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Cleanable In-Line Components 213
& The International Conference on Harmonization of Technical Requirements for
Registration of Pharmaceuticals for Human Use (ICH) (6). This international
conference includes regulatory agencies from Europe, Japan, and the United
States along with industry experts. The primary effort is to harmonize these
regions’ pharmaceutical processing guidelines and product registration with a
focus to minimize duplicate testing of R&D for new medicines. This conference
is also actively developing guideline documents to provide guidance to
industry. These guidelines also offer guidance to equipment fabricators and
third party verifiers as to needs for equipment compliances in specific
manufacturing sectors.
FITTINGS, TUBING, AND PROCESS-LINE CONNECTIONS
A significant aspect of hygienic process systems and equipment is related to
application of special finishes to metallic product contact surfaces. The goal of
these specialized finishes is to eliminate or significantly reduce areas that might
harbor soils or process residues in ways that would preclude their removal by
CIP operations.
Interior Surface Characteristics
Mechanical Polishes
The primary method of applying a special finish involves sequential abrasive
polishing, starting with abrasives of coarse grits and progressing to grits that
ultimately yield the desired surface finish. Generally accepted minimum surface
finish for aproduct contact surface to be cleaned in place would be produced by a
150-grit abrasive. This surface would typically be evaluated by use of astylustipped
profilometer to provide results of 32 m in. average roughness ( R a )(0.8 m m R a ).
While this surface finish has found acceptance in processes involved in the
production of comestibles, base levels of abrasive polishes applied to pharmaceutical
and biotech equipment aregenerally required to yield afinish ranging from
25 m in. R a to 15 m in. R a (0.4 m m R a ).
Electropolish
Often these mechanical surface treatments are followed by an additional electrochemical
process known as electropolish. Here, the surface being treated is
generally submerged in an acid bath and connected to an electric current while
an electrode is passed in close proximity to the surface. The electric current causes
an accelerated dissolution of the metal yielding a significantly higher quality
surface finish and, as an associated benefit, a significantly passive surface to
improve corrosion resistance.
Plating
An alternate electrochemical process is sometimes used to apply ametal overlay
and also yields an extremely smooth surface. This process of electroplating is
frequentlyused to apply layers of nickel to surfaces used in thermal transfer duties.
Although electroplating is able to yield smooth surfaces, these surfaces are also
subject to impact chipping and are also typically less resistant to acid exposure.
Nonmetallic materials are generally not able to have post-manufacturing
surface modifications, with the possible exception of machining certain types.