Qualification of a precise and easy-to-handle sweat  casting imprint method for the prediction and  quantification of anti-perspirant efficacy.
A time- and cost-effective sweat casting method using the forearm as test site to assess the efficacy of several anti-perspirant formulations with a low number of test subjects has been evaluated and qualified. The imprint sweat casting method is based on a 2-component silcone-imprint technique to measure the efficacy of more than eight products in parallel with the same test subject. In studies using aluminum chlorohydrate (ACH) formulations as test anti-perspirants, a clear-cut correlation could be demonstrated between sweat gland activities measured by the imprint method and gravimetric measurement of sweat gland activities. Concentration-dependent inhibition of sweat gland activity could be observed with the imprint technique up to an ACH concentration of 15%, and all formulations containing 2% ACH or above resulted in statistically significant reduction of sweat gland activity (P < 0.001) when compared with untreated control areas. Furthermore, the SDs of individual studies using the imprint technique were in a range of +/-20% of sweat gland activity, which can be regarded rather low for in vivo measurements of a complex process like sweat secretion. A group-wise comparison between the measurements of anti-perspirant activity as determined by the imprint protocol and the Food and Drug Administration (FDA) Guideline compliant gravimetric hot-room protocol revealed that the test results for anti-perspirant activity obtained with the imprint protocol are similar to those obtained with the hot-room protocol. Moreover, the data generated with the imprint protocol have a high predictive value for the outcome of a later guideline-compliant hot-room test. As the imprint casting method tends to be a little more sensitive for formulations with low anti-perspirant activity, and seems to be associated with less interassay variability than the standard gravimetric hot-room test, the imprint casting method may select products which later fail to pass the standard gravimetric hot-room test. Meanwhile the imprint sweat casting has proven to be a robust method useful to support efficacy-oriented product development. Therefore, in later stages of utilization it might even evolve into an efficient claim substantiation tool.
Keyhani
R
R
Beiersdorf AG, Hamburg, Germany. Reza.Keyhani@Beiersdorf.com
Scheede
S
S
Thielecke
I
I
Wenck
H
H
Schmucker
R
R
Schreiner
V
V
Ennen
J
J
Herpens
A
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D051520:Antiperspirants; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013542:Sweat; D055815:Young Adult
D051520:Antiperspirants