Extractive Spectrophotometric Method for the Determination of Lamivudine and Zidovudine in Pharmaceutical Preparations Using Bromocresol Purple

Table 1

Optical characteristics and statistical data of the regression equations for ZVD and LVD with BCP.

Parameter	LVD	ZVD
𝜆max (nm)	414	414
Beer’s law limit (μg mL^−1)^b	25–250	50–300
Molar absorptivity (l mol^−1 cm^−1)	3.68 × 10^3	3.047 × 10^3
Sandell’s sensitivity (μg cm^−2 per 0.001 absorbance unit)	1.604 × 10^−5	1.140 × 10^−5
Regression equation^a
Slope ± SD	0.0037 ± 0.00013	0.0036 ± 0.00026
Intercept ± SD	−0.0153 ± 0.000054	0.0772 ± 0.000050
Correlation coefficient, 𝑟	0.9995	0.9997
LOD (μg mL^−1)	0.106	0.217
LOQ (μg mL^−1)	0.352	0.722
Intra-day^b	0.65	0.54
Inter-day^c	0.87	0.71

^a𝐴=𝑎+𝑏𝐶 (where 𝐶 is the concentration of drug in 𝜇g mL⁻¹).
^bAverage of six determinations.
^cResults of seven different days.