Biomedical subjects

I Antal

Publications and source records attributed to I Antal.

36 records · Page 2Linked to original sources

PubMed1998

Effect of particle size and coating level on the diffuse reflectance of wax matrices.

The aim of this study was to examine the influence of particle size and extent of coating on the diffuse-reflectance spectra of wax matrices containing embedded potassium chloride. Near-infrared spectroscopy was used to analyse the diffuse-reflectance characteristics of the prepared multi-particulate matrices without destructive sample preparation. A 2-factor, 3-level face-centred central composite design was selected to construct a second-order polynomial model which described the effect of particle size and amount of coating on the intensity of the diffusely reflected light. A non-linear model was used to demonstrate the effect of the selected parameters on the intensity of the reflected light; good correlation was obtained between experimental and predicted results. The results indicated that the extent of coating and the particle size of the examined systems in the selected particle size-range modified the intensity of the reflected light. It can be concluded that near-infrared spectroscopy is a sensitive means of measuring not only the particle size of powders (substrates and their mixtures), but also that of coated multi-particulate systems.

Chemistry, Pharmaceutical↗

PubMed1998

[Evaluation of substrate-binder interfacial interactions].

Substrate-binder interfacial interactions were evaluated on the basis of the physico-chemical and mechanical properties of granules and compressed samples. Linear relationship was found between the breaking strength, the diffuse reflectance and the binder content of the examined granule-systems and compressed samples. The increasing amount of binder in the granules improved the adhesive interaction existing between the substrate and the binder. Our results indicate that the mechanical properties of the single particles as well as of the compressed samples were basically determined by the physico-chemical interactions of the substrate-binder interfacial layer. The qualitative and quantitative evaluation of these interactions has a decisive impact on the formulation and in process control of solid dosage forms of optimal mechanical properties.

Binding Sites↗

PubMed1996

Formulation of controlled release drug preparations with antacid effect.

Opportunities for the formulation of long-acting antacid preparations were demonstrated summarizing the results of pharmaceutical technological experiments. The telemetric intragastric data were in correlation with the in vitro measurements and demonstrated the significantly higher bioavailability of long-acting antacid preparations.

Antacids↗

PubMed1996

[Role of mass transfer processes in drug formulation].

Authors call attention on the possibilities that drug release from solid preparations can be influenced by solubility and dissolution rate according to the clinical requirements regarding the duration of action. The therapeutic time interval may be modulated influencing the rate of absorption by controlling dissolution rate and changing the transport through the membranes. The results obtained from dissolution, absorption and efficacy studies of the evaluated active substances (magnesium oxide, metoprolol, nitrofurantoin) demonstrate the significance of mass transfer processes in the drug formulation.

Dosage Forms↗

PubMed1995

In vitro biopharmaceutical investigation of antacid activity in standard dissolution test apparatus.

The pH stat titration and the Rossett-Rice test used especially for the reaction kinetical and in vitro biopharmaceutical investigation of antacids were standardized applying the U.S.P. Dissolution Test Apparatus with paddle stirring element. The developed "artificial stomach" is suitable to simulate also the gastric emptying. The in vitro model may give a new alternative for the in vitro evaluation of antacid effectiveness, because this standardized method may perfectly eliminate the deficiencies of the earlier test prescriptions.

Aluminum Hydroxide↗

PubMed1994

Multicentric extraabdominal desmoid tumour: a case report.

The very rare condition of multicentric desmoid tumours involving two distant and apparently independent sites is reported in a 17-year-old man. The tumours grew simultaneously and reached approximately equal size. No evidence of familiar polyposis or any other feature of Gardner's syndrome were noted. The proximal desmoid tumour developed from the left hip region and extended into the femoral bone, whereas the distal mass was attached to the left popliteal fossa infiltrating the flexor muscles, the nerves and vessels. On the basis of the good results published recently in the literature and our own earlier experiences, the intralesional resection of the desmoid tumours was completed with postoperative fractionated radiotherapy.

Adolescent↗

PubMed1994

Limb saving surgery in bone tumours: experiences in Hungary.

