Effect of Mineral-Oil Addition on Film Stability of Polar Lipid Constituents Derived from Meibum.

We studied the effects of mineral oil (MO) on the properties and structure of a spread monolayer of polar lipid constituents in meibum, by performing cyclic lateral compression-expansion experiments using a Langmuir trough. A meibum sample without nonpolar lipids (meibumΔnonpolar-lipid) was prepared by removing the nonpolar lipids from biological meibum extruded from rabbit eyelids and spread on a water surface for measuring the cyclic surface pressure (π)-film area (A) isotherms with in situ observation of the film morphology using a Brewster angle microscope. The meibumΔnonpolar-lipid formed a homogeneous fluid monolayer and underwent collapse upon compression.

Role of Endogenous Ingredients in Meibum and Film Structures on Stability of the Tear Film Lipid Layer against Lateral Compression.

The property and structure of spread films of meibum extruded from rabbit eyelids and its fractions were investigated using the Langmuir film balance technique and Brewster angle microscopy in order to understand the influence of endogenous ingredients in meibum on the structure and stability of the tear film lipid layer against mechanical stimulus. Surface pressure (?)?film area ( A) isotherms for meibum were measured upon repetitive high-speed compression?expansion cycles and were found almost identical to each other with very small hysteresis, indicating the high stability of the meibum film. Brewster angle microcopy observation implied the spontaneous formation of condensed-phase network structures which consist primarily of wax esters and cholesteryl esters as nonpolar ingredients, coexisting with a monolayer phase of polar lipids two-dimensionally confined by the networks, which were spontaneously formed in the meibum film.

Membrane permeation of giant unilamellar vesicles and corneal epithelial cells with lipophilic vitamin nanoemulsions.

Nanoemulsions of a lipophilic vitamin, retinol palmitate (vitamin A; VA), have a therapeutic effect on corneal damage. The nanoemulsion based on a triblock-type polymer surfactant with polyoxyethylene and polypropylene, EOPOEO (EOPO) showed superior efficacy, as compared with a nanoemulsion based on polyoxyethylene (60) hydrogenated castor oil (HCO). We studied the mechanism of VA nanoemulsions related to efficacy from the viewpoint of the interaction with plasma membrane-mimicking giant unilamellar vesicles (GUVs) and the plasma membrane permeation in corneal epithelial cells.

Efficacy and safety of retinol palmitate ophthalmic solution in the treatment of dry eye: a Japanese Phase II clinical trial.

Purpose: The purpose of this study was to investigate the efficacy and safety of the administration of retinol palmitate (VApal) ophthalmic solution (500 IU/mL) for the treatment of patients with dry eye.

Patients And Methods: This study included 66 patients with dry eye. After a 2-week washout period, patients were randomized (1:1) into either a VApal ophthalmic solution or a placebo group, and a single drop of either solution was administered six times daily for 4 weeks.

Effect of Retinol Palmitate on Corneal and Conjunctival Mucin Gene Expression in a Rat Dry Eye Model After Injury.

Purpose: We examined the wound-healing effect of retinol palmitate (VApal) on mucin gene and protein expressions in a rat dry eye model based on lacrimal gland (LG) resection after injury.

Methods: The rat dry eye model was prepared by surgical resection of the main LG in male Long-Evans rats. After alkaline injury of the central part of the lower palpebral conjunctiva bilaterally, VApal eye drops at 1,500 IU/mL in one eye and a vehicle in the fellow eye were both administered 6 times a day for 7 days.

The effects of vitamin A compounds on hyaluronic acid released from cultured rabbit corneal epithelial cells and keratocytes.

A role of vitamin A in the synthesis of hyaluronic acid by skin cells is well known. Hyaluronic acid is produced by corneal epithelial cells and keratocytes in the eye. We investigated whether rabbit corneal epithelial cells and keratocytes release hyaluronic acid after exposure to vitamin A compounds.

Efficacy of retinol palmitate eye drops for dry eye in rabbits with lacrimal gland resection.

Purpose: We examined the efficacy of retinol palmitate (VApal) for dry eyes using dry eye model rabbits whose lacrimal glands were resected.

Materials And Methods: After alkaline injury on keratoconjunctival epithelium, VApal eye drops were administered 6 times a day for 7 days. The efficacy of VApal was also compared with that of 0.

Adsorption of actives in ophthalmological drugs for over-the-counter on soft contact lens surfaces.

The adsorption of various kinds of ionic/nonionic actives, added in ophthalmological drugs (artificial tear, contact lens wetting solution, eye-drops, and eyewash) for over-the-counter (marketable drugs with no need of any medical prescription) , on soft contact lens (SCL) surfaces has been studied as a function of hydrophobicity of the actives. The common logarithm of the 1-octanol/water partitioning coefficient (AC_log P) has been used in order to normalize the hydrophobicity of the actives employed in this study. No significant adsorption occurs for relatively hydrophilic actives, whereas the adsorption rate is gradually increased with an increase in the hydrophobicity of the actives.

Acylzirconocene Chloride as an "Unmasked" Acyl Anion.

Under mild conditions the acyl group of acylzirconocene chloride 1 formed from an alkene or alkyne and [(C H ) ZrHCl] reacts as an "unmasked" acyl anion. The Lewis acid mediated reactions with aldehydes that yield α-ketol products in high yields demonstrate the versatility of this reagent for C-C coupling.