The Half Decent Pharmaceutical Chemistry Blog

The best thing about working at the chemist’s (in the lab) is that, what you make, is sold directly to costumers. As I previously outlined, people hand you a recipe, written by a doctor, and it’s your duty not only to prepare it, but also to choose the most practical packaging and to calculate the overall price.
Most of the time the last step is the longest: the making of Bach flower remedies, for example, takes no time. Not to mention when you simply have to weigh 200 g of vitamin C.

Fortunately, however, there are galenic preparations that require more work and skills. In these instances, the employee of the chemist’s is always happy as such time-consuming jobs can be handed over to the student.

Last Friday was a very relaxed and laid-back day: the bride dropped in to give the guests some information about the ceremony and it was another employee’s birthday. So, the lab looked even more like a kitchen.

My task for the day, though, was not that relaxing: I had to prepare an ointment. Actually not ANY ointment, but one of the densest you could possibly make.
From a pharmacological point of view, this topical preparation was all but complicate: zinc oxide and rice starch were the important ingredients. The main problem, when it comes to crafting an ointment with high zinc oxide content, is to make sure there aren’t clots. Pharmaceutical industries use a variety of machines to make topical drugs, but the tools employed for hand-made salve is certainly easier: a marble platform and a pair of spatulas.

This means you have to get rid of the clots manually, spending energy and time pressing and spreading the salve with the spatula.
According to the recipe, 400 g of ointment must contain: 100 g of zinc oxide, 100 of rice starch, 40 g of almond oil and, as vehicle, 160 g of Vaseline (the solid one, also known as white petrolatum).

Hmm, terribly viscous and dense. The customer, besides, who regularly buys this galenic preparation, asked if we could make it softer this time, so that it was easier to spread on the skin. This being the first time it was me the person in charge of prepare it, I tried a rather banal but, weirdly never tried before, of the 160 g of Vaseline, 10 g were paraffin oil which not only would have made my work easier, but also increased the fluidity of the ointment.
This kind of customisation is allowed, because they don’t regard the active substances, but only the excipients.

I split the 400 g in two halves, mixed 50 g of zinc oxide with an equal amount of micronized starch and weighed 80 g of Vaseline.
The mixed powder had to be added little by little: the salve, meanwhile, is vigorously spread each time. The almond oil, besides giving a nice scent to the ointment, helps a bit, especially if poured on the mixture every so often, increasing the fluidity.

In the end, thanks to the paraffin oil, the ointment looked great with no clot whatsoever.
Do not think it was an easy or quick one, though: to yield such a good result it took me almost two hours and some calories. But, you know, it’s always better than tiding up drawers and I could eat something whenever I wanted.

Finally it was time to calculate how much the salve was: although there’s no working hours-price correlation, this was the most expensive galenic preparation I’ve ever made as it cost 16.72 €, which is more than industrially made zinc oxide salve.

Beautifully crafted goods are always unique and more expensive.