The preparation of 3,5-dihydroxy-4-isopropylstilbene nanoemulsion and in vitro release

Figures & data

Figure 1 The solubility of DHPS in various components.

Table 1 Impacts of surfactants and co-surfactants on the nanoemulsion formation

Surfactants	Co-surfactants	Smix/oil
		9:1	8:2	7:3	6:4	5:5	4:6	3:7	2:8	1:9
EL-40	Ethanol	√	√	√	–	–	–	–	–	–
	n-butanol	√	√	–	–	–	–	–	–	–
	i-propanol	√	√	–	–	–	–	–	–	–
	1,2-propanediol	√	√	√	–	–	–	–	–	–
Tween-80	Ethanol	–	–	–	–	–	–	–	–	–
	n-butanol	–	–	–	–	–	–	–	–	–
	i-propanol	–	–	–	–	–	–	–	–	–
	1,2-propanediol	–	–	–	–	–	–	–	–	–

Notes: √ represents the formation of nanoemulsion; – represents the absence of formation of nanoemulsion.

Figure 2 The ternary phase diagram under different conditions.

Abbreviation: L₂, O/W microemulsion area.

Figure 3 The ternary phase diagram under different proportion condition.

Abbreviations: L₁, W/O nanoemulsion area; L₂, O/W nanoemulsion area; G, viscous area; G₁, viscous but opacified area; G₂, viscous but clarified area; E, ordinary emulsion area; W, the turbid area.

Figure 4 The phase behavior of nanoemulsions with different Smixs to oil.

Table 2 Physicochemical parameters of DHPS nanoemulsion (n = 3)

Parameter	Results
pH	5.69 ± 0.08
Refractive index	1.3875 ± 0.002
Viscosity/cP	3.25 ± 0.02
Structure type	O/W

Figure 5 The TEM image of DHPS nanoemulsion particles.

Figure 6 The mean size of DHPS nanoemulsion droplets.

Figure 7 FT-Raman spectra.

Table 3 The stability of drug nanoemulsion (n = 3)

Condition	pH	Average diameter/nm	Percentage/%
0 d	5.69 ± 0.01	62.89 ± 0.09	99.78 ± 0.01
60°C,5 d	5.67 ± 0.01	63.19 ± 0.10	99.20 ± 0.03
60°C,10 d	5.64 ± 0.01	62.01 ± 0.08	98.37 ± 0.05
4500 ± 500 lx, 5 d	5.66 ± 0.01	63.12 ± 0.11	98.95 ± 0.02
4500 ± 500 lx, 10 d	5.63 ± 0.02	63.32 ± 0.12	98.45 ± 0.03

Table 4 The accumulative osmotic quantity (Qt) and the penetration rate (J)

Sample	Regression curve	R
Drug DHPS	Qt = 0.53t + 1.73	0.9975
DHPS nanoemulsion	Qt = 24.51t – 3.51	0.9914

Figure 8 The in vitro transdermal release of drug DHPS and DHPS nanoemulsion (n = 3).

Scheme 1 Structure of DHPS.