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Distribution by Scientific Domains

Medical Sciences	60%

Selected Abstracts

Effects of (,)-carveol and HPMC on the in vitro ocular transport and the in vivo intraocular pressure lowering effects of dorzolamide formulations in normotensive New Zealand rabbits

DRUG DEVELOPMENT RESEARCH, Issue 3 2009
Mohsen I. Afouna
Abstract The objective of the current study was to maximize the ocular bioavailability of the carbonic anhydrase inhibitor, dorzolamide hydrochloride (DZD) via (a) enhancement of DZD corneal transport using terpene enhancers, (b) reducing pre-corneal loss of the installed dose via increased formulation viscosity, and (c) assessment of the in vivo intraocular pressure (IOP) lowering effects of test formulations using rabbit. DZD was formulated as a 2% ophthalmic solution containing different concentrations of HPMC as a viscosity improving agent (VIA), and (,)-carveol as a corneal penetration enhancer. The transport of DZD from test formulations was quantitatively determined using in vitro diffusion experiments, the permeability parameters were mathematically calculated, and the in vivo IOP lowering effects were assessed using a Tono-Pen XL® tonometer. The results revealed a good correlation between the in vitro permeability parameters and the in vivo ,IOP. The magnitude of the DZD-IOP lowering effects and durations of actions for DZD formulations were dependent on (a) the concentration of (,)-carveol, and (b) the contact period with ocular tissue which was found to be a single-valued function of the HPMC as VIA. Drug Dev Res 70, 2009. © 2009 Wiley-Liss, Inc. [source]

Effects of dose and particle size on activated carbon treatment to sequester polychlorinated biphenyls and polycyclic aromatic hydrocarbons in marine sediments

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2005
John R. Zimmerman
Abstract Recent laboratory studies show that mixing activated carbon with contaminated sediment reduces the chemical and biological availability of hydrophobic organic contaminants. In this study, we test the effects of varying the activated carbon dose and particle size in reducing the aqueous availability of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) and the uptake of PCBs by two benthic organisms. We mixed PCB- and PAH-contaminated sediment from Hunters Point Naval Shipyard, San Francisco Bay (CA, USA), for one month with activated carbon, at doses of 0.34, 1.7, and 3.4% dry mass basis. We found that increasing the carbon dose increased the effectiveness in reducing PCB bioaccumulation. In 56-d uptake tests with the benthic organisms Neanthes arenaceodentata and Leptocheirus plumulosus, PCB bioaccumulation was reduced by 93 and 90%, respectively, with 3.4% carbon. Increasing the dose also increased the effectiveness in reducing PCB and PAH aqueous concentrations and uptake by semipermeable membrane devices and quiescent flux of PCBs to overlying water. Decreasing activated carbon particle size increased treatment effectiveness in reducing PCB aqueous concentration, and larger-sized activated carbon (400,1,700 ,m) was ineffective with a contact period of one month. We invoke a numerical model based on intraparticle diffusion in sediment and activated carbon particles to help interpret our experimental results. This model was useful in explaining the trends for the effect of activated carbon dose and particle size on PCB aqueous concentrations in well-mixed systems. [source]

Potential Application of Hot Rehydration Alone or in Combination with Hydrogen Peroxide to Control Pectin Methylesterase Activity and Microbial Load in Cold-stored Intermediate-moisture Sun-dried Figs

JOURNAL OF FOOD SCIENCE, Issue 3 2004
D. DEMIRBÜKER
ABSTRACT: Sun-dried figs contain a considerable amount of pectin methylesterase (PME) activity (22 JAM COOH/ min/g). The enzyme causes softening and loss of desired gummy texture in cold-stored intermediate-moisture (IM) sun-dried figs brought to a 28% to 29% moisture range. Partial reduction of PME activity (28%) delayed undesirable textural changes in IM figs rehydrated at 80 °C for 16 min. The heat treatment did not cause a considerable reduction in microbial load. However, the addition of 2.5% H2O2 to the rehydration medium at 80 °C reduced the initial total mesophilic aerobic count of figs by at least 90% and turned the figs from a brown color to a desirable and stable yellow-light brown. The in situ fig catalase remains after rehydration at 80 °C. Thus, by reducing the contact period of figs with H2O2 or by pureeing figs, it is possible to eliminate residual H2O2 and to obtain safe and SO2-free light-colored fig products. [source]

2162: New aspects of the Slug Mucosal Irritation (SMI) assay: Detecting ocular stinging, itching and burning sensations

ACTA OPHTHALMOLOGICA, Issue 2010
J LENOIR
Purpose Our eyes are one of the most important senses. They are very sensitive and irritations may occur easily. A screening method for ocular discomfort would be very helpful in the development and refinement of formulations. In the past, the Slug Mucosal Irritation (SMI) assay demonstrated a relation between an increased mucus production (MP) in slugs and an elevated incidence of stinging, itching and burning (SIB) in human eyes. The aim of this study is to compare subjective ocular discomfort caused by shampoos evaluated in volunteers with results of the SIB-procedure. Methods The stinging potency of 1 artificial tear and 10 shampoos was evaluated with the SIB-procedure by placing 3 slugs per treatment group 3 times on 100 µl of the test item. After each 15 min contact period, MP was measured. Evaluation of the results is based upon the total MP during 3 repeated contact periods. Experiments were repeated 3 times. A Human Eye Irritation test with the same test items will be set up (12-period cross-over study, 24 volunteers, study approved by an independent Commission for Medical Ethics, associated with Ghent University Hospital). The participants are dripped 10 µl of a 5% or 10% shampoo dilution in water or the artificial tear in 1 eye, while in the other eye 10 µl of water is administered. The evaluation of the test substances is done both by participants and the ophthalmologist at several time points. Conclusion With the obtained results we will be able to improve the newly developed protocol and examine the predictability with reference to non- and mildly irritating formulations in humans. We hope to conclude that the SIB-procedure is a good tool to predict clinical ocular discomfort. [source]