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The aim of this study was to characterize a 1:1 molar ratio of a pharmacologically relevant co-amorphous atorvastatin-irbesartan (ATR-IRB) system obtained by quench cooling of the crystalline ATR/IRB physical mixture for potential use in the fixed-dose combination therapy. The system was characterized by employing standard differential scanning calorimetry (DSC), Fourier transform-infrared spectroscopy (FT-IR), and intrinsic dissolution rate studies. Quantum mechanical calculations were performed to obtain information regarding intermolecular interactions in the studied co-amorphous ATR-IRB system. The co-amorphous formulation showed a significant improvement in the intrinsic dissolution rate (IDR) of IRB over pure crystalline as well as its amorphous counterpart. An unusual behavior was observed for ATR, as the IDR of ATR in the co-amorphous formulation was slightly lower than that of amorphous ATR alone. Short-term physical aging studies of up to 8 h proved that the ATR-IRB co-amorphous system remained in the amorphous form. Furthermore, no physical aging occurred in the co-amorphous system. FT-IR, density functional theory calculations, and analysis of Tg value of co-amorphous system using the Couchman–Karasz equation revealed the presence of molecular interactions between APIs, which may contribute to the increased physical stability.
Marcin Skotnicki; Barbara Jadach; Agnieszka Skotnicka; Bartłomiej Milanowski; Lidia Tajber; Marek Pyda; Jacek Kujawski. Physicochemical Characterization of a Co-Amorphous Atorvastatin-Irbesartan System with a Potential Application in Fixed-Dose Combination Therapy. Pharmaceutics 2021, 13, 118 .
AMA StyleMarcin Skotnicki, Barbara Jadach, Agnieszka Skotnicka, Bartłomiej Milanowski, Lidia Tajber, Marek Pyda, Jacek Kujawski. Physicochemical Characterization of a Co-Amorphous Atorvastatin-Irbesartan System with a Potential Application in Fixed-Dose Combination Therapy. Pharmaceutics. 2021; 13 (1):118.
Chicago/Turabian StyleMarcin Skotnicki; Barbara Jadach; Agnieszka Skotnicka; Bartłomiej Milanowski; Lidia Tajber; Marek Pyda; Jacek Kujawski. 2021. "Physicochemical Characterization of a Co-Amorphous Atorvastatin-Irbesartan System with a Potential Application in Fixed-Dose Combination Therapy." Pharmaceutics 13, no. 1: 118.
The objective of this study was to characterise amorphous indapamide (IND) subjected to the physical ageing process by differential scanning calorimetry (DSC). The amorphous indapamide was annealed at different temperatures below the glass transition, i.e., 35, 40, 45, 65, 75 and 85 °C for different lengths of time, from 30 min up to a maximum of 32 h. DSC was used to characterise both the crystalline and the freshly prepared glass and to monitor the extent of relaxation at temperatures below the glass transition (Tg). No ageing occurred at 35, 40 and 45 °C at the measured lengths of times. Molecular relaxation time constants (τKWW) for samples aged at 65, 75 and 85 °C were determined by the Kohlrausch-Williams-Watts (KWW) equation. The fragility parameter m (a measure of the stability below the glass transition) was determined from the Tg dependence from the cooling and heating rates, and IND was found to be relatively stable (“moderately fragile”) in the amorphous state. Temperature-modulated DSC was used to separate reversing and nonreversing processes for unaged amorphous IND. The enthalpy relaxation peak was clearly observed as a part of the nonreversing signal. Heat capacities data for unaged and physically aged IND were fitted to Cp baselines of solid and liquid states of IND, were integrated and enthalpy was presented as a function of temperature.
Agata Drogoń; Marcin Skotnicki; Agnieszka Skotnicka; Marek Pyda. Physical Ageing of Amorphous Indapamide Characterised by Differential Scanning Calorimetry. Pharmaceutics 2020, 12, 800 .
AMA StyleAgata Drogoń, Marcin Skotnicki, Agnieszka Skotnicka, Marek Pyda. Physical Ageing of Amorphous Indapamide Characterised by Differential Scanning Calorimetry. Pharmaceutics. 2020; 12 (9):800.
