Effects of Simulated Field Storage Conditions on Common Dental Medications.

Introduction: Military dental providers often operate in environments with extreme temperature gradients. The purpose of this study was to analyze the effect of simulated storage in extreme cold conditions on 8 medications-4 local anesthetics (2% Lidocaine with 1:100,000 epinephrine, 0.5% Marcaine with 1:200,000 epinephrine, 4% Articaine with 1:100,000 epinephrine, 3% Polocaine), 2 pain medications (Acetaminophen 325 mg, Ibuprofen 800 mg), and 2 antibiotics (Amoxicillin 500 mg, Azithromycin 500 mg), who are commonly used by the military for dental treatment.

Materials and methods: Medications were subjected to simulated freeze-thaw (FT) conditions (MIL-STD-810H), using an environmental chamber to expose any tendency for degradation. The medications were cycled through 13 hours at -10 °C and 11 hours at 4 °C for 28 days, to simulate springtime FT conditions experienced by Kyiv, Ukraine. Samples were analyzed at 0, 7, 14, 21, and 28 days under both environmental stress and room temperature (RT) conditions. Liquid chromatography-mass spectrometry (LC-MS) was completed with electrospray ionization interface and triple quadrupole mass analyzer. Each medication was used as an internal standard (IS) for the other and response factors determined for each. All drugs and their respective IS were measured in multiple reaction monitoring in electrospray positive ionization. Room temperature data from each time point were compared to the respective environmentally stressed drug data using T-tests adjusted via Bonferroni's method (α = 0.01). Parametric first-order autoregressive moving-average repeated-measures analysis of variance using maximum likelihood was performed using the "MIXED" procedure in SAS v9.4 to determine if concentrations were affected by time and environmental stress (α = 0.05).

Results: Lidocaine, Polocaine, Acetaminophen, and Azithromycin concentrations were affected by time and environmental stressing. All other medication concentrations were affected by time but not by environmental stressing.

Conclusions: Utilization and/or storage of commonly used local anesthetics, antibiotics, and pain medications in these climate conditions may experience concentration changes who may affect their efficacy in treating dental-related conditions.