A time correlation study between reflectance spectroscopic cutaneous vasoconstriction and plasma corticosteroid concentration

Skin-blanching is associated with FEV(1), allergy, age and gender in asthma families

BACKGROUND

Inhaled glucocorticosteroids reduce airway inflammation in asthma patients, thereby improving lung function and reducing airway hyperresponsiveness and symptoms. The response to glucocorticosteroids can be measured with the glucocorticosteroid skin-blanching test. We investigated if asthmatics have a lower skin-blanching response to glucocorticosteroids than non-asthmatic subjects and if asthmatics with airway obstruction have lower skin-blanching response than those without obstruction. Finally, we assessed which clinical and inflammatory parameters influence the variability in skin-blanching response.

METHODS

We evaluated the skin-blanching response to topical budesonide in a large group of 315 well-characterized asthmatics and their relatives (asthma n = 114, healthy n = 140, other = 61).

RESULTS

The skin-blanching scores of the asthma probands and their healthy spouses were not significantly different. The skin-blanching score of patients with FEV(1) < 80% predicted was lower than of patients without obstruction. Lower skin-blanching score was significantly associated with lower FEV(1) %predicted, higher age, female gender, absence of allergy and summer season, but not with use of inhaled or oral glucocorticosteroids or packyears smoking.

CONCLUSIONS

Asthmatics do not have lower skin-blanching response to glucocorticosteroids than healthy subjects. Furthermore, lower skin-blanching response to glucocorticosteroids is associated with lower FEV(1), female gender, higher age and the absence of allergy.

The skin-blanching assay

The skin-blanching assay is used for the determination and bioequivalence of dermatologic glucocorticoids (GCs). The exact mechanism of the production of blanching is not fully understood, but it is considered that local vasoconstriction of the skin microvasculature and the consequent blood-flow reduction cause this phenomenon. Several factors influence skin blanching, including drug concentration, duration of application, nature of vehicle, occlusion, posture and location. The intensity of vasoconstriction can be measured in several ways: visual or quantitative methods, such as reflectance spectroscopy, thermography, laser Doppler velocimetry and chromametry. In literature, contradicting results in the correlation of the skin-blanching assay with different tests to determine GC sensitivity have been reported, limiting its clinical usefulness.

Improved risk-benefit ratio for topical triamcinolone acetonide in TransfersomeR in comparison with equipotent cream and ointment: a randomized controlled trial

BACKGROUND

Transfersome is a drug delivery technology based on highly deformable, ultraflexible lipid vesicles which penetrate the skin when applied non-occlusively.

OBJECTIVES

To assess the advantages of this carrier-based formulation in humans, the efficacy and the atrophogenic potential of triamcinolone acetonide (TAC) in Transfersome was compared with commercially available TAC-containing cream and ointment.

METHODS

Healthy volunteers were enrolled in double-blind, placebo-controlled clinical trials with random study medication assignment to the test areas.

RESULTS

A 10-fold lower dose of TAC in Transfersome(R) (2.5 micro g cm-2) was bioequivalent to 25 micro g cm-2 TAC in conventional formulations as measured by erythema suppression (cream: P = 0.01, ointment: P < 0.001). A skin blanching assay revealed different kinetics of the formulations, with a delayed onset of action of the Transfersome and ointment preparations. Ultrasonic measurements revealed a significantly reduced atrophogenic potential. There was a 12.1% reduction in skin thickness given by TAC in Transfersome compared with a 21.1% reduction given by a bioequivalent dose in TAC cream after a 6-week treatment period (P = 0.007).

CONCLUSIONS

Transfersome may significantly improve the risk-benefit ratio of topically applied glucocorticosteroids.