Biomedical subjects

Romána Zelkó

Publications and source records attributed to Romána Zelkó.

At least 19 recordsLinked to original sources

PubMed2006

Self-reported medication and lifestyle adherence in Hungarian patients with Type 2 diabetes.

BACKGROUND: Type 2 diabetes is a complex disorder that requires the patient to pay constant attention to diet, physical activity, glucose monitoring and medication. OBJECTIVE: To evaluate the medication, lifestyle adherence and factors associated to these in Type 2 diabetes in Hungarian patients. SETTING: Fourteen community pharmacies in Hungary between March and May 2004. METHOD: A questionnaire was given to every tenth Type 2 diabetic patient who presented to one of the 14 pharmacies included in this study with a prescription for oral antidiabetics, oral antidiabetics and insulin or exclusively insulin. For the latter two groups, the prerequisite for inclusion in the study was also that their diabetes had developed after the age of 35 and that at some in their treatment regimen they had taken only oral antidiabetics. These latter two criteria were controlled in the patient's general practitioners' (GP) database. General and diabetes-related data were collected in the questionnaire, and the adherence and lifestyle of the participant were assessed. An adapted and validated Hungarian version of the EQ-5D (EuroQol Group, 1993) quality-of-life questionnaire was also included. Descriptive and chi(2) test statistical methods and two sample t-test were used. A significance level of P<0.05 was considered to be significant. MAIN OUTCOME MEASURE: Patient self-reported adherence to diet, physical activity, self monitoring of blood glucose, purchasing of drug(s), drug regimen, association of demographic factors, treatment, lifestyle and quality of life on adherence. RESULTS: Of the 220 questionnaires distributed to diabetic patients, 151 were returned, of which 142 were evaluated (nine did not satisfy the above-mentioned inclusion criteria). With respect to the factors assessed, sub-optimal adherence was assessed for: diet (76.8%), physical activity (33.8%), self-monitoring of blood glucose (81%), drug purchasing (20.4%) and drug taking (52.1%). Smokers comprised 14.8% of the respondents, while 8.5% were heavy drinkers. Fewer than five meals a day were eaten by 46.5% of the patients, and about 43.6% of the patients did not self-monitor blood glucose. The results indicate few significant associations between at least one of the four main areas of adherence (diet, physical activity, purchasing of drug(s), drug regimen) and body mass index, GP consultation frequency, quality-of-life parameters and EQ-5D index. CONCLUSION: The adherence of Hungarian Type 2 diabetics in some areas does not reach optimal levels, especially for diet, self-monitoring, drug purchasing and adherence to drug taking.

Aged↗

PubMed2006

[Phosphor/sulphur ratio: indicator of malignant uterine changes].

The purpose of the present study was to find a correlation between gynaecological diseases--myoma (26), adenocarcinoma uteri (21) - and P/S (phosphor/sulphur) ratios of different regions of uterus. Routine histological specimens were re-examined with the intention to select representative regions of the uteruses for element analysis. Conventional haematoxylineosin stained sections were used to identify histological alterations by light microscopy. Energy-dispersive spectroscopic (EDS) investigations were carried out to analyse the morphology and the related element composition of the samples. The results of the non-parametric statistical test (Wilcoxon two-sample test) indicate that the P/S ratios were significantly higher in adenocarcinoma (0.8891 +/- 0.0757) than in myoma (0.4713 +/- 0.0306). P/S ratio of different pathologic regions of uteruses seems worth examining in a larger study population.

Female↗

PubMed2006

Tracking of enantioselective solubility of rac-norgestrel in the presence of cyclodextrin by a CD spectroscopic method.

Dissolution of hydrophobic rac-norgestrel in aqueous gamma-cyclodextrin (gamma-CyD) and hydroxypropyl-gamma-cyclodextrin (HP-gamma-CyD) solutions was investigated, and enantioselective dissolution was observed. (-)-Norgestrel, the eutomer molecule, was dissolved to a greater extent using each of the CyDs, although the effect was more significant in the case of HP-gamma-CyD. A circular dichroism (CD) spectroscopic method based on measurement of the anisotropy factor was applied for the determination of the enantiomer ratio. The concentration and the enantiomer ratio of norgestrel were determined indirectly in octanol after extraction. Optical rotation dispersion (ORD) measurements could confirm that neither the free CyDs nor their inclusion complexes could get into the organic phase during transport to octanol. Only the norgestrel molecules were able to get into the organic phase, although the enantiomer ratio remained the same as was obtained in the aqueous CyD solution.

