Development and validation of a highly sensitive LC-MS/MS-ESI method for quantification of IIIM-019-A novel nitroimidazole derivative with promising action against Tuberculosis: Application to drug development

In vivo quantification and pharmacokinetic studies of cotinine in mice after smoke exposure by LC-MS/MS

A sensitive analytical method was developed and validated for the quantification of cotinine in mouse plasma after exposure to smoke of 0.5, 1.0, and 1.5 commercially available cigarettes, using liquid chromatography tandem mass spectrometry. The method was validated over a linear concentration range of 0.075-20.0 ng/mL with the R² value being higher than 0.99. Both the precision (coefficient of variation; %) and accuracy (relative error; %) were within acceptable criteria of <15%. The lower limit of quantification (LLOQ) for cotinine was 0.075 ng/mL with sufficient specificity, accuracy, and precision. Following exposure to 0.5, 1.0, and 1.5 cigarette smoke, it was observed that the AUC and the C_max increased linearly as the doses increased. The pharmacokinetics of cotinine was found linear for the range of 0.5-1.5 commercial cigarette smoke. The quantification of the concentration of cotinine in mouse plasma after smoke exposure will facilitate future behavioral and toxicological experiments in animals and may prove useful in predicting cotinine levels in humans during smoking.

Preclinical comprehensive physicochemical and pharmacokinetic profiling of novel nitroimidazole derivative IIIM-019 - A potential oral treatment for tuberculosis

New compounds against tuberculosis are urgently needed to combat the crisis of drug resistance in tuberculosis (TB). We have identified a nitrodihydroimidazooxazole analog, IIIM-019 as a new anti-tubercular agent with a MIC of 0.23 μM against H37Rv. Physicochemical properties, in-vitro pharmacokinetics and in-vivo multiple-doses pharmacokinetics were studied for the compound. In silico physicochemical parameters and Lipinski's violations were determined for drug like properties. Lipophilicity was determined experimentally as Octanol-PBS partition coefficient (log P). Passive and active permeability of the compound was determined by PAMPA and Caco-2 cell permeability analysis, respectively. Plasma protein binding was determined by Rapid equilibrium dialysis. Metabolism by liver microsomes revealed the t1/2 and intrinsic clearance of the compound. Hepatotoxicity of IIIM-019 was determined alone and in combination to first line anti-tubercular drugs. The compound was also estimated for nuclear DNA damage. Single doses of IIIM-019 (2.5, 10, 25 and 100 mg/kg) were administered orally to Balb/c mice and the blood samples were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). IIIM-019 exhibited very good lipophilicity (log P) of 2.47 which makes it optimal for oral administration. The compound showed low solubility and permeability and high plasma protein binding. However, it was highly stable in rat liver microsomes with t1/2 > 2 h and very low intrinsic clearance. It was found to be non-hepatotoxic and did not induce any significant DNA damage at high concentrations even up to 100 μM. IIIM-019 showed satisfactory in-vivo pharmacokinetic properties. By increasing the dose from 2.5 mg/kg to 10 mg/kg, AUC0-t increased from 14935 ng h/ml to 81,478 ng h/ml. However the exposure of IIIM-019 in plasma suggested that the levels reached saturation at higher concentrations. The compound showed a good oral bioavailability of 58.7%. The results insinuate that IIIM-019 should undergo further development as a potential treatment for tuberculosis.