Ocular drug delivery systems

An erodible insert developed as a potential ocular drug-delivery system is marketed as a prescription drug for the lubricant properties of the polymer base. Lacrisert is a sterile ophthalmic insert used in the treatment of moderate to severe dry eye syndrome and is usually recommended for patients unable to obtain symptomatic relief with artificial tear solutions. The insert is composed of 5 mg of hydroxypropylcellulose in a rod-shaped form about 1.27 mm diameter by about 3.5 mm long. No preservative is used, since it is essentially anhydrous. The quite rigid cellulose rod is placed in the lower conjunctival sac and first imbibes water from the tears and after several hours forms a... 

A. K. Mitra, ed. Ocular Drug Delivery Systems, Marcel Dekker, New York, 1993. 

J. Liaw and J. R. Robinson, Ocular penetration en-chancers, in Ocular Drug Delivery Systems (A. K. Mitra, ed.), Marcel Dekker, 1993, pp. 369-381. 

De Campos, A.M., et al. 2004. Chitosan nanoparticles as new ocular drug delivery systems In vitro stability, in vivo fate, and cellular toxicity. Pharm Res 21 803. 

Yandamme, T.F. 2002. Microemulsions as ocular drug delivery systems Recent developments and future challenges. Prog Retin Eye Res 21 15. 

Liposomes are potentially valuable as ocular drug delivery systems due to their simplicity of preparation and versatility in physical characteristics. However, their use is limited by instability (due to hydrolysis of the phospholipids), limited drugloading capacity, technical difficulties in obtaining sterile preparations, and blurred vision due to their size and opacity [42],... 

Many interesting delivery approaches have been investigated during the past decades in order to optimize ocular bioavailability, but much remains to be learned before the perfect ocular drug delivery system can be developed. 

Sasaki, H.,Tei,C.,Nishida,K., and Nakamura, J. (1993), Drug release from an ophthalmic insert of a beta-blocker as an ocular drug delivery system, / Controlled Release, 27(2), 127-137. 

Kreuter, J. (1990), Nanoparticles as bioadhesive ocular drug delivery systems, in Len-aerts, V., and Gurny, R., Eds., Bioadhesive Drug Delivery Systems, CRC Press, Boca Raton, FL, pp. 203-212. 

A newer development in ocular drug delivery systems is the use of large molecules that exhibit reversible phase transitions whereby an aqueous drop delivered to the eye reversibly gels on contact with the precorneal tear film. Such changes in viscous properties can be induced by alterations in temperature, pH, and electrolyte composition. Gelrite, a polysaccharide low-acetyl gellan gum, forms clear gels in the presence of mono- or divalent... 

Chan, J., Maghraby, G., Craig, J.P. and Alany, R.G. (2007) Phase transition water-in-oil microemulsions as ocular drug delivery systems In vitro and in vivo evaluation. Int. J. Pharm., 328, 65-71. 

This reference studies the most recent advances in the development of ocular drug delivery systems. Covering methods to treat or prevent ocular inflammation, retinal vascular disease, retinal degeneration, and proliferative eye disease, this source covers breakthroughs in the management of endophthalmitis, uveitis, diabetic macular edema, and age-related macular degeneration. 

Zimmer A, Kreuter J. Microspheres and nanoparticles used in ocular drug delivery systems. Adv Drug Deliver Rev 1995 16 61-73. 

Lv FF, Zheng LQ, and Tung CH. (2005). Phase behavior of the microemulsions and the stability of the chloramphenicol in the microemulsion-based ocular drug delivery system. International Journal of Pharmaceuticals, 301, 237-246. 

Ocular inserts serve as an alternative approach to overcome the problans that were faced by other ocular drug delivery systems. They represent a significant advancement in the therapy of eye disease. 

The behavior of liposomes as an ocular drug delivery system has been observed to be, in part, because of their surface charge. Positively charged liposomes seem to be preferentially captured at the negatively charged corneal surface, compared with neutral or negatively charged liposomes. ... 

The potential of polymeric nanoparticles as an ocular drug delivery system has been explored by a colloidal system consisting of an aqueous suspension of nanoparticles. These nanoparticles can be rapidly fabricated under extremely mild conditions with their ability to incorporate bioactive compounds. ... 

Patel, V. Agrawal, Y.K. Current status and advanced approaches in ocular drug delivery system. JGTPS 2011, 2 (21), 131-148. 

Ueda, H. et al, 2001. Injectable, in situ forming poly(propylene fiimarate)-based ocular drug delivery systems. Journal of Biomedical Materials Research Part A, 83A(3), 656-666. 

Gelatin-based ocular drug delivery systems... 

PolyOactic add)- and poly(lactic-co-glycolic add)—based ocular drug delivery systems... 

Diagrammatic represciiiation of the Ocuseri ocular drug delivery system (Diagram adapted from Chien (1992) la.47])... 

Cross-sectional view of the Ocusert ocular drug delivery system. Pilo 20 and 40 refer to systems that release pilocarpine at 20 or 40 ig h, respectively, (adapted from Chien (1992) [a.48])... 

N. Kuno, and S. Fujii, Recent advances in ocular drug delivery systems. Polymers, 3, 193-221,2011. 

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