Circular Dichroism↗

PubMed2006

[Physical ageing of amorphous polymeric excipients III. The possible consequences of ageing].

Polymeric excipients are widely used in pharmaceutical technology, and most of them are amorphous or partly amorphous. A well-known property of such materials is that they undergo physical ageing, which is accompanied by volume and enthalpy relaxation and thus might result in severe structural changes in the polymer. This latter phenomenon can influence the properties of excipients and dosage forms, such as processability, mechanical strength and drug release. These alterations are of great significance in the case of solid dosage forms, as physical ageing occurs in the solid state of the polymer. Considering conventional tablets, the structural changes of fillers or binders along with storage can influence the above mentioned properties, while in the case of modified release tablets, matrix-forming and film-forming agents are to be taken into account, as well. In addition to this, by the examination of films, the presence of plasticizers is of great importance, as these materials can facilitate physical ageing via increasing the molecular mobility of the polymer. In the case of certain therapeutic systems (e.g. intrauterine devices), where the base of the dosage form is polymeric, significant changes are to be noted considering the drug release and physiological tolerability of the system.

Dosage Forms↗

PubMed2005

The effect of structured triglycerides on the kinetic stability of total nutrient admixtures.

PURPOSE: The physical stability of two types of total parenteral nutrient (TPN) admixtures was studied as a function of storage time and temperature. One of them contained only structured triglycerides and the other exclusively long-chain triglycerides as lipid components. METHODS: Droplet size of the mixtures was followed by photon correlation spectroscopy for 10 days. Zeta potential and dynamic surface tension measurements were carried out to evaluate the possible changes in the charge and interfacial surface tension of the emulsion droplets during the storage. pH values were monitored in order to follow the possible decomposition processes in the course of storage. RESULTS: Droplet size of emulsions prepared with lipids containing exclusively long-chain triglycerides showed remarkable increase after 4 days of storage in contrast with that of the mixtures containing structured lipids. CONCLUSIONS: The obtained results indicate that besides the advantageous metabolic effects of structured triglycerides, their application is recommended to improve the physical stability of TPN admixtures.

Drug Stability↗

PubMed2005

Tracking of the physical ageing of amorphous pharmaceutical polymeric excipients by positron annihilation spectroscopy.

The structural changes observed in several amorphous polymers, commonly applied in the pharmaceutical technology to ensure conventional or controlled drug release, during relatively short storage periods are illustrated. The results suggest that the apparent structure formation of polymer molecules with water and, possibly, with other additives plays a significant role in the formation of such important physical and chemical parameters of tablets as drug release rate and solubility. Positron annihilation lifetime spectroscopy (PALS) was used to detect the changes of the free volume in the studied polymers under different storage conditions. Positrons react to the structural changes of amorphous polymers very sensitively, so the method can be recommended as useful means for stability tests during the development phase of dosage forms containing such excipients.

Drug Stability↗

PubMed2005

Correlation between the release characteristics of theophylline and the free volume of polyvinylpyrrolidone.

The purpose of this work was to study the drug-release properties of an amorphous polymer, polyvinylpyrrolidone applied conventionally as a binder in tablets. In order to gain data on the wearing properties of tablets, they were stored for a 30 days period under different humidity conditions before the drug-release measurements. The active material chosen for the release study was theophylline. An exponential relationship was found, with good correlation, between the relative humidity of the storage medium and the mean dissolution time of theophylline from polyvinylpyrrolidone tablets and the size of free volume holes. Positron annihilation lifetime spectroscopy (PALS) measurements, performed parallel with the theophylline release study, showed that the main reason for this correlation is the rearrangement of the pore structure of PVP. The results suggest that the water-induced glassy to rubbery transition of the polymer plays a significant role in the drug-release characteristics.

Humidity↗

PubMed2005

Factorial design for the analysis of patient's quality of life in asthma.

Chronic diseases like asthma have a great impact on the everyday life of patients. Evaluation of a patient's quality of life informs us about how the patient is feeling and whether or not he or she is able to function physically, socially and emotionally. The objectives of this study were to assess the quality of life of asthmatic patients and to study the influence of age and disease severity, as independent variables, on the patient's quality of life. A 2-factor, 3-level face-centred central composite design was applied to construct a second-order polynomial model describing the effects of age and the severity on the quality of life. The second-order polynomial model was successfully applied to describe the effect of age and asthma severity with good correlation on the quality of life measured by either generic (Visual analogue scale) or disease specific (St George's Respiratory Questionnaire) instruments in the examined subjects. Our findings suggest quality of life may be used as a non-invasive patient-centred monitoring system as a guide for disease management if measured regularly.

