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

Table 1 System suitability parameters of the proposed HPTLC-densitometric and HPLC–DAD methods

Method	Parameter	Acid/Alk.Deg	Oxi. Deg	SAF	4-HBD	Reference value [41]
HPTLC-densitometry	Retardation factor (Rf) ± 0.02^a	0.03	0.39	0.53	0.64
	Capacity factor (k’)^b	32.33	1.56	0.88	0.56
	Selectivity (α)^c	20.7 1.77 1.57				> 1
	Resolution (Rs)^d	7.52 1.94 1.82				Rs > 1.5
	Tailing factor (T)	1.00	1.50	1.00	1.00	T ≤ 2
HPLC–DAD	Parameter	4-HBD	Oxi Deg	Acid/Alk Deg	SAF	Reference value [42]
	Retention time (min ± 0.2)	1.91	2.41	4.07	5.63
	Selectivity (α)^c	1.71 2.37 1.54				> 1
	Resolution (Rs)^d	1.72 4.28 4.14				Rs > 1.5
	Tailing factor (T)	1.00	1.33	1.00	1.00	T ≤ 2
	Column efficiency (N)	5836	1486	2946	3167	N ˃ 2000
	Height equivalent to theoretical plate HETP (cm/plate)	2.57 × 10^–3	1.00 × 10^–2	5.09 × 10^–3	4.74 × 10^–3

^aRetardation factor (R_f) = distance travelled by the analyte/distance travelled by the solvent front
^bCapacity factor (k’) = (1-R_f)/R_f
^cSelectivity (α) = k’₂/k’₁ calculated for each of two successive peaks
^dResolution (R_s) = Rf₂–Rf₁/0.5 (w₁ + w₂), where R_f is the retardation factor, and w is the peak width calculated for each of two successive peaks for HPTLC and = 2(t_RB–t_RA)/(W_B+W_A) for HPLC

ISSN: 2661-801X