The research programme studied the cure reaction of a phenolic novolak resin and the effects of various additives and fillers on the reaction. The programme utilised the recently developed thermal analysis technique of temperature-modulated differential scanning calorimetry (TMDSC) performed in conjunction with other available thermal analysis techniques. TMDSC enables the signal for the heat of reaction to be separated from the underlying specific heat change in the resin. This meant that the reaction could be studied without interference from any physical changes in the resin. The manufacture of composite brake materials required the use of numerous additives and fillers to produce the desired properties. The influence of such additives on the cure rate and final properties of the resin was known to occur but had not previously been measured due to the difficulties presented by the presence of opaque additives. Some additives also underwent thermally induced physical changes in the temperature range of the cure. The final properties and the processing of new brake materials undergoing development often required trial and error adjustments to compensate for changes in cure rate. An understanding of the influence of additives would enable more rapid commercial development of brake materials through an improvement in the ability to predict both the properties of the product and the optimal processing parameters. Processing efficiency could also be improved through detailed knowledge of the kinetics. Moulding cycle times and post-baking times and temperatures were longer than necessary in order to ensure adequate cure at the end of each stage because of the lack of kinetic data. The cure of phenolic resin has been shown to be highly complicated with numerous alternate and competing reactions. For the manufacture of composite materials, knowledge of the kinetic parameters of individual reactions is not considered to be important; rather the overall kinetic parameters are required for prediction. Therefore the kinetic model parameters that best described the observed behaviour were chosen even though the model had no basis in the molecular interaction theory of reaction. Rather it served as a convenient tool for predictions. Characterisation of the resin proved to be difficult due to the presence of overlapping peaks, and volatile reaction products. TMDSC was successfully used to determine the reaction kinetics of the pure resin and the influence of certain additives on the reaction kinetics. The determination of the kinetic parameters using TMDSC agreed well with the traditional Differential Scanning Calorimetry isothermal and non-isothermal techniques. Both the Perkin-Elmer and TA Instruments were utilised for the research and were found to provide reasonably good agreement with each other. The capabilities and limitations of the individual instruments were critically examined, frequently beyond the manufacturers' specifications. TMDSC suffers from a limitation in the heating rate of the sample compared to DSC. However, it was observed that valuable information could still be obtained from TMDSC despite using heating rates that were higher than specified by manufacturers. Hot Stage Microscopy and thermogravimetry were additional experimental techniques used to aid in the characterisation of the resin. Some inhomogeneity of the resin was identified as well as differences in the behaviour of the cure between open (constant pressure) and closed (constant volume) environments were observed. A novel method of determining the orders of the cure reactions and their kinetic parameters was utilised. Reaction models for the overall cure reactions were postulated and tested by fitment to sections of experimental data in temperature regions which appeared to be free of interference from overlapping peaks. Once an individual peak was reasonably well modelled, adjacent overlapping peaks were able to be modelled both individually and in combinations by fitment to experimental data. The Solver function in Microsoft Excel was utilised to find the best fitting model parameters for the experimental data. The model parameters were able to be refined as overlapping peaks were progressively incorporated into the calculations. This method produced results that agreed well with the traditional method of analysing reaction peak temperatures at multiple scanning rates. Model fitment was shown to be of benefit where overlapping reactions occur. Various model scenarios could be tested and optimised to particular sections of experimental data. This enabled the researcher to easily identify areas of possible anomalies and postulate alternative scenarios. The accuracy of the postulated model was able to be determined by its successful fitment to experimental data from experiments run under different conditions.

