Background:
A successful attempt has been done to develop and validate a simple stability
indicating HPTLC method for the estimation of Mometasone furoate (MF) and its degradation product
in the presence of Salicylic acid (SA). The degradation product was isolated, characterized and tested
for cytotoxicity.
Introduction:
Mometasone furoate (MF) is chemically 9,21-Dichloro-17α-[(2-furanylcarbonyl) oxy]-
11β-hydroxy-16-α-methylpregna-1,4-diene-3,20-dione, a high potency glucocorticoid. Salicylic acid
(SA) has antiseptic, antifungal and keratolytic properties. Combination of MF and SA is available in the
market as an ointment and is used for the treatment of skin inflammation, skin diseases, acne, skin redness
and other conditions. Till now, there is no scientific documentation on HPTLC method for simultaneous
estimation of MF and SA in the topical formulation; stress testing of drugs and determination of
degradation products.
Methods:
Combination of Toluene: Ethyl Acetate: Methanol: Ammonia (6.4:1.5:2.0:0.1) was selected
as the mobile phase. Detection was done by UV absorbance mode at wavelength 250 nm. Topical formulation
containing MF and SA was analyzed by the developed method. The developed method was
validated as per ICH guidelines. The standard drugs were subjected to stress testing like hydrolysis,
oxidative, thermal and photolytic degradation.
Results:
Good separation with Rf values 0.61 ± 0.02 (MF) and 0.21 ± 0.02 (SA) was achieved by optimized
chromatographic conditions. The % drug content was found to be 97.41±1.15 and 99.43 ± 0.73
for MF and SA, respectively in a topical formulation. From the results of validation parameters, the
developed method was found to be specific, accurate, precise, sensitive and robust. After stress testing,
SA was found to be stable under different stress conditions. Whereas, MF was found to be base sensitive
and single degradation product was observed and isolated by preparative TLC. It was characterized
by LC-MS and LC-MS/MS studies. Isolated degradation product was subjected to cytotoxicity testing
on A549 and SiHa cell lines.
Conclusion:
A simple stability indicating HPTLC method was developed and validated for the
estimation of MF and its degradation product in presence of SA. Probable structure of degradation
product of MF and probable pathway of degradation was interpreted. Results of cytotoxicity testing
showed that the degradation product was more cytotoxic as compared to MF against both the cell lines.