Simultaneous Assay of Dexchlorpheniramine Maleate, Betamethasone, and Sodium Benzoate in Syrup by a Reliable and Robust HPLC Method

Table 10

Results of stability studies.

Studies	Average retention time (minutes)	Average peak area (mAu.s)	Average asymmetry of peak	Average number of theoretical plate	RSD (%) of peak area	Recovery (%)
Dexchlorpheniramine maleate
Standard solution
0 h	4.698	2921785	1.3	3924	0.1	—
24 h at   refrigerator	4.702	2917643	1.3	3930	0.1	99.9
24 h at 25°C	4.691	2914786	1.3	3912	0.2	99.8
Sample solution
0 h	4.705	2917613	1.3	3935	0.2	—
24 h at   refrigerator	4.695	2914534	1.3	3919	0.1	99.9
24 h at 25°C	4.701	2912677	1.3	3929	0.4	99.8
Sodium benzoate
Standard solution
0 h	9.403	6169304	1.3	2887	0.1	—
24 h at   refrigerator	9.391	6167025	1.3	2880	0.1	100.0
24 h at 25°C	9.415	6149723	1.3	2894	0.1	99.7
Sample solution
0 h	9.411	6170542	1.3	2892	0.2	—
24 h at   refrigerator	9.396	6165339	1.3	2883	0.1	99.9
24 h at 25°C	9.409	6148732	1.3	2891	0.2	99.6
Betamethasone
Standard solution
0 h	17.807	862754	1.1	7927	0.1	—
24 h at   refrigerator	17.789	861859	1.1	7911	0.1	99.9
24 h at 25°C	17.814	860934	1.1	7933	0.3	99.8
Sample solution
0 h	17.792	861055	1.1	7914	0.1	—
24 h at   refrigerator	17.801	859823	1.1	7922	0.2	99.9
24 h at 25°C	17.797	858506	1.1	7918	0.2	99.7