Research progress on the effect of pH-sensitive drug delivery systems on oral microorganisms

Microorganisms are closely related to the occurrence and development of common oral diseases. Due to the unique physiological and anatomical characteristics of the oral cavity, locally introduced antibacterial drugs cannot be maintained in the effective concentration range under the effect of saliva erosion. Therefore, to enhance the retention and bioavailability of antibacterial drugs in biofilms, some scholars designed pH sensitive drug delivery systems with the fact that the pH value of oral biofilm is lower than the physiological pH value. This article reviews the research reports of a pH-sensitive drug delivery system in the oral cavity and elaborates its application in oral diseases such as dental caries, endodontic disease, periapical disease, peri-implant diseases, and oral candidiasis. Literature review results show that the pH-sensitive drug delivery system loaded with antibacterial drugs could be used for the control of oral microorganisms with excellent pH sensitivity and antibacterial properties, especially in the application of acid-producing bacteria such as Streptococcus mutans for the prevention and treatment of dental caries. However, the research of pH-sensitive drug delivery systems in the oral cavity is still limited to basic research,and in clinical applications, it still faces many challenges, such as a complex design and synthesis, difficulties with lasting effects and eliminating drug-resistance and persistent bacteria. Further optimization of pH sensitive systems, as well as animal experiments and in vivo studies will be the focus of future research.