Ustav chemie pevnych latek

Prague, Czech Republic

Ustav chemie pevnych latek

Prague, Czech Republic

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Seilerova L.,Ustav chemie pevnych latek | Brusova H.,Zentiva | Kratochvil B.,Ustav chemie pevnych latek | Krejcikb L.,Zentiva
Chemicke Listy | Year: 2012

Thermal analysis is a valuable method in pharmaceutical research. A wide range of thermal methods are used in drug development like thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calori -metry (DSC) and other sensitive and specific methods. The present review deals with application of these methods in characterization of drugs and excipients, such as their polymorph stability, glass transition temperature, purity analysis and compatibility of drugs.


Simek M.,Ustav chemie pevnych latek | Grunwaldova V.,Zentiva | Kratochvil B.,Ustav chemie pevnych latek
Chemicke Listy | Year: 2014

The particle size and shape of raw materials influence the manufacture and behavior of solid dosage forms. The most widely used methods of particle size measurement are laser diffraction and image analysis. These methods are based on different principles and measurement ranges. Only the results obtained by the same method under the same conditions can be compared. Laser diffraction is significantly faster if a validated method is known. The method is defined for every raw material to guarantee reproducibility of measurement. Image analysis is inexpensive and does not require the validated method. Shape information is easily provided by image analysis. Laser diffraction is a suitable method for routine quality control. Image analysis is an optimal technique for development of pharmaceuticals.


Seilerova L.,Ustav chemie pevnych latek | Brusova H.,Zentiva | Kratochvil B.,Ustav chemie pevnych latek
Chemicke Listy | Year: 2011

Pharmaceutical excipients may occur in polymorphs and other solid forms and as active pharmaceutical ingredients. Excipients, polymorphs or the forms are not specified in the patient information leaflets on the dosage forms. Polymorphs of lactose, mannitol and sorbitol, various forms of cellulose and its derivatives, starch forms and poly(N-vinylpyrrolidone) are discussed in detail here. Identification of polymorphs and other solid forms can be carried out by X-ray powder diffraction as well as by IR, Raman and solid-state NMR spectroscopies.


Gruberova L.,Ustav chemie pevnych latek | Kratochvil B.,Ustav chemie pevnych latek | Jegorov A.,R.Ø.S.A.
Chemicke Listy | Year: 2014

Powdery pharmaceuticals are prone to electrostatic charging due to collisions of particles and friction with device walls. The generated electrostatic charge is influenced by particle properties, processing and conditions. The charge of active particles and excipients is often inconvenient being able to cause problems in the production of solid dosage forms. The electrostatic charge of powdery particles affects properties of the materials and all procedures as the charge affects the behaviour and purity of the final dosage form. The problem of electrostatic charging of powders is more complicated when two or more compounds with different physical, chemical and dielectric properties are combined. To better understand the mechanism of electrostatic charging it is necessary to explain all the effects that contribute to charging solid active ingredients and excipients. © 2014, Czech Society of Chemical Engineering. All rights reserved.


Franc A.,University of Veterinary And Pharmaceutical Sciences Brno | Vetchy D.,University of Veterinary And Pharmaceutical Sciences Brno | Smilkova L.,University of Veterinary And Pharmaceutical Sciences Brno | Rabiskova M.,University of Veterinary And Pharmaceutical Sciences Brno | Kratochvil B.,Ustav chemie pevnych latek
Chemicke Listy | Year: 2012

This review describes a new trend in the formulation of dosage forms containing poorly water-soluble drugs - lipophilic solutions, dispersions, liposomes and nanoparticles - dealing also with their composition and manufacture. The dispersions are further divided into nonemulsifying, self-emulsifying, self-microemulsifying and self-nanoemulsifying drug delivery systems. The cited systems are able to form micro- and nanoemulsions in contact with gastric juices. Formulations containing lipophilic nanoparticles as well as micro- and nanoemulsions are easily absorbed. A system classifying lipid formulations according to the drug composition is also described. The system enables the taxonomy of lipophilic drugs to be made; it also tries to describe their further metabolic ways in the organism.


Krejcova S.,Ustav chemie pevnych latek | Dousova B.,Ustav chemie pevnych latek | Kadlecova R.,Ceska geologicka sluzba
Chemicke Listy | Year: 2013

The Se concentrations in communal water conduits have been exceeding the admissible limit of the Ministry of Health (10 μg l-1) since 2007. Increased Se contents in soil, rocks and Se-accumulating plants from the surrounding of the collecting wells were found. The main source of Se-contaminated drinking water is probably an illegal rubbish dump.


Simek M.,Ustav chemie pevnych latek | Kratochvil B.,Ustav chemie pevnych latek
Chemicke Listy | Year: 2015

Hot-stage microscopy (HSM) affords combined light microscopy and thermal analysis, enabling the study of materials as a function of temperature and time. This combination involves visual examination and gives valuable information on the compound regarding its melting point, phase transformation, new phase formation, solid-state interactions, particle and solid dispersions analysis during heating. HSM gives a unique opportunity to visually follow thermal changes. Model cases of HSM application show its current usage in pharmaceutical industry thus supporting and inspiring its research. © 2015 Czech Society of Chemical Engineering. All rights reserved.


Gruberova L.,Ustav chemie pevnych latek | Kratochvil B.,Ustav chemie pevnych latek
Chemicke Listy | Year: 2015

Drug release from solid oral dosage form is affected by biochemical and mechanical factors in the upper gastrointestinal tract (GIT). The dosage form is exposed to different conditions in GIT sections and to food effects. Precise simulation of in vivo environment is essential for achieving biorelevant conditions by the in vitro method. New dissolution devices are developed for this purpose. The static devices are mainly used for evaluation of mechanic and hydrodynamic forces (the paddle-beads and rotating beaker method). Nevertheless, the complex dynamic dissolution device represents the required aim. Simple dynamic equipment modifies attributes of the established USP 2 apparatus (the artificial stomach-duodenum model). The dynamic equipments with a new design simulate the whole upper GIT (TIM-1) or itself stomach (the dynamic gastric model and the human gastric simulator). Adequate simulation of in vivo conditions by in vitro tests ensures better prediction of the drug behavior and facilitates the development of new dosage forms. © 2015, Libertas Academica Ltd. All rights reserved.

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