Chemoprevention of skin cancer using low HLB surfactant nanoemulsion of 5-fluorouracil: a preliminary study

Figures & data

Figure 1. Pseudo-ternary phase diagrams showing w/o nanoemulsions zones for aqueous phase (deionized water), oil (Lauroglycol-90), surfactant (Transcutol-HP) and cosurfactant (isopropyl alcohol) at different Smix ratios [a (1:0), b (1:1), c (2:1) and d (3:1)].

Table 1. Composition of low HLB surfactant based nanoemulsions that passed thermodynamic stability tests.

	Formulation composition (% w/w)
Code	Aqueous phase^a (deionized water)	Surfactant (Transcutol-HP)	Cosurfactant (IPA)	Oil phase (Lauroglycol-90)	Smix ratio
F1	10	20	20	50	1:1
F2	15	20	20	45	1:1
F3	20	25	25	30	1:1
F4	10	26.66	13.33	50	2:1
F5	15	26.66	13.33	45	2:1
F6	20	33.33	16.67	30	2:1
F7	10	30	10	50	3:1
F8	15	30	10	45	3:1
F9	20	37.50	12.50	30	3:1

^aAqueous phase containing 1% w/w of 5-fluorouracil (10 mg ċ g⁻¹), IPA-isopropyl alcohol.

Table 2. Characterization of developed nanoemulsions in terms of droplet size distribution, zeta potential, refractive index and viscosity (n = 3).

Formulation	Δdm ± SD (nm)	p¡	ZP (mV)	RI ± SD	η ± SD (cps)
F1	124.30 ± 4.87	0.341	−25.21	1.393 ± 0.008	106.43 ± 6.16
F2	98.60 ± 3.74	0.324	−25.32	1.394 ± 0.009	86.10 ± 6.57
F3	87.50 ± 3.21	0.312	−26.10	1.391 ± 0.010	72.45 ± 5.66
F4	112.20 ± 4.27	0.297	−25.50	1.394 ± 0.009	93.34 ± 5.56
F5	92.70 ± 3.11	0.287	−25.10	1.390 ± 0.008	75.76 ± 5.55
F6	78.20 ± 2.98	0.272	−25.30	1.391 ± 0.005	60.35 ± 4.98
F7	102.50 ± 3.10	0.288	−24.90	1.394 ± 0.005	81.54 ± 6.21
F8	84.10 ± 2.89	0.275	−24.82	1.391 ± 0.011	65.25 ± 6.62
F9	68.20 ± 2.65	0.219	−25.92	1.392 ± 0.013	50.15 ± 3.16

Average droplet diameter (Δ_dm); Polydispersity index (p_¡); Zeta potential (ZP); Refractive index (R_I); Viscosity mean (η); SD: Standard deviation.

Figure 2. In vitro skin permeation profile of 5-fluorouracil through rat skin (mean ± SD, n = 3) from different w/o nanoemulsions (F1–F9) and aqueous solution of 5-fluorouracil (control).

Table 3. Permeability parameters of different w/o nanoemulsions (F1–F9) and control.

Formulation	JSS (µg cm^−2 h^−1)^a	Kp (cm h^−1)^a × 10^−2	Er
Control^b	9.24 ± 1.04	0.092 ± 0.002	–
F1	160.30 ± 7.84	1.603 ± 0.035	17.34
F2	168.30 ± 8.64	1.683 ± 0.038	18.21
F3	180.70 ± 10.80	1.807 ± 0.042	19.55
F4	165.40 ± 8.32	1.654 ± 0.034	17.90
F5	171.00 ± 9.42	1.710 ± 0.039	18.50
F6	183.00 ± 11.15	1.830 ± 0.043	19.80
F7	173.90 ± 9.75	1.739 ± 0.040	18.82
F8	193.10 ± 12.24	1.931 ± 0.047	20.89
F9	206.40 ± 14.56	2.064 ± 0.050	22.33

^aMean ± SD, n = 3.

^baqueous solution of 5-fluorouracil was used as control.

Table 4. Stability studies on F9 in terms of physicochemical parameters at refrigerator temperature.

Time (months)	Δdm ± SD (nm)	p¡	ZP (mV)	RI ± SD	η ± SD (cps)
0	68.20 ± 2.65	0.219	−25.92	1.392 ± 0.013	50.15 ± 3.16
1	68.80 ± 2.81	0.221	−26.22	1.395 ± 0.014	51.03 ± 3.27
2	69.30 ± 2.95	0.224	−26.88	1.398 ± 0.015	50.89 ± 3.36
3	69.90 ± 2.98	0.226	−27.08	1.340 ± 0.015	51.21 ± 3.38

Figure 3. Cell viability (mean % cell viability ± SD, n = 3) of 5-fluorouracil (5-FU) in aqueous solution (free 5-FU), control and optimized nanoemulsion (F9) on SK-MEL-5 melanoma cell lines.

Table 5. Cytotoxicity (%) and IC50 of free 5-FU, optimized nanoemulsion (F9) and control on melanoma cancer cell lines (n = 3).

	Cytotoxicity (% ± SD)			IC50
Concentration (µM)	Free 5-FU	F9	Control	Free 5-FU	F9	Control
0	0	0	0
3.75	−20.00 ± 1.00	2.70 ± 0.11	0.54 ± 0.00
7.50	−16.50 ± 0.92	3.30 ± 0.20	2.60 ± 0.20
15	−3.20 ± 0.16	1.90 ± 0.08	5.20 ± 0.50	ND	38	–
30	1.80 ± 0.20	36.80 ± 2.24	8.30 ± 1.10
60	−10.30 ± 0.70	57.20 ± 3.85	11.10 ± 1.20
120	5.40 ± 0.32	60.60 ± 4.12	12.40 ± 1.30

Concentration leading 50% cell death (IC50), not detected (ND).