A retrospective clinical review of 28 low- and 47 high-grade bone tumours, managed by limb salvage operations, was performed in the Orthopaedics Department of the Semmelweis University Medical School, Budapest. The mean follow-up period was 37.2 months. Ten bone tumours were classified as stage I/A, 18 as I/B, 16 as II/A and 31 as II/B. The overall 3 years survival rate was 97% in low-grade bone tumours, 84% in osteosarcomas and 50% in Ewing's sarcomas. Local recurrences were observed in 14%. Tumour prostheses were implanted in 25 patients (33%); 2 complications in this material were seen. In 50 patients resection and reconstruction with autografts or allografts were performed; 13 complications (26%) were registered in 9 patients. These results suggest that limb saving surgery is an acceptable method in selected cases of early recognized bone tumours which respond well to the chemotherapy.

Adolescent↗

PubMed1993

Examination and evaluation of surgical margins in bone tumours. Comparative pre- and postoperative CT and MR imaging.

An objective method of evaluating surgical margins and the extent of limb-preserving surgery is described in a study of 10 malignant bone tumours. The resected specimen was imaged by computerised tomography and magnetic resonance, and the appearances compared with the preoperative images of the tumour. CT was better than MR for detecting bony changes, but MR was more satisfactory for showing the extraosseous and intramedullary outline of the tumour. These two methods should therefore be combined. Intralesional excision is an absolute indication; marginal excision a relative indication for reoperation.

Adolescent↗

PubMed1993

[Results of the treatment of osteoblastomas].

Until now 19 patients were treated for osteoblastoma in our University Department. Operation was performed in every case and recurrence was found in one patient. The clinical-pathological characteristics of the benign, latent, active and aggressive osteoblastomas are discussed. In benign active process excision, in benign aggressive tumors, depending from the localization, resection en bloc is suggested. In cases localized near to the joint, weighing the damage of function in consequence of a possible resection and the increased risk too, a thorough excision is proposed completed with local adjuvant treatment and frequent control of the patient.

Adolescent↗

PubMed1992

Calcitonin therapy of aneurysmal bone cysts.

Seven aneurysmal bone cysts (ABC) were treated with the hormone calcitonin. Six of the cysts, which were hypovascular responded well to the calcitonin administered directly into the cyst. Ossification and rebuilding of the ABC occurred after some months in every case. One hypervascularized ABC, however, failed to respond either to embolo-therapy or to the calcitonin hormone treatment. The authors recommend calcitonin administration as a useful non-invasive method for the treatment of hypovascular ABC.

Adolescent↗

PubMed1992

[Results of using bone cement and phenol lavage in the surgical management of giant cell bone tumors].

Authors report on experiences gained with phenol lavage used as adjuvant and filling with bone cement in the surgical treatment of giant cell tumors of the bone. The effect of the adjuvant therapy was a considerable decrease in the rate of relapses: in 11 patients 1 relapse was found only in contrary to the 15 relapses in the control material (41 per cent) after 36 excochleations. They think that with adequate indications both the phenol lavage and filling with bone cement are useful supplements to the surgical therapy.

Adolescent↗

PubMed1990

[Pruritic urticarial papules and plaques in pregnancy].

PUPP is a specific eruptive dermatosis in pregnancy, clinically characterized by erythematous papules and plaques with intense itching in periumbilical localization. This disease typically tends to spread to the extremities without involving the head and neck regions. The differential diagnosis of PUPP can be established by immunological and microscopical investigations. Since PUPP is a benign disease with a good prognosis and spontaneous clearing, we recommend only mild symptomatic treatment.

Adult↗

PubMed1990

[Clinical experiences of interval treatment with dermatologic agents containing urea].

Topical vehicles containing urea are increasingly used in dermatology because of their favorable pharmacological properties, which are due to the following capacities of urea: (1) its beneficial influence on the structure and physiology of the skin, and (2) its therapeutic effect in combination with other topically active agents in various skin diseases, such as psoriasis, ichthyosis, and chronic eczema. Our own experiences presented here are in accordance with these statements.

Dermatologic Agents↗

PubMed1990

[Preformulation study of controlled release nitrofurantoin preparations. 2].

In their previous publications the authors rendered account of preparation and stability test of products containing controlled release nitrofurantoin in circumstances of preparing and storing. Following previous publications in vitro active principle release of developed product has been investigated by rotating basket method and by applying Sartorius Dissolution tester. Absorptions of active principle and coated pharmacon have been determined by means of Sartorius Membrane transport tester. On basis of results it can be ascertained that compressed and capsuled products coated with Eudragit L 100-55 has proved to be the most suitable concerning release of active principle as well as in vitro absorption. Taking into account probability values of absorption, active principle release and absorption of product have been properly controlled and so optimal bioavailability of the preparation can be expected.

Absorption↗

PubMed1987