Asthma↗

PubMed2005

[Gastroretentive dosage forms].

Gastroretentive dosage forms are drug delivery systems which remain in the stomach for an extended period of time, and allow both spacial and time control of drug liberation. Their application can be advantageous in the case of drugs that are absorbed mainly from the upper part of the gastrointestinal tract or are unstable in the medium of distal intestinal regions. They can also be used beneficially in the local therapy of the stomach. Because of the complicated and by many factors influenced physiology of this organ, the design of such delivery systems is a task requiring due foresight and knowledge. Gastroretentive dosage forms can be floating, expandable, bioadhesive, modified shape and high density systems according to the physical property leading to prolongation of gastric residence time. Combinations of the listed categories can occur as well. Several spirited ideas and solutions have come up in the literature for the preparation of such delivery systems, but there is still need for development in the field of implementation and prediction of in vivo behaviour before these dosage forms can be elemental part of clinical practice.

Administration, Oral↗

PubMed2005

[Physical ageing of amorphous polymeric excipients I. physicochemical principles].

Most of the polymeric excipients applied in pharmaceutical technology are amorphous, which, as a result of physical ageing, can lead to changes in the stability of these materials and dosage forms prepared from them. For the tracking of physical aging and understanding its consequences, a complex knowledge of the physicochemical properties and behaviour of amorphous polymers is necessary. In the case of these materials, three single-phase physical states can be distinguished: glassy, rubbery and viscous. The transition from glassy to rubbery state occurs at the glass transition temperature, the change of which as a function of the storage conditions provides information about the physical ageing of the material. The ageing process is usually accompanied by enthalpy and volume relaxation, which are considerably influenced by the presence of different plasticizers, e.g. water. These materials usually change the glass transition temperature of the polymer, which is a result of their effect on the free volume of the system. In view of the hygroscopic behaviour and water-uptake mechanisms of polymers, the probability and extent of structural changes caused by physical aging can be predicted.

Cellulose↗

PubMed2004

Comparison of surface morphology and composition of intrauterine devices in relation to patient complaints.

The morphology and the related composition of T-type intrauterine devices (IUDs) made of gold-plated copper were studied in relation to patient complaints. The removed IUDs were examined without pretreatment by scanning electron microscopy and energy dispersive x-ray spectroscopy. Besides the previously found incrustation formation, lamination cracks were observed on the surface of gold-plated copper IUDs causing various side effects (abdominal pain, inflammatory complication). A possible explanation for lamination cracks could be the difference in the heat expansion of the copper and its gold-plated surface and the great difference between the strong acidic galvanizing pH during production and the in utero pH. Stability tests in combination with morphology screening of such IUDs could be required during their development phase to avoid such side effects.

Chemical Phenomena↗

PubMed2004

Comparison of the enthalpy recovery and free volume of polyvinylpyrrolidone during anomalous glassy to rubbery transition.

Previous studies confirmed that along with the structural changes of the amorphous binder, that of the polyvinylpyrrolidone, the tensile strength and consequently, the dissolution behaviour of its tablets changed significantly during the storage period. Structural formation during the glassy to rubbery transition of polyvinylpyrrolidone was followed by the changes in the free volume and enthalpy recovery values of the polymer. The results suggest that the apparent structure formation of water and polymer under glassy to rubbery transition is interrelated in a dynamic and complex manner which can be tracked by the combination of enthalpy recovery studies and positron lifetime measurements. Positron lifetime measurements more sensitively react to the structural rearrangements than enthalpy recovery, thus it can be recommended as a sensitive tool for stability tests during the formulation phase of drug development.

Differential Thermal Analysis↗

PubMed2004

[Utilization study of clozapine, olanzapine and risperidone in Hungary].

Authors examined the use of clozapine, olanzapine and risperidone by reviewing retrospectively their prescribing practice in the period of 1999-2003 in Hungary. The aim of the study was to analyze the utilization aspects of the use of the three novel antipsychotics. Data showed a fast growing trend in the use of olanzapine and risperidone while the use of clozapine is decreasing. The purpose of the present study was to follow the temporal development trends of use of the three examined novel antipsychotics which could result in a cost-effective drug therapy.

