Pharmaceutical ointments are single-phase, semi-solid and spreadable preparations with incorporated active ingredients. The active ingredients are added according to a fixed recipe and dissolved, dispersed or suspended in the base.
Types of bases at a glance
Hydrophobic
They are very greasy, water-repellent and cannot be washed off with water. Only very small amounts of water are worked in by mechanical dispersion.
Hydrophilic
Their bases can be mixed with water. Although they are fat-like, they are not greasy. They are glossy, easy to spread and can be washed off with water.
Water-absorbing
They absorb larger quantities of water when an emulsion is formed.
An emulsion is a finely distributed, stable mixture of two liquids that do not normally mix. One phase is distributed in the other in the form of fine droplets – either as a water-in-oil (W/O) or an oil-in-water (O/W) emulsion.
Homogenising mixers for ointment production
Homogenising mixers are particularly well suited to the production of pharmaceutical ointments. Modern machines can:
- quickly disperse solids in liquids
- hydrate swelling agents and stabilisers
- break up agglomerates and reduce particle size
- produce fine, stable emulsions or suspensions
As a result, homogenising mixers shorten mixing times considerably. At the same time, they significantly improve the stability and consistency of the products.
FAQ: Producing ointments
What is the difference between an ointment and a cream?
According to the pharmacopoeia, ointments are single-phase bases in which actives are dissolved or dispersed. Creams are multiphase, consisting of a lipophilic and an aqueous phase (W/O or O/W).
Which types of ointment exist?
Hydrophobic ointments (e.g. petrolatum, hardly absorb water), water-absorbing ointments (form emulsions with water) and hydrophilic ointments (miscible with water, e.g. macrogol ointments).
Which machine is suitable for ointment production?
Vacuum homogenising mixers with scraper agitator, rotor-stator homogeniser, heating/cooling jacket and powder induction. They disperse actives, break up agglomerates and deaerate the product.
Why produce 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 plans plants for semi-solid dosage forms and offers inspected used homogenising mixers, e.g. Becomix units.