[On the production and the characterization of spray embeddings (author's transl)]

Spray drying of phenobarbital-polyvinyl pyrrolidone (PVP), phenobarbital-polyvinyl alcohol (PVA) and digoxin-PVP solutions yielded embeddings in the form of very fine powders. Depending on the drug-adjuvant ratio, the form in which the drug was embedded in the indifferent carriers was microcrystalline to radio-amorphous. In vitro studies showed that the dissolution of all the spray products was more rapid than that of the corresponding physical mixtures, and that the resulting solutions of the respective drugs were always oversaturated. The oversaturated solutions obtained from embeddings containing the amorphous forms of the difficulty soluble drugs were relatively stable. PVP inhibited the crystallization of phenobarbital to a greater extent than PVA, and led to a higher oversaturation of the drug in the resulting solutions. The in vitro release of digoxin was significantly more rapid from PVP embeddings (and tablets made from them) than from products containing digoxin in crystalline form.