Relation between the temperature and the belt speed in Depyrogenation Tunnel

This question was asked by Mr.Mostafa.

[b]Iam writing down here so that you folks will learn and also post some new questions on this subject so that we all learn a good science.

Normally in Depyrogenation tunnels the temperature at the heating zone will be around 305-310C depending up on the system we use. It is universally calculated that at around this temperature the Endotoxins will be denatured if a vial or ampoule or a glass material is properly washed and exposed.The time of exposure should be around 3.2 minits to 3.5 minits depending up on the size of ampoule/vial used and speed of conveyer of the tunnel. Conveyer is used to carry the washed materials from one end to another end into a sterile zone at a prefixed speed by operator based on parameters derived from validation runs.

How do we arrive to this point?

Lets imagine the width of the conveyer is 1200 mm ( milli meters)

The diameter of vial under consideration is 50 mm.

The Speed at which tunnel is mooving is set by validation team at 135 millimeter/ minit (mm/min)

We have to know how many vials will fit on to conveyer horizantally

Width of conveyer / diameter of vial = 1200/50 = 24 vials in each row ( This is used when capacity is calculated)

Now the heating zone as per the system design (URS) is 1.5 feet

Heating zone 1.5 feet converted into millimeters gives us around 457 mm

( 457/ 50 = 9 rows vertically will be present at a particular instance . That means 9x24= 216 vials will be technically can fit into the core depyrogenation area)

Now the number of rows of vials are mooving = speed of conveyer/ Dia of vials = 135/ 50 = 2.7 rows will mover per minit

Residence time is widt of heating zone / conveyer speed = 457/135 = 3.38 minits

That means at this speed when a praticular conveyer is operated rows of vials will be exposed for about 3.38 minits at about 305-310 degrees centigrade to ensure that all the bacteria are killed and Endotoxins/pyrogens are denatured.

This should be again studied by spiking vials with LPS(Endotoxins) and detecting these vials at Microbiological lab.

This is simple calculation and you can have your own values in this.[/b]




Mr. Mostafa asked Revalidation Period determination

Performance Qualification of Depyrogenating Tunnel shall be carried out in any or all of the following situations or at established frequency whichever is earlier:
•Substitution of existing equipment with new equipment.
•Any major modification in existing equipment since purchase or after the last performance qualification. This must be properly documented through a change control system
•Adjustments made in the instruments, to correct the non-compliance of operational parameters with respect to specifications( if you have more frequent sterility and Endotoxin falures you must test all parameters as part of your Root Cause analysis (RCA) program)

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