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Percutaneous Penetration (percutaneou + penetration)
Selected AbstractsUse tests: ROAT (repeated open application test)/PUT (provocative use test): an overviewCONTACT DERMATITIS, Issue 1 2000Tokio Nakada As one step in defining the clinical relevance of exposure to an allergen identified with patch testing, use tests (provocative use test (PUT), and repeated open application test (ROAT)) have been used. In 1/2 of the cases of seemingly reliable patch tests, use tests are negative, suggesting that the patient's biologic threshold of response had not been reached with open application dosing. Dramatic differences exist in regional skin reactivity and percutaneous penetration. Negative results of use tests on normal skin may become positive on diseased skin. To refine this assay further, more controlled observations and analysis of reaction differences between normal and damaged skin, and among regional anatomic sites might be performed. In addition, we require a standardized measurement for the results. Use testing has significant potential in refinement of the evidence-based diagnosis of clinical relevance. However, for general validation, we should fill the deficiencies described above. [source] Deep percutaneous penetration into muscles and jointsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 7 2006Christine M. Lee Abstract The transdermal absorption of drugs and its subsequent deep tissue delivery is a complex process, with many factors influencing the penetration mechanisms. Nonsteroidal antiinflammatory drugs (NSAIDs) are widely used in the treatment of joint and muscle diseases. However, the dangers associated with oral medications highlight the need for alternative methods of targeting and retaining drugs; one such means is through topical delivery. The drug's lipophilicity, permeability, and fraction unbound found in the viable skin are some physiochemical factors influencing the delivery mechanism after transdermal absorption. These and other variables play a role in determining whether the drug reaches the deep tissues via direct penetration or from systemic redistribution. Pharmacokinetic models have been developed to help elucidate the penetration routes and efficacy for various drugs. While there are still uncertainties regarding the deep tissue penetration kinetics, improvements to current research methodologies may bring about a greater understanding of percutaneous absorption into the deep muscle and joints. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95: 1405,1413, 2006 [source] In vitro percutaneous penetration of acyclovir from solvent systems and Carbopol 971-P hydrogels: Influence of propylene glycolJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2005O. Díez-Sales Abstract The mechanism underlying propylene glycol (PG) effects on acyclovir (ACV) penetration through human epidermis were studied. Solvent systems and Carbopol gels containing increasing percentage of PG (from 0% to 70%, w/w) were used. Viscosity studies of both vehicles were carried out to characterise the influence of rheological behaviour. In solvent systems skin permeation values of ACV increase as the concentration of PG increase yielding a maximum enhancement ratio (ER,=,10) for 70% PG. The release rate of ACV from gels was determined. Higuchi's model was used to estimate the apparent diffusion coefficient of the drug. These values show a decrease as the content of PG in the vehicle increases; this effect could be attributed to the increase of the viscosity in the diffusional pathway. When gels are used skin permeation values of ACV were smaller than those of the solvent systems. This could be attributed to the network structure created by the polymer that increases the length of the diffusional pathway. The maximum ER (=6.8) was for Carbopol gel containing 50% PG. Therefore, these gels can be considered candidates for further research to confirm their usefulness as delivery systems for ACV topical formulations. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:1039,1047, 2005 [source] ,-Monoisostearyl glyceryl ether enhances percutaneous penetration of indometacin in-vivoJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 12 2002Atsushi Suzuki ABSTRACT Molecules that reversibly remove the barrier resistance of skin enhance penetration. ,-Monoisostearyl glyceryl ether (GE-IS) is a novel compound that can be used as a non-ionic surfactant and increases percutaneous penetration of indometacin in rat abdominal skin in-vitro. The present study investigated GE-IS-induced enhancement of indometacin penetration in-vivo. When 1% GE-IS in propylene glycol was applied to rat abdominal skin, serum and muscle concentrations of indometacin increased markedly. Anti-inflammatory activities of test solutions containing both indometacin and GE-IS were investigated in experimental models of acute and chronic inflammation. Application of indometacin with GE-IS to the skin produced greater inhibitory effects on carrageenan-induced rat paw oedema, UV-induced erythema in guinea-pigs, and adjuvant arthritis in rats, compared with application of indometacin alone. The results suggest that GE-IS enhances penetration in-vivo and improves the anti-inflammatory effects of indometacin in animal models. Thus, GE-IS might contribute to the development of cosmetic or medical formulations to improve transfer of bioactive substances to hypodermal sites. [source] Effect of solute lipophilicity on penetration through canine skinAUSTRALIAN VETERINARY JOURNAL, Issue 12 2003PC MILLS Objective To investigate the effect of lipophilicity on the percutaneous penetration of a homologous series of alcohols through canine skin Design Skin harvested from Greyhound thorax was placed in Franz-type diffusion cells and the in vitro passage of radio-labelled (14C) alcohols (ethanol, butanol, hexanol and octanol (Log P 0.19 - 3.0)) through separate skin sections was measured in replicates of five. Permeability coefficient (kP, cm/h), maximum flux (Jmax, mol/cm2/h) and residue remaining within the skin were determined. Results The kP increased with increasing lipophilicity (6.2 times 10 -4± 1.6 times 10 -4 cm/h for ethanol to 1.8 times 10 -2± 3.6 times 10 -3 cm/h for octanol). Alcohol residues remaining within each skin sample followed a similar pattern. An exponential decrease in Jmax with increasing lipophilicity was observed. Conclusion Changes in canine skin permeability occur with increasing alcohol lipophilicity. This finding has practical consequences for the design of topical formulations and optimisation of drug delivery through animal skin. [source] |