[Water uptake of tablets, their disintegration and dissolution are in close relation]. / A vízfelvétel, a dezintegráció és a hatóanyag-kioldódás kapcsolatának vizsgálata tablettákban.

Authors investigated the factors influencing this connection on phenylbutazone tablets. Tablets were prepared by wet granulation using three binders (gelatine, hydroxypropyl-cellulose, hydroxyethylcellulose) in different concentrations. Three disintegrants were compared (polyvinylpolypyrrolidon, formalin-casein and cyclodextrin polymer) on the basis of their disintegrating and dissolution-enhancing properties. It was found, that the binder having surface activity improves the wetting of phenylbutazone tablets. Increasing the concentration of gelatine solution, tablets became harder, disintegrated very slowly and the active agent hardly dissolved. Among disintegrants the polyvinyl polypyrrolidon was found to be the best. This material increases the hardness and the drug release as well. The use of cyclodextrin polymer is limited because of the slow water uptake of its tablets. The water uptake of nondisintegrating tablets was described with the Washburn equation. Water penetrates into disintegrating tablets according to the Weibull distribution. The penetration rate can be characterized with the "characteristic water penetration time (t63.2%), obtained from the Weibull equation. The difference between nondisintegrating and disintegrating tablets can be observed in the dissolution kinetic, too. The drug dissolves from the nondisintegrating tablets according to Noyes-Whitney equation (Eq. 1.), from disintegrating tablets according to the modified Noyes-Whitney equation (Eq. 2.) or Weibull equation (Eq. 3.). The dissolution rate constant (K) obtained from the modified Noyes-Whitney equation is proportional with water uptake and in inverse.

[Deformation of tablets according to breaking hardness]. / Tabletták deformációjának tanulmányozása nyomási szilárdságvizsgálat alapján.

The authors were the first to test the breaking process of tablets in home respect. In experiments on the breaking of tablets a tablet hardness tester developed by the Chemical and Pharmaceutical Works Ltd. Chinoin (Budapest) was used. With an appropriate program, this permitted not only a qualitative evaluation of the breaking curves (Fig. 2-4.) also an assessment of the breaking work relating to the breaking strength and even the work needed for various deformation processes (Tab. I-II.). The concept of the breaking factor was introduced: this allows a differentiation of tablets even if the breaking strengths are the same (see Tab. III. 1-2 tablets; with two samples analysis; p < 0.05.) It is concluded that such breaking strength examinations contribute to a better understanding of the behaviour of substances during compression. These results can be very useful both in preformulation examinations and in tests on the prepared products.

[Use of galactomannan to produce hydrophilic matrix tablets]. / Galaktomannán felhasználása hidrofil mátrix tabletták elöállításában.

Galactomannan currently seems to be a very promising auxiliary. The aim of the present work was to examine the applicability of this auxiliary in tablet-making. Galactomannan is a polysaccharide composed of galactose and mannose, which is distributed by the Swiss firm Meyhall under the name Meyprogat. The products are numbered according to their molecular weight and polymeric degree. Thus, Meyprogat 7, 30, 60, 90, 120 and 150 can be discriminated. It is used in many areas, for example in the food industry as a stabilizing agent, and in medical therapy to cure diabetes and hyperlipidaemia. In pharmaceutical technology, it is used in low concentration (5-10%) as a disintegrant agent and in high concentration (25%) as binding agent. It is able to form a hydrophilic matrix, which results in sustained release. Theophylline was chosen as model agent. After the preformulation examinations, granulations were made by a wet method, and after this tablets were formed. Examinations were made of the granulations, the physical parameters of the tablets were determined, and the release of the effective agent from the tablets was studied. The following conclusions were drawn: 1. Galactomannan yields tablets with very good hardness. 2. Galactomannan is suitable for the formation of hydrophilic matrix tablets. Through use of this macromolecular agent, the rate of dissolution can be influenced in accordance with the desired purpose.

[Effect of gelatin solution on parameters of tablets containing well-compressible active principles]. / Zselatin-oldat befolyása jól préselhetö hatóanyagot tartalmazó tabletták paramétereire.

Theobromine tablets have been prepared by wet granulation using gelatin solutions of various concentrations. It has been established that film formed from 2 per cent gelatin solution does not assure sufficient binding force. Lamella forming tendency could be observed on tablets. Furthermore, it has been ascertained that tablets proper in respects of both physical parameters and active principle release can be prepared with 5 per cent gelatin solution. It seems to be unnecessary to use 10 per cent gelatin solution. Behaviour of gelatin solutions at compression of starch and their role in active principle release have been discussed. Attention has been drawn to loss of biological value because of the "aging" of the gelatin film.

[Application of beta-cyclodextrin during direct pressing of tablets]. / Beta-ciklodextrin alkalmazása tabletták közvetlen préselése során.

In case of tablets prepared by direct procedure the compressibility of beta-cyclodextrin has been studied. It has been established that beta-cyclodextrin--because of its very good flowing behaviour--can successfully be applied as ingredient in direct pressing. When hardness of tablets has to be increased 20% Avicel pH 101 (VN) has been recommended. By comparative test of 1:1 mol physical mixture of chloramphenicol-beta-cyclodextrin and the granulated product it has been ascertained that method of preparation of products, behaviour of applied solid binding materials and degree of applied pressing force decisively influence the compressibility of products. Furthermore, it has been found that application of beta-cyclodextrin influences advantageously the dissolution rate of active principle from tablets.

[Direct compression nitrazepam tablets]. / Untersuchung von direktverpressten Nitrazepamtabletten.

Tablets of nitrazepam were made by direct compression. The influence of different dry binders and other adjuvants on the physical parameters of the tablets and their texture (scanning electron microscope: SEM) were examined. Changes in the physical parameter can be explanded if the texture is known.

[The liberation of phenylbutazone from tablets]. / Untersuchung der Freisetzung von Phenylbutazon aus Tabletten.

The liberation of phenylbutazone from tablets prepared by wet granulation was examined. It was found that the solution process can be described by the equation c = cs (l-e-K.t alpha). The influence of the binder concentration and the disintegrant on the liberation rate was also studied. The increase of the Klucel MF concentration accelerated the liberation of the agents. Among the disintegrants Polyplasdone XL and cyclodextrin block polymer turned out to be very good.

[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.