That's not really truth, nicotine as liquid does penetrate de skin.
De LD50 oral or LD50 dermal is both the same: 50MG/KG.
LD50 means: death of 50% of the test subjects (rats or mice or rabbits)
I'm weighing 80 KG so to kill me would take 4000mg of nicotine.
With a 100mg/ml nicotine base that's 40ml of base liquid completly absorded by the skin.
If you take that one drop is 0.05ml than a couple of drops would not kill you even if you don't wash of.
Now is it dangerous to work with 100mg/ml: YES IT IS.
LD50 means that 50% of the subjects dieded at 50mg/kg, but it also means that some of the subjects dieded at lower levels.
The biggest danger of nicotine solutions is children or pets comming in contact with it.
Are latex gloves a good protection for nicotine?
Yes thats the minimum of protection working with any level of nicotine during a small amount of time.
LATEX GLOVES ARE NOT IMPERMEABLE FOR NICOTINE.
So if you working a long time with high level nicotine (over 48mg/ml) buy yourself some butyl chemical gloves it's to cheap to take a risk.
When I'm making a diy from 100mg/ml, I start with flavor+pg+vg without nicotine then I manipulate the high level nicotine base. After that I wash my hands with the gloves still on and only then remove them. That way nicotine just doen't have a chance getting on to my skin. Of course I wash my hands with soap after removing the gloves.
I've copied the infomation about personal protection from this site:
GESTIS Substance database
PERSONAL PROTECTION
Body protection:
Depending on the risk, wear a tight, long apron and boots or suitable chemical protection clothing.
Respiratory protection:
In an emergency (e.g.: unintentional release of the substance, exceeding the occupational exposure limit value) respiratory protection must be worn. Consider the maximum period for wear.
Respiratory protection: Gas filter A, Colour code brown.
Perhaps also necessary for improved protection:
Respiratory protection: Combination filter A - P2 or A - P3, recommended A - P3, colour code: brown-white.
Use insulating device for concentrations above the usage limits for filter devices, for oxygen concentrations below 17% volume, or in circumstances which are unclear.
Eye protection:
Sufficient eye protection should be worn.
Wear glasses with side protection.
Hand protection:
Use protective gloves. The glove material must be sufficiently impermeable and resistant to the substance. Check the tightness before wear. Gloves should be well cleaned before being removed, then stored in a well ventilated location. Pay attention to skin care.
Skin protection cremes do not protect sufficiently against the substance.
Textile or leather gloves are completely unsuitable.
The following materials are suitable for protective gloves (Permeation time >= 8 hours):
Butyl rubber - Butyl (0,5 mm)
Fluoro carbon rubber - FKM (0,4 mm)
Following materials are unsuitable for protective gloves because of degradation, severe swelling or low permeation time:
Natural rubber/Natural latex - NR
Polychloroprene - CR
Nitrile rubber/Nitrile latex - NBR
Polyvinyl chloride - PVC
The times listed are suggested by measurements taken at 22 °C and constant contact. Temperatures raised by warmed substances, body heat, etc. and a weakening of the effective layer thickness caused by expansion can lead to a significantly shorter breakthrough time. In case of doubt contact the gloves' manufacturer. A 1.5-times increase / decrease in the layer thickness doubles / halves the breakthrough time. This data only applies to the pure substance. Transferred to mixtures of substances, these figures should only be taken as an aid to orientation.