<p>In this thesis, the structure and stability of globular proteins adsorbed onto nanometer-sized hydrophilic silica particles were investigated using differential scanning calorimetry (DSC), hydrogen/deuterium exchange (HDX), and mass spectrometry (MS). The adsorption process itself was characterized with fluorescence and absorption spectroscopy and surface plasmon resonance (SPR). The combination of these methods offered a unique insight into adsorption-induced changes within proteins related to their adsorption characteristics. DSC contributed with thermodynamic information on the overall structural stability within the protein population. HDX in combination with MS contributed information on the structure and stability of adsorbed proteins with focus on changes within the secondary structure elements. In order to increase the structural resolution in this part of the investigation, proteolysis was performed prior to the MS analyzing step. Knowledge on the protein adsorption process was utilized in a practical approach called ligand fishing. In this approach, SPR was used to monitor the chip-based affinity purification of a protein with MS used for protein identification.</p><p>Adsorption isotherms revealed that electrostatic interactions play an important role in the adsorption of proteins to hydrophilic surfaces. DSC investigation revealed that the thermal stability of proteins reduces with increasing electrostatic attraction between the protein and the surface and that this effect diminishes at higher surface coverage. The mass-increase due to exchange between protein hydrogen atoms and deuterium atoms in solution was investigated as a function of time. This gave insight into adsorption-induced changes in the structural stability of proteins. By combining DSC and HDX-MS, it was possible to differentiate between adsorption-induced changes in the secondary and tertiary structure. Additionally, if limited proteolysis was performed, the investigations gave insight into the orientation and protein segment specific changes in the stability of proteins adsorbed to silica surfaces. The adsorption of proteins to silica particles also provided the basis for a new experimental design that allows handling of minute amounts of proteins in a ligand fishing application, as used in the field of functional proteomics.</p>

In this thesis, the structure and stability of globular proteins adsorbed onto nanometer-sized hydrophilic silica particles were investigated using differential scanning calorimetry (DSC), hydrogen/deuterium exchange (HDX), and mass spectrometry (MS). The adsorption process itself was characterized with fluorescence and absorption spectroscopy and surface plasmon resonance (SPR). The combination of these methods offered a unique insight into adsorption-induced changes within proteins related to their adsorption characteristics. DSC contributed with thermodynamic information on the overall structural stability within the protein population. HDX in combination with MS contributed information on the structure and stability of adsorbed proteins with focus on changes within the secondary structure elements. In order to increase the structural resolution in this part of the investigation, proteolysis was performed prior to the MS analyzing step. Knowledge on the protein adsorption process was utilized in a practical approach called ligand fishing. In this approach, SPR was used to monitor the chip-based affinity purification of a protein with MS used for protein identification. Adsorption isotherms revealed that electrostatic interactions play an important role in the adsorption of proteins to hydrophilic surfaces. DSC investigation revealed that the thermal stability of proteins reduces with increasing electrostatic attraction between the protein and the surface and that this effect diminishes at higher surface coverage. The mass-increase due to exchange between protein hydrogen atoms and deuterium atoms in solution was investigated as a function of time. This gave insight into adsorption-induced changes in the structural stability of proteins. By combining DSC and HDX-MS, it was possible to differentiate between adsorption-induced changes in the secondary and tertiary structure. Additionally, if limited proteolysis was performed, the investigations gave insight into the orientation and protein segment specific changes in the stability of proteins adsorbed to silica surfaces. The adsorption of proteins to silica particles also provided the basis for a new experimental design that allows handling of minute amounts of proteins in a ligand fishing application, as used in the field of functional proteomics.

