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Each lab followed their in - house protocol to determine in vitro IC50 values for sixteen inhibitors using four different test systems : Caco - 2 ( 11 labs ) , MDCKII - MDR1 ( 6 labs ) and LLC - PK1 - MDR1 ( 4 labs ) cells , and membrane vesicles containing human P - gp ( 5 labs ) .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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