Evaluation of Ex Vivo Human Skin Permeation of Genistein and Daidzein

Figures & data

FIG. 1 Chemical structures of DAI and GEN.

TABLE 1 Solubility of GEN and DAI contained in the dry soy extract

Vehicle	GEN (mg/ml ± s.d.)	DAI mg/ml ± s.d.)
Polyethylene glycol 400	8.51 ± 0.43	8.53 ± 0.46
Labrasol®	8.05 ± 0.21	5.73 ± 0.12
Transcutol®	6.83 ± 0.03	6.86 ± 0.03
Propylene glycol	4.34 ± 0.03	2.61 ± 0.02
Oleic acid	0.025 ± 0.008	0.001 ± 0.001
Water	0.015 ± 0.005	0.013 ± 0.01

TABLE 2 Permeation parameters of GEN and DAI from the dry soy extract saturated vehicles

	GEN			DAI
Vehicle	Permeated amount after 24 hr (μg/cm^2 ± s.d.)	Flux (μg/cm^2/hr)	Permeability coefficient (Kp)(cm^2/hr)	Permeated amount after 24 hr (μ g/cm^2 ± s.d.)	Flux (μ g/cm^2/hr)	Permeability coefficient (Kp)(cm^2/hr)
Polyethylene glycol 400	31.7 ± 8.7	1.3 ± 0.4	1.5 × 10^− 4	23.9 ± 11.9	1.0 ± 0.5	1.2 × 10^− 4
Labrasol	5.6 ± 0.4	−**	−	−	−	−
Transcutol	5.8 ± 0.2	−**	−	−	−	−
Propylene glycol	12.3 ± 3.2	0.5 ± 0.1	1.2 × 10^−5	9.8 ± 3.9	0.4 ± 0.2	1.5 × 10^−5
Oleic acid	−*	−	−	−	−	−
Water	−	−	−	−	−	−

*Not detectable

**lower than 0.1 μg/cm²/hr.

TABLE 3 Relevant physicochemical parameters of GEN and DAI

	Molecular weight	Melting point (°C)	Virtual log P	Solubility** (mg/ml ± s.d.)
DAI	270.24	320	3.16	11.6 ± 0.1
GEN	254.24	303	2.87	12.3 ± 0.7

*Calculated by VEGA software.

** determined in PEG 400.

TABLE 4 Permeation parameters of pure GEN and DAI from PEG400 (mean ± s.d.)

	Retained amount after 24 hr (μg/cm^2)	Permeated amount after 24 hr (μg/cm^2)	Flux (μg/cm^2/hr)	Permeability coefficient (Kp) (cm^2/hr)
DAI	80.7 ± 3.9	37.3 ± 16.8	1.7 ± 0.8	1.5 × 10^−4
GEN	36.0 ± 0.4	155.7 ± 18.2	7.1 ± 0.8	5.8 × 10^−4