Chicago/Turabian StyleAgata Drogoń; Marcin Skotnicki; Agnieszka Skotnicka; Marek Pyda. 2020. "Physical Ageing of Amorphous Indapamide Characterised by Differential Scanning Calorimetry." Pharmaceutics 12, no. 9: 800.
The study of the experimental and calculated heat capacity, Cp of fish collagen (silver carp) with contents of several additive components was presented. The experimental low-temperature heat capacity was measured in the temperature range of 1.85 to 302.8 K using a Quantum Design Physical Property Measurement System (PPMS) and the higher temperature Cp from 223.15 K to 382.15 K by Differential Scanning Calorimetry (DSC) method. For an interpretation of the experimental, low-temperature data, the vibrational heat capacity of the pure silver carp collagen was calculated based on the contribution of a sum of the vibrational heat capacity of 4248 amino acids. The vibrational heat capacity for each amino acids was taken from Advanced Thermal Analysis System (ATHAS) Data Bank for individual poly (amino acid) residues based on their group and skeletal vibrational spectra. Comparing of the experimental heat capacity of the collagen with additive components and the calculated vibrational heat capacity of the pure silver carp collagen shows that the differences range from around 10% at 100 K to 14% at 300 K temperature. Such thermal analysis can provide information about the contribution to Cp of unknown components or impurities in the investigated system.
A. Czerniecka-Kubicka; G. Neilsen; M.S. Dickson; B.F. Woodfield; M. Janus-Kubiak; L. Kubisz; I. Zarzyka; W. Zielecki; Marcin Skotnicki; D. Hojan-Jezierska; M. Pyda. Vibrational heat capacity of silver carp collagen. International Journal of Biological Macromolecules 2020, 163, 833 -841.
AMA StyleA. Czerniecka-Kubicka, G. Neilsen, M.S. Dickson, B.F. Woodfield, M. Janus-Kubiak, L. Kubisz, I. Zarzyka, W. Zielecki, Marcin Skotnicki, D. Hojan-Jezierska, M. Pyda. Vibrational heat capacity of silver carp collagen. International Journal of Biological Macromolecules. 2020; 163 ():833-841.
Chicago/Turabian StyleA. Czerniecka-Kubicka; G. Neilsen; M.S. Dickson; B.F. Woodfield; M. Janus-Kubiak; L. Kubisz; I. Zarzyka; W. Zielecki; Marcin Skotnicki; D. Hojan-Jezierska; M. Pyda. 2020. "Vibrational heat capacity of silver carp collagen." International Journal of Biological Macromolecules 163, no. : 833-841.
The journal "Polimery", of international circulation, is publishing peerreviewed scientific and technical research papers covering polymer science and technology in the field of plastics, rubbers, chemical fibres and paints.
Agata Drogon; Marcin Skotnicki; Marek Pyda. Physical aging of polylactide-valsartan system investigated by differential scanning calorimetry. Polimery 2020, 65, 533 -541.
AMA StyleAgata Drogon, Marcin Skotnicki, Marek Pyda. Physical aging of polylactide-valsartan system investigated by differential scanning calorimetry. Polimery. 2020; 65 (07/08):533-541.
Chicago/Turabian StyleAgata Drogon; Marcin Skotnicki; Marek Pyda. 2020. "Physical aging of polylactide-valsartan system investigated by differential scanning calorimetry." Polimery 65, no. 07/08: 533-541.
Ionic liquids (ILs) and deep eutectic mixtures (DEMs) are potential solutions to the problems of low solubility, polymorphism, and low bioavailability of drugs. The aim of this work was to develop and investigate ketoprofen (KET)-based ILs/DEMs containing an ester local anesthetic (LA): benzocaine (BEN), procaine (PRO) and tetracaine (TET) as the second component. ILs/DEMs were prepared via a mechanosynthetic process that involved the mixing of KET with an LA in a range of molar ratios and applying a thermal treatment. After heating above the melting point and quench cooling, the formation of supercooled liquids with Tgs that were dependent on the composition was observed for all KET-LA mixtures with exception of that containing 95 mol% of BEN. The KET-LA mixtures containing either ≥ 60 mol% BEN or 95 mol% of TET showed crystallization to BEN and TET, respectively, during either cooling or second heating. KET decreased the crystallization tendency of BEN and TET and increased their glass-forming ability. The KET-PRO systems showed good glass-forming ability and did not crystallize either during the cooling or during the second heating cycle irrespective of the composition. Infrared spectroscopy and molecular modeling indicated that KET and LAs formed DEMs, but in the KET-PRO systems small quantities of carboxylate anions were present.