Antipsychotic Agents↗

PubMed2003

[The effect of physical aging on the structural behavior of amorphous poly(vinylpyrrolidone) polymers].

The purpose of the present study was to examine the physical ageing of amorphous polymers commonly applied in the pharmaceutical technology. Powder samples of polyvinylpyrrolidone were stored under different storage conditions (relative humidity, temperature). Positron annihilation lifetime spectroscopy (PALS) was applied for the analysis of the free volume changes of polymer samples as a function of the storage conditions. By the means of calculations on simplified model molecules it was determined that polymer chains and water molecules are able to form a hydrogen bound "network" under certain humidity conditions. Along with the ageing process the chemical changes of the examined polymers are interrelated in a dynamic and complex manner which can be tracked by the combination of SEM, ab initio calculations and positron lifetime measurements.

Drug Stability↗

PubMed2003

[Utilization and comparison study of antipsychotics at the Department of Psychiatry and Psychotherapy of the Semmelweis University and the Galfi Bela Hospital].

The authors examined the use of antipsychotics at the Department of Psychiatry and Psychotherapy of the Semmelweis University and at the Gálfi Béla Hospital by reviewing retrospectively the drug ordering practice in the period of 1998-2002. The aim of the study was to analyse the utilization aspects of the use of antipsychotic medication. The study also aimed to identify the main trends of prescribing preference and to compare the use of antipsychotics in the two institutions. Data showed that in accordance with the latest professional guidelines the use of novel antipsychotics is increasing. Based on analysis of the antipsychotic use in both clinical practices there were characteristic patterns found that show that the conventional antipsychotic use is still notable. The purpose of the present study was to follow the temporal development trends and present state of antipsychotic use which could result in a cost-effective drug therapy.

Antipsychotic Agents↗

PubMed2003

[Pathogenesis and treatment of Wilson's disease].

Authors review the pathogenesis, symptoms and diagnosis of Wilson's disease. Wilson's disease or hepatolenticular degeneration is an autosomal recessive disorder. It is caused by defective hepatic excretion of copper. The disease is fatal without treatment. The prevention of severe permanent damage depends upon early recognition and diagnosis followed by appropriate lifelong anticopper treatment. The purpose of the therapy of Wilson's disease is to eliminate the copper by chelators (D-penicillamine, triethylene tetramine, ammonium tetrathiomolibdate) and to inhibit the absorption and accumulation of copper by zinc salts (zinc sulphate, zinc acetate, zinc gluconate).

Chelating Agents↗

PubMed2002

Effect of plasticizer on the dynamic surface tension and the free volume of Eudragit systems.

The purpose of the present study was to determine the changes of dynamic surface tension of aqueous Eudragit dispersions quantitatively and compare these data with the free volume of the free films formed from several dispersions of different dibutyl sebacate (DBS) concentrations. Eudragit L 30D and Eudragit RL 30D aqueous colloidal polymer dispersions and their cast free films were examined. The concentration of DBS varied in the dispersions from 0 to 20%. The dynamic surface tension of the dispersions were measured by the Du Nouy ring method while the free volume of cast films were determined by positron annihilation spectroscopy. The obtained results show that dynamic surface tension measurements indicate the white point (WP) of Eudragit dispersions by a significant standard deviation increase. This may suggest the applicability of dynamic surface tension measurements for the determination of the WP of polymeric dispersions. A decrease in the WP temperature of Eudragit dispersions with an increasing plasticizer concentration was observed up to the DBS concentration of 10% w/w. Above this concentration neither the WP of the polymer dispersion nor the free volume of the free films of the polymer were changed remarkably.

Chemistry, Pharmaceutical↗

PubMed2002

[Influence of storage conditions on the physical aging of amorphous polyvinylpyrrolidone].

The aim of the present study was to examine the structural changes of amorphous polyvinylpirrolidone, associated with the physical ageing, by the determination of the free volume of the polymer and to find a correlation between the structural changes of the polymer and the physical stability of tablets containing it. The water absorption from the storage medium resulted in the glassy to rubbery transition of amorphous polyvinylpyrrolidone at room temperature. This spontaneous transition was not continuous in the case of PVP K25. Not only the actual water content but the storage history determines the free volume distribution of the samples. The structural changes associated with the physical ageing influence the physical stability of solid dosage forms containing this polymer.

Drug Stability↗