The problem of inaccurate measurement techniques for quantifying isothermal solidification kinetics during transient liquid phase (TLP) bonding in binary and ternary systems; and resulting uncertainty in the accuracy of analytical and numerical models has been addressed by the development of a new technique using differential scanning calorimetry (DSC). This has enabled characterization of the process kinetics in binary and ternary solid/liquid diffusion couples resulting in advancement of the fundamental theoretical understanding of the mechanics of isothermal solidification. The progress of isothermal solidification was determined by measuring the fraction of liquid remaining after an isothermal hold period of varying length. A 'TLP half sample', or a solid/liquid diffusion couple was setup in the sample crucible of a DSC enabling measurement of the heat flow relative to a reference crucible containing a mass of base metal. A comparison of the endotherm from melting of an interlayer with the exotherm from solidification of the residual liquid gives the fraction of liquid remaining. The Ag-Cu and Ag-Au-Cu systems were employed in this study. Metallurgical techniques were used to compliment the DSC results. The effects of sample geometry on the DSC trace have been characterized. The initial interlayer composition, the heating rate, the reference crucible contents, and the base metal coating must be considered in development of the experimental parameters. Furthermore, the effects of heat conduction into the base metal, baseline shift across the initial melting endotherm, and the exclusion of primary solidification upon cooling combine to systematically reduce the measured fraction of liquid remaining. These effects have been quantified using a modified temperature program, and corrected using a universal factor. A comparison of the experimental results with the predictions of various analytical solutions for isothermal solidification reveals that the moving interface solution can accurately predict the interface kinetics given accurate diffusion data. The DSC method has been used to quantify the process kinetics of isothermal solidification in a ternary alloy system, with results compared to a finite difference model for interface motion. The DSC results show a linear relationship between the interface position and the square root of the isothermal hold time. While the numerical simulations do not agree well with the experimental interface kinetics due to a lack of accurate thermodynamic data, the model does help develop an understanding of the isothermal solidification mechanics. Compositional shift at the solid/liquid interface has been measured experimentally and compared with predictions. The results show that the direction of tie-line shift can be predicted using numerical techniques. Furthermore, tie-line shift has been observed in the DSC results. This study has shown that DSC is an accurate and valuable tool in the development of parameters for processes employing isothermal solidification, such as TLP bonding.

The problem of inaccurate measurement techniques for quantifying isothermal solidification kinetics during transient liquid phase (TLP) bonding in binary and ternary systems; and resulting uncertainty in the accuracy of analytical and numerical models has been addressed by the development of a new technique using differential scanning calorimetry (DSC). This has enabled characterization of the process kinetics in binary and ternary solid/liquid diffusion couples resulting in advancement of the fundamental theoretical understanding of the mechanics of isothermal solidification. The progress of isothermal solidification was determined by measuring the fraction of liquid remaining after an isothermal hold period of varying length. A 'TLP half sample', or a solid/liquid diffusion couple was setup in the sample crucible of a DSC enabling measurement of the heat flow relative to a reference crucible containing a mass of base metal. A comparison of the endotherm from melting of an interlayer with the exotherm from solidification of the residual liquid gives the fraction of liquid remaining. The Ag-Cu and Ag-Au-Cu systems were employed in this study. Metallurgical techniques were used to compliment the DSC results. The effects of sample geometry on the DSC trace have been characterized. The initial interlayer composition, the heating rate, the reference crucible contents, and the base metal coating must be considered in development of the experimental parameters. Furthermore, the effects of heat conduction into the base metal, baseline shift across the initial melting endotherm, and the exclusion of primary solidification upon cooling combine to systematically reduce the measured fraction of liquid remaining. These effects have been quantified using a modified temperature program, and corrected using a universal factor. A comparison of the experimental results with the predictions of various analytical solutions for isothermal solidification reveals that the moving interface solution can accurately predict the interface kinetics given accurate diffusion data. The DSC method has been used to quantify the process kinetics of isothermal solidification in a ternary alloy system, with results compared to a finite difference model for interface motion. The DSC results show a linear relationship between the interface position and the square root of the isothermal hold time. While the numerical simulations do not agree well with the experimental interface kinetics due to a lack of accurate thermodynamic data, the model does help develop an understanding of the isothermal solidification mechanics. Compositional shift at the solid/liquid interface has been measured experimentally and compared with predictions. The results show that the direction of tie-line shift can be predicted using numerical techniques. Furthermore, tie-line shift has been observed in the DSC results. This study has shown that DSC is an accurate and valuable tool in the development of parameters for processes employing isothermal solidification, such as TLP bonding.

