title: A few aspects of transonychial water loss (TOWL): inter-individual, and intra-individual inter-finger, inter-hand and inter-day variabilities, and the influence of nail plate hydration, filing and varnish.
abstract: The aim of the study was to measure transonychial water loss (TOWL) in order to identify the extent of inter-individual, intra-individual inter-finger, inter-hand, and inter-day variabilities, and the influence of nail wetting, filing and varnishing on TOWL, with a view to determine parameters for the measurement of TOWL and its possible applications. Fingernail and toenail TOWL was measured using the condenser-chamber AquaFlux (Biox) and a specially designed Nail Adaptor supplied by Biox. A wide range of TOWL values (28-75g/m(2)h for fingernails and 26-48g/m(2)h for toenails) were found, with significant inter-individual variability. Intra-individual variability was lower; however, in the same individual, inter-finger, inter-hand/foot and inter-day variabilities were found, as well as a strong correlation between nail plate thickness and TOWL. Wetting the nails, even briefly, resulted in a significant rise in TOWL, which subsequently took much longer to return to control values. Filing the nail plate surface with a pharmaceutical file caused large increases in TOWL, whose profile (with number of filing strokes) was fairly different among individuals. As expected, nail varnish application reduced TOWL; the different extent of TOWL reduction by different varnishes suggests a potential use of TOWL measurements for product comparisons.
authors.affiliation: Department of Pharmaceutics, University of London, London, UK. sudax.murdan@pharmacy.ac.uk
authors.forename: Sudaxshina
authors.initials: S
authors.lastname: Murdan
authors.forename: Dhrumit
authors.initials: D
authors.lastname: Hinsu
authors.forename: Marie
authors.initials: M
authors.lastname: Guimier
mesh_terms: D001834:Body Water / Q000378:metabolism*; D005385:Fingers; D006225:Hand; D006801:Humans; D009262:Nails / Q000378:metabolism*; D013997:Time Factors; D014870:Water Loss, Insensible