Here Comes the Bride
On my first week at the chemist’s, I helped an employee to tidy up the drawers: we worked together on any given afternoon trying to reorganize them last week. In the end, the result is pretty satisfactory: although we didn’t manage to empty any drawer, we left a lot of space in each one, so that there’s room enough for any new product to be launched on the market.
Fortunately, however, I’m not going to describe how you tidy up drawers. What I’m going to do, instead, is to talk about either an Italian habit and a pharmaceutical practice: oddly, both have a lot to do with weddings.
The reason why I mentioned such a boring task is because the said colleague is to get married on Saturday. Traditionally, at Italian wedding feasts you eat a lot and rarely dance. Before you leave (or escape: that depends on your attitude), the bride thanks you for coming with a wedding keepsake full of colourful and polished sugared almonds.
Almond aren’t the only thing to undergo a sugar coating process: in the past, most of oral drugs were filmed using this technique. These days, on the contrary, this is widely considered the last resort, when it comes to coating: although you can carry it out in a simple coating pan, it is a discontinuous and time-consuming procedure to go through and the final product will be colourful, smooth, with excellent taste-masking properties and good-looking but without any logo or inscription and, predictably, unable to release the drug with controllable and customisable kinetics.
Still, this doesn’t mean that sugar coating isn’t interesting. What’s more, it reminds you of the good, old times of pioneering pharmaceutical engineering, when, with little money and lots of new drug recently discovered, people had to bring out all their ingenuity. Those were the times when making a tablet was a precise, hand-made activity, because you could just push buttons and let machinery do everything…
Basically, when a tablet undergoes sugar coating, a thick coat is laid using aqueous solutions with up to 50% sugar content. The coat will cause a 50-100% weight increase of the original tablet and, whatever shape the original product was, it will come out as an oval disk.
Sugar coating is now done in coating pans (solid wall ones, to be precise). The pan is usually at 40°C when he cores are inserted. Given that we will spray an aqueous solution, the very first step must provide a protection for the sensitive core against humidity: in the past, wax and tar were the most utilized insulators.
This can be repeated 30-times, so you can see how long this can be.
Finally there is the smoothing step, when imperfections on the surface are corrected by just rolling the pan. This is followed by polishing: waxes or PEGs (or both) are added to the cores and the pan is turned on once again.
The whole procedure may look a little bit dull, but you shouldn’t think the only drawback is time. When the pan is opened, in fact, nasty surprises could be found: irregular final weight distribution, erosion, twinning or explosion of the products (caused by insufficient drying or bad insulation) are somehow the best ones, as they can be easily detected.
