Background:
Prodrugs principle is widely used to improve the pharmacological and pharmacokinetic properties of
some active drugs. Much effort was made to develop metronidazole prodrugs to enhance antibacterial activity and
or to improve pharmacokinetic properties of the molecule or to lower the adverse effects of metronidazole.
Objective:
In this work, the pharmacokinetic properties of some of monoterpenes and eugenol pro metronidazole
molecules that were developed earlier were evaluated in-vitro. The kinetic hydrolysis rate constants and half-life
time estimation of the new metronidazole derivatives were calculated using the validated RP-HPLC method.
Method:
Chromatographic analysis was done using Zorbbax Eclipse eXtra Dense Bonding (XDB)-C18 column of
dimensions (250 mm, 4.6 mm, 5 μm), at ambient column temperature. The mobile phase was a mixture of sodium
dihydrogen phosphate buffer of pH 4.5 and methanol in gradient elution, at 1ml/min flow rate. The method was
fully validated according to the International Council for Harmonization (ICH) guidelines. The hydrolysis process
carried out in an acidic buffer pH 1.2 and in an alkaline buffer pH 7.4 in a thermostatic bath at 37ºC.
Results:
The results followed pseudo-first-order kinetics. All metronidazole prodrugs were stable in the acidic pH,
while they were hydrolysed in the alkaline buffer within a few hours (6-8 hr). The rate constant and half-life values
were calculated, and their values were found to be 0.082- 0.117 hr-1 and 5.9- 8.5 hr., respectively.
Conclusion:
The developed method was accurate, sensitive, and selective for the prodrugs. For most of the
prodrugs, the hydrolysis followed pseudo-first-order kinetics; the method might be utilised to conduct an in-vivo
study for the metronidazole derivatives with monoterpenes and eugenol.
The Profound Unravelling of Equilibrium Thermodynamics and Arrhenius First-Order Kinetics in Relation to Metal Hydride Desorption Reactions
