Study of microbial contamination and dosing accuracy of oral dispensers

The optimal administration of liquid medications requires accurate dose delivery. This is particularly important in the treatment of infants and children, as well as elderly people, who are more sensitive to dosage errors. Previous studies revealed significant dosage inaccuracies with measuring spoons. Oral syringes are therefore generally recommended instead. There is no data on the efficacy of standard cleaning techniques, and consequently on the degree of microbial contamination associated with the repeated use of oral syringes. This study aimed to investigate the level and types of microorganisms found in oral dispensers subjected to simulated in-use conditions. In addition, the dosing accuracy of the oral dispensers is compared with that of measuring spoons supplied and designed for use with specific medications.

Exadoral 5 mL oral dispensers from B. Braun Melsungen AG (Melsungen, Germany) were subjected to simulated in-use conditions and microbial assay. Six different liquid medications representing different substance classes were included. The test lasted 4-15 days with two to four doses withdrawn according to dosage recommendations. Dosing accuracy was assessed using six representative amoxicillin suspensions available on the German market after withdrawing 1.25, 2.5 and 5 mL that correspond to ¼, ½ and full measuring spoons.

Low counts of Micrococcus luteus, Micrococcus lylae, Staphylococcus epidermidis, Staphylococcus chromogenes as well as Bacillus species and Candida lusitaniae may contaminate the interior surface of the oral dispenser, but the microbial count was below the accepted limit of microbial counts permissible for drinking water over the whole test period. Hence, oral dispensers may be considered safe, provided that cleaning procedures are followed exactly. Moreover, oral dispensers, although not specifically designed for the tested medication, showed much higher dosing accuracy in comparison with the specifically designed measuring spoons.

The present study revealed that oral dispensers are accurate measuring devices for the safe administration of liquid medication. Pharmacists and physicians should encourage their patients to use oral dispensers routinely in practice.