Dextromethorphan

HPLC Analysis of Drug Dextromethorphan on Heritage MA Column. Effect of Acetonitrile and Buffer Concentration on Retention Time
Application description

Dextromethorphan is a drug of the morphinan class with sedative, dissociative, and stimulant properties (at higher doses). It is a cough suppressant in many over-the-counter (OTC) cold and cough medicines including Benylin DM, Mucinex DM, Robitussin, NyQuil, Dimetapp, Vicks, Coricidin, Delsym, TheraFlu, Cheracol D, and others. Dextromethorphan has also found numerous other uses in medicine, ranging from pain relief (as either the primary analgesic or an opioid potentiator) over psychological applications to the treatment of addiction. Dextromethorphan and related impurities were analyzed by mixed-mode chromatography on Heritage MA HPLC column. Compounds are separated by reversed-phase and cation-exclusion mechanisms. Retention time, selectivity, and resolution between peaks can be adjusted by modification of amount of ACN, buffer and buffer pH. Various mobile phases can be used with Heritage MA column to accommodate different detection techniques (UV, MS, CAD, ELSD detection).

Conditions of Experiment
Column: Heritage MA
Separation Modes: reversed-phase and cation-exclusion
Column Dimenstions: 4.6 x 150 mm
Mobile Phase: 15% ACN with 30 mM AmAc pH 4
Detection: UV 215 nm
Sample: 0.3 mg/ml
Injection: 3 uL
Flow rate: 1 mL/min
Analytes
Class of compounds: Amines, Aromatic base, Drug
Nature of compounds: Basic, Hydrophobic
Compounds: Dextromethorphan
HPLC Analysis of Dextromethorphan and Counter-Ion on Coresep SB Column in Reversed-Phase Mixed Mode
Application description

Dextromethorphan and bromide counter-ion were analyzed by mixed-mode HPLC on core-shell reversed-phase anion exchange column. Dextromethorphan is retained by strong hydrophobic interaction and the bromide ion is retained by an anion-exchange interaction. Order of elution for basic drug and it’s acidic counter-ion can be changed by modifying the amount of ACN, buffer pH, and buffer concentration. The Coresep SB column can be used for analysis of hydrophobic basic drugs and acidic counter-ions in one run without a ion-pairing reagent. Compounds can be monitored by all common detection techniques.

Conditions of Experiment
Column: Coresep SB
Separation Modes: reversed-phase, anion-exchange and cation-exclusion
Column Dimenstions: 3.2 x 100 mm, 2.7 um, 90A
Mobile Phase: 20% ACN with 0.1% or 0.2% TFA
Detection: UV 255 nm
Sample: 0.3 mg/ml
Injection: 3 uL
Flow rate: 0.6 ml/min
Analytes
Class of compounds: Amines, Aromatic base, Drug
Nature of compounds: Basic, Hydrophobic
Compounds: Dextromethorphan
Fast HPLC Analysis of Three Drugs on Coresep SB Column in Reversed-Phase and Cation-Exclusion Modes
Application description

Three hydrophobic drugs were analyzed with excellent peak shape on the core-shell mixed-mode column. Poor peak shape is very often observed when hydrophobic basic drugs, like dextromethorphan and trimipramine, are analyzed by traditional reversed-phase chromatography. This poor peak shape is caused by the interaction with residual silanol groups on the surface of RP columns. Since the amounts of these groups are not great, easy overloading and tailing occur. In case of mixed-mode chromatography, the polar basic group on the surface of silica gel provides a shielding effect, preventing the interaction of basic groups of analyte and acidic residual silanols. The mixed-mode core-shell column also has a high capacity towards retention of acidic drugs, which contributes to the good peak shape and retention. Method and column can be used to develop robust and reproducible methods for a hydrophobic basic, hydrophilic acidic and hydrophobic acidic compounds and counter-ions.

Conditions of Experiment
Column: Coresep SB
Separation Modes: reversed-phase and cation-exclusion
Column Dimenstions: 3.2 x 100 mm, 2.7 um, 90A
Mobile Phase: 25% ACN with 120 mM of AmFm pH 3
Detection: UV 250 nm, ELSD
Sample: 0.3 mg/ml
Injection: 1 uL
Flow rate: 0.8 ml/min
Analytes
Class of compounds: Amines, Aromatic base, Drug
Nature of compounds: Basic, Hydrophobic
Compounds: Dextromethorphan, Verapamil, Trimipramine