Search Results

You are looking at 1 - 10 of 49 items for :

  • "spray drying" x
  • Chemistry and Chemical Engineering x
  • All content x
Clear All
Journal of Thermal Analysis and Calorimetry
Authors: Antonilêni Medeiros, Ana Santos, F. de Souza, I. Júnior, J. Valdilânio, J. Procópio, D. de Santana, and R. Macêdo

Abstract  

Compatibility studies between active drugs and excipients are substantial in the pharmaceutical technology. The objective of the present work was to develop pre-formulated mixtures of metronidazole (MT) obtained by spray drying (SPDR) and their thermoanalytical characterization. Dynamic and isothermal TG, conventional DSC and DSC coupled to a photovisual system were used. DSC experiments with both techniques confirmed the homogeneity of the conventional and pre-formulated mixtures. The TG data made possible the comparison the thermal stability of the different mixtures. Similar thermal stabilities were found of the conventional and pre-formulated mixtures, with slower particles sizes of MT.

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: Antonilêni Medeiros, Ana Santos, F. de Souza, J. Procópio, Márcia Pinto, and R. Macêdo

Abstract  

Stability of drugs and products has a great practical interest, which is facing to strict regulation. Thermal studies, besides the determination of the thermal properties of the investigated product allow the verification of possible interactions between the drug substances and excipients. The objective of this work was to obtain solid pre-formulates of paracetamol (PC) by spray drying (SPDR), as well as to investigate their thermal behavior. Dynamic and isotherm TG, conventional DSC and DSC-photovisual coupled methods were used to characterize the conventional and pre-formulated mixtures obtained by SPDR. The results of both DSC investigations showed slight alterations in melting temperatures, which suggests incompatibilities. The TG decomposition data of the mixtures evidenced that the dry process via SPDR leads to stability enhancement of the pre-formulated mixtures.

Restricted access

Abstract  

Inclusion complexes of Lippia sidoides essential oil and β-cyclodextrin were obtained by slurry method and its solid powdered form was prepared using spray drying. The influence of the spray drying, as well as the different essential oil:β-cyclodextrin ratio on the characteristics of the final product was investigated. With regard to the total oil retention 1:10 mass/mass ratio as optimal was found between the essential oil and β-cyclodextrin. Thermoanalytical techniques (TG, EGD, TG-MS) were used to support the formation of inclusion complex and to examine their physicochemical properties after accelerated storage conditions. It may be assumed that the thermal properties of the complexes were influenced not only by the different essential oil/ β-cyclodextrin ratio but also by the storage conditions. In the aspect of their thermal stabilities, complex prepared with 1:10 m/m ratio (essential oil:β-cyclodextrin) was the most stable one.

Restricted access

Introduction In food industry spray drying processes are widely used to produce dry free flowing powder starting from a liquid formulation. Since this is a one stage process with high drying capacity it has advantages compared to multi stage

Open access

Aluminate sodalite ceramics, (Sr8Al12O24)(CrO4)2) — SACR, have been prepared from solution spray-dried precursors. The spray drying of a mixed aqueous nitrate solution gave an anhydrous powder which was thermally decomposed in air at 1350 °C to give a crystalline SACR powder with a median volume diameter of 4–6 μm. The SACR powder was dry pressed and sintered to >90% density. The yellow SACR powder showed two phase transitions between 10 and 45 °C with a 25 ° intermediate phase region indicative of a low defect concentration in the crystalline structure. A colour change observed in the sintered ceramic (changing to a mixed green/yellow) and a narrowing of the phase transition region (15–40 °C) are discussed. Dielectric measurements were consistent with the presence of two extrinsic ferroelectric transitions at 17 and 35 °C.

Restricted access

Abstract  

The formation of crystalline inclusion complex of triamterene with β-cyclodextrin (β-CD) was studied, evaluating the thermal behaviour and dispersion state of this drug in different types of binary systems. Spray-drying and co-grinding (oscillating mill) mixtures of triameterene with β-CD were prepared in 1∶1 molar ratio. The changes of crystalline properties of original (untreated) triamterene, β-CD, and composites obtained by co-grinding and spray-drying were investigated in comparison with those produced in simple physical mixtures. The thermal behaviour of the different samples was investigated using DTA. X-ray diffraction was applied as a complementary technique. The results have been explained by formation of amorphous drug particles on spray-drying samples and co-grinding or alternatively by means of a solid dispersion formation or a combination of these two. A contamination effect by grinding media was also observed as increasing grinding time.

Restricted access

Abstract  

The interaction among moisture content, solvent loss and glass transition temperature is relevant for processing of spray-dried pharmaceuticals, since the glass transition temperature determines the application range of a compound. Conventional Differential Scanning Calorimetry (DSC) does usually not allow to separate glass transitions from common kinetic effects like evaporation or crystallization. Based on classical DSC methods, the IsoStepTM method allows the independent determination of heat capacities and kinetic effects, and thus, the separation of kinetic effects from effects arising from heat capacity changes. This technique is used to separate glass transition and evaporation processes, and to find the relation between moisture content and glass transition temperature for a pharmaceutical sample based on a modified Gordon–Taylor equation.

Restricted access

. Jantzen , M. ; Göpel , A. ; Beermann , C. ( 2013 ) “ Direct Spray Drying and Microencapsulation of Probiotic Lactobacillus Reuteri from Slurry Fermentation with Whey ”, in Journal of Applied Microbiology 115 ( 2013 ), pp. 1029 – 1036

Restricted access

Preparation of microspherical granules from aerosilogels

The way of spray drying in overheated water steam

Journal of Thermal Analysis and Calorimetry
Authors: Jadwiga Skubiszewska-Zięba and V. Sydorchuk

Abstract  

The influence of the conditions of aerosil dispersion spray drying process in the medium of overheated water steam on the formation of microspheric granules and their porous structure was studied. Water and ammonium solutions as aerosil particles dispersing agents and water steam and air as heat carriers were used. It was stated that the effects of spray drying depend on the kind of dispersing medium and on the conditions of atmosphere and temperature at which drying and forming of aerosilogel granules takes place.

Restricted access
Restricted access