Anita Umerska; Klaudia Bialek; Julija Zotova; Marcin Skotnicki; Lidia Tajber. Anticrystal Engineering of Ketoprofen and Ester Local Anesthetics: Ionic Liquids or Deep Eutectic Mixtures? Pharmaceutics 2020, 12, 368 .
AMA StyleAnita Umerska, Klaudia Bialek, Julija Zotova, Marcin Skotnicki, Lidia Tajber. Anticrystal Engineering of Ketoprofen and Ester Local Anesthetics: Ionic Liquids or Deep Eutectic Mixtures? Pharmaceutics. 2020; 12 (4):368.
Chicago/Turabian StyleAnita Umerska; Klaudia Bialek; Julija Zotova; Marcin Skotnicki; Lidia Tajber. 2020. "Anticrystal Engineering of Ketoprofen and Ester Local Anesthetics: Ionic Liquids or Deep Eutectic Mixtures?" Pharmaceutics 12, no. 4: 368.
The vibrational heat capacities of bovine collagen in the solid state, below any phase transitions (helix-coil, melting, glass transition, denaturation) in the presence and absence of water, are calculated and compared with experimental data, collected from the literature. The vibrational heat capacities of dry collagen are estimated as a sum of products of the vibrational heat capacity of the individual poly(amino acid) residues and the total number of each kind of sequence of amino acids in the macromolecule of collagen. For the individual poly(amino acid), the vibrational heat capacity is taken from Advanced Thermal Analysis System Data Bank, which was a preliminary estimation using the experimental low-temperature heat capacities data, linked to their vibrational spectra based on the group and skeletal vibration contributions of the poly(amino acid). The difference between the experimental and calculated Cp of the dry collagen is smaller than ± 3%. The vibrational heat capacity of the solid collagen–water system, below any phase transitions, is estimated from a sum of linear combinations of the mass fractions of the vibrational heat capacities of dry collagen and water. The vibrational calculated Cp can be used as a reference baseline for quantitative thermal analysis of experimental Cp in any phase transition obtained by scanning calorimetry for the collagen and collagen–water systems.
Marek Pyda; Patrycja Zawada; Agata Drogon; Marcin Skotnicki; Peggy Cebe. Vibrational heat capacity of collagen and collagen–water. Journal of Thermal Analysis and Calorimetry 2019, 138, 3389 -3401.
AMA StyleMarek Pyda, Patrycja Zawada, Agata Drogon, Marcin Skotnicki, Peggy Cebe. Vibrational heat capacity of collagen and collagen–water. Journal of Thermal Analysis and Calorimetry. 2019; 138 (5):3389-3401.
Chicago/Turabian StyleMarek Pyda; Patrycja Zawada; Agata Drogon; Marcin Skotnicki; Peggy Cebe. 2019. "Vibrational heat capacity of collagen and collagen–water." Journal of Thermal Analysis and Calorimetry 138, no. 5: 3389-3401.
Two novel self-emulsifying drug delivery systems (SEDDS) with atorvastatin calcium, an anti-hyperlipidemic drug, were obtained and adsorbed on different solid inorganic carriers. In order to determine the parameters affecting the drug release process, different physicochemical analyses were performed. Liquid SEDDS were investigated for the water solubilization capacity, viscosity and surface tension. In the case of solid materials differential scanning calorimetry and scanning electron microscopy were conducted in order to check the samples for the presence of drug crystals. The interactions between the components of the materials were analyzed with inverse gas chromatography and Flory-Huggins parameters were calculated. The drug release experiments performed for all investigated formulations revealed that after the initial quick release the drug concentration in the dissolution medium decreased slightly which might be related to the crystallization process. However, the level of the released active ingredient was maintained at 80% for most formulations. It was also shown that the results of drug dissolution studies were independent of the measured physicochemical parameters, even though some clear differences have been observed between the analyzed materials.
Agnieszka Snela; Barbara Jadach; Anna Froelich; Marcin Skotnicki; Kasylda Milczewska; Monika Rojewska; Adam Voelkel; Krystyna Prochaska; Janina Lulek. Self-emulsifying drug delivery systems with atorvastatin adsorbed on solid carriers: formulation and in vitro drug release studies. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2019, 577, 281 -290.
