Sustained release ophthalmic formulations of pilocarpine

Deshpande, S. G.; Shirolkar, Satish V.

doi:10.1111/j.2042-7158.1989.tb06430.x

Cited by 41 publications

(11 citation statements)

References 9 publications

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“…Currently, more than 90% of marketed topical eye drops are in the form of solutions and suspensions because of their convenience and ease of administration [1][2][3]. However, eye drops are notorious for poor ocular bioavailability with less than 5% of administered drugs entering the anterior chamber and reaching the intraocular tissues [2,[4][5][6]. A large part of the drugs is lost into the systemic circulation by blinking, rapid tear turnover rate and drainage into the nasal cavity.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Chitosan/Regenerated Silk Fibroin (Cs/Rsf) Films as a Biomaterial for Contact Lenses-Based Ophthalmic Drug Delivery System

2019

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Objective: The aim of this study was to develop chitosan/regenerated silk fibroin (CS/RSF) films as a biomaterial for contact lenses-based ophthalmic drug delivery system. Methods: CS/RSF films were prepared with polyethylene glycol 400 as a plasticizer by using a film casting technique. Their physicochemical properties were investigated by measuring various properties such as thickness, morphology, chemical interaction, light transparency, mechanical properties, water content, oxygen permeability, thermal properties and enzyme degradation. In addition, cytotoxicity was also studied. Results: At optimal preparation conditions, CS/RSF films showed smooth surfaces with highly visible light transparency of >90%, which meet the visual requirement. CS/RSF films showed high water content, 59-65% by weight, and their Young’s modulus and elongation at break was in the range of 3.8-6 N/mm2 and 113-135%, respectively. The CS/RSF films also could be sterilized by autoclave method as they possessed high thermal decomposition temperature of >260 °C which can be confirmed by both differential scanning calorimetry and thermogravimetric analysis. In addition, CS/RSF films showed no degradation in stimulated tear fluid containing lysozyme for 7 d and showed no cytotoxicity by MTT assay. Conclusion: CS/RSF films showed excellent physicochemical properties and non-cytotoxicity indicating their promising potential use as a biomaterial for contact lenses-based ophthalmic drug delivery system.

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Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Chitosan/Regenerated Silk Fibroin (Cs/Rsf) Films as a Biomaterial for Contact Lenses-Based Ophthalmic Drug Delivery System

2019

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“…Only 1-5% of the drugs contained in the eye drops can be effectively used, while a large part of the drugs enters the systemic circulation by either conjunctival uptake or drainage into the nasal cavity. Moreover, the residence time of eye drops is only 2 min or so [2]. These characteristics of eye drops cause inconvenient use, low efficiency, ineffective therapy, severe side effects, and so forth.…”

Section: Introductionmentioning

confidence: 99%

Hydrogel Contact Lens for Extended Delivery of Ophthalmic Drugs

Wang

et al. 2011

International Journal of Polymer Science

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Soft contact lenses can improve the bioavailability and prolong the residence time of drugs and, therefore, are ideal drug carriers for ophthalmic drug delivery. Hydrogels are the leading materials of soft contact lenses because of their biocompatibility and transparent characteristic. In order to increase the amount of load drug and to control their release at the expected intervals, many strategies are developed to modify the conventional contact lens as well as the novel hydrogel contact lenses that include (i) polymeric hydrogels with controlled hydrophilic/hydrophobic copolymer ratio; (ii) hydrogels for inclusion of drugs in a colloidal structure dispersed in the contact lenses; (iii) ligand-containing hydrogels; (iv) molecularly imprinted polymeric hydrogels; (v) hydrogel with the surface containing multilayer structure for drugs loading and releasing. The advantages and disadvantages of these strategies in modifying or designing hydrogel contact lenses for extended ophthalmic drug delivery are analyzed in this paper.

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“…Several drug carriers have been proposed as ocular controlled delivery systems 1. Although the efficacy of drops and ointments is improved by viscosity enhancers, in situ gelling systems, and mucoadhesive polymers, blinking and tear production are still serious impediments to the anchorage of these carriers 2–4. Inserts can extend the overall delivery period, but are not widely used because of self‐application and tolerance problems 5.…”

Section: Introductionmentioning

confidence: 99%