Effect of an Experimental Formulation Containing Chlorhexidine on Pathogenic Biofilms and Drug Release Behavior in the Presence or Absence of Bacteria.

Ana Ré,Osvaldo Freitas,Maria Bonjovanni,Maíra Ferreira,Carolina Aires

doi:10.3390/pharmaceutics11020088

Abstract

(1) Background: For any antibacterial oral formulation to be successful, it must present effects in the presence of biofilms. Therefore, our aim is to analyze the drug release and the antibiofilm effects of a semi-solid formulation containing chlorhexidine (CHX) in the presence of pathogenic biofilms. (2) Methods: The biofilms of Streptococcus mutans (n = 6) or Porphyromonas gingivalis (n = 3) were formed for 6 and 4 days, respectively, being exposed to: 1) a CHX system or 2) vehicle control without CHX. A group without treatment was included as negative control. The acidogenicity, CHX quantification and bacterial viability were determined. A dissolution assay in a buffer and culture medium in the absence of bacteria was also performed. (3) Results: Although the CHX quantification in the culture medium of both biofilms was lower compared to the buffer (p < 0.05) and the culture medium in the absence of bacteria, the CHX system was able to display antibiofilm effects until 96 h for the S. mutans biofilms (p < 0.05) and 72 h for the P. gingivalis biofilms (p < 0.05). (4) Conclusions: The experimental formulation is able to extend chlorhexidine effects, even in challenging conditions such as in the presence of bacteria, allowing the in vitro control of cariogenic biofilms for 4 days and periodontopathogenic biofilms for 3 days.

Highlights

Biofilm is the major etiological factor for the development of dental caries [1] and is intimately associated with the advancing lesions of periodontitis [2]
(3) Results: the chlorhexidine gluconate (CHX) quantification in the culture medium of both biofilms was lower compared to the buffer (p < 0.05) and the culture medium in the absence of bacteria, the CHX system was able to display antibiofilm effects until 96 h for the S. mutans biofilms (p < 0.05) and 72 h for the P. gingivalis biofilms (p < 0.05)
We evaluated the antimicrobial effects produced by this formulation using two pathogenic biofilm models, one representative of dental caries and the other for periodontitis

Summary

Introduction

Biofilm is the major etiological factor for the development of dental caries [1] and is intimately associated with the advancing lesions of periodontitis [2]. A notable feature of CHX is that it adheres to tooth and mucosal surfaces, which allows a prolonged antimicrobial activity inside the oral cavity [7]. The microenvironment produced by the biofilm could reduce the activity of potent agents such as CHX by preventing antimicrobial diffusion through the deeper layers of the matrix [9]. Based on these issues, the incorporation of CHX into a formulation capable of extending its antimicrobial effect might allow a wide spacing of dosages, optimizing the pharmacologic feature of this molecule and improving biofilm control

Objectives

Methods

Findings

Discussion

Conclusion