ChEMBL

A little something for the weekend. I've just escaped a busy day of childcare, and clear-out of our medicine cupboard. I threw away quite a few things that were two or three years out of date - now I would have quite happily taken them, but the bin seemed a better place. It's not like that suddenly on the date on the box, the active ingredient expires and transforms to a highly toxic compound. Given that temperature has a big effect on chemical rates, and that storage temperature is probably quite variable, the dates will tend to be really really conservative. For the majority of cases though, once would expect that there is simply less of the desired 'active' ingredient, and the drug will be (slightly) less efficacious.

It got me thinking though, what sort of pharmacologically active things will be in old pills, and above is a nice example of the active ingredient,  impurities and degradation products for atorvastatin (which the eagle-eyed amongst you will spot that atorvastatin itself is the top left molecule). Most impurities look like they stand a fair chance of being HMGCoA reductase inhibitors too, and some look quite radically different, in fact heaven knows what they might interact with - but it is an interesting question to ask.