Concurrent estimation of lamivudine, tenofovir disoproxil fumarate, and efavirenz in blended mixture and triple combination tablet formulation by a new stability indicating RP-HPLC method

Future Journal of Pharmaceutical Sciences

Table 6 Results of robustness of standard solution

Variation in parameter		LAM		TDF		EVZ
Variation in parameter		%RSD of peak area	Plate count	%RSD of peak area	Plate count	%RSD of peak area	Plate count
Mobile phase ratio (±1ml)	26:74	1.3	2905	0.97	9659	0.67	11,823
Mobile phase ratio (±1ml)	28:72	1.4	2817	1.35	9253	1.60	11,742
Flow rate (±0.1mL/min)	0.9 mL/min	0.52	2896	0.27	9675	0.47	11,963
Flow rate (±0.1mL/min)	1.1 mL/min	0.51	2841	0.24	9352	0.23	11,452
Wavelength (±2nm)	258	0.35	2831	0.27	9341	0.31	11,994
Wavelength (±2nm)	262	0.36	2912	0.27	9368	0.23	11,535
	%RSD		1.46	%RSD	1.89	%RSD	1.88

%RSD relative standard deviation time
Slight change in method parameter could not influence the USP plate count and tailing factor