Profiling indomethacin impurities using high-performance liquid chromatography and nuclear magnetic resonance

Hess, Sonja; Teubert, Uwe; Ortwein, J; Eger, Kurt

doi:10.1016/s0928-0987(01)00198-1

Cited by 23 publications

(16 citation statements)

References 10 publications

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“…A previously reported HPLC method was used with minor modifications to determine the concentrations of indomethacin (25). A complete Perkin Elmer HPLC system, including a solvent delivery pump, a controller and a UV detector, was used in this study.…”

Section: Dissolution Studiesmentioning

confidence: 99%

Indomethacin–Saccharin Cocrystal: Design, Synthesis and Preliminary Pharmaceutical Characterization

2007

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Section: Dissolution Studiesmentioning

confidence: 99%

Indomethacin–Saccharin Cocrystal: Design, Synthesis and Preliminary Pharmaceutical Characterization

2007

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“…Residual unencapsulated drug was removed by size exclusion chromatography on Sephadex G-50 spin columns at room temperature, using PBS (pH 7.4) as eluent (New 1990). The amount of drug entrapped in LUVs was then determined by liquid chromatography (Hess et al 2001) after dissolving an aliquot of the liposome suspension in EtOH.…”

Section: Determination Of Entrapment Efficiencymentioning

confidence: 99%

Evaluation of in-vivo topical anti-inflammatory activity of indometacin from liposomal vesicles

Puglia

Trombetta

Venuti

et al. 2004

Journal of Pharmacy and Pharmacology

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The aim of this study was to evaluate the in-vivo drug release profile of indometacin-loaded liposomes into the skin. Large unilamellar vesicles (LUVs), composed of dipalmitoyl-L-alpha-phosphatidylcholine and cholesterol (9:1), were obtained using the extrusion method and then incorporated in hydrogels (LUV-A and LUV-B). The delivery of indometacin from the liposomal system was evaluated by determining its in-vivo local anti-inflammatory activity after cutaneous application of liposomal gel formulations; the anti-inflammatory activity is directly proportional to the amount of drug that actually crosses the skin. UVB-induced erythema on healthy human volunteers was chosen as the inflammatory model and the extent of erythema was monitored by the non-invasive technique of reflectance spectrophotometry. The results showed that LUV dispersions containing indometacin provided a high percentage of entrapped drug (approximately 84%). Furthermore, in-vivo findings revealed that the anti-inflammatory effect was more prolonged when indometacin was delivered from a liposomal gel formulation rather than from a gel formulation without liposomes. In particular, the indometacin-loaded gel formulation LUV-A showed a sustained effect, probably related to an interaction between LUV lipids and stratum corneum lipid structure. This interaction produces a depot in the stratum corneum that ensures sustained release of the drug to deeper skin layers.

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“…The analysis for indomethacin was performed following the method reported by Hess et al . [19] using a Phenosphere-NEXT 5μ C18 column (150mm x 4.6mm; Phenomenex, USA). The mobile phase consisted of 75% methanol and 25% of 0.2% phosphoric acid and was used at a flow rate of 1 mL/min.…”

Section: Methodsmentioning

confidence: 99%

Quantification of Process Induced Disorder in Milled Samples Using Different Analytical Techniques

et al. 2010

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The aim of this study was to compare three different analytical methods to detect and quantify the amount of crystalline disorder/ amorphousness in two milled model drugs. X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and Raman spectroscopy were used as analytical methods and indomethacin and simvastatin were chosen as the model compounds. These compounds partly converted from crystalline to disordered forms by milling. Partial least squares regression (PLS) was used to create calibration models for the XRPD and Raman data, which were subsequently used to quantify the milling-induced crystalline disorder/ amorphousness under different process conditions. In the DSC measurements the change in heat capacity at the glass transition was used for quantification. Differently prepared amorphous indomethacin standards (prepared by either melt quench cooling or cryo milling) were compared by principal component analysis (PCA) to account for the fact that the choice of standard ultimately influences the quantification outcome. Finally, the calibration models were built using binary mixtures of crystalline and quench cooled amorphous drug materials. The results imply that the outcome with respect to crystalline disorder for milled drugs depends on the analytical method used and the calibration standard chosen as well as on the drug itself. From the data presented here, it appears that XRPD tends to give a higher percentage of crystalline disorder than Raman spectroscopy and DSC for the same samples. For the samples milled under the harshest milling conditions applied (60 min, sixty 4 mm balls, 25 Hz) a crystalline disorder / amorphous content of 44.0% (XRPD), 10.8% (Raman spectroscopy) and 17.8% (DSC) were detected for indomethacin. For simvastatin 18.3% (XRPD), 15.5% (Raman spectroscopy) and 0% (DSC, no glass transition) crystalline disorder/ amorphousness were detected.

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Profiling indomethacin impurities using high-performance liquid chromatography and nuclear magnetic resonance

Cited by 23 publications

References 10 publications

Indomethacin–Saccharin Cocrystal: Design, Synthesis and Preliminary Pharmaceutical Characterization

Indomethacin–Saccharin Cocrystal: Design, Synthesis and Preliminary Pharmaceutical Characterization

Evaluation of in-vivo topical anti-inflammatory activity of indometacin from liposomal vesicles

Quantification of Process Induced Disorder in Milled Samples Using Different Analytical Techniques

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