Δύο από τα σημαντικότερα δομικά και λειτουργικά βιομόρια του εξωκυττάριου χώρου είναι το κολλαγόνο και οι γλυκοζαμινογλυκάνες (GAGs), ανιοντικοί πολυσακχαρίτες που αποτελούν το βασικό δομικό συστατικό των πρωτεογλυκανών. Οι κύριοι τύποι γλυκοζαμινογλυκανών είναι η θειική χονδροϊτίνη, η θειική δερματάνη, η ηπαρίνη, η θειική ηπαράνη, η θειική κερατάνη και το υαλουρονικό οξύ. Το κολλαγόνο τύπου Ι είναι η πιο άφθονη πρωτεΐνη στους ιστούς των θηλαστικών. Το κολλαγόνο τύπου ΙΙ αποτελεί το κύριο συστατικό του εξωκυττάριου χώρου του αρθρικού χόνδρου και άλλων ιστών. Τα παραπάνω μακρομόρια είναι υπεύθυνα για τη ρύθμιση διαφόρων διεργασιών των κυττάρων τόσο σε φυσιολογικές όσο και σε παθολογικές καταστάσεις, όπως παθήσεις των αρθρώσεων και νεοπλασματικές ασθένειες. Αντικείμενο της παρούσας εργασίας αποτέλεσε η ανάπτυξη μιας μεθοδολογίας για τον προσδιορισμό των αλληλεπιδράσεων μεταξύ γλυκοζαμινογλυκανών και των δύο τύπων κολλαγόνου, η οποία θα συνεισφέρει στη βαθύτερη κατανόηση της βιολογικής τους λειτουργίας. Μερικές από τις τεχνικές που έχουν χρησιμοποιηθεί για το συγκεκριμένο σκοπό είναι η χρωματογραφία συγγένειας, η ηλεκτροφόρηση και η φασματοσκοπία φθορισμού. Η φασματοσκοπία πυρηνικού μαγνητικού συντονισμού (NMR), η περίθλαση ακτίνων-Χ και ο κυκλικός διχρωισμός (Circular Dichroism, CD) προσφέρουν δομικές πληροφορίες για τις αλλαγές στη διαμόρφωση και τα σημεία πρόσδεσης μεταξύ γλυκοζαμινογλυκανών και πρωτεϊνών. Θερμοδυναμικές πληροφορίες για τις αλληλεπιδράσεις πρωτεϊνών-γλυκοζαμινογλυκανών αντλούνται από τη θερμιδομετρία ισόθερμης τιτλοδότησης (Isothermal Titration Calorimetry, ITC), ενώ με την τεχνική της διέγερσης επιφανειακών πλασμονίων (Surface Plasmon Resonance, SPR) μελετώνται η σταθερά σύνδεσης και η σταθερά διάστασης της αλληλεπίδρασης σε πραγματικό χρόνο. Το κυριότερο μειονέκτημα των παραπάνω τεχνικών είναι το ότι δεν προσφέρουν πληροφορίες για χημικούς δεσμούς, ενώ ο χρόνος ανάλυσης είναι μεγάλος και απαιτούνται μεγάλες ποσότητες δειγμάτων. Η τεχνική που χρησιμοποιήθηκε ήταν εκείνη της φασματοσκοπίας micro-Raman, μια μη καταστρεπτική τεχνική, η οποία προσφέρει πληροφορίες για τη χημική δομή του εξεταζόμενου δείγματος, ενώ παράλληλα είναι γρήγορη και ακριβής. Παρασκευάστηκαν δύο είδη μιγμάτων γλυκοζαμινογλυκανών με κολλαγόνο. Στην πρώτη περίπτωση, κολλαγόνο τύπου Ι ή τύπου ΙΙ εμβαπτίστηκε σε διάλυμα θειικής χονδροϊτίνης, ηπαρίνης ή μίγμα τους που παρασκευάστηκε με αναλογία όγκων 1:1. Στη δεύτερη περίπτωση, μίγματα των δύο ουσιών προέκυψαν με ανάμιξη ίσων ποσοτήτων των δύο ουσιών. Τα παραπάνω μίγματα μελετήθηκαν με φασματοσκοπία Raman και με την τεχνική της Διαφορικής Θερμιδομετρίας Σάρωσης (Differential Scanning Calorimetry, DSC) και συγκρίθηκαν με τα φάσματα των προτύπων ουσιών. Κάθε ουσία έχει ένα χαρακτηριστικό φάσμα Raman, η ερμηνεία του οποίου οδήγησε στην ταυτοποίηση χαρακτηριστικών ομάδων των μορίων, όπως οι δεσμοί C-OH, οι θειικές ομάδες (O-SO3-, N-SO3-), η Ν-ακετυλομάδα, οι δεσμοί C=O και οι δεσμοί C-Ν. Οι φασματικές περιοχές που παρουσιάζουν τα πιο έντονα χαρακτηριστικά στα φάσματα Raman των μιγμάτων GAG-κολλαγόνου είναι οι εξής: 800-920 cm-1, 900-1000 cm-1 και 980-1170 cm-1. Όσον αφορά στην τελευταία φασματική περιοχή, παρατηρήθηκε σημαντική μετατόπιση της χαρακτηριστικής κορυφής της δόνησης έκτασης των θειομάδων προς χαμηλότερους κυματάριθμους (από τους 1070 cm-1 περίπου στους 1062-1064 cm-1) και η εμφάνιση μιας κορυφής στους 1072 cm-1, σε σχέση με τα αντίστοιχα φάσματα των προτύπων ουσιών, στα φάσματα όλων των μιγμάτων που μελετήθηκαν. Η μετατόπιση της συγκεκριμένης