AMA StyleAgnieszka Snela, Barbara Jadach, Anna Froelich, Marcin Skotnicki, Kasylda Milczewska, Monika Rojewska, Adam Voelkel, Krystyna Prochaska, Janina Lulek. Self-emulsifying drug delivery systems with atorvastatin adsorbed on solid carriers: formulation and in vitro drug release studies. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2019; 577 ():281-290.
Chicago/Turabian StyleAgnieszka Snela; Barbara Jadach; Anna Froelich; Marcin Skotnicki; Kasylda Milczewska; Monika Rojewska; Adam Voelkel; Krystyna Prochaska; Janina Lulek. 2019. "Self-emulsifying drug delivery systems with atorvastatin adsorbed on solid carriers: formulation and in vitro drug release studies." Colloids and Surfaces A: Physicochemical and Engineering Aspects 577, no. : 281-290.
The heat capacities and total enthalpy of anhydrous indapamide (IND, CAS no.: 26807-65-8) are reported from temperature 1.84 to 523.15 K measured by a Quantum Design Physical Property Measurement System® (PPMS) and differential scanning calorimetry (DSC). The low-temperature experimental heat capacities of crystalline IND from 1.84 to 302.65 K were measured by PPMS and fit to a theoretical model in the low temperature range (T < 7.68 K), orthogonal polynomials in the middle temperature range (7.68 < T < 54.15 K), and a combination of Debye and Einstein functions in the high temperature range (T > 54.15 K). The calculated heat capacities were extended to a higher temperature to be used as a reference line of solid heat capacity, cp(solid). The experimental heat capacity of liquid, cp(liquid) for amorphous indapamide above the glass transition (Tg(midpoint on cooling) = 369.7 ± 0.6 K) was approximated by linear regression and was expressed as cp(liquid) = (0.954 + 0.0023T) J·K–1 g–1. The solid and liquid heat capacities of IND were applied as reference lines for advanced thermal analysis of the experimental, apparent heat capacity data measured by DSC. The change in heat capacity (Δcp) of 0.46 J·K–1 g–1 at Tg for fully amorphous IND and heat of fusion Δfush = 77.5 ± 0.7 J·g–1 at melting temperature (Tm = 439.7 ± 0.4 K) of 100% crystalline anhydrous IND were determined. Knowing equilibrium parameters of phase transitions of amorphous and crystalline forms of IND and heat capacities of solid and liquid IND, total enthalpies for both phases were calculated. Data for unaged and physically aged at 358.15 K for 32 h amorphous IND were presented in the context of absolute heat capacity and integral equilibrium enthalpy of solid and liquid IND phases.
M. Skotnicki; A. Drogoń; J.J. Calvin; Peter Rosen; B.F. Woodfield; M. Pyda. Heat capacity and enthalpy of indapamide. Thermochimica Acta 2019, 674, 36 -43.
AMA StyleM. Skotnicki, A. Drogoń, J.J. Calvin, Peter Rosen, B.F. Woodfield, M. Pyda. Heat capacity and enthalpy of indapamide. Thermochimica Acta. 2019; 674 ():36-43.
Chicago/Turabian StyleM. Skotnicki; A. Drogoń; J.J. Calvin; Peter Rosen; B.F. Woodfield; M. Pyda. 2019. "Heat capacity and enthalpy of indapamide." Thermochimica Acta 674, no. : 36-43.
