Background: The Spectrophotometric method is one of the most suitable analytical techniques
for testing the activity of enzymes under the influence of various factors.
Methods: The effect of H1-antihistamines of loratadine and calcium ions on enzyme catalase under
in vitro conditions was investigated in this paper.
Results and Discussion: It has been shown that loratadine is a partial inhibitor of catalase, but this
effect is diminished in the presence of calcium ions. Calcium as well as other cations are important
for many biological and cellular functions. The kidneys play a central role in the homeostasis of these
ions. The activity of the catalase enzyme under the given conditions, the type of inhibition, and the
kinetic parameters of the enzyme reaction were determined.
Conclusion: We concluded that loratadine is a partially competitive inhibitor.