(2003; 67 pages)
4.5 Limitations of the methodology
Sample containers: Most of the samples were repacked in containers different from the packaging in which the product was marketed, although care was taken to use adequate materials. The closures of the packaging material were however inadequate in the case of liquid preparations and leakage occurred which may have compromised the integrity of the products.
Sample content: The physical and organoleptic properties of some of the CQS were unacceptable, due to crystallization of the content of the container. The crystallization could not be reversed by agitation, and so the samples were rendered unsuitable for analysis. The tendency towards crystallization might have been due to exposure to extremes of temperatures or to loss of content due to the evaporation of liquid vehicle as a result of insufficient sealing of the closures.
The content of some of the samples produced a foul smell, probably due to insufficient preservation. This phenomenon may be related to an unacceptable formulation but it may also be related to insufficient sealing of the closures, or contamination during manufacturing.
In the case of solid dosage forms, broken tablets were noted in some samples. This could be due to a formulation variable that did not support severe handling of the tablets. On the other hand, it may also be that, when removed from the original packaging, the tablets were not adequately repackaged to withstand the stress conditions of transportation.
Sample quantities: Many samples did not have the required number of units for performing all the required tests. In such cases the tests were performed on fewer than the required number of units. Although the results might give an indication of the property evaluated, statistical variance would be high, due to the limited number of units tested. In such cases the results had to be interpreted with caution when trying to arrive at an absolute value for the particular property tested.