After oral administration, naproxen generates several side-effects related to stomach malfunction. Undoubtedly, the enteric dosage forms with naproxen can be considered as safer. Moreover, since it has been evidenced that development and growth of colorectal cancer is related to the presence of cyclooxygenase, naproxen is investigated in terms of the tumor prevention. The aim of the present work was to formulate and evaluate the properties of novel naproxen-loaded macrobeads, made on the basis of low-acyl gellan gum and its blends with carrageenans, guar gum, cellulose sulfate, and dextran sulfates. Seven formulations were prepared by ionotropic gelation. The morphology of the dried beads was evaluated by scanning electron microscopy. The next step focused on Raman spectroscopy and thermal analysis of naproxen, polymers, and the beads. Next, the swelling behavior was examined in three acceptor fluids at pH = 1.2; 4.5, and 7.4. The beads were evaluated regarding naproxen content and encapsulation efficiency. The last stage of the work concerned the drug release studies. Addition of any other polysaccharide than gellan resulted in flattening of the beads upon drying. Differential scanning calorimetry confirmed the crystalline form of naproxen. Raman spectra showed that no apparent interactions occurred. In the acidic environment, all the beads revealed the tendency to absorb water. The beads swelled to the greatest extent at pH = 4.5. Naproxen was released from the beads at a varied rate. At pH = 7.4, the most prolonged release was observed for the beads containing carrageenans. We have proved that blending of gellan with various polysaccharides can change the pH-dependent properties of the beads loaded with naproxen. We believe that the information enclosed in the paper will be of particular importance regarding the development and characteristics of novel oral dosage forms based on natural polymers.
Tomasz Z Osmałek; Anna Froelich; Marcin Soból; Bartłomiej Milanowski; Marcin Skotnicki; Paweł Kunstman; Mirosław Szybowicz. Gellan gum macrobeads loaded with naproxen: The impact of various naturally derived polymers on pH-dependent behavior. Journal of Biomaterials Applications 2018, 33, 140 -155.
AMA StyleTomasz Z Osmałek, Anna Froelich, Marcin Soból, Bartłomiej Milanowski, Marcin Skotnicki, Paweł Kunstman, Mirosław Szybowicz. Gellan gum macrobeads loaded with naproxen: The impact of various naturally derived polymers on pH-dependent behavior. Journal of Biomaterials Applications. 2018; 33 (1):140-155.
Chicago/Turabian StyleTomasz Z Osmałek; Anna Froelich; Marcin Soból; Bartłomiej Milanowski; Marcin Skotnicki; Paweł Kunstman; Mirosław Szybowicz. 2018. "Gellan gum macrobeads loaded with naproxen: The impact of various naturally derived polymers on pH-dependent behavior." Journal of Biomaterials Applications 33, no. 1: 140-155.
Valsartan (VAL) is an antihypertensive drug marketed in an amorphous form. Amorphous materials can have different physicochemical properties depending on preparation method, thermal history, etc., but the nature of such materials is difficult to study by diffraction techniques. This study characterizes two different amorphous forms of valsartan (AR and AM) using solid-state NMR (SSNMR) as a primary investigation tool, supported by solution-state NMR, FT-IR, TMDSC, and dissolution tests. The two forms are found to be clearly distinct, with a significantly higher level of structural arrangement in the AR form, as observed in 13C, 15N, and 1H SSNMR. 13C and 15N NMR indicates that the fully amorphous material (AM) contains an approximately equal ratio of cis–trans conformers about the amide bond, whereas the AR form exists mainly as one conformer, with minor conformational “defects”. 1H ultrafast MAS NMR shows significant differences in the hydrogen bonding involving the tetrazole and acid hydrogens between the two materials, while 15N NMR shows that both forms exist as a 1,2,3,4-tetrazole tautomer. NMR relaxation times show subtle differences in local and bulk molecular mobility, which can be connected with the glass transition, the stability of the glassy material, and its response to aging. Counterintuitively the fully amorphous material is found to have a significantly lower dissolution rate than the apparently more ordered AR material.
Marcin Skotnicki; David C. Apperley; Juan A. Aguilar; Bartłomiej Milanowski; Marek Pyda; Paul Hodgkinson. Characterization of Two Distinct Amorphous Forms of Valsartan by Solid-State NMR. Molecular Pharmaceutics 2015, 13, 211 -222.
AMA StyleMarcin Skotnicki, David C. Apperley, Juan A. Aguilar, Bartłomiej Milanowski, Marek Pyda, Paul Hodgkinson. Characterization of Two Distinct Amorphous Forms of Valsartan by Solid-State NMR. Molecular Pharmaceutics. 2015; 13 (1):211-222.
Chicago/Turabian StyleMarcin Skotnicki; David C. Apperley; Juan A. Aguilar; Bartłomiej Milanowski; Marek Pyda; Paul Hodgkinson. 2015. "Characterization of Two Distinct Amorphous Forms of Valsartan by Solid-State NMR." Molecular Pharmaceutics 13, no. 1: 211-222.
