Development and Validation of a Stability Indicating RP-HPLC Method for the Determination of Two Sun Protection Factors (Koptrizon and Tinosorb S) in Topical Pharmaceutical Formulations Using Experimental Designs

Table 7

ANOVA for 2³ full factorial design: response: RT of Tinosorb S (min).

Source	Sum of squares	df	Mean square	𝐹 value	𝑃 value Prob > 𝐹
Model	0.057184881	3	0.019061627	630.2536737	<0.0001	Significant
A—flow	0.006317517	1	0.006317517	208.8823992	<0.0001
B—column temp.	0.007126362	1	0.007126362	235.6260641	<0.0001
C—THF comp.	0.043741001	1	0.043741001	1446.252558	<0.0001
Curvature	1.67021𝐸−06	1	1.67021𝐸−06	0.055223918	0.8235	Not significant
Residual	0.000151222	5	3.02444𝐸−05
Lack of fit	0.000134936	4	3.37339𝐸−05	2.071326494	0.4746	Not significant
Pure error	1.62861𝐸−05	1	1.62861𝐸−05
Cor total	0.057337773	9
Std. dev.	0.005047971		𝑅^2	0.997333484
Mean	0.484279065		Adjusted 𝑅^2	0.996000226

Values of prob > 𝐹 less than 0.05 indicates that model is significant.