κορυφής αποτελεί ένδειξη αλληλεπίδρασης μεταξύ των δύο ουσιών και καταδεικνύει το σημαντικό ρόλο των θειομάδων των γλυκοζαμινογλυκανών στις αλληλεπιδράσεις τους με τη συγκεκριμένη πρωτεΐνη. Τα αποτελέσματα της φασματοσκοπίας Raman βρίσκονται σε συμφωνία με εκείνα που προκύπτουν από την τεχνική της Διαφορικής Θερμιδομετρίας Σάρωσης (DSC), καθώς τα θερμογραφήματα DSC των μιγμάτων θειικής χονδροϊτίνης-κολλαγόνου τύπου Ι είναι διαφορετικά από εκείνο του μίγματος που προέκυψε από την ανάμιξη των δύο συστατικών, υποδεικνύοντας την ύπαρξη αλληλεπίδρασης μεταξύ των δύο ουσιών. Με την τεχνική της φασματοσκοπίας Raman διαπιστώθηκε ότι το κολλαγόνο τύπου Ι έδειξε μεγαλύτερη «χημική προτίμηση» προς την ηπαρίνη σε σχέση με τη θειική χονδροϊτίνη, ενώ το κολλαγόνο τύπου ΙΙ προτίμησε να αλληλεπιδράσει με τη θειική χονδροϊτίνη. / Collagen and glycosaminoglycans (GAGs) co-exist as major constituents of the extracellular matrix (ECM) in a variety of tissues. Collagen type I is the most abundant protein in the human body, whereas another important type of collagen is type II, which forms the extracellular matrix of cartilage and other tissues. Glycosaminoglycans are negatively charged polysaccharides that occur as a structural component of proteoglycans and can be divided in four major groups: i) chondroitin sulfate and dermatan sulfate, ii) heparin and heparin sulfate, iii) keratan sulfate, and iv) hyaluronic acid. Both GAGs and collagen not only regulate a variety of cellular functions but they also seem to be involved in many pathological conditions, including cancer and joint diseases. Therefore, a more detailed investigation of the interactions between them will result in a deeper understanding of their biological function. Most common methods for identifying GAG-collagen interactions include affinity chromatography, affinity electrophoresis and fluorescence spectroscopy. Nuclear Magnetic Resonance (NMR), X-ray diffraction and Circular Dichroism (CD) provide structural data characterizing conformational changes and contact points between the interacting species. Using Isothermal Titration Calorimetry (ITC), information on the thermodynamics of glycosaminoglycan-protein interactions can be obtained. Surface Plasmon Resonance (SPR) allows the measurement of association and dissociation constants of glycosaminoglycan-protein interactions in real time. The major disadvantage of the techniques described above is the inability to identify specific chemical bonds. Other disadvantages are the long analysis time and that large amounts of the interacting substances are required. In the present work, Raman spectroscopy, a non-destructive, vibrational technique which yields information on the chemical composition of the specimen, was employed for the exploration of the interactions between collagen type I and type II and two glycosaminoglycans, chondroitin sulfate and heparin. Two sets of mixtures composed of glycosaminoglycans and each type of collagen were prepared: i) collagen type I or type II was immersed in aqueous solutions of chondroitin sulfate, heparin and a 1:1 mixture of both GAGs, and ii) GAG-collagen mixtures were obtained by blending suitable amounts of the two substances. Differential Scanning Calorimetry (DSC) was also applied on the latter mixtures. From the Raman spectra identification of vibrational frequencies of the functional groups of the above molecules, such as C-OH linkages, sulfate groups (O-SO3-, N-SO3-), N-acetyl group, carboxyl group and C-Ν linkages is possible. The