Hanan Merey
Prof. of Analytical Chemistry, Faculty of Pharmacy, Cairo University
A stability-indicating micellar liquid chromatographic (MLC) method
was developed and validated for the quantitative determination of timolol
maleate (TM) in the presence of its degradation products resulting
from accelerated degradation in a run time not more than 8 min.
TM was subjected to stress conditions of hydrolysis (including alkaline,
acidic and thermal hydrolysis) and oxidation. An isocratic, rapid
and mobile phase saving the micellar LC method was developed with
a BioBasic phenyl column (150 3 1.0 mm, 5 mm particle size) and a
micellar mobile phase composed of 0.1 M sodium dodecyl sulfate,
10% of 1-propanol and 0.1% of triethylamine in 0.035 M orthophosphoric
acid. The flow rate of the mobile phase was 0.1 mL/min.
UV detection was adjusted at 298 nm and performed at room temperature.
The method has been validated according to the International
Conference on Harmonisation guidelines. The method is successfully
applied for the determination of TM in bulk powder and pharmaceutical
dosage form.