Penetration-Enhancing Effect of Ethanolic Solution of Menthol on Transdermal Permeation of Ondansetron Hydrochloride Across Rat Epidermis

Figures & data

TABLE 1 Composition of HPC gel drug reservoir containing ondansetron hydrochloride and selected concentrations of menthol

	Quantity present in the HPC drug reservoir formulation (%w/w)
Ingredients	I	II	III	IV	V
Ondansetron hydrochloride	1.5	1.5	1.5	1.5	1.5
Menthol	0	2	4	8	10
HPC	2	2	2	2	2
Ethanol (60%v/v) q.s.	100	100	100	100	100

HPC = hydroxypropyl cellulose.

TABLE 2 Mean (+SD) amount permeated (Q₂₄), flux (J), permeability coefficient (k_p) and enhancement ratio (ER) of ondansetron hydrochloride from various solvent systems across rat epidermis (n = 3)

Solvent system	Solubility (mg/mL)	Q24	J (μ g/cm^2.h)	kp (cm/h × 10^− 3)	Mean ER
Water	343.7 ± 0.9	57.60 ± 1.47	2.47 ± 0.13	0.16 ± 0.01	1
Ethanol	507.4 ± 1.2	174.76 ± 6.40	7.58 ± 0.23	0.51 ± 0.02	3.07
Ethanol-water (20:80 v/v)	586.2 ± 0.5	82.44 ± 3.01	3.50 ± 0.11	0.23 ± 0.01	1.42
Ethanol-water (40:60 v/v)	867.9 ± 1.0	125.66 ± 1.11	5.45 ± 0.10	0.36 ± 0.01	2.21
Ethanol-water (60:40 v/v)	924.5 ± 1.2	205.24 ± 6.80	8.91 ± 0.27	0.59 ± 0.02	3.61

*Significant at p < 0.001 when compared with water.

FIG. 1 Mean (± SD) amount of ondansetron hydrochloride permeated across rat epidermis from water alone, ethanol alone, 20:80 v/v, 40:60 v/v or 60:40 v/v of ethanol-water cosolvent systems.

FIG. 2 Mean (±SD) amount of ondansetron hydrochloride permeated across rat epidermis from 2% w/w of HPC gel containing selected concentrations of menthol as a penetration enhancer.

TABLE 3 Effect of menthol on the in vitro permeation parameters of ondansetron hydrochloride from HPC gel reservoir system across rat epidermis (n = 3)

Concentration of menthol (% w/w)	Solubility mg/mL	Q24 (μg/cm^2)	DRE (μ g/g)	J (μ g/cm^2.h)	Kp (cm/h × 10^− 3)	Mean ER
0 (control)	924.5 ± 5.2	162.16 ± 4.57	1200.10 ± 201.56	5.96 ± 0.08	0.39 ± 0.01	1
2	925.67 ± 7.6	1135.48 ± 70.98	1469.25 ± 115.36	49.25 ± 3.39	3.28 ± 0.23	8.26
4	921.70 ± 9.8	1636.48 ± 44.43	1869.63 ± 156.01	68.25 ± 4.78	4.55 ± 0.32	11.45
8	921.01 ± 10.1	1870.88 ± 62.51	2069.98 ± 100.90	77.85 ± 2.85	5.19 ± 0.19	13.06
10	920.00 ± 11.4	1894.38 ± 62.48,^#	2290.56 ± 169.67, ^#	77.81 ± 2.31, ^#	5.19 ± 0.15, ^#	13.06

Data shown as mean ± SD.; DRE: Drug retained in rat epidermis after 24 h of permeation study.

*Significant at p < 0.001 when compared to control; #: p > 0.05 when compared with 8% w/w of menthol. HPC = hydroxypropyl cellulose.