The heat capacity (Cp) of crystalline and amorphous sucrose was determined using standard and quasi-isothermal temperature modulated differential scanning calorimetry. The results were combined with the published data determined by adiabatic calorimetry, and the Cp values are now reported for the wide 5–600 K range. The experimental Cp of solid sucrose at 5–300 K was used to calculate the vibrational, solid Cp based on the vibrational molecular motions. The calculated solid and liquid Cp together with the transition parameters for equilibrium conditions were used as references for detailed quantitative thermal analysis of crystalline and amorphous sucrose. Melting temperature (Tm) of the crystalline sucrose was identified in a broad 442–465 K range with a heat of fusion of 40–46 J/mol determined at heating rates 0.5–20 K/min, respectively. The equilibrium Tm and heat of fusion of crystalline sucrose were estimated at zero heating rate as Tom = 424.4 K and ΔHof = 32 kJ/mol, respectively. The glass transition temperature (Tg) of amorphous sucrose was at 331 K with a change in Cp of 267 J/(mol K) as it was estimated from reversing heat capacity by quasi-isothermal TMDSC on cooling. At heating rates less than 30 K/min, thermal decomposition occurred during melting, while at extreme rate of 1000 K/s, degradation was not observed. Data obtained by fast scanning calorimetry (FSC) at 1000 K/s, showed that Tm was 483 K and Tg was 364 K. Superheating effects were observed during the melting with the maximum value around 46 K at 1000 K/s.
A. Magoń; A. Wurm; C. Schick; Ph. Pangloli; S. Zivanovic; M. Skotnicki; M. Pyda. Reprint of “Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry”. Thermochimica Acta 2014, 603, 149 -161.
AMA StyleA. Magoń, A. Wurm, C. Schick, Ph. Pangloli, S. Zivanovic, M. Skotnicki, M. Pyda. Reprint of “Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry”. Thermochimica Acta. 2014; 603 ():149-161.
Chicago/Turabian StyleA. Magoń; A. Wurm; C. Schick; Ph. Pangloli; S. Zivanovic; M. Skotnicki; M. Pyda. 2014. "Reprint of “Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry”." Thermochimica Acta 603, no. : 149-161.
The objective of this study was to evaluate the thermal behavior of crystalline and amorphous bisoprolol fumarate and its compatibility with amorphous valsartan. This pharmacologically relevant drug combination is a potential candidate for fixed-dose combination formulation. DSC and TMDSC were used to examine thermal behavior of bisoprolol fumarate. SSNMR and XRPD were applied to probe the solid state forms. The thermal behavior of physical mixtures with different concentrations of bisoprolol and valsartan were examined by DSC and TMDSC, and the observed interactions were investigated by XRPD, solution- and solid-state NMR. The phase transitions from thermal methods and solid-state NMR spectra of crystalline and amorphous bisoprolol fumarate are reported. Strong interactions between bisoprolol fumarate and valsartan were observed above 60 C, resulting in the formation of a new amorphous material. Solution- and solid-state NMR provided insight into the molecular nature of the incompatibility. A combined analysis of thermal methods, solution- and solid-state NMR and XRPD experiments allowed the investigation of the conformational and dynamic properties of bisoprolol fumarate. Since bisoprolol fumarate and valsartan react to form a new amorphous product, formulation of a fixed-dose combination would require separate reservoirs for bisoprolol and valsartan to prevent interactions. Similar problems might be expected with other excipients or APIs containing carboxylic groups.
Marcin Skotnicki; Juan A. Aguilar; Marek Pyda; Paul Hodgkinson. Bisoprolol and Bisoprolol-Valsartan Compatibility Studied by Differential Scanning Calorimetry, Nuclear Magnetic Resonance and X-Ray Powder Diffractometry. Pharmaceutical Research 2014, 32, 414 -429.
AMA StyleMarcin Skotnicki, Juan A. Aguilar, Marek Pyda, Paul Hodgkinson. Bisoprolol and Bisoprolol-Valsartan Compatibility Studied by Differential Scanning Calorimetry, Nuclear Magnetic Resonance and X-Ray Powder Diffractometry. Pharmaceutical Research. 2014; 32 (2):414-429.
