Document Type

Thesis - University Access Only

Award Date

2006

Degree Name

Master of Science (MS)

Department / School

Pharmaceutical Sciences

Abstract

The supra molecular bio vectors (SMBV) are nano-sized virus like particulate system consisting of polysaccharide core (PSC) surrounded by phospholipid (PL) layer. When antigen loaded SMBV are administered, because of their structural similarity to a virus, they are expected to elicit strong immunological response against the injected antigen. Here we describe the preparation, in vitro characterization and in vivo studies of SMBV. In the present study, PSC were prepared by crosslinking maltodextrins and coated with phospholipids to obtain SMBV. Bovine serum albumin (BSA) was used as a model antigen and the formulation factors such as duration of homogenization, dilution and PSC: PL ratio was controlled to obtain SMBV with optimal size and loading characteristics. The time of homogenization and extent of dilution of the cross-linked maltodextrins did not show any significant effect on the particle size of SMBV. Increase in the ratio of PSC: PC (phosphatidyl choline) from 90: 10 to 70:30 did not change the extent of antigen loading (p>0. 05). The charge of the phospholipids used did not show significant effect on the size of SMBV particles. The BSA loaded SMBV were purified by using with Sepharose 6B size exclusion column chromatography. The effect of various phospholipid compositions (PC: CH-1: 1; PC: CH: PS-1: 1 :0.2; PC: CH: SA-1: 1 :0.2; PC: CH: DSPG-1: I :0.2) on the loading of BSA on SMBV and the stability studies on the loaded SMBV were carried out. More than 90 % of BSA was found adsorbed on SMBV particles with all the phospholipid combinations tested. More than 90% of the coated BSA was retained even after 4 weeks after the preparation on all the SMBV formulations irrespective of phospholipid compositions used in the preparation process. Liposomes are a widely studied immunoadjuvants. They may serve as an excellent reference standard to compare the efficacy of the SMBV. The phospholipid composition for the liposomal formulation was the same as that of the SMBV formulation. In vivo efficacy of the SMBV and liposomal formulations were tested following subcutaneous administration to two groups of Balb/c mice each containing five mice. Alum was used a positive control group and the blank SMBV was used as negative control group. All the antigen containing formulations were administered at a dose equivalent to 15 μg of BSA. The boosting doses were given on day 7 and day 14. Blood samples on day 10 were collected by retro orbital puncture and IgM and IgG titers were determined. Blood samples were also collected on day 30 by cardiac puncture and various antibody titers, lymphocyte proliferation and the interleukin levels were assayed as per the standard protocols. The statistical analyses were performed using INSTAT computer software (Graph Pad, S

Library of Congress Subject Headings

Antigens

Molecular immunology

Format

application/pdf

Number of Pages

89

Publisher

South Dakota State University

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