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Characterisation of protein stability in rod-insert vaginal rings

Biomedical Sciences Research Institute Computer Science Research Institute Environmental Sciences Research Institute Nanotechnology & Advanced Materials Research Institute

Pattani, Aditya, Lowry, Deborah, Curran, Rhonda M, McGrath, Stephanie, Kett, Vicky L, Andrews, Gavin P and Malcolm, R Karl (2012) Characterisation of protein stability in rod-insert vaginal rings. International Journal of Pharmaceutics, 430 . pp. 89-97. [Journal article]

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DOI: 10.1016/j.ijpharm.2012.03.036

Abstract

A major goal in vaccine development is elimination of the ‘cold chain’, the transport and storage system for maintenance and distribution of the vaccine product. This is particularly pertinent to liquid formulation of vaccines. We have previously described the rod-insert vaginal ring (RiR) device, comprising an elastomeric body into which are inserted lyophilised, rod-shaped, solid drug dosage forms, and having potential for sustained mucosal delivery of biomacromolecules, such as HIV envelope protein-based vaccine candidates. Given the solid, lyophilised nature of these insert dosage forms, we hypothesised that antigen stability may be significantly increased compared with more conventional solubilised vaginal gel format. In this study, we prepared and tested vaginal ring devices fitted with lyophilised rod inserts containing the model antigen bovine serum albumin (BSA). Both the RiRs and the gels that were freeze-dried to prepare the inserts were evaluated for BSA stability using PAGE, turbidimetry, microbial load, MALDITOF and qualitative precipitate solubility measurements. When stored at 4 ◦C, but not when stored at 40 ◦C/75% RH, the RiR formulation offered protection against structural and conformational changes to BSA. The insert also retained matrix integrity and release characteristics. The results demonstrate that lypophilised gels can provide relative protection against degradation at lower temperatures compared to semi-solid gels. The major mechanism of degradation at 40 ◦C/75% RH was shown to be protein aggregation. Finally, in a preliminary study, we found that addition of trehalose to the formulation significantly reduces the rate of BSA degradation compared to the original formulation when stored at 40 ◦C/75% RH. Establishing the mechanism of degradation, and finding that degradation is decelerated in the presence of trehalose, will help inform further development of RiRs specifically and polymer based freeze-dried systems in general.

Item Type:Journal article
Faculties and Schools:Faculty of Life and Health Sciences
Faculty of Life and Health Sciences > School of Nursing
Research Institutes and Groups:Institute of Nursing and Health Research
Institute of Nursing and Health Research > Maternal, Fetal and Infant Research
ID Code:23181
Deposited By:Dr Rhonda Curran
Deposited On:28 Aug 2012 15:04
Last Modified:28 Aug 2012 15:04

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