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Biomedical subjects

R Voigt

Publications and source records attributed to R Voigt.

At least 127 records · Page 7Linked to original sources
PubMed1985

[The increase in the liberation rate of propyphenazone from preoral solid dosage forms].

The authors report on the influence of the granulation and tabletting applying macromolecular agents (polyvinylpolypyrrolidone Heweten 40, polyethylenglycol 6000, polyvinylpyrrolidone K25, polyvinylpyrrolidone K90 and potato starch) on the liberation rate of propyphenazone which exhibits by its hydrophobicity unfavourable dissolution parameters. A significant increase of the liberation rate of propyphenazone (re-crystallized from various media) has been realized by direct pressing of polyvinylpolypyrrolidone and Heweten 40 as well as by gelatine solution granulation, with which the last method exhibits the advantage of an increased accuracy of dosage and a decreased friability. The gelatine granulation of the drug itself as well as the starch granulate addition resulted in an increased dissolution rate. The addition of other agents (polyvinylpyrrolidone K25, K90 and polyethylenglycol 6000) as well as the pressing of a propyphenazone produced by re-crystallization of an aqueous tenside solution, which distinguishes by an extreme dissolution rate, were not at all suitable for the tabletting. The tablet disintegration caused by hydrophile disintegration media, is the condition granting the liberation of the hydrophobic drug. The wettability and thus the dissolution rate of the drug are increased by the liberation.

Antipyrine↗
PubMed1985

[Effect of tensides on the dissolution rate and crystal pattern of propylphenazone].

Propyphenazone has been recrystallized from different polarity solvents by means of various non-ionic tensides (Tween 20 and 80, Brij 35 and Myrj 51) and the ionic sodium lauryl sulphate. The tenside amount adsorbed by propyphenazone could be determined by measurements of the surface tension. Differences between the adsorption of the non-ionic tensides and the ionic product could be stated. Differences of the crystal areas can be eliminated by adding tensides to polar and apolar solvents. All the recrystallization products distinguish by a significant increase of the dissolution rate.

Antipyrine↗
PubMed1985

[Urodynamic results before and after operative treatment of stress incontinence in the female].

On the basis of the urogynaecological results of 66 women before and after vaginal hysterectomy with plastic operation of the diaphragm who were controlled by means of the complex diagnostics programme of incontinence of urine a separation in women who were cured after operation and such ones who post-operatively remained incontinent. Furthermore, the pre- and postoperative data of 6 women were compiled who were treated with an abdominovaginal loop plastics. The results with the references to literature are discussed.

Female↗
PubMed1985

[Availability of propylphenazocine from suppositories. 1. In vitro bioavailability].

Comparing examinations of the in-vitro availability of propyphenazone from suppositories of different fat bases (Rosupol U, Witepsol H 15) did not display any differences in the release behaviour. Compared with propyphenazone preparations, aminophenazone suppositories of the same concentration exhibit a significantly increased in-vitro availability.

Antipyrine↗
PubMed1985

[Spray film coating of spherical microgranules with non-aqueous varnish film-formers].

To coat crystals and spherical microgranules with polymer films, the influence of different components of the spray on the release behaviour of the coating product has been tested by means of a spray coating process. The examinations which had been based on cellulose acetatephthalate and various polyacrylate types, were aimed at technological lab parameters of the process as well as at the choice of the solvents, the polymer type and the plasticiser admixture. The liberation test has been made in artificial digestives. The results show that the knowledge of the effects of varied dispensing components will enable as well an optimization of the technological process as a purposeful control of the required retarded effects of the final product.

Drug Compounding↗
PubMed1984

[Personal experiences with the standardized incontinence questionnaire. A comparison with results of urodynamic studies].

The results of the urodynamic investigations in 217 patients with female urinary incontinence are compared to the results of the standardized questionnaire of Gaudenz regarding stress incontinence and urgency incontinence. Investigations showed that the stress incontinence and urgency incontinence score of Gaudenz permits the first rough classification of the symptoms of urinary incontinence from the patient's history. A management discussion as to operative or conservative treatment should not be undertaken according to the questionnaire since the percentage of non correlation between the questionnaire and the urodynamic studies is too high. Our results are demonstrated in tables and the results are discussed with reference to the literature.

Cystoscopy↗
PubMed1984

[Malignant pleural mesotheliomas. Comparison of roentgenologic and autopsy findings].

In 100 pleural mesotheliomas follow up x-ray studies were compared to autopsy findings. Initially x-ray examinations show effusions in 62%, diffuse pleural thickening in 29% and solitary pleural nodules in 6%, prior to death effusions and pleural thickening are usually combined. In 17 tumor nodules doubling times ranged from 0.5 to 3 months. The epithelial type of mesotheliomas is predominantly combined with pleural effusions, while pleural thickening is more often found in the mesenchymal type of the tumor.

