Users' preferences and perceptions of the comprehensibility and readability of medication labels.

OBJECTIVE: To evaluate the labeling preferences of medication users and characterize their perceptions of the comprehensibility and readability of medication labels. METHODS: We conducted a population-based cross-sectional study of medication users aged 18 years or older in 10 Brazilian capital cities. Perceptions of the comprehensibility and readability of medication labels in relation to sociodemographic characteristics were evaluated by Poisson regression models with robust variance. Labeling preferences were assessed through questions addressing possible improvements and through the use of digitally simulated packages. RESULTS: Of 6,255 medication users interviewed, more than half found it difficult or very difficult to read (50.8%) and/or understand (52.0%) medication labels. Difficulties were more pronounced for participants aged 40 years or older, with lower levels of education, and non-whites. Increasing the font size (93.7%), describing the indications for use (95.9%) and contraindications (95.6%) on the label, and highlighting the expiration date (96.3%) were the most widely accepted improvements. In the evaluation of simulated packages, users preferred factors that improved readability, such as increased font size, use of graphic elements and color to highlight the concentration of the active ingredient, and contrast between the font color and background. The new simulated package design, with increased font size, color to highlight the concentration and contrast between the font color and background, was preferred over the standard design by 77.0% of participants. CONCLUSION: Based on users' perceptions, increased font size and use of graphic elements and color to emphasize critical information, such as expiration date and concentration, are factors that contribute to making medication labels clearer to users. Pharmaceutical industries and policy makers should consider these items when developing labels and defining policies on this issue.

Mode of action of antimicrobial peptide P45 on Listeria monocytogenes.

The mode of action of an antimicrobial peptide produced by Bacillus sp. P45 isolated from the intestine of the Amazonian basin fish Piaractus mesopotamicus was investigated. The antimicrobial peptide was purified from culture supernatants by precipitation with ammonium sulfate and gel filtration chromatography. The peptide has an EC(50) of 300 AU (activity units) ml(-1) and kills all viable cells of Listeria monocytogenes with a concentration of 800 AU ml(-1). A decrease in OD was observed when L. monocytogenes cultures were treated with the peptide, suggesting that cells were lysed. Transmission electron microscopy showed damage of the cell envelope and loss of protoplasmic material. The peptide P45 was bactericidal and bacteriolytic to L. monocytogenes. There is evidence that the mode of action is interfering at cell membranes and the cell wall. The knowledge of the mode of action of antimicrobial peptides is an essential step to consider their utilization in food or clinic.