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PubMed1979

[Production of granules with controlled drug release rate (author's transl)].

A procedure for microgranulation is described (cf. [7]) which is based on the use of formaldehyde-treated gelatin. The drug (Drotaverin: No-Spa) contained in the matrix is released, dependently of the formaldehyde concentration in the matrix, at a predetermined rate. The release (first-order kinetics) is rapid at low formaldehyde concentrations, and slower at higher formaldehyde concentrations.

Chemistry, Pharmaceutical↗
PubMed1977

Plasma concentrations of isosorbide dinitrate after oral administration of a sustained-release formulation to human subjects.

1. A peak of mean plasma concentrations of isosorbide dinitrate of 5.8 ng/ml was reached at 0.5 h after a single oral dose of 5 mg in a standard tablet formulation. Thereafter mean concentrations declined with a half-life of about 48 min. 2. A peak of mean concentrations of isosorbide dinitrate of 3.2 ng/ml was reached at 2--4 h after a single oral dose of 20mg in a sustained-realease capsule formulation (Iso Mack Retard). Thereafter mean concentrations declined by about twofold during 6 h and were still detectable at 12 h after dosing. 3. When corrected by dose/bodyweight variations, the mean area under the isosorbide dinitrate plasma concentration curve from the sustained-release capule was 76% of that from the standard tablet and this formulation-related difference in bioavailability was statistically significant (p less than 0.05). 4. The results showed that sustained-release formulation is a useful way to maintain plasma concentrations of isosorbide dinitrate for several hours.

Adult↗
PubMed1977

[Problems of dose finding: sexual hormones (author's transl)].

1. Reproduction processes are differently regulated in different species. The gestagen/estrogen ratio is of paramount importance for the evaluation of gestagens. Steroids possessing inherent estrogenicity might act as estrogens in, e.g., rodents like rats and mice, but might be active as gestagens in women (e.g. norethinodrel). 2. There is a good and partly significant correlation between the activity of various gestagens in a number of experimental test models and clinical trials. The same is true for the antiovulatory activity of various gestagens in rats and women. Oral rat tests, however, are not relevant. Receptor tests are not at all suitable for dose finding. 3. Erroneously dissociated peripheral and central (inhibition of ovulation) activity of gestagens are found only if different animal species are used (e.g., test on gonadotropin inhibition in rats, gestagen test in rabbits). This is not the case if both kinds of tests are done in one species (e.g., ovulation inhibition test in rats and test on the peripheral progestational activity in rats). 4. As far as the combined oral contraceptives containing estrogens and gestagens are concerned, it seems that both components are involved in the inhibition of ovulation in rats and women. There is additive synergism. 5. Conclusions concerning the activity and duration of effect in the clinic can be drawn from the intensity and duration of the progestational effect in rabbits. 6. The oral and subcutaneous activity of estrogens in different tests in rats and mice is in parts very well correlated. This is also true for the antiovulatory activity. 7. Comparison of the estrogenic activity of ethinyl estradiol and mestranol in rats, mice and women still leaves the question unanswered whether ethinyl estradiol is more potent than mestranol. 8. Certain conclusions regarding the depot effect in the clinic can be drawn from the duration of the estrogenic activity in the Allen-Doisy test. This test is at least suitable for the selection of the optimal depot estrogen. 9. As concerns androgens, clinical dose finding is so difficult because there are no or only poor clinical parameters for androgenicity. The oral evaluation of androgens in rats and mice provides no evidence for whether or not an androgen is orally active in men. Frequently, one can only resort to conclusions form analogy. 10. The duration of androgenic activity in rats allows certain conclusions to be drawn regarding the duration of activity in men. Dose finding, however, is difficult. 11. Steroids in which the anabolic and androgenic activity in the levator ani muscle/accessory sexual gland test are dissociated (anabolics) do also show dissociation of these two partial activities in the clinic. 12. The levator ani muscle/accessory sexual gland test in rats allows also conclusions to be drawn as to the depot activity in the clinic. 13...

Anabolic Agents↗
PubMed1977

[On the dose-effect relation of allopurinol (author's transl)].

