Effect of textured eye drop bottles on the photostability of pranoprofen 0.1% ophthalmic solution.

Context: Ophthalmic solutions are usually filled in a plastic bottle due to its durability and disposability. In Japan, photostability is one of the concerns for the quality control because an eye drop bottle must be a transparent container.

Objective: The present work studied the effect of textured eye drop bottles on its light blocking to improve the photostability of ophthalmic solutions.

Comparative studies of N-glycans and glycosaminoglycans present in SIRC (Statens Seruminstitut rabbit cornea) cells and corneal epithelial cells from rabbit eyes.

Purpose: We compared cultured Statens Seruminstitut rabbit cornea (SIRC) cells and corneal epithelial cells from rabbit eyes by analyzing their N-glycans and glycosaminoglycans (GAGs). This work is a fundamental study on the efficacy of using cultured cells instead of animals for drug development.

Materials And Methods: N-Glycans and GAGs from SIRC cell monolayers and corneal epithelial cells of rabbit eyes were analyzed by capillary electrophoresis (CE) and a combination of high-performance liquid chromatography (HPLC) and mass spectrometry.

Comparative studies of HPLC-fluorometry and LC/MS method for the determination of N-acetylneuraminic acid as a marker of deteriorated ophthalmic solutions.

Methods for determining the deterioration of ophthalmic solutions using both high-performance liquid chromatography (HPLC) with fluorescence detection and liquid chromatography coupled with selected ion monitoring mass spectrometry (LC/MS) are described. The methods are based on the determination of N-acetylneuraminic acid (NeuAc) released by the hydrolysis of foreign bodies that contaminate eye drops during use. The released NeuAc was either labeled with 1,2-diamino-4,5-methylenedioxybenzene (DMB) for fluorometric detection or detected without derivatization by mass spectrometry.

Corneal critical barrier against the penetration of dexamethasone and lomefloxacin hydrochloride: evaluation by the activation energy for drug partition and diffusion in cornea.

The cornea is a solid barrier against drug permeation. We searched the critical barrier of corneal drug permeation using a hydrophobic drug, dexamethasone (DM), and a hydrophilic drug, lomefloxacin hydrochloride (LFLX). The activation energies for permeability of DM and LFLX across the intact cornea were 88.

Stability of latanoprost in an ophthalmic lipid emulsion using polyvinyl alcohol.

Latanoprost in water is not stable against heat stress due to hydrolysis of the isopropyl ester in the latanoprost molecule. Therefore, the storage condition of latanoprost ophthalmic solution, Xalatan brand, was in a low temperature (2-8 degrees C). We formulated a favorable ophthalmic lipid emulsion of latanoprost using polyvinyl alcohol as emulsifier which showed a good heat stability.

Decreased mucin concentrations in tear fluids of contact lens wearers.

Characteristics of tear-film may be influenced by contact lens wear, because contact lenses present the habitual, direct rubbing action of the lids upon the covered ocular surface and may cause changes of tear-film. In the present paper, influence of contact lens on proteins in tear samples was studied using carbohydrates attached to the protein as a marker. We found that N-acetylneuraminic acid (Neu5Ac) was significantly decreased in tear samples of volunteers wearing contact lens (wearing, 86.

Formulation of an ophthalmic lipid emulsion containing an anti-inflammatory steroidal drug, difluprednate.

Preparation of oil-in-water (o/w) type lipid emulsion is one of the approaches to formulate drugs that are poorly water-soluble but can be dissolved in the oil phase of the emulsions. A synthetic glucocorticoid medicine, difluprednate (DFBA), is a water-insoluble compound. We formulated DFBA (0.

An HPLC method to evaluate purity of a steroidal drug, loteprednol etabonate.

Validation of an analytical method for impurities and degradation products in an active pharmaceutical ingredient is important to assessment of quality and safety in a new pharmaceutical product. In the present study, a high-performance liquid chromatographic method was validated to evaluate purity of loteprednol etabonate (LE). LE and its four related substances, major process impurities and degradation products (PJ-90, PJ-91, LE-11-keto and LE-methyl ester) were well resolved using a phenyl-stationary phase under isocratic conditions.

Capturing of acidic macromolecules from biological samples using a temperature-responsive polymer modified with poly-l-lysine.

We synthesized a temperature-responsive polymer, N-(isopropylacrylamide)-methacrylic acid copolymer, to which poly-l-lysine was introduced. The synthesized polymer as well as the parent polymer showed reversible soluble-insoluble changes in response to temperature changes across the lower critical solution temperature at 32 degree C in an aqueous solution. We found that the polymer efficiently captured acidic bio-macromolecules such as RNA, glycosaminoglycans and mucin-type glycoproteins in biological samples, and the captured molecules were recovered using aqueous NaCl solutions at high concentration.

Evaluation of ophthalmic suspensions using surface tension.

Uniformity and precision of single dose are required for ophthalmic suspensions including water-insoluble ingredients. Solid sediments formed after standing still must be immediately re-dispersible and distributed homogeneously before use. However, selection of an appropriate water-soluble polymer as suspending agent is a challenging problem.

Hyaluronic acid: separation and biological implications.

Hyaluronic acid (hyaluronan) is a ubiquitous extracellular matrix component, and present at high concentrations in skin, joints and cornea. In the skin, it is synthesized primarily by dermal fibroblasts and by epidermal keratinocytes. Hyaluronic acid usually exists as a high molecular mass (600,000-1,000,000) and non-sulfated glycosaminoglycan composed of a disaccharide unit of [bond]3GlcNAc beta 1[bond]4GlcA beta 1[bond].

Analysis of an anti-inflammatory steroidal drug, difluprednate, in aqueous humor by combination of semi-micro HPLC and column switching method.

A specific and sensitive method for the determination for difluprednate (DFBA) and its metabolite (deacetylated DFBA, DFB) in aqueous humor was developed. DFBA and DFB were initially absorbed on a Pinkerton-type column, then analyzed by high-performance liquid chromatography using a semi-micro column after column switching. Under the optimized conditions, calibration curves for DFBA and DFB showed good linearity over the range of 1.