Pharmacokinetics Interaction of Non-Steroid Anti Inflammatory Drugs to <sup>99m</sup>Tc-MDP Radiopharmaceuticals for Bone Imaging and Its Biodistribution

Abstract

99m Tc-MDP has been developed as a radiopharmaceutical for bone imaging in nuclear medicine. A drug therapy can alter the pharmacokinetic profiles and biodistribution patterns of radiopharmaceuticals. To achieve an optimum diagnostic outcome, this research focused on pharmacokinetics interaction between two kinds of nonsteroidal anti-inflammatory drugs ( NSAID ) drugs , meloxicam and sodium diclofenac with 99m Tc-MDP using mice ( Mus musculus ) . There were five groups of animal model and each group consists of three mice except for group II and III which consists of six mice . The groups were classified as untreated mice (I) , mice treated with meloxicam for 3 days ( II) , treated with sodium diclofenac for 3 days (III), treated with meloxicam once or at onset (IV), and mice with sodium diclofenac once or at onset (V). Pharmacokinetics interaction and biodistribution test were conducted by injecting 1 00 µCi/ 1 00 µL 99m Tc-MDP intravenously. Blood samples were withdrawn from each mouse which were then weighted and counted using single channel analyzer. The %ID/g of 99m Tc-MDP in blood of untreated mice (I), mice treated with meloxicam (II) and sodium diclofenac (III) 5 minutes post injection were 3.71, 8.96 and 9.15 % respectively, then decrease to 0.12, 0.01, and 0.01 %, respectively, 24 hours post injection. The results of T-test showed there were no significan t differences in distribution of 99m Tc-MDP in untreated mice (I) and in treated mice either with meloxicam (II) or sodium diclofenac (III). However, there was significant difference in elimination of 99m Tc-MDP in untreated mice (I) and in treated mice either with meloxicam (II) or sodium diclofenac (III). T he bone uptakes of 99m Tc-MDP were 9.03 ± 0.41, 3.52 + 0.52, 3.62 + 0.45, 8.44 + 1.39, and 8.09 ± 0.86 % in group I, II, III, IV, and V, respectively. T-test showed there were significant differences in bone uptake of 99m Tc-MDP in mice with previously treated with meloxicam and sodium diclofenac for 3 days. From th ese result, it can be concluded that an administration of meloxicam and sodium diclofenac could accelerate elimination half-life that cause low uptake of 99m Tc-MDP radiopharmaceuticalon the bone as the primary target. Therefore, it is necessary to follow up using image study to determine the significance of the effects on image quality.