. Author manuscript; available in PMC: 2016 Mar 25.

Published in final edited form as: J Pharm Sci. 2015 Jan 21;104(4):1499–1507. doi: 10.1002/jps.24334

Table 2.

Estimates of the Disposition of Chemical for Skin Exposed to Air or Liquid with a High Saturation Limit at the End of the Exposure for Four Example Compounds at Three Different Exposure Durations and at Maximum Activity (i.e., Saturated in an Aqueous Vehicle)^*

Compound		χ	t_exp	t_exp/t_lag	F_abs	F_abs (alt)	m₀	m_T	F_abs × m₀/m_T	t_90%/t_lag	t_90%
Ethanol	Air	155	5 min	0.29	0.20	0.19	48.8	9.71	1.00	1.9	0.6
			1 h	3.4	0.34	0.34	98.6	114	0.29
			10 × t_lag	10	0.34	0.34	98.8	330	0.10
	Liquid	1000	5 min	0.29	0.19	0.19	48.8	9.51	1.00	1.9	0.6
			1 h	3.4	0.33	0.33	98.6	114	0.29
			10 × t_lag	10	0.33	0.33	98.8	330	0.10
Diphenylamine	Air	5.3	5 min	0.062	0.24	0.21	0.081	0.019	1.00	2.0	2.7
			1 h	0.75	0.40	0.41	0.270	0.119	0.90
			10 × t_lag	10	0.44	0.44	0.354	1.22	0.13
	Liquid	1000	5 min	0.062	0.091	0.056	0.081	0.007	1.00	1.9	2.5
			1 h	0.75	0.28	0.30	0.270	0.088	0.87
			10 × t_lag	10	0.33	0.33	0.354	1.18	0.10
Benzylbutyl-phthalate	Air	0.48	5 min	0.0094	0.69	0.68	0.043	0.029	1.00	4.7	41
			1 h	0.11	0.72	0.71	0.147	0.105	1.00
			10 × t_lag	10	0.78	0.78	0.476	1.80	0.21
	Liquid	1000	5 min	0.0094	0.036	0.010	0.043	0.002	1.00	1.9	17
			1 h	0.11	0.12	0.094	0.147	0.018	1.00
			10 × t_lag	10	0.33	0.33	0.476	1.59	0.10
p-Nitroaniline	Air	0.060	5 min	0.065	0.95	0.95	1.00	0.95	1.00	5.6	7.2
			1 h	0.78	0.96	0.96	3.31	3.34	0.95
			10 × t_lag	10	0.96	0.96	4.28	17.0	0.24
	Liquid	1000	5 min	0.065	0.093	0.058	1.00	0.093	1.00	1.9	2.5
			1 h	0.78	0.29	0.30	3.31	1.11	0.85
			10 × t_lag	10	0.33	0.33	4.28	14.3	0.10

Definitions (in alphabetical order): F_abs, fraction of chemical in the SC at end of the chemical exposure that is predicted to absorb systemically (unitless). Calculated with 1st 20 terms of Eq. (16); F_abs (alt), alternate form of F_abs calculated from Eq. (20); m₀, initial mass in membrane at the end of the exposure duration (mg), assuming an exposed area of 180 cm² and a vehicle concentration equal to the water saturation value; m_T, total mass absorbed into the body from the entire transient exposure (mg), both during and after the exposure, assuming the same exposure area and vehicle concentration, t_90%, estimated time to 90% of F_abs (h); t_lag, lag time for chemical transport through the SC (h), taken from Table 1; t_exp, length of time that skin is exposed to the chemical; χ, ratio of the evaporation rate from the SC surface to the dermal absorption rate through the SC (unitless), calculated for air exposure as described in Table 1.