Leak test of Blisters / Strips / Containers /Dry Syrup bottles/Vials

Leak Test Apparatus

What is Leak Test and Leak test Apparatus:

The test which is used to check the integrity of packed strips, blisters, Bottles and small sachets containing tablets, Capsules and Dry Powders is called leak test.

Leak test Apparatus is used to test the quality of the packaging process and to check that the seals enclosing the product are perfectly intact and no water should go inside the pack. It is designed to find the smallest holes or Puncture and imperfections in packed Products .

General requirements :

Leak test shall be performed by Production and Quality assurance during packing operation. Leak test shall be performed Before starting of packing operation, every 3 to 4 hours interval, after Break, End of Operation and after change in Foil roll.

Take 4 litter of fresh potable water in Vacuum desiccator and add 10 to 12 drops of methylene blue solution and ensure complete mixing of methylene blue.

In order to identify the leakage in Blister or stripes methylene blue colour is used and Change the solution in the desiccator everyday or whenever required.

Procedure of Leak test Apparatus :

Collect sufficient no. of consecutive strips or blisters from the sealing station so as to cover all the blisters/stripes sealed in one cycle and Place the required number of strips or blisters in desiccator and put the disk on desiccator.

Place blister / strips / containers / vials in the vacuum desiccators containing purified water coloured with 2 – 3 drops of 2% w/v solution of Methylene blue and covers it with the perforated disc to hold the sample submerged. Ensure that water level is above the perforated plate.

In case of Dry Syrup bottles, place number of bottles in desiccator after induction sealing equivalent to the No. of capping heads while in case of screw capping place number of bottles equivalent to the No. of capping heads.

In case of Bottle Packing (Tablets/Capsules ) collect  empty bottles by crossing it with permanent marker pen & pass it through Cap sealing & induction sealing machine  while in case of Screw capping collect  empty bottles equivalent to the No. of capping heads.

Close the desicator and switch on the power supply then apply 305 mm of Hg or 12 inch of Hg  vacuum by adjusting vacuum gauge and hold vacuum for 2 minutes.

Then slowly release the vacuum and remove the samples from the desicator and Wipe the samples with tissue paper or lint free cloth then Examine for leakage of water into the pockets by defoiling, removing the seal of the vials or container.

Any tablet or capsules etc. found in blue colour on the surface of tablet or capsules it means sample fail in the leak test and discard all the tablets/capsules/Bottles taken for leak test.

What Happen if Leak test is Failed :

If one tablet / capsule of even one blisters / strips / vials fails repeat the test with further blisters / strips / containers / vials. No blisters / strips / containers / vials should show leakage then stop the  machine and rectify the problem and if required investigation shall be performed.

If leakage is through surface of Strip then check the foils used for the pinholes.

Remove 2 – 3 meters foil and visually examine for the pinholes, raise an online rejection form for the foil if pinholes are observed, return it and get new foil & proceed and check the sealing, foil or cap with wad for any damage.

If leakage is from sides (For strips / blister):

Check for the heater temperature by using thermometer

Check for knurling and pressure of Pressure Sealing Roller.

Check for any damage to the Counter Sealing Roller.

Adjust the temperature if it is low.

If knurling on the roller is not good, clean the roller by using soft wire brush and with cleaning liquid.

If sealing is not proper adjust the pressure of the roller and If powder in channel, clean the channel, if necessary dedust the uncoated tablets.

If leakage is from sides (For containers):

Check for the powder level of induction sealer and check for the distance between the sealer and container.

Check for powder on neck of the container, if uncoated tablets / powder are being packed or rayon on container if rayon is used for packing.

Adjust the power level by increasing or decreasing the power level by pressing the up and down arrows on control panel.

For vials (if the leakage is in vials):

Check, adjust the pressure on chuck and sealing rollers and repeat the test till it complies.

If leak test fails, quarantine the shippers between the previous acceptable test and failed test collect five blisters / strips / containers / vials for leak test from each layer of the packed shipper starting from the first, and perform the leak test

Calibration of Leak test Apparatus :

Calibration shall be performed Once in three months or Calibration should be performed after     any maintenance job.

Adjust the set time to 2 minutes. Press the start button and simultaneously start the calibrated stopwatch.

Check the time on the stopwatch and record the observations in calibration report at the end of the test.

Acceptance Criteria:

Time on the stopwatch should be in the limit of 2 min ± 2 seconds.

If results are out of acceptance criteria, then affix “DO NOT USE-BREAKDOWN” label on the instrument.

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8 thoughts on “Leak test of Blisters / Strips / Containers /Dry Syrup bottles/Vials

  1. Appreciating the time and effort you put into your site and in depth information you provide. It’s nice to come across a blog every once in a while that isn’t the same unwanted rehashed material. Great read! I’ve bookmarked your site and I’m including your RSS feeds to my Google account.


  2. Can you please confirm the pressure to set to check the leak test? Whether it is 305mm of Hg or 380mm of Hg? or pressure vary from company to company as per their requirement??


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