Validating Processes For Surface Preparation
Barbara Kanegsberg and Mantosh Chawla, May 2002
Validation of processes for surface preparation is crucial to many industries,
including pharmaceuticals, biomedical device and even food preparation. The
effectiveness of the methods for surface preparation in these industries should
be established, documented and monitored on an on-going basis.
Validation helps ensure that the surface has been cleaned to an acceptable
contamination level. This maximum tolerable contamination level may be termed
the target level. Sampling and analysis techniques must have the specificity,
sensitivity, reliability and robustness to assure that contamination does
not exceed the target limit. The areas of surface where contamination
is most adherent
or where the negative consequences of contamination are greatest must receive
special attention. The nature of potential contaminants must also be considered.
While much attention is paid to biological debris, microbes, and pyrogens,
other organic and inorganic contaminants can potentially impact product quality.
As applied to processes for surface preparation, validation is a quantifiable,
structured approach to demonstrate and document process effectiveness and
process consistency. The following are suggestions for a comprehensive
validation process.
Process efficacy must be evaluated prior to implementing the procedure.
The procedure should require re-validation after changes to the processes
that
may significantly affect the types and amount of contamination left on
the surface, or when significant changes are made to the cleaning process
and
result of re-validation must be documented.
The essence of process validation is documented, scientific proof of
consistent successful process performance. Full, detailed documentation
is an integral
part of the validation process to show that the process consistently
performs as expected and yields a result that consistently meets predetermined
specifications.
Predetermined specifications in this situation refer to the maximum
acceptable level of contamination that can be tolerated on the surface.
Written
procedures must be established detailing the surface preparation processes.
Those
responsible for performing, approving and documenting the validation
study and the acceptance
criteria must be included, as should documentation of the frequency
of process monitoring. Written procedures on how process changes
will be
validated and
requirements for documentation of validation should also be developed.
Sampling and analysis methods must provide for sample collection and
detection of levels of contamination relevant to the target limit.
The technique
must be suited to the types and the target level of contamination.
The detection
technique should be reviewed periodically for its effectiveness and
relevance to the type and level of contaminants currently encountered.
Prior to
accepting and implementing a validation procedure, the analytical
or surface testing
technique itself should be evaluated and successfully replicated
at least three times. Where possible, direct surface monitoring is
desirable
and
may be preferred
over indirect, extractive methods. Part configuration and test method
sensitivity must be considered.
Establishing appropriate target levels of maximum acceptable contamination
is a challenge. Generally, the main consideration should be as
to how much surface contamination can be tolerated. There are many
ways
of
establishing contamination limits. Cost must be considered in determining
the target
contamination level. For each level of surface contamination there
is an
associated cost
of achieving that level. In addition, with each level of contamination
there is a level of non-conformance or failures. The
cost associated with each
level of non-conformance must also be considered. The maximum
acceptable level (Target
Level) is the one where the incremental cost of removing more
contamination is not offset by the corresponding reduction in the non-conformance
or failure cost. If, however, the cost of non-conformance is
a
health threatening,
or
life threatening product failure, then the target contamination
level must be adjusted to an appropriately low level.The situation
is akin
to extrapolating
from animal studies to humans using the lowest dose of a drug
or chemical at which no adverse effects are seen.The appropriate “safety factor” or
risk factor will depend on the nature of the observed problem
animals or the anticipated consequence in humans.
Some general considerations in establishing target levels include
the effect of different levels of contamination on the success
of subsequent
operations;
the detection capability of the various analytical techniques
available; the anticipated end-use and performance requirement
of the product;
and the economic
and social cost of non-conformance or failure.
Barbara Kanegsberg at BFK Solutions, 16924 Livorno Dr., Pacific Palisades, CA
90272, 310-459-3614; barbara@bfksolutions.com;
contact Mantosh Chawla atPhotoemission Tech., (PET), 3255 Grande Vista Dr.,
Newbury Park, CA, 91320; 805-499-7667
