Any juice (250 ml) at one-fourth strength caused two-thirds the increase in availability of the drug compared to water.
Is the sentence correct?
"any juice" is too broad for a scientific assertion. Did you prove that with guava juice? Mangosteen juice?
If you have, as part of your Method section, named the juices used in the experiment, then
"Each of the juices (250 ml), at one-fourth strength, produced a 66% increase in availability of the drug compared with water."