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Reversed-phase HPLC impurities/degradants

Fig. 19. Reversed-phase HPLC trace of a degraded 2.5 mg sample of the complex indo-loquinoline alkaloid cryptospirolepine (18) after storage in fi 6-DMSO for 10 years under uncontrolled conditions.243 No trace of the starting alkaloid remains. The two major impurities, labeled DP-1 and DP-2, constituted approximately 50% of the total sample. DP-1 was identified as the known alkaloid cryptolepinone (33) on the basis of 1H reference, COSY, and HSQC spectra. The elucidation of the structure of DP-2 required the utilization of a complete gamut of 2D-NMR spectra and the use of cryogenic NMR probe capabilities. (Reprinted with permission from Ref. 243. Copyright 2002, HeteroCorp.)... Fig. 19. Reversed-phase HPLC trace of a degraded 2.5 mg sample of the complex indo-loquinoline alkaloid cryptospirolepine (18) after storage in fi 6-DMSO for 10 years under uncontrolled conditions.243 No trace of the starting alkaloid remains. The two major impurities, labeled DP-1 and DP-2, constituted approximately 50% of the total sample. DP-1 was identified as the known alkaloid cryptolepinone (33) on the basis of 1H reference, COSY, and HSQC spectra. The elucidation of the structure of DP-2 required the utilization of a complete gamut of 2D-NMR spectra and the use of cryogenic NMR probe capabilities. (Reprinted with permission from Ref. 243. Copyright 2002, HeteroCorp.)...
Gradient reversed-phase HPLC methodology is used to quantify pergolide mesylate and its potential related substances (synthetic impurities and degradation products). A Supelco LC-18-DB column (25 cm x 4.6 mm 5 micron particle size) is used in conjunction with a flow rate of 1 mL/min. Detection is obtained with a U V detector set at 280 nm. The mobile phase components are a 0.5% morpholine buffer (v/v) in water (pH 7.0 with phosphoric acid) (A) and HPLC-grade methanol/acetonitrile/tetrahydrofuran (1 1 1) (B). A linear gradient is initiated at 30% (B) and increased 2%/minute for 35 minutes to a final concentration of 100% (B) then returned to 30% (B) and re-equilibrated for 20 minutes. The sample is analyzed at a concentration of approximately 3 mg/mL. [Pg.407]

Table 1 summarises HPLC methods which have been published for analysis of amoxicillin and its impurities and degradation products in the drug substances and formulated products. Most of these methods use the reverse phase mode on Cl8 columns, with UV detection and a mobile phase containing a small amount of methanol or acetonitrile in phosphate... [Pg.34]

Examination of the synthetic route used in production allows for the prediction of potential residual synthetic impurities present in the drug substance. The API structure allows for the postulation of degradation pathways via hydrolytic, oxidative, catalytic, and other mechanisms. Both of these evaluations serve to facilitate the interpretation of (subsequent) identification tests. An examination of the physicochemical properties also allows for the rational establishment of method screening experiments by precluding certain conditions. For example, the use of normal-phase HPLC will be eliminated if the API is a salt or shows limited solubility in nonpolar organic solvents. Similarly, if the API (or suspected related substances) has no significant chromophore above 250 nm, the use of tetrahydrofuran (THE) and other solvents as mobile-phase components is severely limited. For compounds with an ionizable group, variation of pH will have considerable influence on elution behavior and can be exploited to optimize the selectivity of a reversed-phase separation. [Pg.352]


See other pages where Reversed-phase HPLC impurities/degradants is mentioned: [Pg.338]    [Pg.533]    [Pg.163]    [Pg.172]    [Pg.142]    [Pg.90]    [Pg.171]    [Pg.3430]    [Pg.92]    [Pg.351]    [Pg.292]    [Pg.346]    [Pg.442]    [Pg.540]    [Pg.36]    [Pg.38]    [Pg.251]    [Pg.1561]    [Pg.392]   


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Degradation impurities

Impurities/degradants

Impurity phases

Reverse-phase HPLC

Reversed-phase HPLC

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