A novel stability-indicating chromatographic quantification of the antiparkinsonian drug safinamide in its pharmaceutical formulation employing HPTLC densitometry and ion-pair HPLC–DAD

Table 3 Regression and validation parameters of the proposed HPTLC-densitometric and HPLC–UV methods for the determination of Safinamide along with its impurity in pure form

Method Parameter	HPTLC-densitometric method		HPLC–DAD method
Method Parameter	SAF	4-HBD	SAF	4-HBD
Range	2.00–15.00 µg/band	0.50–3.40 µg/band	3.00–150.00 μg/mL	0.50–7.00 μg/mL
Regression equations parameters
Slope (b)^a	–	–	15.441	44.689
Coefficient 1 (b1)^b	− 64.966	− 913.12	–	–
Coefficient 2 (b2)^b	2317.3	6280	–	–
Intercept (a)^{a, b}	324.49	− 1942.8	− 1.9547	8.0267
Correlation Coefficient (r)	0.9999	0.9999	1.000	0.9997
Accuracy (Mean ± SD)	100.13 ± 1.286	100.11 ± 1.389	100.24 ± 1.092	100.24 ± 1.631
Precision
(%RSD)^c	0.291	0.674	0.309	0.656
(%RSD)^d	1.252	0.842	0.745	1.495
LOD^e	–	0.019	–	0.153
LOQ^e	–	0.056	–	0.463
Robustness^f	1.658	1.944	1.952	1.913

^aRegression equation for HPLC: A = a + bc, where ‘A’ is the average peak area and ‘c’ is the concentration (μg/mL)
^bCoefficient 1 and 2 are the coefficients of X² and X, respectively. Following a polynomial regression: A = b1x² + b2x + a, where ‘A’ is the average peak area, ‘c’ is the concentration (μg/band), ‘b1’ and ‘b2’ are coefficients 1 and 2, respectively and ‘a’ is the intercept
^cIntra-day precision [average of three different concentration of three replicates each (n = 9) within the same day], for HPTLC the concentrations were (4.00, 6.00, 10.00 µg/band) for SAF, and (1.00, 1.40, 2.40 µg/band) for 4-HBD, For HPLC: the concentrations were (0.80, 3.00, 5.00 μg/mL) for 4-HBD, and (44.00, 66.00, 132.00 μg/mL) for SAF
^dInter-day precision [average of three different concentration of three replicates each (n = 9) repeated on three successive days], the concentrations were the same as in intra-day precision
^eLOD and LOQ are calculated according to ICH, 3.3 × SD of the residuals/slope and 10 × SD of the residuals/slope, respectively
^fFor HPTLC: average of the change in scanning wavelength (±1 nm), ethyl acetate ratio (±1%), developing distance (±0.5 cm) and saturation time (±5 min). For HPLC: average for flow rate (±0.1 mL/min) and pH (±0.1)

ISSN: 2661-801X