Systemic detection of doxycycline after local administration

Area of Science:

• Periodontology
• Pharmacokinetics
• Drug Delivery Systems

Background:

• Controlled release delivery (CRD) systems aim to prolong topical antibiotic half-life in gingival crevicular fluid (GCF).
• CRD systems are designed to prevent systemic antibiotic contamination.
• Topical doxycycline application in periodontitis treatment warrants investigation for systemic absorption.

Purpose of the Study:

• To evaluate systemic absorption of doxycycline following subgingival application of a controlled release gel.
• To compare systemic doxycycline levels after single-site versus multi-site applications.

Main Methods:

• Two groups of severe periodontitis patients received subgingival doxycycline gel (14%): UNISITE (one defect) and MULTISITE (3-9 defects).
• Doxycycline concentrations in saliva, GCF, and serum were quantified using high-performance liquid chromatography (HPLC).

Main Results:

• Salivary doxycycline levels were significantly higher in the MULTISITE group compared to the UNISITE group.
• GCF doxycycline concentrations were similar between both groups.
• Systemic absorption occurred in both groups, with higher serum concentrations observed in the MULTISITE group, though generally below HPLC detection limits within an hour.

Conclusions:

• Topical doxycycline administration, even for single sites without periodontal dressing, can result in systemic absorption.
• Detected systemic doxycycline levels are substantially lower than those required for antibacterial activity.
• The study highlights the potential for low-level systemic exposure with topical doxycycline in periodontitis treatment.