Development and characterization of polymer-coated liposomes for vaginal delivery of sildenafil citrate

Figures & data

Table 1. Composition and characterization of different liposomal formulations (mean ± SD, n = 3).

	Composition (molar ratio)
Formula	Lipoid S 100	Cholesterol	Polymer coat	PS (nm)	PDI	Zeta potential (mV)	EE (%)	Bioadhesion (dyne/cm^2)	k
F1	1	1	–	2632 ± 44	0.26 ± 0.13	−7.75 ± 1.2	66.36 ± 3.4	ND^a	ND
F2	7	4	–	1118 ± 53	0.37 ± 0.05	−0.45 ± 0.7	78.11 ± 5.1	ND	ND
F3	9	1	–	940 ± 25	0.21 ± 0.02	4.14 ± 1.5	89.68 ± 2.6	1705.01 ± 24.5	19.49 ± 0.7
F3C	9	1	Chitosan	1676 ± 75	0.40 ± 0.04	25.11 ± 2.3	72.24 ± 1.2	2697.75 ± 68.7	30.78 ± 3.4^b5.81 ± 1.4^c
F3H	9	1	HPMC	2648 ± 32	0.62 ± 0.11	19.52 ± 1.1	78.39 ± 4.5	4905.23 ± 55.3	5.33 ± 0.5

^aNot determined.

^b Initial phase of release profile.

^c Second phase of release profile.

Figure 1. Transmission electron micrographs of A: uncoated liposomes (F3), B: chitosan-coated liposomes (F3C).

Figure 2. Percent of drug released from drug solution, uncoated liposomes (F3), chitosan-coated liposomes (F3C) and HPMC-coated liposomes (F3H) (n = 3).

Figure 3. Percent of drug permeated through excised bovine vaginal mucosa from drug solution, uncoated liposomes (F3), chitosan-coated liposomes (F3C) and HPMC-coated liposomes (F3H) (n = 3).

Figure 4. FTIR spectra of (a) chitosan, (b) uncoated liposomes (F3), (c) chitosan-coated liposomes (F3C) and (d) sildenafil citrate.

Figure 5. Photomicrograph of uterus from (a) group 1, control, untreated rat (×100), (b) group 2, rat treated with sildenafil solution (×100), (c) group 3, rat treated with chitosan coated liposomal dispersion, arrows show dilated and congested endometrial blood vessels, which appear as red spots (×100) (d) same as (c) at higher magnification (×400).