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Biomedical subjects

H Kala

Publications and source records attributed to H Kala.

At least 55 records · Page 3Linked to original sources
PubMed1985

[Improvement of the solubility of problem drugs. 1. Production of iomeglamic acid fused and solidified products].

The insoluble X-ray diagnostic iomeglamic acid could be converted to a more soluble modification by melting and solidifying it in liquid nitrogen. The amorphous state is proved by X-ray diffraction and differential thermal analysis. During storage, recristallisation of the product appears. By means of the proved amorphous state, it seems possible to determine the amount of the amorphous state, which makes the drug more soluble from solid dispersions.

Chemistry, Pharmaceutical↗
PubMed1985

[Use of poly(meth)acrylates for the control and release of pholedrine sulfate from microdragees].

Pellets with pholedrine sulphate are coated by means of a fluid-bed process with six different poly(meth)acrylate coating materials. The coatings showed drug release widely different. A wide pH-independent release showed film-coated pellets with Eudragit RS, RL and E 30D as coating material. By application of Scopacryl D 336, D 339 and D 340 the acceleration of liberation by the pH-value of 7,4 is related to the increasing amount of acrylic acid in polymer. The rate of release can be controlled by mixing coatings with different permeability in wide range. Diagram of logarithm permeability coefficient against the mixing proportion can be used for selection a coating composition with wished permeability.

Capsules↗
PubMed1984

[The determination of the Enslin number].

An apparatus after Ezersky was used for the determination of the Enslin number, thereby some error possibilities mentioned in the literature were investigated and compared with the method after the 2. AB-DDR. The dependence of the Enslin number on the height of the powder bed was proofed also at little layer thickness of some substances. The error possibilities are: tending of the powder bed by burning of the lower wet part, occurring of air bubbles below the powder bed and also the capillary action directed against the incorporation at the tip of a completely filled graduated pipet. The apparatus after the 2. AB-DDR as the apparatus after Ezersky, especially with graduated pipet without tip, produced measuring values with little deviation. The latter apparatus allowes a more rational using.

Absorption↗
PubMed1984

[Use of polyacrylate dispersions for nebulization of phenobarbital. 2. In vitro testing of tablets with phenobarbital polyacrylate microspheres].

Using factorial design the authors investigate the qualification of phenobarbital microcapsules with polyacrylate to produce retard tablets. The drug release of the tablets depended significantly on the pressure, the drug concentration and the form of the tablets (microcapsules or corresponding physical mixtures of the ingredients. The drug release from the tablets with microcapsules was more slowly than from tablets with physical mixtures, because there are additional barriers and the formation of a more fixed matrix. The increase of the polyacrylate (from 20 up to 40%) and of the pressure (from 50 up to 100 MPa) inhibits significantly the drug release from the matrices. REM-pictures explain the structure of the tablet surfaces before and after the liberation test.

Acrylic Resins↗
PubMed1984

[Pressure-course events in the tabletting of phenylbutazone].

The distribution to different compression phases via formation of the 1. derivation of the increased force curve is elucidated by the example of the phenylbutazone (2. AB-DDR) compression by means of an instrumented, slow-motion (1 r. p. m.) excentric press, equipped with piezoelectric force recorders and semiconductor transducers articulated to the upper stamp. In the case of phenylbutazone it is subdivided into at least three sections.

Chemical Phenomena↗
PubMed1984

[The effect of dehydration loss of tablet excipients on the energy- distance diagram and on tablet characteristics].

Four tabletting agents of the micro-crystalline cellulose type (Heweten 10, Heweten 12, Heweten 40 and Avicel PH 101) as well as a potato starch lactose granulate had been tabletted on an instrumented slow-motion eccentric press (1 r. p. m.) following storage at different relative humidities. The data resulting from force-punch displacement measurements had been related to the radial steadiness to breakage and the dehydration loss of the relevant agent.

Cellulose↗
PubMed1984

[Use of polyacrylate dispersions for spray coating phenobarbital. 1: Production and in vitro study of microcapsules].

The production of microcapsules (model drug: phenobarbital) using aqueous polyacrylate dispersions by means of spray drying is described. The influence of the following factors on formation and quality of the microcapsules is discussed: particle size of the drug, composition of the polyacrylate, viscosity of the spray material and quantitative relation between the drug and the coating material. The morphology of the microcapsules is investigated by means of light and screen electronic microscopy. The liberation of the drug is evaluated. Mainly dry spheric microcapsules arise in a one-working step. Their properties are influenced by variation of the polyacrylate composition. The liberation of the drug decreases with decreasing drug concentration (80-20%) and in dependence of the polyacrylate dispersion for spray coating and the resulting film.

Acrylic Resins↗
PubMed1983

[Possibility of influencing drug release from polymers--using the example of bead polymers].

By the example of the model drug phenobarbital, the authors report of the possibilities of influencing the liberation of drugs from acrylate-based bead polymers. The drug-containing bead polymers produced were studied in vitro (half-change method, beaker device according to Moldenhauer, artificial digestive juices according to Münzel, without addition of enzymes). The composition of a unit-dose preparation, composed of several batches prepared under different conditions, is dealt with. The release values obtained largely meet the requirements made on depot preparations.

Acrylic Resins↗
PubMed1983

[Construction, operation and initial experience with a laboratory apparatus for fluid-bed coating of particles].

Starting from the developmental work of Dittgen and co-workers [1] and of Gröning [2], the authors constructed an air-suspension device which permits to coat crystals, granules and pellets on a laboratory scale. The device developed is a glass apparatus for coating almost 10 g of particles. The motion of the particles to be coated is characterized by a high-speed rotation on a circular orbit associated with a raise by the air current and a fall caused by gravity. This combined motion prevents the development of zones of varying particle sizes. The usefulness of this apparatus is demonstrated by the example of the application of a polyacrylate depot coating to pholedrine sulphate and quinidine sulphate pellets. Scanning electron micrographs are used for the optical assessment of the coating.

Methamphetamine↗
PubMed1982

[On the compressibility of micronized celluloses of the Avicel and the Heweten type (author's transl)].

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.

Cellulose↗
PubMed1982

[On the compression behaviour of spray-dried sulphathiazole (author's transl)].

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.

Chemical Phenomena↗