Coating percentage

How much % of coating material is used in following?
Film coating
sugar coating
enteric coating

Generally in film coated tablet formulations the weight gain is very very less which can not be calculated as percentage, it is just few mg per tablet (say 5 to 10 mg).
In case of sugar coated tablets the weight gain of tablet after coating is significane in the range of 70% to 100% depending upon size and shape of tablets.
In case of enteric coated tablets the weight gain is in the range of 20% to 30% depending upon the tablet size and shape and more importanantly , the tablets must comply DT’ requirements (in both Acid medium & Alakaline medium).

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Sir can you please tell me how to calculate film coating dispersion
If solid content is 12%w/w and avg weight of tablet is 248mg and buildup is 3%.
Batch size -1500No’s

3% weight gain means for each tablet the weight gain due to coating will be (248 x 3) / 100 = 7.44 mg.
Hence for 1500 tablets the total weight gain will be 7.44 x 1500 = 11.16 g
As the solid content of film coating dispersion is 12% w/w , you will theoritcally require near to 100 mL of dispersion (12 g solids eq. to 11.6 g). However considering process & handling losses you may require more quantity of coating dispersion solution depending upon size of coating pan, vessles, stirrer, spray gun etc.


Can you pls guide on calculation of yield after coating stage.

We have used 24mg/tab coating material and after coating the per tablet weight will increase only 14mg instead of 24mg in this case how to calculated the final yield of a batch to close the BMR (by 24mg or by 14mg).

Assume our uncoated tablet size is 1075mg and we used 24mg of coating colour and after coating to a desired thickness and finishing 14mg will increase in weight and 10mg loss. What will be the final tablet theoretical weight its 1099mg or 1089mg.?

Pls guide.
And also guide me, is ay posibility of loss of coating materials during coating stage by vaccum and suction.

Please note following,
Yield of a pharmaceutical product is explained as follows,

“Theoretical yield” means the quantity that would be produced at any appropriate phase of manufacture, processing, or packing of a particular drug product, based upon the quantity of components to be used, in the absence of any loss or error in actual production.

“Actual yield” means the quantity that is actually produced at any appropriate phase of manufacture, processing, or packing of a particular drug product.

Therefore, what you have specified is weight gain of coated tablets and not the yield.
The final tablet weight as obsevred will be 1089 mg. The process loss will be 10 mg per tablet.

Theoritical weight gain after coating of core tablets should be specified in the Master formula of the product.
Also, the average weight of uncloated (core) tablet and coated (final) tablet with acceptable variations (limits + & - from the average weight) should be specified in the core & coated (finished product) tablet specifications.

When calculating coating formula weights of a batch of tablets, we should consider weight gain per tablet and coating material losses during processing steps such as Coating solution preparation, transferring in to reservoirs / containers through tansfer pipes, actual coating process, adherence of coating material to the coating pan & hndling losses etc. Accordingly, extra coating materials should dispensed and coating solution should be prepared as per Master formula. All observations must be recorded in the Batch Production Record of that batch including process & handling losses based on yiels calculations at every major stage in the production process.

There should yield limits established after conducting process validation of batches. Yield deviations must be investigated to find out reasons of loss of materials and loss of product at every stage of production. Because this is a loss to the company.

Considering above aspects please verfiy from your Master formula and batch records about weight gain of tablets is within specifications or not.

The coating yield of tablets after coating will be =
[Number of core tablets used for coating / Number of coated tablets obtained after rejecting defective tablets] X 100
Similarly, for every stage of production the yield must be calculated, such as Dried granules, Lubricated blend, Compression, Coating & final packing of tablets.

Number of tablets can be calculated based on its observed average weight (core and coated) =

[Total weight of core tablets / Observed Average weight] of core tablets] &
[Total weight of coated tablets / Observed Average weight of coated tablet]

Please note that yield calculation shown in my previous communication (as above) is the percentage yield (%) obtained at every major stage of production such as coating & it is with respect to the input quantity of tablets taken for coating.

Similarly, % yields can be calculated at every major stages of production as discussed in my previous communication.