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Strategies for sustained antimicrobial delivery to biofilms

Grant number: 15/17712-9
Support Opportunities:Regular Research Grants
Duration: September 01, 2016 - February 28, 2019
Field of knowledge:Health Sciences - Pharmacy - Pharmaceutical Technology
Principal Investigator:Carolina Patrícia Aires
Grantee:Carolina Patrícia Aires
Host Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
Associated researchers:Osvaldo de Freitas


Diseases caused by biofilms are a major public health problem, being responsible for the increased morbidity of patients and the hospital stay and healthcare costs. Among the biofilm-dependent diseases most studied today are the urinary tract and oral diseases. Thus, the broadcasting of drugs that might have prolonged effect in a pharmaceutical formulation of controlled release can be very promising, since biofilm-dependent diseases are serious difficulties in the diffusion of drugs due to the organized structure of his mother. In addition, the formulation can be optimized it will be conceived and developed in conditions close to the biological conditions. The objective of the study is to evaluate the effect of a sustained release semi-solid system of drug in the presence of models of oral biofilm and biofilm-related diseases of the urinary tract. Thus, the first part of the study will be used to obtain a releasing semisolid drug system which is feasible to physiological conditions proposed considering the presence of bacteria and their extracellular products remain in the dynamics of a dynamic liquid medium. A system for in situ gelation glyceryl monolinoleate base is developed and previous studies will be performed to assess factors relevant to their use in biofilm models as the pharmaceutical formulation and the time duration of drug release. In the second part of the study, the biofilm will be formed. For this, representative bacteria colonization of pathogenic oral biofilm and urinary tract pathogenic biofilm are cultivated. The first oral biofilm model will be formed by Streptococcus mutans typically related to the development of the supragingival plaque. The second model, subgingival, will consist of Porphyromonas gingivalis, considered potential periodontopatógena. The third model will be formed by Escherichia coli, Gram negative bacteria related to urinary tract infections. Despite being an in vitro study designs, the same mimic the physiological conditions that may be important for developing a product which overcomes the challenges of a biological environment. Biofilms of P. gingivalis or S. mutans are formed on glass slides dipped into conical tubes containing culture medium and one of the following treatments: 1) no treatment (control experiment); System without drug as a negative control; 2) system containing chlorhexidine 0.12%. Since E. coli biofilm will also be formed on glass slides but it will be exposed to the following treatments: 1) no treatment (control experiment); System without drug as a negative control; Hydroethanolic system containing extract of Baccharis dracunculifolia, a natural product with promising effects in oral biofilms. The acidogenicity of biofilms will be measured daily and the amount of active ingredient released in the culture medium. After the trial period for growth of each biofilm, they will be collected and homogenized by sonication. The bacterial viability will be monitored by counting bacteria in blood agar extracellular polysaccharides are extracted and quantified, and the amount of residual drug in biofilms is analyzed by HPLC. The formulation will be evaluated in relation to its mass, crystalline mesophase and the residual active ingredient. To compare the groups, will be initially analyzed the homogeneity and variability of results. As usual the distribution of values, ANOVA will be used followed by post-hoc test for comparison between groups. If the distribution is not normal, a comparison will be made using the Kruskal-Wallis test. The significance level adopted will be 5%. From the results of this study, clinical studies will begin to be developed. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
KAWAKITA, ERIKA R. H.; RE, ANA CAROLINA S.; PEIXOTO, MARIA PAULA G.; FERREIRA, MAIRA P.; RICOMINI-FILHO, ANTONIO P.; FREITAS, OSVALDO; AIRES, CAROLINA P.. Effect of Chitosan Dispersion and Microparticles on Older Streptococcus mutans Biofilms. Molecules, v. 24, n. 9, . (15/17712-9, 15/04363-6)
RE, ANA CAROLINA S.; BONJOVANNI, MARIA CAROLINA; FERREIRA, MAIRA P.; FREITAS, OSVALDO; AIRES, CAROLINA P.. Effect of an Experimental Formulation Containing Chlorhexidine on Pathogenic Biofilms and Drug Release Behavior in the Presence or Absence of Bacteria. PHARMACEUTICS, v. 11, n. 2, . (15/17712-9)

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