Stability-Indicating Photochemical Method for the Assay of Thiamine by Spectrophotometry

Table 4

Assay of TH in vitamin preparations (25 ± 1°C).

Method	Labeled^a (mg/100 ml)	Vitamin preparations stored in original package (pH 3-4)
		Fresh			Aged (6 months)
		Found^b (mg/100 ml)	Recovery^c (%)	RSD (%)	Found (mg/100 ml)	Recovery (%)	RSD (%)
USP LC method
Sample 1	30	30.2	100.7	1.7	28.8	96.0	1.6
Sample 2	50	49.8	99.6	1.9	46.5	93.0	1.8
Sample 3	83	83.6	100.7	1.6	78.5	94.6	1.7
Proposed method
Sample 1	30	30.0	100.0	1.2	27.5	91.7	1.6
Sample 2	50	48.2	98.6	1.4	45.9	91.8	1.5
Sample 3	83	82.5	99.4	1.7	73.6	88.6	1.8

^aThe labeled amount of thiamin is the amount (mg/100 ml) stated on the label of the vitamin preparations. ^b. ^cPercent recovery of TH in vitamin preparation = ((amount found in mg/100 ml)/(labeled amount in mg/100 ml)) × 100.