###Over printing### & line clearance sheet by Vishnu Datta M
Line clearance sheet
• This is sometimes known as
‘batch coding’ as well as the more
popular term, overprinting.
• This has become a necessary evil
in the modern world.
• All overprinting (this may include
off-line methods as well) is used to
add variable data as late in the
production cycle as possible, i.e.
batch/lot numbers, manufacture
and expiry dates, price blocks for
the Middle East in particular and
registration numbers for many other
• If these problems are approached
by the method of using fixed copy
for a large area of the world allied
with a fairly sophisticated
overprinting system, one can save
the cost of the system in inventory
• The overprinting of ‘variable’
information as late as possible in
the label application and carton
closing processes gives the
production company a high degree
of flexibility to allow for un
forecasted emergency information
to be added.
• This copy is normally added to the
printed label or carton either just
prior to the packaging operation or
during the operation itself.
• As with all printed copy, the print
must be indelible, legible and not
fade during the shelf life of the
product under normal usage
• It is usual to overprint in black and
occasionally red. Note that red is
traditionally used for warnings or
poison markings, so check carefully
• Overprinting is usually carried out
with one or other of the following
printing processes: hot foil
stamping, flexographic, letterpress,
tampon, thermal printing, and
• Some of the information required
may be in the form of bar codes.
This has stimulated the European
Pressure Sensitive Manufacturers
Association (EPMSA) in line with
the Article Numbering Association
(ANA) EAN guidelines, to produce
a standard for bar code overprinting
on pressure sensitive labels.
• EAN bar codes can now be
successfully printed onto labels
using flexographics, or thermal
• It can be
• Contact printing techniques
• Non-contact printing techniques
• An EAN-13 barcode (originally
European Article Number, but now
renamed International Article Number
even though the abbreviation EAN
has been retained) is a 13 digit (12
data and 1 check) barcoding standard
which is a superset of the original 12digit Universal Product Code (UPC)
system developed in the United
• Contact printing is the more traditional type of
printing in the industry
• Letterpress —the traditional slugs of type in either
lead/antimony alloy or hardened steel letters.
Usually locked up (set) in a chase (holder), or
using a ‘baselock’ type of system where the type
has a foot which slips into a holder and can be
locked by a spring clip, being inked each pass and
‘kissing’ the substrate to deposit the ink.
• Can be used on most substrates, but is best on
paper and board which is not too shiny. Cast
coated papers and boards give problems.
• Debossing —the same as letterpress
except that no ink is involved and the
characters are pressed quite hard into
the substrate. Used occasionally for
paper, but more normally for blister
and strip packs. This method is likely
to generate complaints, due to the
difficulty of reading it clearly.
• Hot foil
• Thermal transfer printing
• Offset litho
• Impact dot matrix
Non-contact printing techniques
i. Drop-on-demand printers
ii. Continuous flow works by using piezo
electric crystal to generate an ultrasonic
beam to disturb the flow of ink by
producing uniform sized droplets. These
are then electrostatically charged under
computer control. The charged droplets
are deflected to a catching mechanism
and the neutral ones pass onto the
substrate forming the image.
On-line or off-line printing?
• In all overprinting operations the economics of the
situation must be addressed, e.g. on-line or off-line.
• On-line overprinting has the advantage of being directly
under the control of the person in charge of the operation,
but has the disadvantage that if there is a problem with the
overprinting operation the production line halts.
• Off-line overprinting has the advantages of not directly
holding up production if it has problems, and having staff
that are usually better trained and specialist in printing.
The disadvantages are that generally extra overprinted
components have to be supplied to compensate for
potential packaging line problems, and the overprinting
operation can sometimes become a bottleneck.
What is Line clearance ?
• An important requirement of GMP is
that the packaging and labelling
facilities are inspected before use to
assure that all drug product have
been removed from previous
operation and that packaging and
labelling materials not suitable for
subsequent operation have also been
• A line clearance/inspection is required for all
packaging/labeling operations to ensure that
there is no drug product remaining from the
previous batch and that packaging and
labeling materials not suitable for subsequent
operations have been removed.
• Results of the clearance/inspection are
documented in the production batch record.
The master production records provide a
description of the drug product including size,
shape, distinguishing markings, and color.
• Procedure: The fillingpackaging line and
areas immediately closed to it should be
free from all filledpackaged products as
well as the packaging and labelling
materials from the previous
fillingpackaging operation. Reject on the
line such as inadequately filled bottles,
broken or damaged packs, strips with
empty pouches and then should also be
removed and destroyed. Spillages on
the line and immediate areas should be
•Particular attention should be paid to left-over
labels and cartons with overprinted lot details
from the previous run, especially when a new
batch of same product is to be packed on line.
It should be certified that packaging equipment
has been properly cleaned and a tag
(preferably green colored and marked
‘CLEANED ’). The tag should also indicate the
date of cleaning and the name of the product
for which the equipment was last used and
should be signed by the supervisor .
• If the equipment has been idle even for
a short period of time before use, it
should be re-inspected for cleanness
and re-cleaned before use, if required.
The green tag should indicate the date
of the new cleaning and should be
initialed by supervisor. Information
regarding cleaning of major packing
equipment should be recorded in the ‘
Equipment Cleaning and Use Log ’ of
the packaging department.
• If the line clearance is satisfactory, the
relevant portion of the fillingpackaging order
should be filled and initiated by the
supervisor. Filling or packaging of the batch
should not commence until the clearance has
been initiated by the supervisor on the filling
packaging order. Where the fillingpackaging
has been interrupted, a new line clearance
check has to be made. In such cases, all the
materials should be returned, under close
supervision to their respective identified
containers until the new clearance has been
• PHARMACEUTICAL PACKAGING
TECHNOLOGY Edited by
D.A.Dean,E.R.Evans,I.H.Hall Taylor and Francis
• Good Manufacturing Practices for
Pharmaceuticals sixth edition James Swarbrick
• "All of science is nothing more than the
refinement of everyday thinking."