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Biomedical subjects

K Pintye-Hódi

Publications and source records attributed to K Pintye-Hódi.

At least 19 recordsLinked to original sources
PubMed2006

Metolose-PEG interaction as seen by positron annihilation spectroscopy.

The plasticizing effects of poly(ethylene glycol) (PEG 400) on methylcellulose (Metolose) cast films were studied by conventional physicochemical methods and positron annihilation spectroscopy. The PEG concentrations relative to the total polymer content were varied within the range 0-75% (w/w). At low concentrations (below 33.3%, w/w), the plasticizer was found to build in into the methylcellulose structure. On the other hand, at higher concentrations (above 50%, w/w), it formed small separate phases in the films. Positron annihilation spectroscopy (PALS) was applied to track the Metolose-PEG interaction. Controlled ageing of Metolose-PEG films at room temperature and at 75% RH revealed a significant difference between the ageing processes of the monophase and those of the separate phase films. The ageing involves two steps in both cases: a fast and a slow one. The PALS measurements demonstrated that the slow process is hindered in the phase-separated samples.

Elasticity↗
PubMed2006

Study of deformation process of stored polymethacrylate free films.

In the present study the effects of the additives and of storage on the deformation of films prepared from methacrylic acid/ethyl acrylate copolymer with and without polysorbate 80 were evaluated. The films containing polysorbate 80 revealed a longer deformation process with a different deformation curve shape and higher force and work of deformation. Storage induced very significant changes in the characteristics of the films. The decrease in the deformation work was more relevant than the reduction in the deformation force. Increase of the storage time increased the changes in these parameters. The presence of polysorbate 80 in the films reduced the change in behaviour of the films at lower relative humidity.

Drug Stability↗
PubMed2005

Examination of homogeneity with X-ray beams.

The effects of blending time and rotation speed on the homogeneity of powder blends were examined. The concentrations of the samples were measured with an energy-dispersive X-ray fluorescence analyser, and control measurements were made with a UV spectrophotometer. The paired sample t-test showed that, for a large majority of the samples for which measurements were made to determine the concentrations, there was no essential difference. It may be stated, in accordance with the fitted equation, that the rotation speed and the square of the blending time exert significant effects on the distribution of the active ingredient. The energy-dispersive X-ray fluorescence analyser can be applied well for direct determination of the homogeneity of certain powder blends.

Chemistry, Pharmaceutical↗
PubMed2004

Iron(II) sulfate release from drop-formed lipophilic matrices developed by special hot-melt technology.

Iron(II) sulfate-containing lipophilic matrices were developed by a special hot-melt technology (melt solidification in drops), using stearin, white wax and their mixture as conventional bed materials. The special technology resulted in spherical particles which can be filled directly into capsules; these store iron as a depot and ensure a slow and uniform release, whereby the irritation of the gastric mucosa by the iron can be decreased. The rates of dissolution of the iron(II) sulfate from the various lipophilic matrices were different, but fundamentally low. Kinetic calculations demonstrated that the rate of dissolution of the iron(II) sulfate was of approximately zero kinetic order. The results of in vivo experiments on rabbits correlated well with the in vitro data. The plasma curves for the animals treated with the iron(II) sulfate preparations varied with the excipients in the depot products. The properties and ratio of the bed materials influenced the release of the iron(II) sulfate. In all probability, the release of the active agent can be regulated through the use of a melt of stearin and white wax in different ratios. The development products functioned as a sustained-release system and ensured elimination of the irritation of the gastric mucosa. At the same time, the results justified the applicability of the special hot-melt technology in the development of the solid dosage form.

Animals↗
PubMed2001

Study of in vitro and in vivo dissolution of theophylline from film-coated pellets.

Tests were performed on the influence of polymer coating films on the rates and the extents of in vitro and in vivo liberation of theophylline from pellets. Uncoated and coated pellets were used in the experiments. The coating material was Eudragit L; The film thickness was varied. The in vivo liberation of theophylline was studied in rabbits. The serum level of the released drug measured with a TDX Analyser. No appreciable difference was observed between the uncoated and the coated pellets as concern the maximum release data, but a significant shift was found in t(max) for Eudragit L coated pellets.

Acrylic Resins↗
PubMed2000

Influence of Avicel PH-301 on the compressibility of alpha-methyldopa and phenobarbitone in direct compression.

The aim of this work was to investigate the compressibility behavior of alpha-methyldopa and phenobarbitone using a Korsch EK0 instrumented eccentric tablet machine, with force-time and force-displacement curves constructed and applied to calculate different compressional values to study the compressional behavior. The results of this work revealed a difference in compressibility behavior between the two drugs during the compressional process. alpha-Methyldopa gave an abnormal compressional curve with high friction in the pre- and postcompressional phases. A residual force could be seen on the lower punch. Furthermore, capping and sticking were observed visually during tablet pressing, indicating poor compressibility behavior. In the case of phenobarbitone, no friction was observed in the precompressional phase, but there was higher friction in the postcompressional phase, especially in the ejection phase. The compressibility of the drugs was improved by the addition of Avicel PH-301 and magnesium stearate.

Anticonvulsants↗
PubMed1990

Production and investigating of tablets containing furosemide and beta-cyclodextrin.

Furosemide is a very active drug with an excellent saluretic effect, but it dissolves in water only with difficulty. Furosemide products with beta-cyclodextrin (CD) have been made by five methods, and it has been established that most drugs are liberated most quickly from the kneaded product for the 12.72% combinations. The dissolution characteristics of furosemide are improved in tablets made from the kneaded product. By this means an essentially quicker effect can be achieved, a lower drug quantity is necessary for a similar effect, a smaller therapeutic risk in involved, and the technique is economical too.

Cyclodextrins↗
PubMed1988

[The liberation of phenylbutazone from tablets].

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.

Drug Compounding↗
PubMed1988

[Direct compression nitrazepam tablets].

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.

Drug Compounding↗
PubMed1987

[The polymorphism of drugs in powders and tablets. 1. The preparation and characterization of polymorphic modifications of phenobarbital].

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.

Chemistry, Pharmaceutical↗
PubMed1987

[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].

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.

Chemical Phenomena↗
PubMed1987

Release kinetics of potassium aspartate in polyvinyl chloride matrix formulation.

The authors prepared potassium aspartate matrix tablets in combination with polyvinyl chloride. The physical parameters were measured and the dissolution rates were determined. During the in vitro release rate experiments, it was determined that the dissolution kinetics obey both zero order and Higuchi diffusion model order kinetics.

Aspartic Acid↗