Pharmacokinetic Evaluation of Injectable Platelet-rich Fibrin Containing Metronidazole as a Local Drug Delivery Agent in Periodontal Therapy: An In-vitro Study

Introduction: Periodontitis is a complex disease influenced by microorganisms, systemic factors and environmental factors. Traditional treatments like scaling often fail in moderate to severe cases due to limited access to deep pockets. Local Drug Delivery (LDD) systems, such as films and gels, offer higher drug concentrations at infection sites but are flushed out by saliva and Gingival Crevicular Fluid (GCF). Injectable Platelet-rich Fibrin (i-PRF) provides a slow, sustained release of metronidazole, enhancing the outcomes of periodontal therapy. Aim: To evaluate the possibility of using i-PRF as a controlled release drug vehicle in periodontal therapy. Materials and Methods: This study was an in-vitro analysis conducted at the Department of Periodontology, Bharati Vidyapeeth Dental College and Hospital, Pune, Maharashtra, India, in September 2024. A patient with a chief complaint of food lodgement and periodontitis was selected and blood was collected for further analysis. A drug stock solution was prepared by mixing 10 mg of metronidazole in 10 mL of deionised water, which was vortexed for three minutes to achieve a final concentration of 1 mg/mL. The i-PRF was prepared. The top PRF layer was aspirated into a 2 mL syringe and maintained in liquid consistency for about 10-15 minutes until it clotted through the slow polymerisation of the fibrin structure. Samples were collected at the 1st, 3rd, 5th and 7th hours and were repeated on the 3rd, 5th, 7th, 9th and 14th days, followed by spectrophotometric analysis. Results: In the present study, the spectrophotometric analysis indicated the presence of the drug in all samples taken over the period from one hour to the 14th day. Initially, the concentration of the eluted samples showed a gradual decline between the 1st and 7th hours. A pronounced and rapid decrease in drug concentration was observed up to the 3rd day and drug elution continued steadily until the 14th day. Conclusion: The i-PRF shows promise and can be effectively used as an LDD system in periodontal therapy. Its favourable characteristics, such as its syringeable form, which starts as a liquid and later transforms into a gel, make it an ideal candidate for precise application. Moreover, being composed of autologous fibrin, i-PRF can be directly delivered into the periodontal pocket, where it adapts to the shape of the pocket and adheres to both soft and hard tissues. This flexibility of i-PRF improves the retention of drug-loaded i-PRF in the restricted environment of the periodontal pocket, ensuring prolonged contact and efficacy of the treatment.