Preparations for Inhalation

Question 1

What are Preparations for Inhalation?

Answer 1

They are liquid, semi-solid or solid preparations containing one or more active substances that may be dissolved or dispersed in a suitable vehicle. Depending on the type of preparation, they may contain preservatives and other excipients such as propellants, cosolvents, diluents, carriers, solubilising and stabilising agents, etc. The excipients do not adversely affect the functions of the mucosa of the respiratory tract or its cilia.

Preparations for inhalation that are suspensions or emulsions are readily dispersible on shaking and they remain sufficiently stable to enable the correct dose to be delivered.

Preparations for inhalation are supplied in multidose or single-dose containers.

Question 2

Preparations for inhalation intended to be administered as aerosols (dispersions of solid or liquid particles in a gas) are administered by means of one of the following devices:

Answer 2

— a nebuliser;
— an inhaler (pressurised metered-dose inhaler, non-pressurised metered-dose inhaler or powder inhaler).
Several categories of preparations for inhalation may be distinguished:
— preparations to be converted into vapour;
— preparations for nebulisation;
— pressurised metered-dose preparations for inhalation;
— non-pressurised metered-dose preparations for inhalation;
— inhalation powders.

Question 3

Uniformity of delivered dose, inter-inhaler testing

Answer 3

During manufacture of preparations for inhalation supplied in multidose inhalers, the uniformity of delivered dose must be ensured within an inhaler (intra-inhaler) and between inhalers (inter-inhaler).
An example of a suitable procedure is to take 10 inhalers and collect a single dose from each inhaler, collecting the dose at the beginning (from 3 inhalers), middle (from 4 inhalers) and end (from 3 inhalers) of the number of doses stated on the label. Other inter-inhaler testing procedures are possible, where justified.

Question 4

Inhalation products - labelling

Answer 4

The label states, where applicable, the name of any added preservative.
For preparations administered by inhaler, the label states:
— the delivered dose or, if justified and authorised (e.g. where the dose has been established as a metered dose or as a pre-metered dose), the metered dose or the pre-metered dose;
— where applicable, the number of deliveries that constitute the minimum recommended dose;
— the number of deliveries per inhaler.
The pH of liquid preparations for nebulisation is not lower than 3 and not higher than 10.

Question 5

Inhalation products - Testing

Answer 5

uniformity of mass
Uniformity of delivered dose, intra-inhaler testing
Number of deliveries per inhaler
Leak rate