Background:
The carbamide peroxide is the most commonly active ingredient used for home
dental whitening products, its quantification in pharmaceutical products is of extreme importance due to
the relation with the products potency and the previously related low carbamide peroxide stability.
Once, there is only one official carbamide peroxide determination based on iodometric titration, this
method is time-consuming and generates a lot of residues. The aim of this study was to carry out development
and validation of a simple and fast ultraviolet spectrophotometer assay to quantify an innovative
dental whitening gel.
Methods:
The proposed method was validated according international conference on harmonization
guideline. Procedure is based on the iodide/iodine redox chemistry; iodine released through the action
of hydrogen peroxide of carbamide peroxide with ultraviolet detection at 350 nm.
Results:
The procedure was linear in the concentration range of 1.0-4.0 µg/mL, specific to the excipients,
robust for the evaluated parameters (variation of wavelength (± 5 nm); reagent addition (± 10%)),
showing the results of RSD 1.88 and 0.39% respectively. Repeatability precision was RSD = 1.42%,
with accurate RSD = 2.15% by adding reference solution. The assay used only water as solvent for
sample preparation. In comparison to the pharmacopeial method, the latter is more time-consuming, as
it generates a lot of residues, and it could not quantify small CP dosages.
Conclusion:
Thus, the proposed method was proved to be suitable to determine carbamide peroxide
during the development and characterization of nanoparticle formulations in the present study.
Cloning and characterization of the katA gene of Rhizobium meliloti encoding a hydrogen peroxide-inducible catalase.
