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Fredrik Setterwall - One of the best experts on this subject based on the ideXlab platform.

  • liquid solid Phase Equilibrium study of tetradecane and hexadecane binary mixtures as Phase change materials pcms for comfort cooling storage
    Fluid Phase Equilibria, 2003
    Co-Authors: Viktoria Martin, Fredrik Setterwall
    Abstract:

    Phase diagrams (Equilibrium diagrams) are a convenient way of depicting the concentration-temperature-pressure relationships of a chemical system at Equilibrium. They are invaluable to PCMs thermal storage researches and developers. In the present paper, the Liquid-Solid Phase Equilibrium of binary mixture system of tetradedcane and hexadecane has been studied. For theoretical evaluation of the thermodynamic Equilibrium between the liquid Phase and solid Phase of tetradecane and hexadecane, several methods were compared: the UNIFAC group-contribution method, the model of Won, and Pedersen's model. The temperature-composition Phase diagram of the binary system has been obtained by the calculation. The diagram illustrates a binary, isomorphous system with a temperature minimum. Differential scanning calorimetry (DSC) was used to study the Phase transformation of the binary system. DSC was run at different ramp rates and results indicate that these mixtures melt and freeze over a temperature range and the temperature range depends on the DSC ramp rate, and in a short mixture concentration interval appears low temperature solid-solid peaks. From the DSC results presented, it is concluded that the behaviour of binary mixtures of n-alkanes is far more complicated than considered in earlier studies. The Phase diagram and all information from DSC are very important for designing PCM storage system.

Viktoria Martin - One of the best experts on this subject based on the ideXlab platform.

  • liquid solid Phase Equilibrium study of tetradecane and hexadecane binary mixtures as Phase change materials pcms for comfort cooling storage
    Fluid Phase Equilibria, 2003
    Co-Authors: Viktoria Martin, Fredrik Setterwall
    Abstract:

    Phase diagrams (Equilibrium diagrams) are a convenient way of depicting the concentration-temperature-pressure relationships of a chemical system at Equilibrium. They are invaluable to PCMs thermal storage researches and developers. In the present paper, the Liquid-Solid Phase Equilibrium of binary mixture system of tetradedcane and hexadecane has been studied. For theoretical evaluation of the thermodynamic Equilibrium between the liquid Phase and solid Phase of tetradecane and hexadecane, several methods were compared: the UNIFAC group-contribution method, the model of Won, and Pedersen's model. The temperature-composition Phase diagram of the binary system has been obtained by the calculation. The diagram illustrates a binary, isomorphous system with a temperature minimum. Differential scanning calorimetry (DSC) was used to study the Phase transformation of the binary system. DSC was run at different ramp rates and results indicate that these mixtures melt and freeze over a temperature range and the temperature range depends on the DSC ramp rate, and in a short mixture concentration interval appears low temperature solid-solid peaks. From the DSC results presented, it is concluded that the behaviour of binary mixtures of n-alkanes is far more complicated than considered in earlier studies. The Phase diagram and all information from DSC are very important for designing PCM storage system.

Steven L Krill - One of the best experts on this subject based on the ideXlab platform.

  • drug excipient complexation in lipid based delivery systems an investigation of the tipranavir 1 3 dioctanolyglycerol complex
    Journal of Pharmaceutical Sciences, 2009
    Co-Authors: Shirlynn Chen, Mayur S Dudhedia, Zeren Wang, Richard T Darrington, Toby Tamblyn, John A Smoliga, Pauljames Jones, Steven L Krill
    Abstract:

    Abstract This report describes the solubility properties of a poorly soluble drug–excipient complex in a lipid based formulation. Tipranavir (TPV) was used as the model drug and 1,3-dioctanoylglycerol (DOG) as the excipient. The TPV–DOG complex was prepared by dissolving TPV and DOG in ethanol at 60°C followed by evaporation of ethanol. The formation of the complex with a 4:1 TPV-to-DOG molar ratio was confirmed by XRPD, DSC, and NMR. At 25°C, total solubility of TPV decreased with increasing DOG concentration. The solubility properties of the TPV–DOG complex can be described by two simultaneous equilibria: a liquid–solid Phase Equilibrium of the complex and a species Equilibrium among the various species in the liquid Phase. A model equation was derived accordingly with two parameters, the intrinsic solubility of the complex (So), and the solution complex constant (K41). The model was in good agreement with experimental results. The values of So and K41 are 0.0186 ± 0.0025 (M) and 21.97 ± 7.19 (1/M4), respectively. The equation can successfully predict the concentrations of total and free TPV as a function of DOG in the formulation. The approach developed provides a useful tool for rationale selection of excipients and their levels to avoid drug precipitation in lipid based formulations.

Shirlynn Chen - One of the best experts on this subject based on the ideXlab platform.

  • drug excipient complexation in lipid based delivery systems an investigation of the tipranavir 1 3 dioctanolyglycerol complex
    Journal of Pharmaceutical Sciences, 2009
    Co-Authors: Shirlynn Chen, Mayur S Dudhedia, Zeren Wang, Richard T Darrington, Toby Tamblyn, John A Smoliga, Pauljames Jones, Steven L Krill
    Abstract:

    Abstract This report describes the solubility properties of a poorly soluble drug–excipient complex in a lipid based formulation. Tipranavir (TPV) was used as the model drug and 1,3-dioctanoylglycerol (DOG) as the excipient. The TPV–DOG complex was prepared by dissolving TPV and DOG in ethanol at 60°C followed by evaporation of ethanol. The formation of the complex with a 4:1 TPV-to-DOG molar ratio was confirmed by XRPD, DSC, and NMR. At 25°C, total solubility of TPV decreased with increasing DOG concentration. The solubility properties of the TPV–DOG complex can be described by two simultaneous equilibria: a liquid–solid Phase Equilibrium of the complex and a species Equilibrium among the various species in the liquid Phase. A model equation was derived accordingly with two parameters, the intrinsic solubility of the complex (So), and the solution complex constant (K41). The model was in good agreement with experimental results. The values of So and K41 are 0.0186 ± 0.0025 (M) and 21.97 ± 7.19 (1/M4), respectively. The equation can successfully predict the concentrations of total and free TPV as a function of DOG in the formulation. The approach developed provides a useful tool for rationale selection of excipients and their levels to avoid drug precipitation in lipid based formulations.

Mayur S Dudhedia - One of the best experts on this subject based on the ideXlab platform.

  • drug excipient complexation in lipid based delivery systems an investigation of the tipranavir 1 3 dioctanolyglycerol complex
    Journal of Pharmaceutical Sciences, 2009
    Co-Authors: Shirlynn Chen, Mayur S Dudhedia, Zeren Wang, Richard T Darrington, Toby Tamblyn, John A Smoliga, Pauljames Jones, Steven L Krill
    Abstract:

    Abstract This report describes the solubility properties of a poorly soluble drug–excipient complex in a lipid based formulation. Tipranavir (TPV) was used as the model drug and 1,3-dioctanoylglycerol (DOG) as the excipient. The TPV–DOG complex was prepared by dissolving TPV and DOG in ethanol at 60°C followed by evaporation of ethanol. The formation of the complex with a 4:1 TPV-to-DOG molar ratio was confirmed by XRPD, DSC, and NMR. At 25°C, total solubility of TPV decreased with increasing DOG concentration. The solubility properties of the TPV–DOG complex can be described by two simultaneous equilibria: a liquid–solid Phase Equilibrium of the complex and a species Equilibrium among the various species in the liquid Phase. A model equation was derived accordingly with two parameters, the intrinsic solubility of the complex (So), and the solution complex constant (K41). The model was in good agreement with experimental results. The values of So and K41 are 0.0186 ± 0.0025 (M) and 21.97 ± 7.19 (1/M4), respectively. The equation can successfully predict the concentrations of total and free TPV as a function of DOG in the formulation. The approach developed provides a useful tool for rationale selection of excipients and their levels to avoid drug precipitation in lipid based formulations.