Testing the uniformity of the individual delivered doses for oral solutions

Introduction

In the care units, various liquid drug administration practices have been noticed, for example with the use of different models of syringes.

This study aims to assess the uniformity of the individual delivered doses for oral multidose solutions, and the accuracy of each delivered doses, with 3 models of syringes.

Matériel & méthodes

• 3 models of syringes tested: Plastipak Baxter®, Nutrisafe Vygon®, and Nutrifit Vygon®.

• 9 oral solutions tested: Azathioprine, cyclophosphamide, Hydrochlorothiazide, ketamine, melatonin (2 formulas), omeprazole, spironolactone, and urea.

• The « uniformity of mass of delivered doses from multidose containers » by the European pharmacopeia 9th edition was applied on the 3 models of syringes, on the 9 oral solutions. The accuracy of delivered doses was assessed at the chosen threshold of 10% from the theoretical dose.

Results

The uniformity of individual delivered doses is conform to Pharmacopeia for the 3 models of syringes.

The accuracy of delivered doses test is conform for each syringe and oral solution, except for the urea and the initial formula of melatonin, for which the average dose varied >10% from the theoretical dose.

Discussion/conclusion

Each oral solution has a conform uniformity of the individual delivered doses with the 3 models of syringes.

The accuracy of delivered doses of urea and of the initial formula of melatonin is not conform.

Melatonin is very hydrophobic and the first formulation was not homogeneous. A new formula including a surfactant (which improves the homogeneity of the suspension) was tested. The new formula has a conform accuracy of delivered dose test with the 3 models of syringes.

The non-conformity of accuracy of delivered dose of urea may be due to the saturation of the solution and to the refrigerated storage leading to a lack of homogeneity.
In case of tender of oral syringes, testing other models of syringes for the individual delivered doses might be relevant; these tests would be an additional criterion for the technical analysis for tender.