Background:
Allergic diseases are considered as the major burden on public health with increased prevalence
globally. Histamine H1-receptor antagonists are the foremost commonly used drugs in the treatment of allergic
disorders. The target drug in this study, loratadine, belongs to this class of drugs and its biometabolite desloratadine
which is also a non-sedating H1 receptor antagonist with anti-histaminic activity being 2.5 to 4 times greater than
loratadine. This study aimed to develop and validate a novel isocratic Reversed-phase High-Performance Liquid
Chromatography (RP-HPLC) method for rapid and simultaneous separation and determination of loratadine and its
metabolite, desloratadine in human plasma.
Methods:
The drug extraction method from plasma was based on protein precipitation technique. The separation was
carried out on a Thermo Scientific BDS Hypersil C18 column (5μm, 250 x 4.60 mm) in a mobile phase of MeOH:
0.025M KH2PO4 adjusted to pH 3.50 using orthophosphoric acid (85: 15, v/v) at an ambient temperature. The flow
rate was maintained at 1 mL/min and maximum absorption was measured using the PDA detector at 248 nm.
Results:
The retention times of loratadine and desloratadine in plasma samples were recorded to be 4.10 and 5.08
minutes, respectively, indicating a short analysis time. Limits of detection were found to be 1.80 and 1.97 ng/mL for
loratadine and desloratadine, respectively, showing a high degree of sensitivity of the method. The method was then
validated according to FDA guidelines for the determination of the two analytes in human plasma.
Conclusion:
The results obtained indicate that the proposed method is rapid, sensitive in the nanogram range, accurate,
selective, robust and reproducible compared to other reported methods.