1-Acyl-indoles. II. A New Syntheses of 1-(p-chlorobenzoyl)-5-methoxy-3-indolylacetic Acid and Its Polymorphism

Yamamoto, Hisao

doi:10.1248/cpb.16.17

Cited by 71 publications

(24 citation statements)

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“…It has been shown that indomethacin has two monotropic polymorphs, γ (which is the most stable form) and α (which is a metastable form) (Borka 1974;Yamamoto, 1968). FTIR spectroscopy was carried out on several formulations to ascertain whether any possible structural changes occurred at the molecular level.…”

Section: Solid State Studies Of Solid Dispersions and Physical Mixturesmentioning

confidence: 99%

Triboelectrification and dissolution property enhancements of solid dispersions

Asare-Addo

Šupuk

Al-Hamidi

et al. 2015

International Journal of Pharmaceutics

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The use of solid dispersion techniques to modify physicochemical properties and improve solubility and dissolution rate may result in alteration to electrostatic properties of particles. Particle triboelectrification, plays an important part in powder processing, affecting end product quality due to particle deposition and powder loss. This study investigates the use of glucosamine hydrochloride (GLU) in solid dispersions with indomethacin. Solvents selected for the preparation of the dispersions were acetone, acetone-water, ethanol and ethanol-water. Solid state characterizations (DSC, FTIR and XRPD) and dissolution were conducted. Dispersions were subjected to charging using a custom built device based on a shaking concept, consisting of a Faraday cup connected to an electrometer. All dispersions improved the dissolution rate of indomethacin. Analysis showed the method of preparation of the dispersion induced polymorphic forms of the drug. Indomethacin had a high propensity for charging (-411 nC/g). GLU had a very low charge (-1 nC/g). All dispersions had low charges (-1 to 14 nC/g). Acetone as a solvent, or in combination with water, produced samples with an electronegative charge in polarity. The same approach with ethanol produced electropositive charging. The results show the selection of solvents can influence powder charge thereby improving powder handling as well as dissolution properties.

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Section: Solid State Studies Of Solid Dispersions and Physical Mixturesmentioning

confidence: 99%

Triboelectrification and dissolution property enhancements of solid dispersions

Asare-Addo

Šupuk

Al-Hamidi

et al. 2015

International Journal of Pharmaceutics

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“…II when suspended in solvents with stirring (2). Indomethacin is a nonsteroidal anti-inflammatory drug, and it exists in three true polymorphic forms (α, γ, and δ) and an amorphous form (3,4). It also forms solvates with tert-butyl alcohol and methanolate (5).…”

Section: Introductionmentioning

confidence: 99%

A Kinetic Study of the Polymorphic Transformation of Nimodipine and Indomethacin during High Shear Granulation

Guo

Wang

et al. 2011

AAPS PharmSciTech

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Abstract. The objective of the present study was to investigate the mechanism, kinetics, and factors affecting the polymorphic transformation of nimodipine (NMD) and indomethacin (IMC) during high shear granulation. Granules containing active pharmaceutical ingredient, microcrystalline cellulose, and low-substituted hydroxypropylcellulose were prepared with ethanolic hydroxypropylcellulose solution, and the effects of independent process variables including impeller speed and granulating temperature were taken into consideration. Two polymorphs of the model drugs and granules were characterized by X-ray powder diffraction analysis and quantitatively determined by differential scanning calorimetry. A theoretical kinetic method of ten kinetic models was applied to analyze the polymorphic transformation of model drugs. The results obtained revealed that both the transformation of modification I to modification II of NMD and the transformation of the α form to the γ form of IMC followed a twodimensional nuclei growth mechanism. The activation energy of transformation was calculated to be 7.933 and 56.09 kJ·mol −1 from Arrhenius plot, respectively. Both the granulating temperature and the impeller speed affected the transformation rate of the drugs and, in particular, the high shear stress significantly accelerated the transformation process. By analyzing the growth mechanisms of granules in high-shear mixer, it was concluded that the polymorphic transformation of NMD and IMC took place in accordance with granule growth in a high-shear mixer.

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“…The polymorphism of IND has been extensively studied before. 492 Yamamoto [19] first described three polymorphs, namely a, b and 93 c. Borka [20] [26,27] are also known to exist. plateau of about 11 mg/L was reached during dissolution.…”

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confidence: 99%