title: Physicochemical properties and in vivo assessment of timolol-loaded poly(D,L-lactide-co-glycolide) films for long-term intraocular pressure lowering effects.
abstract: Timolol-loaded poly(D,L-lactide-co-glycolide; PLGA) films were prepared for achieving the long-term intraocular pressure (IOP) lowering effect on glaucoma treatment. The physicochemical properties and in vivo effects of films were determined and characterize the delivery system. PLGA, span 20, propylene glycol (PG), and timolol base were dissolved in dichloromethane (DCM) and kept in a stainless mold; timolol films were prepared after the evaporation of DCM. Timolol disc-shape film preparation (TDF), containing 1 mg of timolol in 0.37 cm(2) area, was fabricated by using a trephine and placed onto the cul de sac of alpha-chymotrypsin-induced ocular hypertension rabbits for assessing the IOP lowering effect. The prepared films characterized a Young's modulus ranged from 1.13 to approximately 2.49 MPa, and related to the content percentages of PLGA, PG, and the residual DCM. The timolol film could maintain drug release for 1 week. Following a single-dose application in ocular hypertension rabbits, the prepared TDF could achieve a long-term IOP lowering effect and maintain the IOP change (in comparison with baseline) of approximately 7 mmHg within 1 week. The aqueous humor levels of timolol were low within a range of 0.8 to approximately 0.24 microg/mL for the initial 24 h and less than 0.15 microg/mL for 4-7 days. The investigated film formulation might be potentially developed for the application of long-term ocular delivery systems.
authors.affiliation: School of Pharmacy, Tri-Service General Hospital, National Defense Medical Center, National Defense University, Taipei, Taiwan, Republic of China.
authors.forename: Sheng-Fu
authors.initials: SF
authors.lastname: Huang
authors.forename: Jiin-Long
authors.initials: JL
authors.lastname: Chen
authors.forename: Ming-Kung
authors.initials: MK
authors.lastname: Yeh
authors.forename: Chiao-Hsi
authors.initials: CH
authors.lastname: Chiang
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics / Q000627:therapeutic use*; D000818:Animals; D001082:Aqueous Humor / Q000187:drug effects / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004195:Disease Models, Animal; D016503:Drug Delivery Systems / Q000379:methods*; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D009798:Ocular Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D011098:Polyglactin 910 / Q000737:chemistry*; D011817:Rabbits; D012995:Solubility; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D013999:Timolol / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000319:Adrenergic beta-Antagonists; D011098:Polyglactin 910; D013999:Timolol