The hypuricemic action(y) of 1H-pyrazolo(3,4-d)pyrimidin-4-ol (allopurinol) is dependent on the serum concentration of uric acid (x). After treatment with allopurinol at doses of 300 mg daily for 8 days there exists a highly significant correlation corresponding the equation y = 0.875x + 3.950. At a level of 8 mg/dl without any therapy serum uric acid concentration is expected to decrease by an average of 3 mg/dl if allopurinol is applied at daily doses of 300 mg in a preparation with or without any retarding effect. Following a dose reduction to 150 mg allopurinol daily over a period of 8 days, too, the mean diminution of the hypuricemic action amounts only to 0.43 +/- 0.26 mg/dl (S.D.). In some cases, however, long-term therapy with allopurinol at daily doses of 150 mg is insufficient to guarantee a normuricemic state.

Adult↗
PubMed1976

Quinidine syncope: torsade de pointes with low quinidine plasma concentrations.

In 2 patients without clinically significant ischemic heart diseases, oral quinidine was used to control supraventricular arrhythmias. In both patients, syncopal attacks occurred, caused by a particular type of ventricular tachyarrhythmia called torsades de pointes. Quinidine plasma concentrations were low (2.6 and 1.2 mg/1, respectively); QRS duration was normal, but the Q-T interval was markedly prolonged.

Aged↗
PubMed1975

[Zollinger-Ellison syndrome treated medically by an inhibitor of H2 histamine receptors].

Metiamide an histamine H2-receptors antagonist has been used to treat a case of Zollinger-Ellison syndrome characterized by a long standing diarrhea, an important gastric hypersecretion and a moderatly elevated plasma gastrin but without digestive ulceration. At the dose of 600 mg per day, Metiamide induced a complete suppression of acid secretion, an effect which lasted for 15 days after stopping the drug. Accordingly and since the only finding at time of laparotomy was a small lymph node enlarged with endocrine metastatic tissue, the stomach was left intact and Metiamide pursued. During the first 4 months of chronic administration of Metiamide, acid secretion was maintained at levels below 25 p.cent of initial values. Ulteriorly however, although dosages of Metiamide were increased, acid hypersecretion resumed and a duodenal ulcer developed. Total gastrectomy was then performed 11 months after the beginning of Metiamide. In spite of the failure of Metiamide treatment, the long term follow up of this case of Zollinger-Ellison Syndrome, allowed us to get theoretical and practical informations.

Adult↗
PubMed1976

[Drug-drug interactions (author's transl)].

This short outline of drug-drug interactions does not claim to cover the entire field. The task of this paper is to illustrate the most important principles of drug-drug interactions by paradigms taken from the experience of the practitioner. One consequence of drug-drug interactions is the change in pharmacolinetic parameters important for the therapeutical effect of drugs in the organism. Very often the elucidation of the mechanisms of drug-drug interactions in man is impossible; therefore, for clinical pharmacologists experiments on animals remain the tool in order to gain more knowledge in this field.

Age Factors↗
PubMed1976

[Galenical possibilities and problems in protraction of drug effects (author's transl)].

In recent years, dosage forms with sustained release have obtained a significant importance. The technological possibilities for manufacturing are described as coating, embedding and matrix procedures. The range of auxiliary substances, which are responsible for the retardation of drug activity, reaches from lipophilic compounds as lipoids, fatty alcohols and compounds which are forming hydrogels as cellulose derivatives and natural polysaccharides to synthetic polymers derived from acrylic acid. The formulation of the dosage forms requires particular care in respect to the amount of initial and maintenance doses. On account of technological processes, for example during manufacturing of tablets, under certain circumstances the liberation rate is altered. In vitro test methods allow comparisons only then when the results can be counter-checked by in vitro experiments. The release of drug follows different mechanisms, which are described, entirely or in part, to be reactions following the time law of zero or first order. In special cases, a linear correlation is observed as a function of square root of time. The calculation of given special equations for events within the dosage form is feasible from blood-level values.

Biological Availability↗
PubMed1976

[The influence of neuroleptic drugs on urinary excretion of non-protein nitrogen (author's transl)].

During treatment with thioxanthenes or phenothiazines of schizophrenic patients non-protein nitrogen in urine was measured. The values were calculated in relation to the excretion of creatinine. a) Flupentixol or fluphenazine applied in optimal dosage, increased the excretion of urea and the amino acids asp, glu + gln, and gly. b) Moreover, if the drug induced a parkinsonoid (thioridazine) the excretion of ser and thr was increased, too. The usual desalting procedure by ion-exchanging resins before chromatography increases the contents of several amino acids, e.g. asp, asn, ala, gly, cys, ser, thr, indicating a breakdown of some instable products.

Amino Acids↗