Humans↗
PubMed1984

[Factors influencing the in vitro and in vivo liberation of drugs from hydrogels].

Interactions of drugs containing macro-molecular agents (cellulose derivatives, polyvinylpyrrolidone) as determined by equilibrium dialyses influence on the in-vitro liberation (hydrophilic membrane) from hydrogels of the same viscosity acc. to the binding intensity. Utilizing a lipophilic membrane, this can be proved, too, the liberation intensity, however, is substantially determined by the lipoidwater distribution behaviour of the drugs. In-vivo liberations revealed in this, that differentiations in the liberation from methylcellulose and polyvinylpyrrolidone gels occur solely in drugs having a more intense affinity. The penetration intensity of the hydrogel into skin is, however, not caused by the binding tendency but by the lipoidwater distribution behaviour of the drugs. Analysing the in-vitro liberation with the use of a lipophilic membrane or knowing the distribution coefficient, informations on the level of the probable drug penetration gel/skin can be given.

Biological Availability↗
PubMed1984

[Comparative studies on the study of drug-excipient interactions with vapor pressure osmometry and equilibrium dialysis].

The authors discuss how far the vapour osmometry enables to make statements on the interaction between drugs and macromolecular agents as well as on their dependence upon various test parameters. The results are compared to those of the equilibrium dialysis. Sulfathiazole sodium and the polyvinylpyrrolidones PVP K 25 and PVP K 90 are used the sample substances. Concerning the interaction dependence upon the concentrations of drugs or agents, resp., both the methods revealed findings of comparable trends. An increased agent concentration or a reduced drug concentration results in an increased sulfathiazole-PVP interaction. An exothermic binding process can be derived from tonometric and dialysis results. Vapour osmometric measurements not only restricting to the interactions drugs-agents, but also recording all the interactions caused by variations of the particle number, the findings obtained by means of buffered solution do not permit a comparability of both the methods. Although the equilibrium dialysis takes precedence in the exact registration of drug-agent interactions, the vapour osmometry has an advantage in the registration of drug interactions with membrane-permeating agents.

Buffers↗
PubMed1984

[Management of twin pregnancy with different development].

By means of a case report of a dizygotic twin pregnancy with extreme difference of weight our diagnostic and therapeutic procedure is reported. Beside ultrasound biometry it was made use of the placental perfusion measurement as a functional parameter of the fetoplacental unit. In the case reported a separate judgement of the placental areas of the two fetuses was possible.

Female↗
PubMed1983

An atypical Aspergillus flavus from a case of bronchopulmonary aspergilloma. A contribution to the cultural and serological diagnosis of A. flavus infections.

A slow-growing, non-pigmented hyphomycete was isolated from sputum and a fungus ball removed at autopsy from the lung. The patient, an alcoholic, also suffered from cirrhosis and primary carcinoma of the liver. The atypical and otherwise non-recognizable isolate showed a growth typical of Aspergillus flavus when cultured on sterilized peanuts. This observation indicates the diagnostic significance of such strains which have become atypical, as etiologic agents and sources of antigen. Serologically, the antigen of the atypical strain proved to be stronger than that of a typical A. flavus strain. In view of the simultaneous presence of the liver carcinoma and the absence of aflatoxin production by the atypical strain, the possible role of chronic colonization of the lung by A. flavus is discussed.

Aflatoxins↗
PubMed1983

[Pharmaceutical and biologic availability of chlorpromazine from macromolecule-containing tablets].

The use of sufficiently high concentrations of polyvinylpyrrolidone (PVP), hydroxyethyl cellulose (HEC) and methyl cellulose (MC) in tablet formulations leads to depot preparations of the prolonged- or sustained-release type. Having swollen up with the dissolution medium, the tablets form a hydrated matrix from which the active agent diffuses for a considerable time at constant speed. The verification of the bioavailability of chlorpromazine from PVP-, MC- and HEC-containing tablets and of a macromoleculefree standard preparation on rabbits showed considerable differences among the plasma curves. With reference to the standard preparation, the cellulose-containing preparations have a relative bioavailability of 38.8 and 45.7%, respectively. The constancy of the plasma level values for almost 8 h is remarkable. The plasma level profile of these formulations corresponds to that of a depot form of the sustained-release type.

Animals↗
PubMed1983

[Effect of adjuvants on the pharmaceutical and biological availability of chlorpromazine hydrochloride].

It is reported of the influence of adjuvants upon the pharmaceutical and biological availability of chlorpromazine hydrochloride from tablets. Sodium carboxymethyl cellulose, microcrystalline cellulose (Heweten 40) and potato starch have been used for tabletting. The adjuvants added act on the pharmaceutical availability, certain differences being due to a discriminate swelling behaviour. The differences observed in vitro exert no effect on the bioavailability of the drug in the rabbit. Thus, the tablets produced with the adjuvants mentioned have proved to be preparations of almost equivalent similar biopharmaceutical behaviour.

Animals↗