Timolol Maleate

Mazzo, David J.; Loper, Alice E.

doi:10.1016/s0099-5428(08)60566-3

Cited by 22 publications

(12 citation statements)

References 18 publications

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“…The results obtained at low pH, and for HEMA and HEMA/MMA hydrogels at higher pH, are explicable in terms of the nonionic nature of the hydrogels under these conditions, which both limits swelling and prevents ionic interaction with timolol (which was positively charged in all the loading experiments except those carried out at pH 10, the p K a of protonated timolol being 9.2) 21. The results obtained with HEMA/MAA hydrogels at higher pH suggest the action of two mechanisms: one reflected by a steady rise in uptake with MAA content and the other by a gain in uptake upon inclusion of 100 mM MAA.…”

Section: Resultsmentioning

confidence: 88%

“…Because timolol is stable in solution at the temperatures used for polymerization of HEMA,21 it seemed possible that its uptake by HEMA‐based soft contact lenses might be enhanced by molecular imprinting with the aid of appropriate comonomers. In this work we investigated the effect of imprinting on timolol uptake by hydrogels composed of HEMA copolymerized with small amounts of methyl methacrylate (MMA) or methacrylic acid (MAA); we characterized the release of the drug from the freshly synthesized copolymers and reloaded hydrogels, and we investigated whether the mechanical properties of the copolymers were appropriate for their use as soft contact lenses.…”

Section: Introductionmentioning

confidence: 99%

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Soft Contact Lenses Capable of Sustained Delivery of Timolol

Alvarez‐Lorenzo

Hiratani

Gómez-Amoza

et al. 2002

Journal of Pharmaceutical Sciences

204

133

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Section: Resultsmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Soft Contact Lenses Capable of Sustained Delivery of Timolol

Alvarez‐Lorenzo

Hiratani

Gómez-Amoza

et al. 2002

Journal of Pharmaceutical Sciences

204

133

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“…One-milliliter aliquots were withdrawn from the diffusion medium every hour for the past 8 h and the same quantity of fresh, pre-warmed diffusion medium was replaced. The samples withdrawn were analyzed spectrophotometrically at 294 nm[ 19 ] for timolol maleate using a Shimazdu double-beam UV-Visible spectrophotometer. (Shimadzu corporation, kanda-nithikicho 1- chome, chiyoda- ku, Tokyo, Japan)…”

Section: Methodsmentioning

confidence: 99%

Stimuli-sensitive hydrogels: A novel ophthalmic drug delivery system

Singh¹,

Bushetti²,

Appala³

et al. 2010

Indian J Ophthalmol

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Background:Stimuli-sensitive hydrogels are three-dimensional, hydrophilic, polymeric networks capable of imbibing large amounts of water or biological fluids on stimulation, such as pH, temperature and ionic change.Aim:To develop hydrogels that are sensitive to stimuli, i.e. pH, in the cul-de-sac of the eye for providing a prolonged effect and increased bioavailability with reduction in frequency of administration.Materials and Methods:Hydrogels were formulated by using timolol maleate as the model drug, polyacrylic acid as the gelling agents, hydroxyl ethyl cellulose as the viscolizer and sodium chloride as the isotonic agent. Stirring of ingredients in pH 4 phosphate buffer at high speed was carried out. The dynamic dialysis technique was used for drug release studies. In vivo study for reduction in intraocular pressure was carried out by using albino rabbits.Statistical Analysis:Drug release studies data were used for statistical analysis in first-order plots, Higuchi plots and Peppas exponential plots. Student t-test was performed for in vivo study.Results:Viscosity of the hydrogel increases from 3.84 cps to 9.54 cps due to change in pH 4 to pH 7.4. The slope value of the Peppas equation was found to be 0.3081, 0.3743 and 0.2964. Up to 80% of drug was released in an 8 h drug release study. Sterile hydrogels with no ocular irritation were obtained.Conclusions:Hydrogels show increase in viscosity due to change in pH. Hydrogels were therapeutically effacious, stable, non-irritant and showed Fickian diffusion. In vivo results clearly show a prolonged reduction in intraocular pressure, which was helpful for reduction in the frequency of administration.

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“…The unselective b-adrenoblocking agent timolol, (S)-1-[(1,1dimethylethyl)-amino]-3-[[4-(morpholinyl)-1,2,5-thiadiazol-3yl]oxy]-2-propanol (S)-14, is widely used in ophthalmology to treat various forms of glaucoma [62b, 65]. Recently, it has been found that its dosage form (hemimaleate) crystallizes as a continuous solid solution [66].…”

Section: Spontaneous Resolution Of Synthetic Precursorsmentioning

confidence: 99%

Stereoselective Crystallization as a Basis for Single‐Enantiomer Drug Production

Бредихин

Бредихина

2017

Chem Eng & Technol

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In the 21st century, single enantiomeric chiral active pharmaceutical ingredients (APIs) prevail among new drugs. Their preparation is made easier by using direct methods for the separation of racemates. The history of this issue is summarized and information about new and updated methods of conglomerate identification and practical implementation options for direct resolutions is provided. Examples are given for the application of direct methods for obtaining enantiopure APIs by the resolution of their racemic synthetic precursors, using a slight modification of the target product and finally by direct resolution of the racemic chiral drugs as such.

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Timolol Maleate

Cited by 22 publications

References 18 publications

Soft Contact Lenses Capable of Sustained Delivery of Timolol

Soft Contact Lenses Capable of Sustained Delivery of Timolol

Stimuli-sensitive hydrogels: A novel ophthalmic drug delivery system

Stereoselective Crystallization as a Basis for Single‐Enantiomer Drug Production

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