Development of Contact Lenses from a Biomaterial Point of View – Materials, Manufacture, and Clinical Application

Efron, Nathan; Maldonado‐Codina, Carole

doi:10.1016/b978-0-08-055294-1.00270-1

Cited by 22 publications

(17 citation statements)

References 44 publications

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“…The transmittance values obtained fall within the range reported in literature for soft contact lenses materials [40,41]. These values remain practically constant after loading the hydrogels with the antibiotic (96.570.03% for PHEMA-T and 95.970.04% for PHEMA-UV).…”

Section: Characterization Of the Hydrogelssupporting

confidence: 69%

About the effect of eye blinking on drug release from pHEMA-based hydrogels: anin vitrostudy

Galante

Paradiso

Moutinho

et al. 2015

Journal of Biomaterials Science, Polymer Edition

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Abstract:The development of new ophthalmic drug delivery systems capable of increasing the residence time of drugs in the eye and improve its bioavailability relatively to eyedrops has been object of intense research in recent years. Several studies have shown that drug loaded therapeutic soft contact lenses (SCLs) constitute a promising approach, with several potential advantages as compared with collyria. The main objective of this work is to study the effect of repetitive load and friction cycles caused by the eye blinking, on the drug release from hydrogels used in SCLs which, as far as we know, was never investigated before. Two poly-2-hydroxyethylmethacrylate based hydrogels, pHEMA-T and pHEMA-UV, were used as model materials. Levofloxaxin was chosen as model drug. The hydrogels were fully characterized in what concerns structural and physicochemical properties. PHEMA-UV revealed some superficial porosity and a lower short range order than PHEMA-T. We observe that the load and friction cycles enhanced the drug release from pHEMA-UV hydrogels. The application of a simple mathematical model, which takes into account the drug dilution caused by the tear flow, showed that the enhancement of the drug release caused by blinking on this hydrogel may be relevant in in vivo conditions. Powered by Editorial Manager® and ProduXion Manager® from Aries Systems CorporationConversely, the more sustained drug release from pHEMA-T is not affected by load and friction cycles. The conclusion is that, depending on the physicochemical and microstructural characteristics of the hydrogels, blinking is a factor that may affect the amount of drug delivered to the eye by SCLs and should thus be considered. Powered by Editorial Manager® and ProduXion Manager® from Aries Systems CorporationAbout the effect of eye blinking on drug release from pHEMA based hydrogels:an in vitro study The development of new ophthalmic drug delivery systems capable of increasing the residence time of drugs in the eye and improve its bioavailability relatively to eyedrops has been object of intense research in recent years. Several studies have shown that drug loaded therapeutic soft contact lenses (SCLs) constitute a promising approach, with several potential advantages as compared with collyria. The main objective of this work is to study the effect of repetitive load and friction cycles caused by the eye blinking, on the drug release from hydrogels used in SCLs which, as far as we know, was never investigated before.Two poly-2-hydroxyethylmethacrylate based hydrogels, pHEMA-T and pHEMA-UV, were used as model materials. Levofloxaxin was chosen as model drug. The hydrogels were fully characterized in what concerns structural and physicochemical properties. PHEMA-UV revealed some superficial porosity and a lower short range order than PHEMA-T.We observe that the load and friction cycles enhanced the drug release from pHEMA-UV hydrogels. The application of a simple mathematical model, which takes into account the drug dilution caused by the tear flow, show...

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Section: Characterization Of the Hydrogelssupporting

confidence: 69%

About the effect of eye blinking on drug release from pHEMA-based hydrogels: anin vitrostudy

Galante

Paradiso

Moutinho

et al. 2015

Journal of Biomaterials Science, Polymer Edition

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“…The transmittance of the coated hydrogel with both types of liposome (DMPC and DMPC + CHOL) was not significantly affected relatively to the control sample; all the measured samples have over 90% transparency, matching the minimum transmittance value required for SCLs . In detail, the DMPC coating decreases the hydrogel transmittance from 99.0 ± 0.2% to 98.7 ± 0.3% while the DMPC + CHOL coating reduces the transmittance to 97.6 ± 0.4%.…”

