Cellular materials have many known applications, from aerospace technology  to food production and pharmaceutics. There is a wide range of beneficial applications for the user of this type of structure. The pharmaceutical industry has also recognised the benefits e.g. low density, buoyancy, carrier and drug volume reduction, controllable drug delivery, extended residence time, matrix material type. Low density floating formulations can increase gastric residence time of the drugs; therefore the drug release will be sustained. 

Our aim was to produce a solid floating formulation by first foaming (gas injection). PEG-4000 was used as a carrier, in which air was added and dispersed in the molten state using a homogenizer, and metronidazole was used as the active ingredient. As a continuation of the research, PEG-4000 was again used as a carrier. The foaming was carried out by sonochemical method - ultrasound, which shortened the production time. The active ingredients were used metronidazole and acyclovir. Most recently, instead of polyethylene glycol carrier, a natural plant-derived agar agar polysaccharide was used to produce solid foam, in this case the active ingredient was acyclovir. The foaming was again performed with an ultrasonic homogenizer under atmospheric pressure. The structure of the formulated solid foam was investigated by microCT. Our experiments showed that a stable foam can be obtained by rapid homogenization without surfactant and other additives. The durability and disintegration in the gastric environment of the solid foam capsules obtained were investigated, as well as the release of the active ingredient.