Chicago/Turabian StyleMarcin Skotnicki; Juan A. Aguilar; Marek Pyda; Paul Hodgkinson. 2014. "Bisoprolol and Bisoprolol-Valsartan Compatibility Studied by Differential Scanning Calorimetry, Nuclear Magnetic Resonance and X-Ray Powder Diffractometry." Pharmaceutical Research 32, no. 2: 414-429.
The heat capacity (Cp) of crystalline and amorphous sucrose was determined using standard and quasi-isothermal temperature modulated differential scanning calorimetry. The results were combined with the published data determined by adiabatic calorimetry, and the Cp values are now reported for the wide 5–600 K range. The experimental Cp of solid sucrose at 5–300 K was used to calculate the vibrational, solid Cp based on the vibrational molecular motions. The calculated solid and liquid Cp together with the transition parameters for equilibrium conditions were used as references for detailed quantitative thermal analysis of crystalline and amorphous sucrose. Melting temperature (Tm) of the crystalline sucrose was identified in a broad 442–465 K range with a heat of fusion of 40–46 J/mol determined at heating rates 0.5–20 K/min, respectively. The equilibrium Tm and heat of fusion of crystalline sucrose were estimated at zero heating rate as Tom = 424.4 K and ΔHof = 32 kJ/mol, respectively. The glass transition temperature (Tg) of amorphous sucrose was at 331 K with a change in Cp of 267 J/(mol K) as it was estimated from reversing heat capacity by quasi-isothermal TMDSC on cooling. At heating rates less than 30 K/min, thermal decomposition occurred during melting, while at extreme rate of 1000 K/s, degradation was not observed. Data obtained by fast scanning calorimetry (FSC) at 1000 K/s, showed that Tm was 483 K and Tg was 364 K. Superheating effects were observed during the melting with the maximum value around 46 K at 1000 K/s.
A. Magoń; A. Wurm; Christoph Schick; Ph. Pangloli; S. Zivanovic; M. Skotnicki; M. Pyda. Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry. Thermochimica Acta 2014, 589, 183 -196.
AMA StyleA. Magoń, A. Wurm, Christoph Schick, Ph. Pangloli, S. Zivanovic, M. Skotnicki, M. Pyda. Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry. Thermochimica Acta. 2014; 589 ():183-196.
Chicago/Turabian StyleA. Magoń; A. Wurm; Christoph Schick; Ph. Pangloli; S. Zivanovic; M. Skotnicki; M. Pyda. 2014. "Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry." Thermochimica Acta 589, no. : 183-196.
Thermal behavior of angiotensin II type 1 (AT1) receptor antagonist, Valsartan (VAL), was examined employing thermogravimetric analysis (TGA), standard differential scanning calorimetry (DSC) and temperature-modulated differential scanning calorimetry (TMDSC). The stability of VAL was measured by TGA from 25 to 600°C. Decomposition of Valsartan starts around 160°C. The DSC curve shows two endotherms, occurring around 80°C and 100°C, related to evaporation of water and enthalpy relaxation, respectively. Valsartan was identified by DSC as an amorphous material and it was confirmed by X-ray powder diffraction. The glass transition of fresh Valsartan appears around 76°C (fictive temperature). TMDSC allows separation of the total heat flow rate into reversing and nonreversing parts. The nonreversing curve corresponds to the enthalpy relaxation and the reversing curve shows changes of heat capacity around 94°C. In the second run, TMDSC curve shows the glass transition process occurring at around 74°C. Results from standard DSC and TMDSC of Valsartan were compared over the whole range of temperature.
Marcin Skotnicki; Agnieszka Gaweł; Peggy Cebe; Marek Pyda. Thermal behavior and phase identification of Valsartan by standard and temperature-modulated differential scanning calorimetry. Drug Development and Industrial Pharmacy 2012, 39, 1508 -1514.
AMA StyleMarcin Skotnicki, Agnieszka Gaweł, Peggy Cebe, Marek Pyda. Thermal behavior and phase identification of Valsartan by standard and temperature-modulated differential scanning calorimetry. Drug Development and Industrial Pharmacy. 2012; 39 (10):1508-1514.
Chicago/Turabian StyleMarcin Skotnicki; Agnieszka Gaweł; Peggy Cebe; Marek Pyda. 2012. "Thermal behavior and phase identification of Valsartan by standard and temperature-modulated differential scanning calorimetry." Drug Development and Industrial Pharmacy 39, no. 10: 1508-1514.