prominent features arising from the Raman spectra of GAG-collagen interactions are found in the regions 800-920 cm-1, 900-1000 cm-1 and 980-1170 cm-1. Processing of the spectra of all GAG-collagen mixtures has revealed that a shift of the most characteristic vibration of chondroitin sulfate’s and heparin’s spectrum from 1070 cm-1 to 1062-1064 cm-1, while a vibration at approximately 1072 cm-1 emerges. The sulfate band shift is indicative of an interaction between collagen and glycosaminoglycans and depicts the important role of the sulfate group of glycosaminoglycans in the interactions with the protein. This observation was in accordance with the results from Differential Scanning Calorimetry (DSC), which demonstrated an interaction between collagen and chondroitin sulfate. A stronger preference of collagen type I to interact with heparin rather than chondroitin sulfate and of collagen type II to interact with chondroitin sulfate was also observed.

No description available.

Incorporation of monoacetylferrocene to the sulfonated polystyrene ionomers imparted some changes in the properties of sulfonated polystyrene. Sulfonation was carried out by acetic anhydride and concentrated sulphuric acid. The sulfonation reaction and the degree of sulfonation were determined by analytical titration and adiabatic bomb calorimeter . For this purpose, sulfonated polystyrene (SPS) samples with varying percentages of sulfonation were prepared between 0.85% and 6.51%. Monoacetyl ferrocene was used in equivalent amount of sulfonation through addition procedure. FTIR Spectroscopy was one of the major techniques used to support the successful addition of AcFe to the SPS samples. Altering the sulfonation degree did not change the characteristic peak positions, but increased the peak intensities with increasing the degrees of sulfonation. Mechanical properties of resultant polymers were investigated. As a result, elastic modulus of polymers decreased by the amount of monoacetylferrocene. Thermal characteristic were found by Differential Scanning Calorimeter (DSC). Thermal analysis revealed that sulfonated polystyrene samples after addition of monoacetylferrocene displayed lower values of Tg. Microscopic analysis were made by Scanning Electron Microscopy (SEM) and single phase for each sample was observed. Besides, energy dispersed micro analysis showed an increase in the intensity of the iron (II) peaks that is related to the amount of monoacetylferrocene added to the SPS samples. Flame retardancy for each polymer was also examined and found that addition of monoacetylferrocene to sulfonated polystyrene does not change the Limiting Oxygen Index value (LOI)(17). However, LOI value for polystyrene is 18.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / This paper describes a study of reaction parameters in a ball mill in the synthesis of 1H-pyrazole acid catalyzed. The studied parameters were: amount of reactants, frequency, reaction time, amount of catalyst, number of milling balls, different catalysts, diameter and material of the milling balls. Another study was conducted to study the mechanism of solid-solid reaction involved in the cyclocondensation between enaminones and hydrazine hydrochloride acid catalyzed. These mixtures were studied by thermal analysis (TGA and DSC), where eight enaminones were evaluated and four eutectic mixtures were identified. / Este trabalho descreve o estudo de parâmetros reacionais em moinho de bolas na síntese de 1H-pirazol catalisada por ácido. Os parâmetros estudados foram: quantidade de reagentes, frequência, tempo, quantidade de catalisador, número de esferas, diferentes catalisadores, diâmetro e material das esferas de moagem. Outro trabalho realizado foi o estudo do mecanismo de reação sólido-sólido envolvido na reação de ciclocondensação entre enaminonas e cloridrato de hidrazina catalisada por ácido. Estas misturas foram estudadas através de análises térmicas (TGA e DSC), sendo que de oito enaminonas avaliadas, 4 misturas eutéticas binárias foram identificadas.

