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Biomedical subjects

H Moldenhauer

Publications and source records attributed to H Moldenhauer.

At least 37 records · Page 2Linked to original sources
PubMed1981

[On the production and the characterization of spray embeddings (author's transl)].

Spray drying of phenobarbital-polyvinyl pyrrolidone (PVP), phenobarbital-polyvinyl alcohol (PVA) and digoxin-PVP solutions yielded embeddings in the form of very fine powders. Depending on the drug-adjuvant ratio, the form in which the drug was embedded in the indifferent carriers was microcrystalline to radio-amorphous. In vitro studies showed that the dissolution of all the spray products was more rapid than that of the corresponding physical mixtures, and that the resulting solutions of the respective drugs were always oversaturated. The oversaturated solutions obtained from embeddings containing the amorphous forms of the difficulty soluble drugs were relatively stable. PVP inhibited the crystallization of phenobarbital to a greater extent than PVA, and led to a higher oversaturation of the drug in the resulting solutions. The in vitro release of digoxin was significantly more rapid from PVP embeddings (and tablets made from them) than from products containing digoxin in crystalline form.

Chemistry, Pharmaceutical↗
PubMed1980

[Studies on the solubility and the distribution behaviour of butaperazine dihydrogen maleate (author's transl)].

The present paper deals with the study of those parameters of butaperazine dihydrogen maleate, the knowledge of which is of importance in planning dosage forms for oral use. The solubility of the free butaperazine base in artificial intestinal juice (2.03 mg / 100 ml) was determined by means of the pKa values (pKa = 3.58 and pKa = 8.14). The total solubility decreases as the pH value of the dissolving medium increases, because the concentration of the base limits the solubility of the drug. Only the base can be distributed between n-heptane and an aqueous phase. The actual distribution coefficients are very high and explain the high solubility in fat. The water-lipid transfer was also estimated quantitatively. The highest velocities of transfer were observed at a pH value somewhat less than 7.0, as it is commonly measured in the small intestine. At pH 8.0, the low solubility of butaperazine became the velocity-limiting factor of the transfer. The velocities of the back transfer suggest that it is not wise to study the distribution behaviour of butaperazine in a three-phase model if the transfer at a buffer pH 7.4 is the centre of interest.

Gastric Juice↗
PubMed1980

[On the manufacture and testing of butaperazine matrix tablets with silicone varnish NH 30 as a structural substance (author's transl)].

It is reported of the manufacture and testing of matrix tablets containing butaperazine dihydrogen maleinate as a model substance and silicone varnish NH 30 as a structural constituent. On in vitro testing in artificial gstric juice (pH = 1.2), The drug was fully available when the tablets had been prepared by the method of separate granulation. Furthermore, the release of the drug was studied by means of the half-change method at different pH values, in artificial intestinal juice (pH = 7.5) and under sink conditions. The last-mentioned method is concerned with the drug transferred in vitro. Variations in pressing pressure and varnish concentration permit to prepare tablets of planned release characteristics. The release rates were higher in systems with n-heptane as the lipophil phase than in systems under non-sink conditions. This method is sensitive enough to differentiate among batches of tablets varying in drug release.

Delayed-Action Preparations↗
PubMed1980

[In vivo testing of a 3-hydroxymethylpyridine hydrogen tartrate matrix tablet. Part 2: Comparison between the in vivo drug release from the matrix form and that from Radecol-tablets (author's transl)].

The release characteristics of 3-hydroxymethylpyridine hydrogen tartrate matrix tablets (3-hydroxymethylpyridine = HMP) were studied in vivo by determining the metabolites excreted in the urine and compared with those of commercially available Radecol tablets. After the liberation of an initial dose, the drug is release little by little from the matrix tablet. The ingested silicone matrix is not altered by the passage through the gastrointestinal tract, it is excreted unchanged. No side-effects were seen after the application of two matrix tablets (approximately 150 mg HMP).

Adult↗
PubMed1979

[The use of spray drying in pharmacy (author's transl)].

Owing to the favourable physical conditions of the evaporation process, the technique of spray drying has been used for some time to obtain dried products from solutions, suspensions, emulsions and fluid extracts. In the pharmaceutical industry, it may be utilized as a -drying technique, -micronizing procedure, -procedure for the manufacture of polymorphic or amorphic forms of active substances, -technique for producing microcapsules and spray embeddings, -method for manufacturing direct-tablettable active substances. The technical development which ranges from spray dryers for laboratory experiments to industrial plants, and the continuous operation are favourable prerequisites for research and use on an ever greater scale.

Adjuvants, Pharmaceutic↗