Okay, this is what I can offer to the discussion. I don`t know specifics of this drug
but I know quite a bit about mucual and dermal absorption theory. I will give you what I know. Please keep in mind that the majority of my knowledge in this revolves around hormones but I am aware of many of the basics for this subject.
First the thinner the skin the higher the absorption. This means if you attempt to absorb something through the back/ stomach/ shoulders/ chest/ etc areas it will take longer and less will be absorbed then the neck/ behind the ears/ genitals/ armpits/ inner thigh/ elbow, etc In addition to that mucus membranes are very thin and that includes the bowels, bladder, vaginal vault, mouth, inner eye lids, genitals and nose. Bear in mind the thinner the tissue the greater the chances of irritation. The mucus membranes alone are easily damaged and rely on a complex balance to function and survive.
Wash that area, but maybe don't rinse as well. Many have noticed that if a soap residue is left on the skin after cleaning that it results in higher absorption rates both in quantity and speed. However if you have applied other topical products on the same area prior it will slow absorption rates. So the deal is wash the area, lightly rinse the area, then after use and certainly prior to secondary use wash the area properly to remove any residue of the previous product.
If you have to rub the product into the skin make sure to cover the hand that is rubbing with a latex
/ vinyl/ nitrile glove or at the least some plastic wrap or a sandwhich bag to protect your hand from absorbing the product. The reason for this is the same reason you can't tattoo hands easily. The skin in the hand readily absorbs the product but will not retain it. It will be flushed out of your hand quickly as your hand sweats and breath. This is critcal to protect the dosage. In people using topical hormones we have seen a difference of half to less a quarter of the doses needed then with an unprotected hand.
In addition most topical products will enter skin at a faster and higher rate if the skin is covered with an occlusive dressing. So always use either a piece of tegaderm or plastic wrap and tape over the treated area. The reason for this is that when the skin can't breath and sweat and heat build up allowing the skin to become more permable by increasing things like pore size and the space between the cell at a cellular levels. Using an occlusive dressing (one that air and water can't pass through) will also protect other from skin to skin transmission.
Despite all factors the skin is meant to keep things out and because of that many drugs
simply have too large doses to be able to get enough through the skin to be effective. Generally doses that are in mg instead of mcg can't be dosed topically without some sort of product to change the skin and make it more permable. There are chemicals which do that but they aren't the best things to be putting on the skin. Remember that skin is our protection against the world and if we damage it then we leave ourself open to all sorts of toxins. DMSO is one of those products that can do it but the risks are high not the least of which it smell awful and so will you if you use it. This is another reason to cover the skin if you must use a dermal absorption enhancer. In general doses over 10mg won't be able to use a topical route except with mucus membranes and doses of over 100- 500mg tend to be generally impossible topically.
PH is also important when trying to use a product topically. Off hand I can't remember though what PH we are looking for and the article is on an old hard drive, so I will have to edit later on this issue.
It is also a waste because with most skin the general rule is 10:1, i.e. 10mg applied equals 1mg absorbed. This dose flucuate based on other factors but even then the best you should hope for is 10:3 ratio. Mucus membranes are different and can range from 10:3 to 10:9 with the proper steps and prep. So of all the mucus membranes are the best for absorption if you get away from the possible damage to the membrane.
Despite all of this if you choose skin preps be aware and start small. Some people are unique and absorbs greater amounts then normal. I once saw a man taking topical testosterone and without using any of the above tricks he only needed a tenth of the recommended dose when most need much more then the recommended dose. When he switched to my techniques he cut that in half while maintaining the same blood levels. So start small and if you find that you are oding wash the area at least five times with dish detergant and seek immediate medical care.