8.3.3.1　Temperature

When the environment temperature rises，the skin's absorption capacity is increased because of the accelerated material diffusion speed and dilated skin blood vessels.A study found that when the temperature was increased from 26℃ to 35℃，the dispersion of epidermal water could double.Another study found that when the temperature rised from 32℃to 37℃，the in vitro transdermal efficiency of fentanyl also doubled.(https://www.daowen.com)