Authors:Orsolya Jójárt-Laczkovich and Piroska Szabó-Révész
Amorphization is nowadays a method that is frequently applied in the pharmaceutical industry. The primary aim of this study
is to achieve the amorphization of clopidogrel hydrogen sulphate as an active pharmaceutical ingredient (API) with various
solvents and to choose the most suitable one. A secondary aim was to determine the glass-transition temperature (Tg) of this API and to classify it as a good or poor glass former. To investigate the amorphous form, differential scanning
calorimetry, X-ray powder diffraction, and FT-IR analysis were applied. The melting point (Tm) was 177.4 °C (450.6 K), and Tg was determined to be 88.9 °C (362.1 K). The quotient Tg/Tm was 0.80, and this API was therefore classified as a good glass former.
Authors:P. Sipos, A. Szabó, I. Erős, and Piroska Szabó-Révész
A study was made of the possibilities of gradually decreasing the concentration of the toxic organic solvent in the process
of microsphere preparation. Ammonio methacrylate copolymer-based microspheres were prepared by spray drying or conventional
solvent evaporation techniques, and compared. The formulations were designed by varying the preparation methods and the concentrations
of four polar cosolvents as independent variables.
DSC was used to study the relationship between the changes in the independent variables and three of the main thermal events
of the microspheres. Raman spectroscopy was used to investigate and confirm the possible interactions between drug and copolymer.
Appropriate choice of the independent variables led to the molecularly dispersed drug in the polymer matrix. It was demonstrated
that only the nature of the preparation method caused significant variations in the structure and thermal behaviour of the
Authors:Anikó Szepes, Anke Fiebig, J. Ulrich, and Piroska Szabó-Révész
The aim of this work was to investigate the influence of different levels of microwave irradiation on the structure and particle
size characteristics of α-lactose monohydrate. The structural study of the samples was carried out by XRD, the presence of
lactose polymorphs in the test samples was determined by DSC and the particle size distribution was measured by laser diffraction.
The samples subjected to microwave irradiation retained their original X-ray patterns. No significant differences in thermal
transition characteristics and particle size were observed. Hence, neither the occurrence of crystalline-amorphous transition
resulted by microwave irradiation nor the presence of lactose polymorphs in the test samples can be assumed. The unmodified
properties can be attributed to the fact that the water of crystallization is very difficult to remove from the crystal structure
and is not free to move during microwave treatment, which results in stability to microwaves.
Our results allow the conclusion that microwave processing of α-lactose monohydrate has no influence on further pharmaceutical
technological properties, which are related to the structure and the particle size distribution of this substance.
Authors:Eszter Csizmazia, Mária Budai-Szűcs, István Erős, Zsolt Makai, Piroska Szabó-Révész, Gábor Varju, and Erzsébet Csányi
Our aim was to develop potential dermal drug delivery systems (DDSs) with a good and lasting moisturizing effect. Lyotropic
liquid crystals (LLCs), gel-emulsions and hydrogels were investigated by means of thermogravimetry, which can give information
about the structure of these preparations, and we could study the water binding mechanisms indirectly in them. We found that
the preparations with a complex structure and strong water bonds hydrate the skin well and lastingly by in vivo tests. Since
the thermoanalytical results correlate with the in vivo test results, this method could be suited for predicting the moisturizing
effect of the vehicles and provide the possibility to select the potential semisolid DDSs for in vivo tests cost and time
Authors:Z. Aigner, L. Mécs, G. Sohár, K. Wellinger, Piroska Szabó-Révész, and K. Tóth
The purpose of this investigation was to further elucidate calorimetric properties of cartilage samples from femoral head
necrosis and osteoarthritis from live surgeries. The natural course of this disease is one of steady progression with eventual
collapse of the femoral head, followed by secondary osteoarthritis in the hip joint. All samples showed a clear denaturation
peak on the calorimetric curve. Cartilage obtained from necrotic femoral head required the lowest amount of energy for decomposition.
The use differential scanning calorimetry as part of thermal analysis was a reliable method for differentiating.
Authors:L. Mécs, Z. Aigner, G. Sohár, Piroska Szabó-Révész, and K. Tóth
The purpose of this study was to further characterize the altered metabolism spondylolisthesis that promotes disease progression.
Degenerative human cartilage (intervertebral disc, facet joint and vertebral end-plate) was obtained during 15 posterior lumbar
spine interbody fusion procedures performed at the University of Szeged. The thermal properties of samples were determined
by differential scanning calorimetry (Mettler-Toledo DSC 821e). Greatest change in the enthalpy was observed in the intervertebral disc samples: −1600.78 J g−1. Denaturation caused by heating in the normal human hyaline cartilage needed −1493.31 J g−1 energy. Characterization of the altered metabolism that promotes disease progression should lead to future treatment options.
Authors:J. Csotye, Z. Aigner, G. Sohár, Piroska Szabó-Révész, and K. Tóth
The glenohumeral joint is not a classical mass bearing joint, the treatment of primary osteoarthritis is conservative. In
all other cases, when the arthritis is associated with unbalance of the soft tissues, the treatment solution of this pathology
is arthroplasty. The purpose of this study was to examine the altered metabolism in human degenerated cartilage of the shoulder
joint. With the rise of temperature an endothermic reaction was observed in all cases. The use differential scanning calorimetry
as part of thermal analysis was a reliable method for differentiating normal hyaline cartilage from degenerated samples.
Authors:K. Tóth, G. Sohár, Z. Aigner, F. Greksa, and Piroska Szabó-Révész
During recent years, knowledge of rheumatoid arthritis has increased, and management of the disease has improved. A limited
number of papers have been published before on the subject of thermal analysis of degenerative cartilage but rheumatoid arthritis
(RA) has not been studied previously. A new protocol had to be established before the investigation. The purpose of this study
was to further characterize the altered metabolism in human RA cartilage that promotes disease progression.
Previously, these methods have not been used for this purpose. The use of thermal analysis could be an effective method for
controlling the relationship between biomarkers and disease progression.
Authors:Mária Szűcs, Patrizia Vaghi, Giuseppina Sandri, M. Bonferoni, Carla Caramella, Piroska Szabó-Révész, and I. Erős
Polymeric emulsifiers provide exceptional stability to oil-in-water, water-in-oil or multiple emulsions by their steric stabilization.
Pemulens as polymeric emulsifiers are able to stabilize o/w type emulsions because their short lipophilic part integrates into the oil droplets while their long hydrophilic part forms
a micro gel around the droplet. In our present study the microstructure and integration of the polymeric emulsifier at the
water-oil interface was investigated with thermogravimetric and microscopical methods. It was established that depending on
the amount of both of the polymeric emulsifier and added coemulsifier the microstructure of the system changes.
Authors:G. Várhegyi, M. J. Antal, Piroska Szabó, Emma Jakab, and F. Till
The complexity of the phenomena which arise during the heating of the various substances seldom can be described by a single reaction kinetic equation. As a consequence, sophisticated models with several unknown parameters have to be developed. The determination of the unknown parameters and the validation of the models requires the simultaneous evaluation of whole series of experiments. We can accept a model and its parameters if, and only if we get a reasonable fit to several experiments carried out at different experimental conditions. In the field of the thermal analysis the method of least squares alone seldom can select abest model or abest set of parameter values. Nevertheless, the careful evaluation of the experiments may help in the discerning between various chemical or physical assumptions by the quality of the corresponding fit between the experimental and the simulated date. The problem is illustrated by the thermal de-composition of cellulose under various experimental conditions.