (sparingly water soluble) were chosen as model drug compounds to characterize release rates, which are higher in films of the breath figure morphology rather than in non-porous films. The results are of significance in the design of biodegradable films used as coatings to modulate delivery.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, LA, USA.
authors.forename: Thiruselvam
authors.initials: T
authors.lastname: Ponnusamy
authors.forename: Louise B
authors.initials: LB
authors.lastname: Lawson
authors.forename: Lucy C
authors.initials: LC
authors.lastname: Freytag
authors.forename: Diane A
authors.initials: DA
authors.lastname: Blake
authors.forename: Ramesh S
authors.initials: RS
authors.lastname: Ayyala
authors.forename: Vijay T
authors.initials: VT
authors.lastname: John
mesh_terms: D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D004337:Drug Carriers; D004339:Drug Compounding; D007052:Ibuprofen / Q000008:administration & dosage; D019344:Lactic Acid / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D016062:Porosity; D020156:Salicylic Acid / Q000008:administration & dosage; D012995:Solubility; D013499:Surface Properties; D013997:Time Factors
chemical_list: D020099:Coated Materials, Biocompatible; D004337:Drug Carriers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011092:Polyethylene Glycols; D020156:Salicylic Acid; D007052:Ibuprofen
keywords: PLGA; breath figure; degradation; drug delivery; microporous thin film