The strength of a product is a part of its entire name. The strength must correspond to the amount of active substance and help to recognise the product and its correct use.
The Quality Review Documents Group (QRD) has created instructions on reporting the strength for preparations approved in the centralised procedure: QRD Recommendations on the Expression of Strength in the Name of Centrally Authorised Human Medicinal Products (PDF)
For safety reasons, the above instruction is also followed in other marketing authorisation processes to ensure uniformity of labelling policies.
Parenteral preparations are medicinal products usually administered as injections or infusions by health care professionals. In Finland, the strength of parenteral preparations is traditionally expressed as the concentration of the active substance per millilitre for liquid preparations or the total amount of active substance for dry preparations. According to the QRD instruction above, the practice of expressing the strength of a parenteral preparation depends on whether a package contains a single dose used in its entirety, whether the preparation is administered in several doses, or whether the dose taken from the package is based on e.g. the patient’s weight, in which case only a part of the package contents is used. In the first case the strength is expressed as total quantity of the active substance in the packge and in two other cases the strength is expressed as the concentration. Thus, depending on the method of administration, the strength of a liquid preparation can also be expressed as the total quantity of the active substance, and the concentration of a dry substance as a concentration per millilitre.
In the Finnish market, there are still preparations labelled the traditional way and the according to the QRD recommendation. Therefore, the strength of an originator might be expressed as a concentration (mg/ml) while that of a generic product is expressed as a total quantity (mg).