A. SAMPLING PLAN OF WHO

1.Purpose of sampling?
2. Sample Retention
3. Sampling Plan
Samples should be stored according to the storage conditions as specified for the respective API, excipient or drug product.
Packaging materials similar to those in which the bulk is supplied should be used for long-term storage.

 

Sampling of starting materials

 Uniform material: sample can be taken from any part.

Non-uniform material: Special sampling tools are needed.
Alternatively, if applicable, restore uniformity before sampling (e.g. stratified liquid may be stirred or a solid deposit in a liquid may be dissolved by gently warming and stirring) – validated method !
In these cases, in order to prepare representative samples, see ISO 2859.
Partially processed natural products (animal, herbal and mineral) should be treated as intrinsically non-uniform. For info, sampling of herbal drugs, see European Pharmacopoeia chapter 2.8.20.


Sampling of intermediates in manufacturing and bulk products

Intermediates: liquids and semi-solid products; powdered solids or granulates; unit dosages forms in bulk (tablets, capsules).
Pay attention to the segregation of bulk materials during transportation.
These products may be assumed as uniform if the transportation process has been validated, AND:
They are labelled with name of the manufacturer and a single batch number;
They have been produced according to GMP; and
They are supplied with a certificate, issued in the country of origin, according to the WHO Certification Scheme on the quality of pharmaceutical products moving in international commerce

Sampling of finished products

A consignment of packaging materials may NOT be considered homogeneous if:
Materials manufactured on different days or machines
Materials manufactured on one machine, but different stations (e.g. printing stations, moulding stations)
Packaging manufactured with different source materials
Change in quality during the process (colour variation, text legibility or change of printing plate, container-wall thickness...)
Important to take random samples from across the consignment.
Consider focus sampling based on the above mentioned risk factors.

Sampling plans for starting materials 


I.“n-plan”


II.“p-plan”


III. “r-plan”
a. n- plan : Only used when material is considered uniform and from a recognised source. n = 1 + sqrt(N)  where N is the No. of containers received and n = no of containers to be sampled
The “n-plan” is NOT statistically based and should be used only as a guiding principle.
The “n-plan” is NOT recommended for use by control laboratories of manufacturers that are required to analyse and release or reject each received consignment of the starting materials used to produce a drug product.
b. p-plan : 
May be used when material is considered uniform, from a recognised source and the main purpose is to test for identity. p =0.4(Sqrt(N))
c. r - plan : May be used when material is considered non-uniform and/or obtained from a not well know source . Can be used for herbal medicinal products used as starting materials.