Purpose: To investigate in vitro the factors affecting microdialysis probe delivery and recovery of puerarin .

Methods: The recovery and delivery of puerarin were tested for extraction efficiency and retro-dialysis methods. Factors such as drug concentration, stirring speed, additives and length of membrane were studied to determine differences between recovery and delivery.

Results: It was observed that the delivery of the targeting analyte was different from its recovery. Both delivery and recovery of puerarin were independent of the concentration of the drug. Probe delivery increased from 62.18 to 67.98 % (p < 0.01), recovery from 59.19 to 78.44 % (p < 0.01), as stirring speed was increased from 0 to 800 rpm. The difference between them directly correlated with stirring speed in the range 2.99 to 10.46 %. Besides additives, length of membrane also had a strong influence on delivery and recovery. Probe delivery in saline containing 10 % each of ethanol and propylene glycol declined from 62.18 to 42.12 % (p < 0.01), while recovery increased slightly but insignificantly (p < 0.01). Both delivery and recovery declined when the length of membrane was reduced.

Conclusion: The in vitro experiments indicate that it would be incorrect to equate delivery with recovery of puerarin in in vivo microdialysis experiments.