Fig 1.
Static diffusion (Franz) cell.
Photo (a) and schematic diagram (b) of a Franz cell, showing the sample chamber (1) and collar (2), made from stainless steel, and lower collection chamber (3) made of quartz. The nail sample was placed on a lip in the collar such that the upper surface of the nail was orientated upwards, the sample chamber was then screwed onto the collar, clamping the nail in place. Compounds were applied to the well created by the sample chamber and the top of the nail plate. The collection chamber was filled with UPW.
Table 1.
Hydrophobicity (lipophilicity, LogP) and Molecular Weight (Mw) of test compounds.
Fig 2.
Quantification of compounds associated with nail samples.
Nail lysates were prepared from nail discs and analysed by LC-MS/MS. Caffeine could not be identified due to lack of stability in 5 M NaOH used to lyse the nail (Table C in S1 File). Data were normalised to the weight of the individual nail samples. Error bars represent standard error of the mean of data from 4–5 different nails for each compound.
Fig 3.
Total drug that passed through the nail.
(a) The number of Franz cells in which drug was detected to have passed through the nail. (b) Drug flux through the nail. Error bars representing standard error of the mean are shown for compounds where at least 3 values were above the LLoQ.