Photodegradation assessment of ciprofloxacin, moxifloxacin, norfloxacin and ofloxacin in the presence of excipients from tablets by UPLC-MS/MS and DSC

Table 1 Validation of the method

Parameter	CIP	MOX	NOR	OFL
RT (min) ^a	2.52 ± 0.05	3.22 ± 0.05	2.44 ± 0.05	2.47 ± 0.04
Resolution ^a,b	1.50	0.92	1.51	0.80
LOD (mg mL ^-1 )	0.06	0.06	0.09	0.10
LOQ (mg mL ^-1 )	0.18	0.18	0.26	0.30
Linear range (mg mL ^-1 )	0.18 – 2.00	0.18 – 1.50	0.26 – 2.00	0.30 – 1.50
Regression equation (y):
Slope (a ± S _a )	139288.9 ± 1140.1	286408.6 ± 3181.1	166591.5 ± 2043.2	284748.3 ± 5341.4
Intercept (b ± S _b )	−635.2 ± 1176.9	4474.6 ± 2691.5	−228.6 ± 2067.2	4043.2 ± 4455.5
t = b/S _b	0.54 < t_α,f statistically insignificant	1.66 < t_α,f statistically insignificant	0.11 < t_α,f statistically insignificant	0.91 < t_α,f statistically insignificant
Normality of residuals ^c (Shapiro-Wilk test)	0.9343 (p = 0.49)	0.9619 (p = 0.81)	0.9387 (p = 0.54)	0.9462 (p = 0.62)
Correlation coefficient	0.9997	0.9995	0.9994	0.9986
R ² value	0.9994	0.9989	0.9986	0.9968
Precision (% RSD)	1.04	0.74	1.09	0.64
Intermediate precision (% RSD)	1.30	0.99	1.18	0.80

Regression equation y = ac + b; c - concentration of solution; y- peak area; S_a – standard deviation of slope;S_b - standard deviation of intercept, t- calculated value of Student’s t-test, t_α,f =2.776 critical value of Student’s t-test for degrees of freedom f = 4 and significance level α = 0.05;
^aMean ± SD (n = 6).
^bResolutions were calculated between two adjacent peaks.
^c normal distribution of residuals if p > 0.05.

ISSN: 2661-801X