How important is the amount of active ingredient in an ointment?

Question

I own a small tin of "Dr Chase" ointment that is probably 40 years old. This stuff is amazing. In my family we save it for particularly stubborn or difficult cuts and sores because it will heal anything. Recently, I had something on my leg that Polysporin was not helping - after a week of twice daily Polysporin I got out the Dr Chase and in two days it was better. It is a matter of family legend that it must contain radiation or mercury or something because it is just not like any other ointment. As far as I know, it's not made any more. I would love to replace my tin and use it more often, but I haven't been able to find it. However, I can read the back of the tin just fine and it consists of: - Zinc Oxide, 18.6 % w/w - Phenol, 0.59% w/w Zinc Oxide suspensions are easy to find (diaper cream) but they don't have phenol in them. I have turned up a Canadian ointment (how convenient, I am in Canada) called Ozonol that contains 0.18% phenol and 3.72% zinc oxide. How likely is this to be as good? The Dr Chase is a tiny little tin, 2" across, and you use very little at a time of this very thick ointment - it's just like diaper cream. The Ozonal comes in a tube. Perhaps I could just use more each time? Is the more dilute cream likely to be a reasonable substitute for the thick ointment?

Answer 1

The Ozonol is not likely to be a suitable substitute for the original Dr. Chase ointment. The reason for this being that the original is much more concentrated in ZnO (zinc oxide) and in the phenol as well. You could probably make your own by purchasing pure ZnO, pure phenol and then some aloe or lanolin or some other base to put them in. The 18.6% w/w means that for every 100 grams of ointment, you have 18.6 g of ZnO. Same for 0.59% w/w phenol. In 100 grams of ointment, you'd have 0.59 g phenol. So, for example, to prepare 50 grams of ointment, you'd use 9.3 g of ZnO + 0.3 g phenol, + 40.4 g of base (aloe, lanolin, etc). Just go to your local pharmacy and ask if they sell the ingredients. Good luck.