Os métodos termo-analíticos são ferramentas úteis na avaliação da compatibilidade entre fármacos e adjuvantes, com destaque à calorimetria exploratória diferencial. Neste trabalho foram avaliados a compatibilidade e o comportamento térmico entre a isoniazida e adjuvantes tecnológicos primários usualmente empregados em formas farmacêuticas sólidas. A compatibilidade foi examinada por meio da preparação de misturas físicas binárias do tipo fármaco/adjuvante. Foi investigada também a influência da granulação por via úmida e do processo de compactação para as misturas de isoniazida e adjuvantes com função de material de enchimento e carga e deslizante. A isoniazida apresentou um comportamento térmico não encontrado na literatura. Os adjuvantes avaliados foram: ácido esteárico, amido, celulose microcristalina, crospovidona, croscarmelose sódica, dióxido de silício coloidal estearato de magnésio, glicolato de amido sódico, hipromelose, lactose, manitol, polidona e talco. Para as misturas físicas, a maioria dos adjuvantes mostrou-se compatível com o fármaco em questão. Foram verificadas interações com o ácido esteárico, o glicolato de amido sódico, a lactose, o manitol e a povidona. A isoniazida mostrou a formação de uma mistura eutética com o manitol e de interação química com a lactose. A agregação por via úmida e o processo de compactação não mostraram influências adicionais na compatibilidade das misturas avaliadas. Os resultados observados foram confirmados por métodos não-térmicos como difratometria de raios X, espectroscopia de infravermelho e ressonância nuclear magnética. / Thermo-analytical methods, and specially Differential Scanning Calorimetry, are useful support for the evaluation of compatibility between drug substances and pharmaceutical excipients. In this work were studied the compatibility and the thermal behavior of isoniazid and pharmaceutical excipients, commonly used for the formulation of solid dosage forms. Colloidal silicon dioxide, corn starch, crospovidone, hypromellose, lactose, magnesium stearate, mannitol, microcrystalline cellulose, povidone, sodium croscarmellose, sodium starch glycolate, stearic acid and talc were the excipients employed in these experiments. The compatibility was analyzed testing binary physical drug/excipient admixtures. The effect of wet granulation and compression was also investigated, in this case especially between isoniazid, fillers and lubricant. For almost all excipients no incompatibilities with isoniazid were observed. Interactions were detected when the drug substance was added to stearic acid, sodium starch glycolate, lactose, mannitol and povidone. Isoniazid formed a euthetic mixture with mannitol, whereas a possible chemical reaction occurred between isoniazid and lactose. Wet granulation and compaction of the tested admixtures did not affect the results observed above. These observations were confirmed by non-thermal techniques, such as X-Ray diffractometry, infrared spectroscopy and nuclear magnetic resonance.