Multiple analytical methods for determination of formoterol and glycopyrronium simultaneously in their novel combined metered dose inhaler

Table 1 Optimization of the chromatographic parameters for separation of mixture of FF and GLY by the proposed IPC method

Parameter		No. of theoretical plates (N)		Mass distribution ratio (Dm)		Resolution (Rs)	Relative retention (α)
Parameter		FF	GLY	FF	GLY	Rs	PP
pH	3.0	3274	2981	1.19	2.96	6.55	2.49
	4.0	1213	2630	1.15	2.82	5.0	2.45
	5.0	1024	2081	1.1	2.66	4.82	2.41
	6.0	887	1673	1.08	2.65	4.39	2.45
Organic modifier type	Acetonitril	3274	2981	1.19	2.96	6.55	2.49
Organic modifier type	Methanol	2036	1285	0.89	1.17	5.6	1.31
Ratio of [acidified water: acetonitrile] 0.025% SDS	(30:70)	Un retained peak
	(40:60)	3247	2981	1.19	2.96	6.55	2.49
	(45:55)	2200	2410	1.27	3.05	4.92	2.39
	(50:50)	2070	725	1.94	4.42	3.75	2.27
	(60:40)	1834	512	2.14	4.78	4.5	2.23
Conc. of SDS %	0.015	Un ret.	1862	0	1.4	0	0
	0.02	1246	2584	0.66	2.0	5.33	3.0
	0.025	3274	2681	1.19	2.96	6.55	2.49
	0.03	1601	1910	0.88	2.61	5.64	2.93

Where: number of theoretical plates (N) = 5.45(t_R/W_h/2)²
Resolution (R) = 2∆ t_R/W₁ + W₂
Mass distribution ratio (Dm) = t_R− t_m/t_m
Relative retention (α) = Dm₂/Dm₁
t_R is the retention time of the substance measured from the point of injection and t_M is the retention time of a non-retained marker and W_h/2 is the peak width at the half height
W₁ and W₂ are the width of the peaks of the two components at their bases

ISSN: 2661-801X