Capsaicin-loaded vesicular systems designed for enhancing localized delivery for psoriasis therapy

Figures & data

Figure 1. TEM photographs of (A) Liposomal, (B) Niosomal, and (C) Emulsomal formulations.

Table I. The characterization of the formulations by particle size, PI and EE %.

Formulation	Lipid phase	Gelling systems	Size (nm)	PI	EE%
Emulsomes	PC + CH + Tristearin	–	172.8 ± 10	0.116 ± 0.019	83.79 ± 3.58%
Liposomes	PC + CH	–	368.5 ± 43	0.136 ± 0.024	70.98 ± 2.36%
Niosomes	Span 80 + CH	–	342.7 ± 35	0.167 ± 0.045	54.30 ± 2.16%
Emul-gel	PC + CH + Tristearin	Carbopol-934	198.2 ± 17	0.162 ± 0.037	81.12 ± 3.19%
Lipo-gel	PC + CH	Carbopol-934	382.4 ± 39	0.184 ± 0.049	68.58 ± 3.41
Nio-gel	Span 80 + CH	Carbopol-934	374.7 ± 33	0.193 ± 0.056	50.77 ± 2.32

Each value represents the mean ± SD (n = 3).

Figure 2. In vitro release of CAP in PBS (pH 7.4) for liposomal, niosomal, and emulsomal formulations, and plain gel. Values are expressed as mean ± standard deviation (n = 3).

Figure 3. In vitro skin permeation of CAP for emul-gel, lipogel, nio-gel and plain drug- gel. Values are expressed as mean ± standard deviation (n = 3).

Table II. Results of in vitro permeation and skin retention studies from vesicular-gel systems and plain-drug gel: amount permeated through the skin after 24 h, flux and percentage of CAP accumulated into the skin at the end of the permeation experiments (24 h).

Formulation code	CAP permeated through the skin at 24 hrs (μg/cm^2)	Flux (μg/cm^2/hr)	Total FLZ accumulated into the skin (%)
Emul-gel	32.78 ± 2.84	2.6 ± 0.06	31.97 ± 2.82
Lipo-gel	19.67 ± 1.65	1.19 ± 0.01	23.02 ± 2.39
Nio-gel	16.34 ± 1.02	0.92 ± 0.03	17.97 ± 1.96
Plain Drug Solution	7.34 ± 1.04	0.65 ± 0.01	8.26 ± 1.02

The data were expressed as percentage of dose applied per unit area. Each point represents the mean ± S.D. (n = 3).

Figure 4. Percent CAP for emul-gel, lipo-gel, nio-gel and plain drug-gel for in vitro permeation and skin retention studies. Values are expressed as mean ± standard deviation (n = 3).

Figure 5. Percent CAP for emul-gel, lipo-gel, nio-gel and plain drug- gel in SC for in vivo studies. Values are expressed as mean ± standard deviation (n = 3).

Figure 6. Percent CAP for emul-gel, lipo-gel, nio-gel and plain drug-gel in viable skin for in vivo studies. Values are expressed as mean ± standard deviation (n = 3).

Table III. Mean erythemal scores and PII observed for various CAP formulations obtained at the end of 24, 48, and 72 h (n = 3).

Formulation code	Erythemal scores
	24-hr	48-hr	72-hr	PII
Emul-gel	0	0	0	0
Lipo-gel	0	0	0	0
Nio-gel	1	1	0	0.67
Plain Drug-gel	3	2	1	2
Control (no formulation)	0	0	0	0

Figure 7. CLSM images of a cross-section of rat skin with different dye-loaded formulations. The formulations were applied for 4 h: (a) lipo-gel (b) nio-gel (c) emul-gel. The scale bar represents 200 μm.

Figure 8. CLSM images of a cross-section of rat skin with different dye-loaded formulations for determining the depth of penetration into deeper skin. The formulations were applied for 4 h (a) lipo-gel (b) nio-gel (c) emul-gel.

Table IV. Blind summarized scoring data from CLSM images.

Formulation	Stratum corneum (SC)	Epidermis and dermis
Lipo-gel	+++	++
Nio-gel	+++	+
Emul-gel	+++	+++

Figure 9. Comparison of the CAP fluxes from plain drug-gel and different vesicular-gel systems across normal and hyperproliferative skin. Each value represents the mean ± standard deviation (n = 3).