Olive oil and clove oil-based nanoemulsion for topical delivery of terbinafine hydrochloride: in vitro and ex vivo evaluation

Figures & data

Table 1. Compositions of nanoemulsion formulations for formation of pseudo-ternary phase diagrams.

Batch	Oil: Smix	Oil		Smix		Water
		%(v/v)	mL	%(v/v)	mL	%(v/v)	mL
R1	1:9	5	0.5	45	4.5	50	5.0
R2	2:8	10	1.0	40	4.0	50	5.0
R3	3:7	15	1.5	35	3.5	50	5.0
R4	4:6	20	2.0	30	3.0	50	5.0
R5	5:5	25	2.5	25	2.5	50	5.0
R6	6:4	30	3.0	20	2.0	50	5.0
R7	7:3	35	3.5	15	1.5	50	5.0
R8	8:2	40	4.0	10	1.0	50	5.0
R9	9:1	45	4.5	5	0.5	50	5.0

All the batches R₁–R₉ were formulated for both the oils (clove oil and olive oil) with all the S_mix ratios (1:1, 1:2, and 2:1).

Table 2. Compositions of TF-HCl-loaded nanoemulsions formed with olive oil (F₁–F₆) and clove oil (F₇–F₁₂).

Batch		Oil:Smix ratio	Oil		Smix		Smix ratio
			%	mL	%	mL
Olive oil	F1	5:5	25	2.5	25	2.5	1:1
	F2	6:4	30	3.0	20	2.0	1:1
	F3	5:5	25	2.5	25	2.5	1:2
	F4	6:4	30	3.0	20	2.0	1:2
	F5	5:5	25	2.5	25	2.5	2:1
	F6	6:4	30	3.0	20	2.0	2:1
Clove oil	F7	5:5	25	2.5	25	2.5	1:1
	F8	6:4	30	3.0	20	2.0	1:1
	F9	5:5	25	2.5	25	2.5	1:2
	F10	6:4	30	3.0	20	2.0	1:2
	F11	5:5	25	2.5	25	2.5	2:1
	F12	6:4	30	3.0	20	2.0	2:1

In each batch, the drug amount was 100 mg and amount of water 5 mL.

Table 3. Solubility of TF-HCl to different oils, surfactants, and co-solvents (n = 3).

Material	Solubility (mg/mL)
Oils
Clove oil	90.31 ± 2.73
Olive oil	82.42 ± 1.82
Castor oil	75.15 ± 3.04
Coconut oil	12.22 ± 2.01
Surfactants
Tween 80	50.24 ± 1.28
Tween 20	45.87 ± 3.52
Co-solvents
Ethanol	30.28 ± 1.26
Isopropyl alcohol	20.43 ± 4.45

Figure 1. Pseudo-ternary phase diagrams for drug free nanoemulsions with S_mix values of (A) 2:1, (B) 1:2 and (C) 1:1. Both the oils showed similar kind of nanoemulsion behavior. The circles presented in the figure are showing successful nanoemulsion formation area.

Figure 2. Size distributions by intensity of nanoemulsion formulations (A) batch F₁, and (B) Batch F₇.

Table 4. Droplet sizes and PDI values of 5:5 oil:S_Mix nanoemulsions.

Batch	Average droplet size (nm)	PDI
F1	490 ± 8	0.34 ± 0.19
F3	635 ± 11	0.69 ± 0.14
F5	863 ± 4	0.25 ± 0.07
F7	222 ± 12	0.35 ± 0.13
F9	787 ± 6	0.01 ± 0.14
F11	924 ± 9	0.48 ± 0.34

Figure 3. FTIR spectra from top to down: TF-HCl, olive oil, clove oil, Tween 80, ethanol, nanoemulsion F₁, and nanoemulsion F₇. Wavelength areas representing functional groups of TF-HCl are framed in the figure: C = C stretching (green), C–N bending (black), and aromatic alkenyl C = C–H (blue) stretching bands (Anju and Kuriachan, 2017). These peaks were found either unchanged or very slightly shifted in nanoemulsion spectra.

Figure 4. Zeta potential values of nanoemulsion formulations F₁ and F₇.

Figure 5. SEM images of nanoemulsion formulations F₁ (left) and F₇ (right).

Table 5. pH, viscosity, refractive index, and entrapment efficiency values for the two optimized nanoemulsion formulations F₁ and F₇ (n = 3).

Batch	pH	Viscosity (cP)	Refractive Index	Entrapment efficiency (%)
F1	5.8 ± 1.1	1.20 ± 0.11	1.33 ± 0.08	97.53 ± 2.24
F7	6.0 ± 2.1	0.89 ± 0.77	1.33 ± 0.05	96.83 ± 3.58

Table 6. Skin irritation results 24 h after the application.

Animal	Group 1		Group 2		Group 3
	Control		Treated with F7 nanoemulsion		Treated with conventional cream
	Erythema	Edema	Erythema	Edema	Erythema	Edema
1	0	0	0	1	1	1
2	0	0	1	0	1	0
3	0	0	1	1	0	1
4	0	0	2	0	1	1
5	0	0	1	1	1	1
6	0	0	0	1	1	1
Average	0	0	0.8 ± 0.6	0.7 ± 0.5	0.8 ± 0.4	0.8 ± 0.4

Group 1 was the control group, Group 2 animals were treated with nanoemulsion formulation F₇, and group 3 animals were treated with conventional commercial cream (Lamisil). The numbers in the erythema scale are following: 0 none, 1 slight, 2 well defined, 3 moderate, 4 scar formation. In the edema scale the numbers are: 0 none, 1 slight, 2 well defined, 3 moderate, 4 severe.

Figure 6. Cumulative permeated drug as a function of time in skin permeation studies of conventional commercial cream and two optimized nanoemulsion formulations F₁ and F₇ (n = 3).

Figure 7. Drug retention studies of conventional cream and nanoemulsion formulation (F₇) with time (n = 3).

Figure 8. Photographs of skin sections of control group (Group 1), group treated with nanoemulsion F₇ (Group 2), and group treated with conventional commercial cream (Lamisil) (Group 3). No signs of edema or erythema were seen (the size of shaved area is approximately 2 × 2 cm²).

Table 7. CBC results for control group animals (Group 1), nanoemulsion F₇ treated animals (Group 2), and conventional cream (Lamisil) treated animals (Group 3) (n = 3).

	Group 1: control group	Group 2: nanoemulsion F7	Group 3: conventional cream (lamisil)
White blood cells	12.5 ± 0.1	11.2 ± 0.1	8.2 ± 0.1
Red blood cells	8.1 ± 0.0	8.6 ± 0.0	7.8 ± 0.0
Platelets	853 ± 1	706 ± 1	589 ± 1

Figure 9. Skin photomicrographs (magnification 40x) of histopathological samples of (A) control Group 1 (B) nanoemulsion treated Group 2, and (C) conventional cream (Lamisil) treated Group 3.

Anju V, Kuriachan M. (2017). Formulation and evaluation of terbinafine hydrochloride loaded microsponge based gel for topical sustained delivery. Int J Pharm Pharm Res 10:69–93.

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Data availability statement

The data presented in this study are available on request from the corresponding author (Mohammad Imran Khan).