Enhanced Transdermal Delivery of Acyclovir Sodium via Elastic Liposomes

Figures & data

FIG. 1 Photomicrograph shows TEM of elastic liposomes (× 30000).

TABLE 1 Composition and characterization of elastic liposomal formulations

Formulation code	HSPC:S (%w/w)	Average vesicle size (nm)	Entrapment efficiency (%)	Turbidity (N.T.U.)	Polydispersity Index	Elasticity
TF-S401	95:5	155 ± 1.3	55.1 ± 0.47	22.2 ± 1.2	0.053	22.27 ± 1.6
TF-S402	90:10	149 ± 2.3	57.4 ± 0.54	23.3 ± 2.3	0.058	23.35 ± 2.4
TF-S403	85:15	137 ± 1.9	59.8 ± 1.26	25.2 ± 2.4	0.048	26.52 ± 1.5
TF-S404	80:20	118 ± 2.4	51.8 ± 0.84	18.7 ± 1.3	0.082	16.13 ± 3.2
TF-S405	75:25	109 ± 1.6	49.6 ± 0.37	16.4 ± 2.5	0.088	8.48 ± 1.3
TF-S601	95:5	148 ± 2.3	57.7 ± 2.10	23.3 ± 1.7	0.043	24.23 ± 2.5
TF-S602	90:10	140 ± 1.5	59.5 ± 1.63	24.7 ± 1.4	0.052	28.69 ± 3.1
TF-S603	85:15	131 ± 2.1	61.6 ± 1.24	28.4 ± 1.4	0.042	30.56 ± 1.3
TF-S604	80:20	117 ± 2.1	54.3 ± 1.06	18.3 ± 1.8	0.074	15.28 ± 1.7
TF-S605	75:25	100 ± 2.2	52.1 ± 0.74	15.0 ± 1.3	0.083	7.77 ± 1.2
TF-S801	95:5	137 ± 1.0	62.1 ± 1.29	26.2 ± 2.3	0.050	27.18 ± 3.2
TF-S802	90:10	129 ± 2.4	64.5 ± 2.23	27.4 ± 3.1	0.042	29.05 ± 2.4
TF-S803	85:15	120 ± 1.2	66.4 ± 0.42**	31.9 ± 1.3	0.032	39.33 ± 3.6
TF-S804	80:20	106 ± 1.5	59.2 ± 0.92	20.4 ± 1.8	0.068	16.47 ± 1.3
TF-S805	75:25	96 ± 2.0	54.8 ± 0.34	18.4 ± 2.0	0.079	9.98 ± 0.9
Liposomes		118 ± 1.0	43.1 ± 1.76	22.5 ± 1.7	0.022	6.15 ± 0.5

Values represent mean_± SD (n = 3).

TF-S40, TF-S60, and TF-S80: elastic liposomal formulations containing Span 40/60/80, respectively, as formulation variable.

* HSPC:S = hydrogenated soya phosphatidyl choline: surfactant.

**Denotes maximum entrapment efficiency.

FIG. 2 (A) Fluorescent intensity (AU) versus skin depth (μm) studies reveal skin penetration profile of elastic liposomes. AU = arbitrary unit and (B) virtual channel-like structures can be visualized (yellow arrows represent the stained channels) at the skin depth of 10 μm.

FIG. 3 Percentage cumulative drug release from elastic liposomal formulation, conventional liposomal formulation, and plain drug solution through albino rat skin (mean ± S.E., n = 3).

TABLE 2 Permeation parameters of acyclovir-loaded formulations across rat skin after 24 hours

Formulations	Transdermal flux μg/cm^2/hr	Lag Time (hr)	Enhancement Ratio
TF-S403	5.73± 2.1	1.4	5.81
TF-S603	6.19± 1.6	1.0	6.28
TF-S803	6.21± 1.8	0.6	6.3
Liposomes	3.12± 2.1	2.6	3.17
Plain drug	0.98± 1.7	3.2	-

Values represent mean ± SD (n = 3).

FIG. 4 Drug plasma concentration profile after transdermal application of different formulations (mean ± S.E. n = 6).

TABLE 3 Pharmacokinetic parameters of acyclovir

Formulations	Cmax(ng/ml)	AUC (ng.hr/ml)
Plain drug solution	40 ± 5.1	482 ± 25
Liposomes	82 ± 11.9	1394 ± 41
Elastic liposomes	192 ± 10.3	3456 ± 117

Values represent mean ± SD (n = 6).

C_max = maximum concentration of drug in plasma; AUC = area under the curve.