Prepared By : Subrata SInha (Senior Analyst) Analytical method validation’s superlative characteristic, linearity is comprehensively explained in this slide show. Linearity commonly understood as proportional relationship between two units, in context of method validation, it refers toproportional relationship between test results and concentrations.

1. www.sigmatest.org

2. LINEARITY
Definition:- Linearity is a mathematical
relationship between two variable
quantities (they may be of the same
unit), which are directly proportional
to each other.
Graphically it represents a straight line
when plotted against each other.
www.sigmatest.org

3. GRAPHICAL
PRESENTATION OF
LINEARITY
y = 10.107x - 2.381
R² = 0.9997
-100
0
100
200
300
400
500
600
700
0 10 20 30 40 50 60 70
Y-axis
X-axis
Linearity Graph
www.sigmatest.org

4. NEEDNESS OF LINEARITY
NON –LINEAR APPROCH LINEAR APPROCH
END TIME END TIME
25 min 35 min 25 min 45 min
15 min 35 min 15 min 35 min
10 min 20 min 10 min 30 min
START TIME START TIME
www.sigmatest.org

5. NEEDNESS OF
LINEARITY
 From the above graphical presentation of non-
linear and linear, We can definitely say that in
the linear case we need only one variable value
and the other variable value can be accurately
determined. But in the case of non-linear we
cannot accurately (definitely) determine the
other variable’s value, even when one of the
variable’s value is known.
www.sigmatest.org

6. ROLE OF LINEARITY IN
ANALYTICAL METHOD VALIDATION
The linearity of an analytical method is it’s ability to
elicit test results that are directly proportional to the
concentration of the analyte in samples within a given
range.
This is why to check the proportionality of result with
concentrations, it is necessary to justify the linearity
between LOWER Concentration & UPPER
Concentration.
www.sigmatest.org

7. DEFINITION OF SOME PARAMETERS
RELATED TO LINEARITY
 Lower Concentration:- LOQ is the lower concentration i.e.
starting point of the linearity in analytical method validation.
 Upper Concentration:- Cmax value is the upper concentration
of the linearity in analytical method validation. But it may be
lower according to available quantity of the analyte in sample.
 Cmax is a pharmacokinetics term. It is the maximum (or
peak) serum concentration that an analyte achieves in a
specified test area of the body after the analyte has been
administrated.
www.sigmatest.org

8. JUSTIFICATION OF
LINEARITY
 The strength & direction of the linear relationship
between two variable quantities is termed as
correlation coefficient. It is denoted by r.
 Mathematically it is expressed by r2, i.e. square of r,
which is called coefficient of determination. The
coefficient of determination (r2) ranges from 0 to 1.
The range of r2 denotes how straight the line is.
 Accepted value of r2 is NLT 0.95
www.sigmatest.org

9. The End of
Linearity Chapter
www.sigmatest.org