Development and Optimization of Terpene-Enriched Vesicles (Terpesomes) for Effective Ocular Delivery of Fenticonazole Nitrate: In vitro Characterization and in vivo Assessment

Figures & data

Table 1 The Independent and Dependent Variables for the 3² Full Factorial Design Used for the Preparation of FTN Loaded TPs

Factors (Independent Variables)	Levels
X1: Terpene type	Eugenol	Fenchone	Limonene
X2: Terpene amount (mg)	10	20	30
Responses (dependent variables)	Constraints
Y1: EE (%)	Maximize
Y2: PS (nm)	Minimize
Y3: PDI	Minimize

Abbreviations: FTN, fenticonazole nitrate; TPs, terpesomes; EE%, entrapment efficiency percent; PS, particle size; PDI, polydispersity index.

Table 2 Output Data of the 3² Full Factorial Analysis of TPs Formulations and Predicted and Observed Values for the Selected TPs (TP2)

Responses	EE%	PS (nm)	PDI
Adequate precision	13.81	51.30	9.36
Adjusted R^2	0.89	0.99	0.83
Predicted R^2	0.78	0.98	0.64
Significant factors	X1, X2	X1, X2	X2
Predicted value of selected formula (TP2)	78.68	285.65	0.49
Observed value of selected formula (TP2)	78.61	283.30	0.50

Abbreviations: TPs, terpesomes; EE%, entrapment efficiency percentage; PS, particle size; PDI, polydispersity index.

Figure 1 The effect of (A) terpene type and (B) terpene amount on EE% of FTN loaded TPs.

Abbreviations: EE%, entrapment efficiency percent; FTN, fenticonazole nitrate; TP, terpesomes.

Figure 2 The effect of (A) terpene type and (B) terpene amount on PS of FTN loaded TPs.

Abbreviations: PS, particle size; FTN, fenticonazole nitrate; TP, terpesomes.

Figure 3 The effect of (A) terpene type and (B) terpene amount on PDI of FTN loaded TPs.

Abbreviations: PDI, polydispersity index; FTN, fenticonazole nitrate; TP, terpesomes.

Table 3 Experimental Runs, Independent Variables, and Measured Response of the 3² Full Factorial Experimental Design of FTN Loaded TPs

Formulation Code	Terpene Type	Terpene Amount (mg)	EE%	PS (nm)	PDI
TP1	Eugenol	10	80.85±0.41	425.80±18.31	0.73±0.12
TP2	Eugenol	20	78.68±0.36	285.30±0.61	0.50±0.004
TP3	Eugenol	30	73.18±0.31	233.30±2.62	0.51±0.008
TP4	Fenchone	10	82.23±0.89	824.80±36.55	0.76±0.10
TP5	Fenchone	20	81.11±0.37	796.70±30.55	0.72±0.10
TP6	Fenchone	30	73.61±3.26	467.20±13.58	0.46±0.04
TP7	Limonene	10	89.96±0.76	1378.00±77.56	0.83±0.02
TP8	Limonene	20	86.71±0.25	793.70±40.56	0.54±0.02
TP9	Limonene	30	81.12±0.78	777.70±23.03	0.46±0.11

Note: Data represented as mean ± standard deviation (n = 3).

Abbreviations: FTN, fenticonazole nitrate; TP, terpesomes; EE%, entrapment efficiency percentage; PS, particle size; PDI, polydispersity index.

Table 4 Characterization Results for the Selected TPs (TP2) and the Optimized TPs

Formula	EE%	PS (nm)	PDI	ZP (mV)
TP2	78.68±0.36	285.30±0.61	0.50±0.00	5.43±0.19
Optimized TPs	79.02±2.35	287.25±9.55	0.46±0.01	35.40±1.10

Abbreviations: TPs, terpesomes; EE%, entrapment efficiency percent; PS, particle size; PDI, polydispersity index; ZP, zeta potential.

Figure 4 Morphology of the optimized TPs.

Abbreviations: FTN, fenticonazole nitrate; TPs, terpesomes.

Figure 5 In-vitro release profile of FTN from the optimized TPs in comparison with that of drug suspension.

Abbreviations: FTN, fenticonazole nitrate; TPs, terpesomes.

Figure 6 In vivo study graphical chart of FTN suspension and FTN-loaded TPs treated groups.

Abbreviations: FTN, fenticonazole nitrate; TPs, terpesomes.

Figure 7 Photomicrographs showing histopathological sections (hematoxylin and eosin stained) of normal untreated rabbit’s eye (group I) and rabbit’s eye treated with FTN loaded optimized TPs (group II). (A) illustrates histological structure of the cornea and (B) illustrates histological structure of the retina, choroid and sclera.

Abbreviations: FTN, fenticonazole nitrate; TPs, terpesomes.