IJUP08 - Universidade do Porto

Functional Insulin Quantification upon its Nanoencapsulation
M. J. Barbosa 1,3 *, J. Faria 2,3 *, O. Queirós 3 , A. Ribeiro 3 and R. Moreira 3
1 Faculty of Science, University of Oporto and ICBAS, University of Oporto, Portugal.
2 Faculty of Science, University of Oporto, Portugal.
3 Instituto Superior de Ciências da Saúde – Norte, Centro de Investigação em Ciências da Saúde
(CICS), Grupo de Biologia Molecular e Celular, CESPU, Portugal.
* These authors contributed equally to this work.
Insulin is the most import drug used in the therapeutics of diabetes mellitus, a metabolic
disorder with increasing prevalence. Several alternative routes of administration, other than
the subcutaneous one, are currently under development, in order to improve patients’
quality of life [1]. Among them, insulin encapsulation within biodegradable polymer
particles regarding its oral administration constitutes a promising strategy [2].
In the present study, an in vitro methodology was developed to evaluate the preservation of
the hormone’s functionality following its submission to nanoencapsulation. The
methodology was optimized using commercially available insulin, through rat L6
myoblasts stimulation with different hormone concentrations and for distinct periods of
time. Detection of Akt phosphorylated form through Western blotting assays was used as
an indicator of an effective stimulation by insulin and, thus, of the retention of its active
conformation [3]. Akt/PKB, one of insulin signalling pathway phosphorylation products, is
a protein kinase involved in many of the hormone’s biological actions, including glucose
transport and modulation of gene expression.
Assays using insulin recovered from nanoparticles revealed that the emulsification/internal
gelation technique preserves part of insulin’s functionality. The methodology may be of
use as a rapid, ethical, specific and conclusive means of bioactivity screening in
pharmaceutical formulations containing the hormone.
References:
[1] Gerich, J.E. (2002), Novel insulins: expanding options in diabetes management, The American
Journal of Medicine, 113, 308-316.
[2] Silva, C.M., Ribeiro, A.J., Figueiredo, I.V., Gonçalves, A.R. and Veiga, F. (2006), Alginate
microspheres prepared by internal gelation: development and effect on insulin stability,
International Journal of Pharmaceutics, 311, 1-10.
[3] Patel, N., Craddock, B.L., Staniforth, J.N., Tobyn, M.J. and Welham, M.J. (2001), Spray-dried
insulin particles retain biological activity in rapid in-vitro assay, Journal of Pharmacy and
Pharmacology, 53, 1415-1418.
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