Permeability and partition coefficient of aqueous sodium chloride in soft contact lenses

Guan, Lei; Jiménez, M. E. González; Walowski, C.; Boushehri, Ali; Prausnitz, John M.; Radke, Clayton J.

doi:10.1002/app.33336

Cited by 33 publications

(61 citation statements)

References 35 publications

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“…In all cases, the DAILIES TOTAL1 Ò -core partition coefficients are similar to those of O 2 OPTIX™. This result indicates that the chemical and physical structures of the core of DAILIES TOTAL1 Ò and O 2 OPTIX™ are similar, confirming the reported SiHy structure of the DAILIES TOTAL1 Ò core [9,27,28]. Hydrophilic solutes partition primarily into the hydrophilic domains of SiHys.…”

Section: Resultssupporting

confidence: 88%

“…This chemical property is important for understanding care-solution and tear-film component uptake into lenses, since an ionic lens attracts counterion solutes and repels coion solutes [9,13,16]. Comparison of aqueous-solute partitioning at pH 4 compared with that at pH 7.4 reveals that the surface-gel layers of DAILIES TOTAL1 Ò are anionic at physiological pH 7.4.…”

Section: Discussionmentioning

confidence: 96%

“…Similarly, partitioning of tear components in SCLs, such as proteins, salts and lipids, can affect lens behavior during wear [1,[7][8][9][10][11]. Further, solute partitioning is critical for possible use of SCLs as a drug-delivery vehicle [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Fluorescent solute-partitioning characterization of layered soft contact lenses

Dursch

Liu

et al. 2015

Acta Biomaterialia

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a b s t r a c tPartitioning of aqueous packaging, wetting, and care-solution agents into and out of soft contact lenses (SCLs) is important for improving wear comfort and also for characterizing lens physico-chemical properties. We illustrate both features of partitioning by application of fluorescent-solute partitioning into DAILIES TOTAL1 Ò (delefilcon A) water-gradient SCLs, which exhibit a layered structure of a siliconehydrogel (SiHy) core sandwiched between thin surface-gel layers. Two-photon fluorescence confocal laser-scanning microscopy and attenuated total-reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) characterize the lens and assess uptake profiles of six prototypical fluorescent solutes. Comparison of solute uptake in a SiHy-core prototype lens (i.e., O 2 OPTIX TM ) validates the core SiHy structure of DAILIES TOTAL1 Ò . To establish surface-layer charge, partition coefficients and water contents are obtained for aqueous pH values of 4 and 7.4. Solute fluorescence-intensity profiles clearly confirm a layered structure for the DAILIES TOTAL1 Ò lenses. In all cases, aqueous solute partition coefficients are greater in the surface layers than in the SiHy core, signifying higher water in the surface gels. ATR-FTIR confirms surface-layer mass water contents of 82 ± 3%. Water uptake and hydrophilic-solute uptake at pH 4 compared with that at pH 7.4 reveal that the surface-gel layers are anionic at physiologic pH 7.4, whereas both the SiHy core and O 2 OPTIX™ (lotrafilcon B) are nonionic. We successfully confirm the layered structure of DAILIES TOTAL1 Ò , consisting of an 80-lm-thick SiHy core surrounded by 10-lm-thick polyelectrolyte surface-gel layers of significantly greater water content and aqueous solute uptake compared with the core. Accordingly, fluorescent-solute partitioning in SCLs provides information on gel structure and composition, in addition to quantifying uptake and release amounts and rates.

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Section: Resultssupporting

confidence: 88%

Section: Discussionmentioning

confidence: 96%

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Fluorescent solute-partitioning characterization of layered soft contact lenses

Dursch

Liu

et al. 2015

Acta Biomaterialia

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“…In recent work, Guan et al 8 for aqueous NaCl diffusion between HEMA-based and siloxane-based soft contact lenses. 8 In summary, from this study we can conclude that stirring on the donor chamber does not have a significant effect on the measurement obtained. Differences between stirring and non-stirring were in the order of less than 5%.…”

Section: Discussionmentioning

confidence: 99%

Reduction in ionic permeability of a silicone hydrogel contact lenses after one month of daily wear

Silva¹,

Compañ²,

González-Meijóme³

2015

Mater. Res. Express

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Purpose: To compare the ionic permeability using the ionoflux method of new and worn samples of a silicone hydrogel contact lens material.Methods: An ionoflux experimental setup was established to measure the ionic permeability (NaCl) of soft contact lenses. Samples of a silicone hydrogel lens (Comfilcon A, Coopervision, Pleasanton, CA) with optical powers of -1.00, -1.50 and -4.75 diopters (D) were used in this study. Three samples of each power were measured after being worn for 1 month on a daily wear basis. Lenses were cleaned and disinfected every night multipurpose disinfecting solutions. Three samples of new lenses from the same batch were also measured to evaluate the effect of lens wear on the ionic permeability of the lens material. Before measurement, the lenses were previously equilibrated with a solution of NaCl 1M during one week before of each measurement. Results:The apparent ionic permeability between lenses with -1.00 and -1.50 D increment 15 % in the -1.50D.In the case of -1.00 and -4.75 D lenses there is an increase of 26%. Conclusions:The ionic permeability of silicone hydrogel lenses of different optical powers was not significantly different. Worn lenses present a significant reduction of the ionic permeability after a month of wear.

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“…where l C-C is the length of a covalent carbon-carbon bond in the backbone (1.54 Å), C n is the Flory characteristic ratio or rigidity factor (6.9 for p-HEMA gels) [22], q 2 is the mass density of dry polymer (1.26 g/ml), M r is the molecular wt. of a repeat unit (130 g/mol in this case) [22], E is the Young's tensile modulus, / 2 is the polymer fraction in a swollen gel and n is gel mesh size, defined as the statistical length between two crosslinks.…”

Section: Effect On P-hema Hydrogel Mesh Sizementioning

confidence: 99%