How the Encapsulation Reconciliation Calculator works

Encapsulation reconciliation compares the number of capsules that the fill material should have produced with the number actually filled. The theoretical count comes from the weight of fill material divided by the target fill weight. The actual count comes from the total weight of filled capsules divided by the average filled capsule weight.

The calculator also gives the theoretical filled capsule weight, which is the target fill weight plus the empty shell weight.

Encapsulation arithmetic

Example: 60.0 kg of blend, 300 mg fill

60.0 kg of blend is to be filled at 300 mg per capsule into shells of 96 mg. The filled capsules weigh 77.4 kg, and the average filled capsule weighs 398 mg.

1. Theoretical capsules = 60.0 × 1,000,000 ÷ 300 = 200,000
2. Theoretical filled capsule weight = 300 + 96 = 396 mg
3. Actual capsules = 77.4 × 1,000,000 ÷ 398 = 194,472
4. % Yield = 194,472 ÷ 200,000 × 100 = 97.24%

Encapsulation yield limits

• Limits: use the yield limit in the approved batch record.
• Filled weight: the actual average filled weight should be close to the theoretical figure (396 mg here). A large difference means the fill weight is off target and should be explained.
• Capsule weight variation: check the individual weights against the pharmacopoeial limits. See the Weight Variation Calculator.
• Shell weight: use the average empty shell weight of the lot, not a catalogue figure.

Practical tips for capsule filling

Loss at this stage comes from capsules rejected during in-process weight checks, fill material lost to dust extraction, machine rejects such as unlocked or damaged shells, and start-up and clean-down. Weigh and record rejects separately from sampling, and keep the empty shell reconciliation next to the fill reconciliation, so both the shells used and the material used can be accounted for.

Encapsulation reconciliation errors

• Forgetting to add the shell weight to the target fill weight.
• Using the target filled weight instead of the measured average.
• Counting empty or rejected shells as filled capsules.
• Mixing grams and kilograms.
• Leaving out rejects and samples when explaining the loss.

If encapsulation yield is outside the limit

Confirm the target fill weight and the shell weight used in the calculation, then compare the average filled capsule weight with the theoretical figure. A large difference shows a fill weight problem that affects the count. After that, account for the capsules removed for weight checks and samples, the rejected capsules from the machine and the metal detector or checkweigher, the powder collected by the dust extraction, and the start-up and clean-down losses. Also reconcile the empty shells issued against the shells used and returned, since a shell discrepancy often explains a count discrepancy.

Recording the encapsulation reconciliation

Record the weight of the blend or pellets issued to the filling machine, the target fill weight, the average empty shell weight for the lot and the total weight of filled capsules at the end of the run. The average filled capsule weight should be calculated from a sample of capsules taken across the whole run, not only from the start-up checks, because fill weight can drift as the hopper level changes. Use the same unit for every weight in the calculation, and state it on the record. A reviewer should be able to recalculate the theoretical count, the actual count and the yield from the recorded figures without further explanation.

Standards and references

The checks on this page relate to the documents below. Standards are revised from time to time, so confirm the current edition and follow your own approved procedures.

• 21 CFR 211.103, Calculation of yield
• 21 CFR 211.188, Batch production and control records
• 21 CFR 211.192, Production record review
• EU GMP Part I, Chapter 5, Production

Questions on encapsulation reconciliation

How do I calculate the theoretical filled capsule weight?

Add the target fill weight to the average empty shell weight.

What causes capsule loss during encapsulation?

Capsules rejected at in-process weight checks, fill material lost to dust collection, and mechanical rejects from the machine.

Is the same formula valid for pellets?

Yes. Use the target pellet fill weight instead of the powder fill weight.

Related tools and guides: Batch Reconciliation Explained · Percentage Yield Calculator · Weight Variation Calculator · Blister Reconciliation

By Sajjad Ahmad. For reference and education only; verify limits against your SOPs and the current pharmacopoeia. See the methodology.