Objective: To determine equilibrium solubility of capsaicin in different menstruums and investigate drug loading property of thermoplastic polyurethanes (TPU). Method: Excess capsaicin was mixed in pure water

ethanol solution

glycerol solution and propylene glycol solution

respectively

and was shaken for 24 h.UV was employed for determination of capsaicin dissolved in these solvents and the equilibrium solubility was calculated.What's more

the equilibrium solubility of capsaicin in these tested menstruums under the conditions of different temperatures and pH values was also assayed.After that

drug loading behavior of TPU in various menstruums containing capsaicin with different liquid temperature as well as pH values were evaluated. Result: At room temperature

the largest equilibrium solubility of capsaicin was achieved in 50%propylene glycol solution.As temperature increased

the equilibrium solubility was risen.The acidity of solvent impacted the equilibrium solubility

especially pH value of capsaicin in the high concentration of short-chain alcohols.The drug loading capacity of TPU was effected by the liquid temperature and pH values of the tested menstruums. Conclusion: The 50% propylene glycol solution holds the largest equilibrium solubility of capsaicin

which positively correlates with temperature.In addition

pH values of these tested solvents should be noticed in evaluation of this alkaloid in these tested menstruums.Increasing drug concentration in menstruum will contribute to improve TPU loading with capsaicin.