Chemistry Reference
In-Depth Information
Multiple Regression Analysis:
A type of linear regression in which two or more
multivariate independent variables are fit to a linear model of one depen-
dent variable.
Nominal Concentration:
Theoretical or expected concentration.
Normal or Gaussian Distribution:
A sampling of data defined by a mean and a
standard deviation that exhibits the frequency of a bell-shaped or Gaussian
curve.
Observation:
Experimentally derived data.
Operational Qualification (OQ):
OQ testing is done to verify that the instrument
and/or instrument modules operate as intended.
Out-of-Specification (OOS) Results:
All suspect results that fall outside specifica-
tions or established acceptance criteria.
Outlier:
Data that fails to meet a statistical test for acceptance.
Partial Validation:
Validation of the affected performance characteristics of
a method or procedure resulting from changes to the method or test
substances.
Percent Recovery:
The observed or assay value divided by the true or theoretical
value multiplied by 100.
Performance Qualification (PQ):
PQ testing is performed under the actual run-
ning conditions across the anticipated working range. In practice, a known
method, with known, predetermined specifications is used to verify that
all the modules are performing together to achieve their intended purpose.
In practice, OQ and PQ frequently blend together in a holistic approach.
For HPLC, the PQ test should use a method with a well-characterized
analyte mixture, column, and mobile phase. Actual user PQ tests should
incorporate the essence of the system suitability section of the General
Chromatography Chapter 621 in the USP in order to show suitability under
conditions of actual use.
Precision:
The degree of agreement among individual test results when an ana-
lytical method is used repeatedly to multiple samplings of a homogeneous
sample.
See
Repeatability, Intermediate Precision, and Reproducibility.
Procedural Blank:
A sample of known composition (e.g., placebo) that does not
contain the analyte of interest that is processed, prepared, or handled in the
same way (procedure) as an unknown sample or standard.
Procedure:
A specified way to perform an activity by execution of an approved
document intended to produce a result defined by a specification.
Purity Tests:
Analytical procedure that accurately assesses the impurity content of
an analyte, for example, related substances test, heavy metals, and residual
solvent tests.
Qualification:
A subset of the validation process that verifies proper module and
system performance prior to the instrument being placed on-line in a regu-
lated environment.
Quality Assurance (QA):
The sum total of the organized arrangements made with
the object of ensuring that all APIs are of the quality required for their
intended use and that quality systems are maintained.
Quality Control (QC):
Checking or testing that specifications are met.
