EC stands for Ethyl Cynoacrylate which is resin that is much more highly refined for use on porous surfaces. Pharmaceutical quality means that the resin is even more highly refined for use on the human body. All Creative adhesives and Fabric# resins are pharmaceutical grade EC Resins.
As opposed to
MC adhesives (which stands for Methyl Cynoacrylate) are adhesives which are industrial grade, more unrefined, like super glue, lock tite etc which are unsuitable for use on porous surfaces, such as the the human body. They are porous, attract moisture and are carcinogenic. Those who use Super Glue and the like will do serious damage to their nails as well as the fact that Super glue doesn't work for long as it breaks down in water quite easily and attracts moisture under the 'stick on' which is why so many women have horrendous black and green nails after wearing 'stick ons' for a long period of time.
You see ... you get what you pay for even though you do not always know the reason why!! The more refined an EC adhsive is, the more expensive it is !!
There are many different grades of resin (hundreds) actually. High end and low end and all the others in between as always. The higher the quality, the longer the enhancements last! These systems are not all the same despite what many people think ... most just don't understand the chemistry or the difference in quality because you can't SEE it. But you can experience the difference.