Ocular Delivery (ocular + delivery)

Distribution by Scientific Domains

Selected Abstracts

2261: Development and evaluation of PLGA nanoparticles with cyclosporine and the inclusion of HP,CD for ocular use

Ocular delivery of peptides requires new concepts in order to optimize the bioavailability and its therapeutic effect. The first peptide selected in present research project is Cyclosporine A (CyA) used in the treatment of the dry eye syndrome and against corneal graft rejection. The aim of the project is the development of nanoparticles with physicochemical properties for a suitable and prolonged release of CyA, using a factorial design. These drug delivery systems will be produced employing PLGA using the emulsification solvent evaporation method. Positively charged polymers as chitosan or Eudragit® will be incorporated to obtain nanoparticles with a positive particle charge. Electrostatic interactions with the negatively charged mucins lead to a prolonged residence time at the precorneal area. Nanoparticles will be evaluated on zeta potential, particle size and their in vitro drug release properties. CyA and CyA complexed with HP,CD will be compared. The most suitable preparations will be selected in a next phase of the project for an in vivo study using an animal model. [source]

PLGA nanospheres for the ocular delivery of flurbiprofen: Drug release and interactions

E. Vega
Abstract Poly(D,L -lactide- co -glycolide) nanospheres incorporating flurbiprofen were prepared by the solvent displacement technique for purposes of assessing (i) drug,polymer physicochemical interactions, (ii) flurbiprofen release from the polymer matrix and (iii) eye permeation of the drug formulated in the colloidal system. The resulting nanospheres were on average 200,300 nm in size and bore a negative charge (,-potential around ,25 mV). They were shown by atomic force microscopy and transmission electron microscopy to be spherical and regular in shape. Thermal methods, infrared spectroscopy and X-ray diffraction showed that the drug was dispersed inside the particles. These tests evidenced an eutectic mixture meaning more widespread dispersion of the drug in the polymer system. Entrapped flurbiprofen was released in vitro from the polymer system by dissolution and diffusion in high drug loaded nanospheres, whereas those with a lesser load showed only diffusion. The ex vivo corneal permeation study showed that flurbiprofen-loaded nanospheres enhanced drug penetration by about twofold over commercial eye drops containing poly(vinyl alcohol) and by about fourfold over flurbiprofen in pH 7.4 phosphate buffer. The corneal hydration level of each cornea was determined to evaluate potential corneal damage. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:5306,5317, 2008 [source]

Sustained ocular delivery of tilisolol to rabbits after topical administration or intravitreal injection of lipophilic prodrug incorporated in liposomes

Shigeru Kawakami
To improve the retention time of tilisolol in the precorneal area or vitreous body, we prepared liposomes incorporating the O -palmitoyl prodrug of tilisolol. O -Palmitoyl tilisolol was completely incorporated in the liposomes. After topical administration of O -palmitoyl tilisolol liposomes to the rabbit eye, O -palmitoyl tilisolol rapidly disappeared from the tear fluid. The inclusion of 2% carmellose sodium slightly prolonged the retention of O -palmitoyl tilisolol in the tear fluid. After intravitreal injection of O -palmitoyl tilisolol liposomes, there was a relatively prolonged retention of O -palmitoyl tilisolol in the vitreous body. At 24 and 48 h after intravitreal injection of O -palmitoyl tilisolol liposomes, the tilisolol concentration in the vitreous body was significantly higher compared with the concentration after intravitreal injection of tilisolol liposomes. [source]

An antibiotic releasing contact lens

Purpose To characterize a drug-eluting contact lens designed to release ciprofloxacin to the eye in a controlled manner for an extended period of time. Methods Thin fiilms, containing ciprofloxacin or fluorescein encapsulated in PLGA (Poly[lactic-co-glycolic acid]), were coating by pHEMA (poly[hydroxyethyl methacrylate]) by ultraviolet light polymerization, creating prototype contact lenses. The films were characterized by scanning electron microscopy. Release studies were conducted in phosphate buffered saline at 37°C with continuous shaking. Ciprofloxacin eluted from the contact lens was studied in an antimicrobial assay to verify antimicrobial effectiveness. Results Ciprofloxacin and fluorescein were released from the contact lenses in a controlled manner, demonstrating zero-order release kinetics under infinite sink conditions for over 4 weeks. The rate of drug release was controlled by modifying either the ratio of drug to PLGA or the molecular weight of the PLGA employed. Both the PLGA and the pHEMA affected release kinetics. Ciprofloxacin released from the contact lenses inhibited ciprofloxacin-sensitive Staphylococcus aureus at all time-points tested. Conclusion A thin drug-PLGA film coated with pHEMA could potentially be used to create contact lenses which can serve as a platform for ocular delivery of antibiotics and other medications, with widespread therapeutic applications. [source]