Pharmaceutical ointments are single-phase, semi-solid, spreadable preparations containing incorporated active ingredients. The active ingredients are added according to a fixed recipe and dissolved, dispersed or suspended in the base.
Types of ointment at a glance
Hydrophobic
They are very greasy, water-repellent and cannot be washed off with water. Water is worked in only in very small quantities, using mechanical dispersion techniques.
Hydrophilic
Their bases can be mixed with water. Although they are fat-like, they are not greasy. They have a sheen, spread easily and can be washed off with water.
Water-absorbing
They absorb larger quantities of water when forming an emulsion.
An emulsion is a finely distributed, stable mixture of two normally immiscible liquids. One phase is distributed in the other in the form of fine droplets – either as a water-in-oil (W/O) or as an oil-in-water emulsion (O/W).
Homogenising mixers for ointment manufacturing
Homogenising mixers are particularly well suited to manufacturing pharmaceutical ointments. Modern machines can:
- Bring solids into liquids and disperse them rapidly
- Hydrate swelling agents and stabilisers
- Break up agglomerates and reduce particle size
- Produce fine, stable emulsions or suspensions reliably
As a result, homogenising mixers shorten the mixing time considerably. At the same time, they significantly improve the stability and consistency of the products.
FAQ: Manufacturing ointments
What is the difference between an ointment and a cream?
According to the pharmacopoeia, ointments are single-phase bases in which active ingredients are dissolved or dispersed. Creams are multi-phase and consist of a lipophilic and an aqueous phase (W/O or O/W).
What types of ointment are there?
Hydrophobic ointments (e.g. petrolatum, hardly any water absorption), water-absorbing ointments (form emulsions with water) and hydrophilic ointments (miscible with water, e.g. macrogol ointments).
Which machine is suitable for manufacturing ointments?
Vacuum homogenising mixers with a scraper agitator, rotor-stator homogeniser, heating/cooling jacket and powder induction. They disperse active ingredients, break up agglomerates and deaerate the product.
Why is production carried out under vacuum?
Vacuum prevents air inclusions, improves shelf life and appearance, and allows powders and phases to be drawn in directly below the liquid level.
Does SEEFRIED supply plants for ointments and creams?
Yes. SEEFRIED Verfahrenstechnik designs plants for semi-solid dosage forms and offers inspected used homogenising mixers, e.g. Becomix plants.