Lag time data for characterizing the pore pathway of intact and chemically pretreated human epidermal membrane

Li, S.Kevin; Suh, Wonhee; Parikh, Hemanshu H; Ghanem, Abdel‐Halim; Mehta, Samir C.; Peck, Kendall D.; Higuchi, William I.

doi:10.1016/s0378-5173(98)00139-2

Cited by 31 publications

(20 citation statements)

References 39 publications

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“…It should be pointed out that the resistance of drug diffusion in the aqueous boundary layer is several orders of magnitudes smaller than that of the stratum corneum (18,28,29), and is therefore considered negligible for drug transport under normal circumstances. However, the thermal resistance of the aqueous boundary layer is significant; the specific thermal resistance of water is in the same order of magnitude as that of the skin.…”

Section: Resultsmentioning

confidence: 99%

Characterization of Temperature Profiles in Skin and Transdermal Delivery System When Exposed to Temperature Gradients In Vivo and In Vitro

et al. 2017

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Purpose Performance of a transdermal delivery system (TDS) can be affected by exposure to elevated temperature, which can lead to unintended safety issues. This study investigated TDS and skin temperatures and their relationship in vivo, characterized the effective thermal resistance of skin, and identified the in vitro diffusion cell conditions that would correlate with in vivo observations. Methods Experiments were performed in humans and in Franz diffusion cells with human cadaver skin to record skin and TDS temperatures at room temperature and with exposure to a heat flux. Skin temperatures were regulated with two methods: a heating lamp in vivo and in vitro, or thermostatic control of the receiver chamber in vitro. Results In vivo basal skin temperatures beneath TDS at different anatomical sites were not statistically different. The maximum tolerable skin surface temperature was approximately 42–43°C in vivo. The temperature difference between skin surface and TDS surface increased with increasing temperature, or with increasing TDS thermal resistance in vivo and in vitro. Conclusions Based on the effective thermal resistance of skin in vivo and in vitro, the heating lamp method is an adequate in vitro method. However, the in vitro-in vivo correlation of temperature could be affected by the thermal boundary layer in the receiver chamber.

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Section: Resultsmentioning

confidence: 99%

Characterization of Temperature Profiles in Skin and Transdermal Delivery System When Exposed to Temperature Gradients In Vivo and In Vitro

et al. 2017

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“…The application of alternating current iontophoresis can maintain a constant state of enhanced electrical conductance of the human epidermal membrane [29]. The enhanced conductance was attributed to the induction of pores by the application of the electric field [30,31,32]. Application of a constant direct current provides controlled permeation and reduces the inter-subject variability; therefore, initial experiments were carried out to understand the electromigration properties of urea in the presence of other charged particles.…”

Section: Discussionmentioning

confidence: 99%

Reverse iontophoresis: a non-invasive technique for measuring blood urea level

Değim

İlbasmiş

Dündaröz

et al. 2003

Pediatric Nephrology

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Monitoring of the urea level of patients with insufficient kidney function requires repetitive blood sampling. The potentially painful nature of blood sampling and the difficulty of venous access, particularly in premature neonates, as well as possible complications of needle injuries, create many disadvantages. A non-invasive technique needs to be developed for monitoring the urea level for these patients. Reverse iontophoresis has recently gained importance and the possibility of extracting some compounds from body fluids using reverse iontophoresis has been reported in the literature. Moreover, a small, watch-type device has been developed for the determination of blood glucose levels using a similar approach. The aim of the current study was to investigate the possibility of extracting urea from blood through skin using reverse iontophoresis to monitor blood urea levels without taking a blood sample. In vitro iontophoresis studies have indicated that urea may be successfully transferred through the full thickness of human skin. The reverse iontophoresis technique was applied to 17 patients with kidney insufficiency and urea was successfully extracted through their skin into the collection solution. A high correlation ( r(2)=0.878) between urea concentrations in collection solutions and urea levels in the blood was observed. These results suggest that it is possible to make a watch-type device for monitoring blood urea levels.

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“…On the other hand, CyDs act as penetration enhancers by increasing drug availability at the surface of the biological barrier and they are hypothesized to increase the drug transport through a kinetic barrier existing at the skin vehicle interface [24]. In addition, drugs can be absorbed into the skin by aqueous pathway through hair follicles, sweat duct or intracellular aqueous pores in the stratum corneum [25][26][27]. CyD complexation can increase drug flux through such aqueous pores or barriers [28].…”

Section: Ex Vivo Permeation Studies Through Full Thickness Rat Abdomimentioning

confidence: 98%

A Transdermal Delivery System for Glipizide

Ammar

Salama²,

Ghorab³

et al. 2006

CDD

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Glipizide is one of the most commonly prescribed drugs for treatment of type 2 diabetes. Oral therapy with glipizide comprises problems of bioavailability fluctuations and may be associated with severe hypoglycaemia and gastric disturbances. As a potential for convenient, safe and effective antidiabetic therapy, the rationale of this study was to develop a transdermal delivery system for glipizide. For this purpose, inclusion complexes of the drug in beta-cyclodextrin (beta-CyD), dimethyl-beta-cyclodextrin (DM-beta-CyD), hydroxypropyl-beta-cyclodextrin (HP-beta-CyD), and hydroxypropyl-gamma-cyclodextrin (HP-gamma-CyD) were prepared. Several percutaneous formulations of the drug and the prepared complexes in different bases (o/w emulsion, polyethylene glycol, carboxymethyl cellulose and Carbopol) were developed. Release studies revealed an improved release of the drug from formulations containing glipizide-CyD complexes. Ex vivo permeation studies through full thickness rat abdominal skin were conducted, whereby the effect of several conventional penetration enhancers (propylene glycol [PG], oleic acid, urea, dimethyl sulfoxide, menthol, limonene and cineole) was monitored. Highest flux was obtained from ointments prepared with Carbopol gel base containing a combination of PG and oleic acid as well as ointments prepared in the same base utilizing glipizide-DM-beta-CyD complex and urea. In vivo studies on diabetic male Wistar rats revealed a marked therapeutic efficacy sustained for about 48 hours. In this respect, two formulations showed best biological performance. In the first formulation, the drug was incorporated in Carbopol gel base in the presence of 20% PG together with 15% oleic acid. The second was prepared by incorporating glipizide-DM-beta-CyD complex in Carbopol gel base in presence of 15% urea. The glucose tolerance test showed suppression of hyperglycaemia induced in glucose-loaded rats. The above-mentioned results might shed a strong beam of light on the feasibility of using glipizide in a transdermal delivery system for treatment of type 2 diabetes with the aim of improving both patient compliance and pathophysiology of the disease.

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Lag time data for characterizing the pore pathway of intact and chemically pretreated human epidermal membrane

Cited by 31 publications

References 39 publications

Characterization of Temperature Profiles in Skin and Transdermal Delivery System When Exposed to Temperature Gradients In Vivo and In Vitro

Characterization of Temperature Profiles in Skin and Transdermal Delivery System When Exposed to Temperature Gradients In Vivo and In Vitro

Reverse iontophoresis: a non-invasive technique for measuring blood urea level

A Transdermal Delivery System for Glipizide

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