Section: Resultsmentioning

confidence: 73%

“…These observations are in agreement with the QCM-D results: the higher stiffness and viscosity of the DMPC 1 CHOL liposomes suggests that they are more resistant to rupture because the lipids are more densely packed, as described in Serro et al 26 The transmittance of the coated hydrogel with both types of liposome (DMPC and DMPC 1 CHOL) was not significantly affected relatively to the control sample; all the measured samples have over 90% transparency, matching the minimum transmittance value required for SCLs. 42 In detail, the DMPC coating decreases the hydrogel transmittance from 99.0 6 0.2% to 98.7 6 0.3% while the DMPC 1 CHOL coating reduces the transmittance to 97.6 6 0.4%. Figure 6 compares the cumulative release curves of LVF obtained in static sink conditions with those obtained under friction conditions, which attempt to simulate the eye blinking effect.…”

Section: Coating Characterizationmentioning

confidence: 93%

Drug release from liposome coated hydrogels for soft contact lenses: the blinking and temperature effect

Paradiso

Colaço

Mata

et al. 2016

J. Biomed. Mater. Res.

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In this article, liposome-based coatings aiming to control drug release from therapeutic soft contact lenses (SCLs) materials are analyzed. A PHEMA based hydrogel material loaded with levofloxacin is used as model system for this research. The coatings are formed by polyelectrolyte layers containing liposomes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and DMPC + cholesterol (DMPC + CHOL). The effect of friction and temperature on the drug release is investigated. The aim of the friction tests is to simulate the blinking of the eyelid in order to verify if the SCLs materials coated with liposomes are able to keep their properties, in particular the drug release ability. It was observed that under the study conditions, friction did not affect significantly the drug release from the liposome coated PHEMA material. In contrast, increasing the temperature of release leads to an increase of the drug diffusion rate through the hydrogel. This phenomenon is recorded both in the control and in the coated samples. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1799-1807, 2017.

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“…Both mixtures were injected into a mould consisting of two silanized glass plates separated by a spacer of polyurethane or teflon. The glass plates were silanized with a solution of dimethyldichlorosilane in carbon tetrachloride according to the procedure described by Vazquez et al to facilitate the hydrogel removal from the mould. After silanization, the glasses were rinsed with dichloromethane and dried with nitrogen.…”

Section: Methodsmentioning

confidence: 99%

Effect of plasma treatment on the performance of two drug‐loaded hydrogel formulations for therapeutic contact lenses

et al. 2014

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Although the plasma technology has long been applied to treat contact lenses, the effect of this treatment on the performance of drug-loaded contact lenses is still unclear. The objective of this work is to study the effect of nitrogen plasma treatment on two drug-loaded polymeric formulations which previously demonstrated to be suitable for therapeutic contact lenses: a poly-hydroxyethylmethacrylate (pHEMA) based hydrogel loaded with levofloxacin and a silicone-based hydrogel loaded with chlorhexidine. Modifications of the surface and the optical properties, and alterations in the drug release profiles and possible losses of the antimicrobial activities of the drugs induced by the plasma treatment were assessed. The results showed that, depending on the system and on the processing conditions, the plasma treatment may be beneficial for increasing wettability and refractive index, without degrading the lens surface. From the point of view of drug delivery, plasma irradiation at moderate power (200 W) decreased the initial release rate and the amount of released drug, maintaining the drug activity. For lower (100 W) and higher powers (300 W), almost no effect was detected because the treatment was, respectively, too soft and too aggressive for the lens materials.

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Development of Contact Lenses from a Biomaterial Point of View – Materials, Manufacture, and Clinical Application

Cited by 22 publications

References 44 publications

About the effect of eye blinking on drug release from pHEMA-based hydrogels: anin vitrostudy

About the effect of eye blinking on drug release from pHEMA-based hydrogels: anin vitrostudy

Drug release from liposome coated hydrogels for soft contact lenses: the blinking and temperature effect

Effect of plasma treatment on the performance of two drug‐loaded hydrogel formulations for therapeutic contact lenses

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