New Spectrophotometric and Conductometric Methods for Macrolide Antibiotics Determination in Pure and Pharmaceutical Dosage Forms Using Rose Bengal

Table 1

Quantitative parameters for the spectrophotometric determination of erythromycin thiocyanate (I), clarithromycin (II), and azithromycin dihydrate (III) with rose bengal copper.

Parameter	(I)	(II)	(III)
𝜆 max (nm)	558	557	560
Beer's law ranges (𝜇g/mL)	15–60	7.5–40	4–20
Regression equation**
Slope (𝑏)	0.0193	0.0209	0.0617
Intercept (𝑎)	−0.1413	−0.022	−0.1247
Correlation coefficient (𝑟^2)	0.9999	0.9999	0.9999
LOD 𝜇g/mL	1	0.93	0.31
LOQ 𝜇g/mL	3.04	2.8	0.95
Ringbom optimum concentration; range (𝜇g/mL)	20–50	10–35	9–16
Sandell's sensitivity 𝜇g·cm^−2	0.07	0.05	0.02
𝜀 (×10^4) L·mol^−1·cm^−1	1.12	1.47	3.78

*Average of three experiments.
**A = 𝑎 + 𝑏c.