SC V B. Preservative-free Unlicensed Medicines
Pharmaceutical products that are intended for multiple-use after opening are required to contain suitable preservatives that will minimise the risk of microbiological contamination during manufacture and storage, after opening and during use. There is limited information on the acceptability and safety of preservatives for neonates and young children. In the first few months of life, immature physiology and metabolism may mean that preservatives considered safe in adults or older children are not appropriate for the very young. One of the reasons that an unlicensed form of a licensed formulation is developed is the need for a preservative-free preparation. Oral medicines for neonates and children, eye drops and nebuliser solutions are examples of these.
There are a number of situations where the use of preservatives in certain patient populations has been shown to cause adverse reactions and should be avoided. A risk assessment should be undertaken on the use of the preservative in the intended population. There should be evidence of acceptability and safety; absence of evidence of harm should not be taken to mean that a preservative is acceptable.
In addition, for aqueous formulations the risks and benefits of presenting the medicine in either single- or multi-dose containers, with or without an antimicrobial preservative, must be assessed.
Preservative-free Eye Drops
Eye drops are required to be sterile until opened and so preservative-free eye drops must be manufactured as sterile solutions. BP monographs for eye drops are open monographs that do not specify a formulation or a concentration and so will apply equally to preserved and preservative-free preparations. In the absence of a preservative, however, there is a risk of microbiological contamination immediately after the container is opened. Preservative-free eye drops should be for single patient use within one clinical session. The product should be applied immediately after opening and, subject to the above, any remaining solution discarded unless an alternative procedure has been justified and validated.
Preservative-free Oral Liquids
It is widely recognised and accepted that oral liquids for children and neonates should not contain antimicrobial preservatives, if possible. Toxic reactions have been reported to all of the commonly used preservatives. Formulation of oral liquids for children is further complicated by the preference for sugar-free and alcohol-free preparations.
Minimal risk is considered achieved for preservative-free oral liquids if these are presented in single-dose containers, which have been subjected to a process that renders the contents sterile, and the product is used immediately after first opening. Where this is not possible, appropriate means of preparation, suitable packaging and storage conditions should be defined that achieve and maintain the expected quality of the product throughout its period of use.
In addition, suitable measures should be in place to ensure that users of the product are aware of, and have knowledge of, the optimum procedures for handling and storage of the product in use to minimise the risk of microbial contamination and the subsequent risks to patients.
The following options need to be considered to reduce the risk of microbial contamination during manufacture and the risk of microbial growth and contamination during storage and in use.