Development and validation of HPTLC method for simultaneous estimation of curcumin and galangin in polyherbal capsule dosage form

Peer review under responsibility of Taibah University.

Figures & data

Fig. 1 Structure of Curcumin.

Fig. 2 Structure of Galangin.

Fig. 3 UV spectra of CU and GA.

Table 1 Linear regression data for calibration plots of the analyzed drugs using the proposed HPTLC methods.

Parameters	Results
	CU	GA
Wavelength (nm)	404	404
Retention factor (Rf)	0.28 ± 0.02	0.48 ± 0.06
Linearity range (ng/spot)	80–450	200–1200
Correlation coefficient (r^2)	0.9986	0.9991
Slope	19.51	10.86
Intercept	1431.60	440.18
% RSD of slope	0.45	0.78
LOD (ng/spot)	18.31	40.50
LOQ (ng/spot)	55.50	122.74

Fig. 4 Calibration curve for standard curcumin.

Fig. 5 Calibration curve for standard galangin.

Table 2 Intra-day and inter-day precision of CU and GA.

Analyte	Concentration (ng/spot)	Found ± SD^a (ng/spot)	RSD^b (%)
Intra-day precision
CU	100	91.67 ± 0.61	0.08
	250	227.43 ± 0.72	0.77
	400	360.46 ± 0.92	0.20
GA	300	297.23 ± 0.88	0.56
	700	677.73 ± 0.77	0.46
	1100	1022.40 ± 0.87	0.33
Inter-day precision
CU	100	97.57 ± 0.77	0.30
	250	234.66 ± 0.87	0.45
	400	365.56 ± 0.69	0.29
GA	300	297.33 ± 0.94	0.26
	700	686.46 ± 0.87	0.14
	1100	1032.87 ± 0.74	0.42

a Mean ± standard deviation for three determinations.

b % relative standard deviation.

Table 3 Robustness evaluation of the method for CU.

Factor	Level	CU		GA
		% RSD of peak area	Rf ± SD	% RSD of peak area	Rf ± SD
A: Development distance
7	−1	0.33	0.30 ± 0.06	0.23	0.50 ± 0.02
8	0	0.34	0.28 ± 0.02	0.33	0.48 ± 0.06
9	1	0.28	0. 31 ± 0.04	0.26	0.54 ± 0.05
B: Percentage of n-hexane in the mobile phase (v/v)
6	−1	0.43	0.32 ± 0.04	0.40	0.51 ± 0.05
7	0	0.41	0.28 ± 0.02	0.36	0.48 ± 0.06
8	1	0.44	0.21 ± 0.01	0.41	0.43 ± 0.02
C: Chamber saturation time
20	−1	0.17	0.27 ± 0.03	0.18	0.49 ± 0.07
30	0	0.17	0.28 ± 0.02	0.16	0.48 ± 0.06
40	1	0.18	0. 28 ± 0.04	0.19	0.51 ± 0.02

Table 4 Accuracy studies of CU and GA at 80%, 100% and 120% addition by the proposed TLC densitometric method.

Analyte	Amount in sample (μg)	Amount added (μg)	Measured conc. ± SD	% Recovery	% RSD
CU	200	160	340.87	94.68	0.04
	200	200	396.55	99.13	0.01
	200	240	438.22	99.59	0.01
GA	600	480	1078.88	99.89	0.03
	600	600	1187.68	98.91	0.01
	600	720	1317.92	99.77	0.03

Fig. 6 Densitogram of CU and GA.

Table 5 Application of the proposed HPTLC method for determination of the analyzed drugs in commercial formulation.

Analyte	% Recovery	% RSD
CU	99.12 ± 0.27	0.11
GA	98.44 ± 0.33	0.09