Chlorhexidine Retention & Release in Oral Cavity: Latest Evidence (2020)
My previous article on how to protect the healthcare workers by preventing the droplet spread from the patient’s mouth mentions that in order to prevent the SARSCoV2 droplet spread, we need mouthwashes, which through their persistent attachment and sustained release (aka substantivity) in the oral cavity, not only reduce the viral load in saliva but also maintain it low for sufficiently long. It’s during this safe period of low viral loads when the chances of droplet spread are reduced that the doctors can complete their patient appointment.
Here I present the evidence on Chlorhexidine (CHX) retention in the oral cavity and its sustained release into saliva.
What we already know?
CHX readily adsorbs to oral surfaces, including pellicle-coated teeth, mucosa and saliva proteins (mucin and albumin), which explains its ability to remain within the oral cavity and its persistent bacteriostatic action (high substantivity) lasting for at least 24 hours.
The persistent bacteriostatic effect of CHX makes it the “gold standard” in oral antiseptics.
What was missing until now?
Until now, there was only an assumption that CHX adsorbs and retains after the oral application on mucosal surfaces and dental pellicle in vivo. We needed some compelling direct evidence on the same.
What was done in this study?
This study investigated, for the first time, the retention of CHX in different oral sites over a 24 hour period using MALDI-TOF mass spectrometry.
Why MALDI-TOF mass spectrometry?
Matrix-Assisted Laser Desorption/Ionization-Time Of Flight mass spectrometry is a powerful tool for the pharmacokinetic analyses of different oral medications in the scientific and industrial fields. This technique can answer questions about the availability, substantivity, and hence the frequency of application needed.
What did this study show?
1. Significant amounts of CHX continued to be present in the oral cavity for an extended time after the one-time 30 seconds mouth rinsing.
2. CHX remained in the oral cavity at mcg/ml levels for 11 hours after mouth rinsing and was even detected 24 hours after application.
3. Salivary CHX concentration remained at mcg/ml levels for 6 hours after mouth rinsing.
4. CHX concentration (oral mucosa) > 3x more> CHX concentration (saliva).
5. The decline of intraoral CHX levels during the first 6 hours after rinsing and it was then retained at low concentrations for at least 24 hours.
Conclusion:
1. The present study confirms the assumption that dental pellicle and oral mucosa represent the main reservoirs of CHX after application.
2. CHX releases within the time from these reservoirs to the saliva in lower concentrations.
Reference: [Archives of Oral Biology, Feb 2020]
https://www.sciencedirect.com/science/article/abs/pii/S0003996919305230
