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 6

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

Source	Sum of squares	df	Mean square	𝐹 value	𝑃 value prob > 𝐹
Model	0.073284126	3	0.024428	743.3259616	<0.0001	Significant
A—flow	0.008862903	1	0.008863	269.6911034	<0.0001
B—column temp.	0.009766119	1	0.009766	297.1752743	<0.0001
C—THF comp.	0.054655104	1	0.054655	1663.111507	<0.0001
Curvature	8.82574𝐸−05	1	8.83𝐸−05	2.68560136	0.1622	Not significant
Residual	0.000164316	5	3.29𝐸−05
Lack of fit	0.000164316	4	4.11𝐸−05
Pure error	0	1	0
Cor total	0.073536699	9
Std. dev.	0.006488107		𝑅^2	0.996565345
Mean	0.591672677		Adjusted 𝑅^2	0.994848018

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