Chromatography Forum

Hi All

We are busy testing Paroxtine HCl (anhydrous) as per Ph. Eur. This product is very hygroscopic, and converts very quickly to the hemihydrate form. Does anone have suggestions on how to handle the sample during testing? We have suggested the following:
1. Before testing, the samples shall be stored in a desiccator over freshly dried silica gel.
2. Control the relative humidity in the lab to below 55% and ensure the sample is kept in a well sealed container.

Are these precautions sufficient or should we consider others to prevent the samples from converting to the hemihydrate form.

Mike

You need to look very closely at the containers you use for sample storage. Consider using heat sealed foil packages with desiccants to transfer samples to the lab. We used heat sealed foil wrapped inside 2 layers of plastic bags each with desiccant satchets, inside a plastic sample bottle, with more desiccant. These did not then need to be stored inside a desiccator.

Formalise your sampling procedure, try to minimise the time delay between sampling and testing. Document this in an SOP. The raw material containers will need to be re-sealed properly after sampling too.

Structure your testing schedule to perform water test first and other critical tests in as short a time as possible.
Train your staff. (You'd be surprised how many people don't realise what hygroscopic really means, or that a loosely fitted lid is not good enough to keep out moisture)

We didn't try to control lab humidity, just minimize the time that the sample is exposed to open air.

Thanks GaryR

Your suggestions have helped me alot. We will try to implement some of your suggestions.

Regards

Mike