The masking effects of BMI-40 on six kinds of bitter tasting medicines were investigated. As a result, BMI-40 alone significantly masked the bitterness of the ground Polymyxin B sulfate tablet (gPL-B). Thereafter, the masking effects of BMI-40 and flavored BMI-40 (with 10% milk cocoa+ 10% sugar) on gPL-B (a hundred thousand U/mL) were compared with those of BMI-60 and flavored BMI-60. After increasing the concentration of BMI-40 by 4%, the masking effects of BMI-40 were same as those of BMI-60 and both were below the threshold of bitterness which was reported to be 3.0 point (BMI-40: 2.5±0.3, BMI-60: 2.3±0.3). On the other hand, flavored BMI-40 was more effective than flavored BMI-60 at a 1-4% additional concentration (p<0.001), and its bitterness intensity was below the threshold (2.0±0.3-1.0±0).
The mechanism of masking bitterness by using BMI-40, which contained about 50% branched dextran, was next investigated. At a 1% concentration, the rate of bitterness intensity of BMI-40 on gPL-B decreased after adding milk cocoa but not after adding sugar in comparison with that of BMI-60 (BMI-40: 42.5%, BMI-60: 64.6%).
The masking effects of 3%, 5% branched dextran, which contained BMI-40 but not BMI-60, significantly increased by adding milk cocoa, while branched dextran alone was not effective.
These results suggested that 1% flavored BMI-40 (with 10% milk cocoa and 10% sugar) is clinically useful for masking the bitterness of gPL-B. Furthermore, the masking mechanism of BMI-40 is also considered to be different from that of BMI-60.
