A novel transdermal nanoethosomal gel of betahistine dihydrochloride for weight gain control: in-vitro and in-vivo characterization

Figures & data

Table 1 Observed responses in Box–Behnken design for BDH in different ethosomal formulations

Formulation code	Independent variables			Dependent variables (mean ± SD)
	X1	X2	X3	Y1	Y2	Y3	Y4
1	0	1	1	84.32±4.78	82.72±0.84	55.09±1.56	0.25±0.04
2	1	1	0	291.40±3.93	83.34±0.97	42.59±2.56	0.16±0.05
3	0	−1	−1	148.00±2.15	83.43±0.76	46.51±1.99	0.20±0.03
4	0	−1	1	103.10±2.43	83.67±0.55	58.43±2.45	0.25±0.04
5	1	−1	0	236.50±5.61	83.48±0.74	38.66±3.56	0.18±0.02
6	0	1	−1	136.90±10.0	83.48±0.80	46.37±3.43	0.16±0.03
7	0	0	0	233.60±3.31	82.62±0.82	44.62±1.50	0.19±0.01
8	−1	−1	0	142.40±2.15	83.05±0.34	51.60±1.78	0.26±0.04
9	−1	0	−1	68.55±1.04	83.10±0.47	42.59±1.97	0.18±0.05
10	−1	1	0	55.48±1.30	82.31±0.67	47.97±2.23	0.22±0.03
11	−1	0	1	78.68±3.37	82.33±0.87	72.35±3.78	0.35±0.05
12	1	0	1	156.80±1.65	83.33±0.54	43.60±0.56	0.16±0.05
13	1	0	−1	290.50±4.30	83.24±0.82	49.30±0.94	0.20±0.02
14	0	0	0	226.50±2.22	82.45±0.96	44.62±2.12	0.16±0.01
15	0	0	0	238.90±3.45	82.62±0.72	44.62±1.02	0.19±0.03
16*	−1	−1	−1	55.28±2.25	85.46±0.50	46.50±0.79	0.21±0.02
Independent variables	Low (−1)	Medium (0)	High (+1)
X1 = Phosphatidylcholine concentration (%W/V)	2	3	4
X2 = Propylene glycol concentration (%V/V)	10	15	20
X3 = Ethanol concentration (%V/V)	30	40	50

Notes: Y1: size (nm), Y2: EE%, Y3: Q_{6 h} (% released after 6 h), and Y4: Flux (mg/cm²/h).

* Optimized formulation.

Abbreviations: BDH, betahistine dihydrochloride; EE, entrapment efficiency.

Table 2 Composition of experimental diet

Component	% (W/W)
Casein	21
Methionine	0.2
Corn starch	47.4
Sucrose	20
Corn oil	5.4
Mineral mixture	4
Vitamin mixture	1
Cellulose	1

Table 3 Data of regression analysis for responses Y1, Y2, Y3, and Y4 for fitting to quadratic model

Quadratic model	R^2	Adjusted R^2	Predicted R^2	SD	% CV
Y1	0.99	0.99	0.96	7.42	4.47
Y2	0.99	0.97	0.93	0.077	0.093
Y3	0.99	0.98	0.91	1.06	2.17
Y4	0.98	0.95	0.89	0.011	5.39
Regression equation of the fitted quadratic model
Y1= +233.00 + 78.76X1 − 7.74X2 − 27.63X3 + 35.45X1X2 − 35.96X1X2 −1.92X2X3 −10.5X1^2 − 41.05X2^2 − 73.87X3^2
Y2 = +82.56 + 0.33X1 − 0.22X2 − 0.14X3 + 0.15X1X2 + 0.23X1X3 − 0.25X2X3 + 00.085X1^2 + 0.39X2^2 + 0.37X3^2
Y3 = +44.94 − 5.04X1 − 0.40X2 + 5.59X3 +1.89X1X2 − 8.87X1X3 − 0.8X2X3 + 0.31X1^2 − 0.052X2^2 + 6.71X3^2
Y4 = +0.18 − 0.039X1 − 0.012X2 + 0.034X3 + 0.005X1X2 − 0.052X1X3 + 0.01X2X3 + 0.016X1^2 + 0.008X2^2 + 0.026X3^2

Figure 1 3D-response surface plots showing the effect of independent variables on vesicle size and EE%.

Abbreviations: EE, entrapment efficiency; PC, phosphatidylcholine; PG, propylene glycol.

Figure 2 3D-response surface plots showing the effect of independent variables on % cumulative release (Q_{6 h}) and flux.

Abbreviations: PC, phosphatidylcholine; PG, propylene glycol.

Figure 3 TEM photomicrograph of the optimized BDH ethosomes (F16).

Abbreviations: BDH, betahistine dihydrochloride; TEM, transmission electron microscopy.

Figure 4 Cumulative % released from aqueous solution of BDH and BDH ethosomal gel in phosphate buffer pH 7.4.

Abbreviation: BDH, betahistine dihydrochloride.

Figure 5 Ex-vivo permeation of both free BDH in gel and BDH ethosomal gel in phosphate buffer pH 7.4.

Abbreviation: BDH, betahistine dihydrochloride.

Figure 6 Results of pharmacodynamic activity of BDH.

Notes: (A) Weight gain study. (B) Food intake study. *Significant difference from control and placebo. **Significant difference from control, placebo, and BDH gel with P<0.05.
Abbreviation: BDH, betahistine dihydrochloride.

Figure 7 Light photomicrographs of morphology and adipose tissue of rat’s skin after (A) control, (B) placebo, (C) BDH gel, and (D) BDH ethosomal gel applications at a magnification of 40× and 100× respectively.

Abbreviation: BDH, betahistine dihydrochloride.