In the preparation of omeprazole enteric coated capsules 2 mg and 5 mg, a purple discoloration occurs. How to avoid this?

All kinds of discolourations are signalled at preparations, which contain omeprazole. The purple discoloration under the influence of polymers used for enteric enclosure is known:

http://www.ingentaconnect.com/content/govi/pharmaz/2005/00000060/00000002/art00007?crawler=true

This reference was delivered by Apoth Frank of Paris.

But also sometimes yellow or grey discoloration of the suspension is reported.  

The place where the discoloration occurs is a proof that of the solution, which is used for the enteric enclosure, a minutest part creeps into the capsule.   So there is a need to look for a possibility to close the capsules better before Make them gastro-resistant. The method is time consuming and requires a certain agility. But in my humble opinion she is the only solution.

The hermetic closure of the capsules can be obtained in two ways, which are quite analogous.

1. One takes a random waxy compound such as e.g. Cetyl alcohol or walschot and melts part of the mass in a beaker. Before placing the cap on the body of the filled   capsule, the cup is dipped to the half height in the melted mass. You can drip and gently slide the cup   over the body of the capsule. After a few hours the waxy product is back solidified

2. One prepares a dozen ML solution, which contains alcohol and water 1:1. The procedure described above is followed by which the   cups are now immersed in the alcohol-water mixture. Let it dry for a morning.  

on another forum, Mr Annick Van Roosbroeck proposed the   method of filling the omeprazole mixture into a capsule N ° 3 and then retracted it into a capsule n ° 1.   No doubt that this method is useful and is likely to take less time to complete. An important question, which poses is the exemption of the omeprazole. After all, the filled lactose-omeprazole mixture might well be   "embedded"   can be in a thick melted gelatin mass. It would be good if this method were tried once in vitro   .  

Personally I would method 2, which also   Apoth. Venkat Venkat used in a different context,   first try and meet those that do not then switch to Method 1