Sustained release of acyclovir from nano-liposomes and nano-niosomes: an in vitro study

Abstract

The present study was designed to develop and compare acyclovir containing nano-vesicular liposomes and niosomes based on cholesterol, soya L-alpha-lecithin and nonionic surfactant, span 20. The effort was made to study in vitro whether acyclovir-loaded nanovesicles could sustain the release of the drug by increasing residence time and thus, acyclovir could reduce its dose-related systemic toxicity. There were good vesicular distributions in both of the niosomes and the liposomes. The obtained vesicles were within 1 microm and about 35% of them were within a size of 100 nm. The percentage of drug loading varied and the niosomal vesicles contained more drug as compared with the liposomes. When the in vitro drug release was compared, it was found that the liposomes released about 90% drug in 150 min whereas the drug release was just 50% from the niosomal vesicles in 200 min. Again, the niosomes showed better stability compared with the liposomes. Thus, niosome could be a better choice for intravenous delivery of acyclovir.

Figure 1

Vesicular fusion and drug crystallization of a formulation with sucrose to lipid ratio 1:1.

Figure 2

Infrared spectrum of pure drug, acyclovir.

Figure 3

Infrared spectrum of physical mixture of excipients.

Figure 4

Infrared spectrum of physical mixture of excipients and drug, acyclovir.

Figure 5

Infrared spectrum of fresh freeze-dried niosomes.

Figure 6

Infrared spectrum of freeze-dried niosomes stored at 4 °C.

Figure 7

Infrared spectrum of freeze-dried niosomes stored at −20 °C.

Figure 8

Infrared spectrum of freeze-dried reconstituted niosomes stored at −20 °C.

Figure 9

Lipid peroxidation (in micro M) of different formulations. Data show mean± SD (n = 5). l1(reconstituted lyophilized) and l2(lyophilized) are the fresh liposomal and n1(reconstituted lyophilized), n2 (lyophilized), and n3(reconstituted lyophilized niosomes kept at 4 °C for 1 h) are the fresh (not stored except n3) niosomal formulations. Again L1 (reconstituted lyophilized liposomes stored at −20 °C), L2 (lyophilized liposomes stored at −20 °C) and N1 (reconstituted lyophilized niosomes stored at −20 °C), N2 (lyophilized niosomes stored at −20 °C) and N3 (reconstituted lyophilized niosomes stored at 4 °C) are those formulations stored at different temperatures as mentioned.

Figure 10

Size distribution data of N1 formulation using image analyzer.

Figure 11

Size distribution data of the formulation N1. Here “b1, b2, b3” and “b11, b22, b33” were the various size range between 100 nm and 1 μm.

Figure 12

Photograph of nonionic vesicular dispersions using scanning electron microscopy.

Figure 13

Photograph of distribution of liposome vesicles using scanning electron microscopy.

Figure 14

Scanning electron microscopic photograph of liposome dispersion taking from supernatant of the formulation before centrifugation.

Figure 15

In vitro drug release profile from one niosomal (N1) and one liposomal (L1) formulations. Data shows mean ± SD (n = 3).