Sample: a portion of a material collected according to a defined sampling procedure. The size of any sample should be sufficient to carry out all anticipated test procedures, including all repetitions. If the quantity of material available is not sufficient for the intended analyses and for the retention samples, the inspector must record that the sampled material is the available sample (see below) and the evaluation of the results must take account of the limitations deriving from the insufficient sample size.
Samples should be stored in accordance with storage instructions for the respective drug; closures and labels should be of such a kind that unauthorized opening can be detected.
Available sample: whatever total quantity of sample material is available.
Final sample: sample ready for the application of the test procedure.
Original sample: sample collected directly from the material.
Pooled sample: sample resulting from the pooling of all or parts of two or more samples of the material.
Random sample: sample in which the different fractions of the material have equal probability of being represented.
Representative sample: sample obtained according to a sampling procedure designed to ensure that the different properties of a nonuniform material are proportionately represented.
Retention sample: sample collected and reserved for future controls. The size of a retention sample should be sufficient to allow at least two confirmatory analyses. In some cases statutory regulations may require one or more retention samples, each of which must be separately packaged and sealed.
Selected sample: sample obtained according to a sampling procedure designed to select a fraction of the material that is likely to have special properties. A selected sample that is likely to contain deteriorated, contaminated, adulterated or otherwise unacceptable material is known as an extreme sample.