[The polymorphism of drugs in powders and tablets. 4. The effect of the polymorphism of drugs on the physical properties and drug release of phenobarbital tablets]. / Untersuchungen zur Polymorphie von Arzneistoffen in Pulvern und Tabletten. 4. Mitteilung, Einfluss der Polymorphie des Wirkstoffes auf die physikalischen Eigenschaften und die Wirkstofffreigabe aus Phenobarbitaltabletten.

Four products of phenobarbital (I, II1, II2, III) are manufactured into tablets with the dry binders Avicel PH 101 or Heweten 40 using different pressures by direct tabletting. The physical properties of the resulting tablets are different according to the modification of phenobarbital, the binders used and the pressure during tabletting. The dissolution behaviour of the drug may be changed by the different technological and physical parameters.

[The polymorphism of drugs in powders and tablets. 1. The preparation and characterization of polymorphic modifications of phenobarbital]. / Untersuchungen zur Polymorphie von Arzneistoffen in Pulvern und Tabletten. 1. Mitteilung: Zur Herstellung und Charakterisierung polymorpher Modifikationen des Phenobarbitals.

The characterisation of three phenobarbital modifications by thermic examination procedures (DSC, DTA) is being described. Modification I was obtained by thermic treatment of the brands (modification II) from Hungary and the GDR. The spray product prepared, consisting of very fine hollow spheres, was identified as modification III. Besides the particle size distribution the form of the particle was determined by scanning electron microscopy (REM). The best results regarding saturation solubility and speed of dissolution were found for the spray product.

[The use of dry binding materials for the direct compression of phenylbutazone]. / Anwendung von Trockenbindemitteln für die Direktpressung von Phenylbutazon.

Direct compression of phenylbutazone is possible only with addition of excipients of several kinds, because its material properties are unfavourable. It is necessary to use besides disintegrant glidant, lubricant and antistatic agents too. The authors investigated the influence of two microcrystalline cellulose binders (Avicel and Heweten) for the pressability of phenylbutazone and on properties of the tablets, respectively. It was determined the physical parameters of the tablets and the dissolution characteristics of the active ingredient. It has been found, that Heweten optimized the exactness of dosage of the tablets as well as resulted in a faster dissolution than Avicel. Therefore, Heweten proved to be the more suitable binder.

[Factors influencing the therapeutic effect of ointment gels]. / Die Arzneiwirkung beeinflussende Faktoren der Salbengele.

It is published on new results of research from the institute of the author in which were examined some combined ointment gels putting recently in circulation and new emulsifiers from that may be prepared compositions with suitable rheological stability and large water-absorbing capacity. These systems have suitable thermostability and retentivity of water. The release of many active ingredients were investigated with in-vitro and in-vivo-methods.

[The texture and properties of sulfaethidol tablets]. / Untersuchungen über die Textur und die Eigenschaften von Sulfaethidol-Tabletten.

Scanning-electron-microscopic and X-ray diffractometric studies on the effect of the pressing power on the physical parameters of compressed tablets and on the texture of tablets containing sulfaethidol as the active principle, have shown that the crystal structure remains unchanged. The alterations observed in the physical parameters can be explained on the basis of present knowledge of the texture.

[Influence of the pressing force on the physical features of sulfathiazole tablets and the dissolution rate of the active ingredient]. / Einfluss des Pressdruckes auf die physikalischen Eigenschaften von Sulfathiazoltabletten und die Auflösungsgeschwindigkeit des Wirkstoffes.

When the pressing force increased in the examined system, so did the mechanical firmness of the tablets. A logarithmic connection exists between the pressing force and the compression strength and between the pressing force and the porosity, while the connection between the pressing force and the abrasion loss was a connection of power-function. The changing of the pressing force don't alter significantly the disintegration time of the tablets and the dissolution rate of the drug. However there is a considerable difference between the dissolution rate of the sulfathiazolee-powder and that of the tablets. The binders used in the pressing process were surface-active, therefore they accelerated the dissolution by moistening the surface of the sulfathiazol crystals.

[On the polymorphism of barbiturates in powders and tablets. 6: Properties and behaviour of a spray-dried barbital preparation]. / Zur Polymorphie der Barbiturate in Pulvern und Tabletten. 6. Mitteilung: Eigenschaften und Verhalten eines sprühgetrockneten Produktes von Barbital.

The manufacture of a spray-dried barbital preparation is described, the properties, tabletting behaviour and release of which were studied in comparison to the initial substance. Spray-drying led to a compression-resistant mixture of amorphous and crystalline particles. As most of these particles have a spherical shape, the tablets obtained from this mixture were of great compactness, which inhibited the penetration of the medium and, consequently, delayed the release of the drug, too.

[On the compression behaviour of spray-dried sulphathiazole (author's transl)]. / Uber das Kompressionsverhalten von sprühgetrocknetem Sulfathiazol.

The authors prepared a spray-dried sulphathiazole product consisting of hollow pellets, the drug being in the form of its metastable modification I (melting point, 200 degrees C). On the basis of force-time diagrams and of current parameters relative to the elasto-plastic deformability of substances intended for tabletting, the compression behaviour of the spraydried product was compared with that of sulphathiazole (modification I) tempered at 180 degrees C for 150 min. Scanning-electron-microscopic studies on tablet surfaces offered further insight into the compressibility of the spraydried product.

[Electron-microscopic studies on the texture of sulphathiazole and sulphathiazole tablets (author's transl)]. / Elektronenmikroskopische Texturuntersuchungen an Sulfathiazol und Sulfathiazol-Tabletten.

The authors performed scanning-electron-microscopic studies to investigate the texture of sulphathiazole tablets. This method permitted to demonstrate the texture-forming effect of micronized celluloses used as dry binding agents. The differences in dissolution rate are interpreted.

[On the compressibility of micronized celluloses of the Avicel and the Heweten type (author's transl)]. / Zur Kompressibilität von mikrokörnigen Cellulosen vom type avicel und Heweten.

Experimental studies on the effect of various micronized celluloses (Avicel PH 101 and Heweten 40) on the compressibility and the dissolution of sulphathiazole showed that the binding power of Heweten 40 is inferior to that of Avicel PH 101, whereas the mechanical strength of the tablets conforms to specifications. Referring to the dissolution rates, it can be said that the use of Heweten 40 is more advantageous.