Search results for "Transdermal"

Enhancement of nortriptyline penetration through human epidermis: influence of chemical enhancers and iontophoresis.

2008

Abstract Different known percutaneous chemical enhancers and iontophoresis have been tested in-vitro to study their ability to increase transdermal absorption of nortriptyline hydrochloride (20 mg mL−1). The chemicals 1-dodecanol, Span 20, Azone, (R)-(+)-limonene or isopropyl myristate were used as an overnight pretreatment at 5% (w/w) in ethanol. Furthermore, isopropyl myristate (20%, w/w) and propylene glycol (15%, w/w) were tested in the same vehicle. Iontophoresis was applied directly to the nortriptyline hydrochloride donor solution for three different concentrations (20, 2 and 0.5 mgmL−1). The chemical enhancers slightly increased the nortriptyline transdermal flux but iontophoresis w…

Clinical Problems with Transdermal Fentanyl Titration from 25 to 50 μg/hr

2001

Controlled iontophoretic release of glucocorticoids through epithelial cell monolayers

1998

In the present study the iontophoretic transdermal delivery of three different glucocorticoids through a confluent monolayer of MDCK cells, mimicking biological barriers, was studied. For this experiment an in vitro model with platinum electrodes for iontophoresis and MDCK cells was developed. With this model investigations concerning the biocompatibility of the cells depending on different current densities and the iontophoretic permeation of the three glucocorticoids through the cell monolayer were carried out. The permeation behavior of this living biological barrier should be very similar to the non-living barrier, human stratum corneum. Different current densities (12.74-38.22 microA/c…

The effect of hormone replacement therapy on Ca2+ mobilization and P-selectin (CD62P) expression in platelets examined under flow cytometry.

2004

A series of events, such as increase of cytoplasmic free calcium (Ca 2+ ) and expression of P-selectin (CD62P), an adhesion molecule, on the platelet surface, are significant indicators of platelet activation. We have used flow cytometry to examine Ca 2+ mobilization and CD62P expression in platelets in whole blood obtained in women prior to, and after, different forms of hormone replacement therapy. Thirty-two women completed a protocol consisting of two consecutive 1-month periods under oestradlol (E 2 ), administered orally (2 mg/day) or transdermally (50 μg/day) in random order, followed by a 4-week transdermal sequential regime, in which, during the last 14 days, either progesterone (3…

Nortriptyline hydrochloride skin absorption: development of a transdermal patch.

2007

The influence of propylen glycol (PG), ethanol, and oleic acid (OA) on nortriptyline hydrochloride (NTH) penetration through human epidermis was studied in vitro at two different pH values (5.5 and 7.4). The influence of lactic acid and polysorbate 80 was studied for a pH of 5.5. Permeation studies through Heat Separated Epidermis, as well as the enhancing effect of the different vehicles, showed a pH dependency. A pH value of 5.5 in the donor solution decreases significantly the permeability coefficient (Kp) with respect to a pH value of 7.4 (0.011+/-0.004 x 10(-6) versus 0.36+/-0.04 x 10(-6)cm/s). The vehicles showed an increasing enhancement effect in the order: polysorbate 80>ethanol/PG…

Penetration enhancer containing vesicles as carriers for dermal delivery of tretinoin.

2011

The ability of a recently developed novel class of liposomes to promote dermal delivery of tretinoin (TRA) was evaluated. New penetration enhancer-containing vesicles (PEVs) were prepared adding to conventional phosphatidylcholine vesicles (control liposomes) different hydrophilic penetration enhancers: Oramix® NS10 (OrNS10), Labrasol® (Lab), Transcutol® P (Trc), and propylene glycol (PG). Vesicles were characterized by morphology, size distribution, zeta potential, incorporation efficiency, stability, rheological behaviour, and deformability. Small, negatively charged, non-deformable, multilamellar vesicles were obtained. Rheological studies showed that PEVs had fluidity higher than conven…

High-performance liquid chromatographic determination of sumatriptan after in vitro transdermal diffusion studies.

2004

A simple, accurate, precise and rapid HPLC method with UV detection has been validated in order to determine the in vitro transdermal absorption of sumatriptan succinate. The HPLC method is a modification of that described by Nozal et al. [M.J. Nozal, J.L. Bernal, L. Toribio, M.T. Martin, F.J. Diez, J. Pharm. Biomed. Anal. 30 (2002) 285-291]. Separation was carried out on a 250 mm Kromasil C18 column at room temperature. The detector response, at 282.7 nm, was found to be linear in a concentration range between 0.145 and 145 microM. The limit of detection (LOD) was 0.019 microM and the limit of quantification (LOQ) was 0.145 microM.

Halloysite nanotubes for efficient loading, stabilization and controlled release of insulin

2018

Hypothesis: Oral insulin administration is not actually effective due to insulin rapid degradation, inactivation and digestion by proteolytic enzymes which results in low bioavailability. Moreover insulin is poorly permeable and lack of lipophilicity. These limits can be overcome by the loading of protein in some nanostructured carrier such as halloysite nanotubes (HNTs). Experiments: Herein we propose an easy strategy to obtain HNT hybrid materials for the delivery of insulin. We report a detailed description on the thermal behavior and stability of insulin loaded and released from the HNTs hybrid by the combination of several techniques. Findings: Release experiments of insulin from the H…

Controlled transdermal iontophoresis by ion-exchange fiber

2000

The objective of this study was to assess the transdermal delivery of drugs using iontophoresis with cation- and anion-exchange fibers as controlled drug delivery vehicles. Complexation of charged model drugs with the ion-exchange fibers was studied as a method to achieve controlled transdermal drug delivery. Drug release from the cation-exchange fiber into a physiological saline was dependent on the lipophilicity of the drug. The release rates of lipophilic tacrine and propranolol were significantly slower than that of hydrophilic nadolol. Permeation of tacrine across the skin was directly related to the iontophoretic current density and drug concentration used. Anion-exchange fiber was te…

Comparing metoclopramide electrotransport kinetics in vitro and in vivo.

2010

The purpose of this work was to investigate the transdermal iontophoretic delivery of metoclopramide and to determine (i) the dependence of electrotransport on current density and drug concentration, (ii) the relative contributions of electromigration and electroosmosis and (iii) the feasibility of administering therapeutic amounts of drug, using a drug-sparing iontophoretic configuration. Iontophoretic delivery of metoclopramide (MCL) across dermatomed porcine ear skin was investigated in vitro as a function of concentration (10, 20, 40, 80 and 100mM) and current density (0.1, 0.2 and 0.3mAcm(-2)) using vertical flow-through diffusion cells. In vivo studies were performed in Wistar rats (4…