Introduction
Doxycycline hyclate (DOX), a broad-spectrum antibiotic, is part of the Unified Health System (SUS) in Brazil, which is free-distributed to all by prescription.
Unfortunately 1DOX is quite susceptible to light. 2A commonly applied approach to increase the stability of drugs is the formation of complexes with β-cyclodextrin (βCD). Despite the growing number of studies using cyclodextrins (CDs) in the formation of IC, this approach would not work to isolate the drug from the medium in which it is placed, but the external environment, because of the characteristic of DOX to be photosensitive and thus to compare their antimicrobial activity.
After thermal and spectroscopic analysis to confirming the inclusion of DOX in βCD and showed how it is complexed, we carried out the development and validation of microbiological turbidimetric method for the quantification of DOX.
The aim of this work was to compare, using the turbidimetric microbiological method, both the antimicrobial activity of the IC with DOX as the antimicrobial activity between them after exposure to UV light.
Results and Discussion
The microbiological method turbidimetric allows the determination of potency of the drug, by measuring the turbidity (absorbance), caused by inhibition of microorganisms by DOX.
The validation of microbiological turbidimetric method for the quantification of DOX was essential for the comparison of antimicrobial activity between DOX complexed and not complexed.
The comparison analysis of activity between DOX and IC were performed simultaneously. After incubation period DOX solution presents a higher turbidity of the culture medium.
The conditions were identical for both DOX and IC in UV exposition. After incubation period DOX solution presents a higher turbidity of the culture medium.
Conclusions
The CI was approximately 20% more potent than DOX. When subjected to UV exposure, the IC is also higher, with about 30% higher antimicrobial activity of DOX.
Through these tests would be interesting for the pharmaceutical industry began to discuss the idea of working with IC. After all, the antimicrobial activity in this case was greater than that found in the free drug by protect DOX from external factors, which can conduct to new drug discovery.
Acknowledgements
CAPES, CNPq, FAPESP, UNESP, União Química Indústria Farmacêutica, Consejo Nacional de Investigaciones Científicas y Tecnológicas de la Nación (CONICET).
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1Reynolds, J. E. F. (Ed). Martindale the Extra Pharmacopoeia. 35a ed.
2Lyra, M. A. M.; Alves, L .D. S.; Fontes, D. A. F.; Soares-Sobrinho, J. L.; Rolin-Neto, P. J. Ferramentas analíticas aplicadas à caracterização de complexos de inclusão fármaco-ciclodextrina, Revista de Ciências Farmacêuticas Básica e Aplicada, v. 31(2), p.117-124, 2010.
