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Determination of oseltamivir quality by colorimetric and liquid chromatographic methods.

Green MD, Nettey H, Wirtz RA - Emerging Infect. Dis. (2008)

Bottom Line: Hoffmann-La Roche Ltd., Basel, Switzerland) because of a growing concern about counterfeit oseltamivir.Both methods were evaluated for variability and selectivity and subsequently applied to batches of oseltamivir products acquired through the Internet.Colorimetric and chromatographic analysis showed all batches of oseltamivir product were within +/-15% of the stated amount of active ingredient.

View Article: PubMed Central - PubMed

Affiliation: Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. mgreen@cdc.gov

ABSTRACT
We developed a colorimetric and chromatographic assay for oseltamivir to assess the authenticity of Tamiflu (F. Hoffmann-La Roche Ltd., Basel, Switzerland) because of a growing concern about counterfeit oseltamivir. The colorimetric assay is quantitative and relies on an extractable colored ion-pair complex of oseltamivir with Congo red or bromochlorophenol blue. The reverse-phase chromatographic assay uses an alkaline mobile phase with UV detection. Both methods were evaluated for variability and selectivity and subsequently applied to batches of oseltamivir products acquired through the Internet. The Congo red test showed greater assay sensitivity, linearity, and accuracy. Colorimetric and chromatographic analysis showed all batches of oseltamivir product were within +/-15% of the stated amount of active ingredient.

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Chromatogram of oseltamivir from Tamiflu purchased over the Internet.
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Figure 4: Chromatogram of oseltamivir from Tamiflu purchased over the Internet.

Mentions: Intraday and interday accuracy and precision were within ±11% for oseltamivir phosphate concentrations of 0.6 mg/mL to 4.5 mg/mL (Table 1). Mobile phase pH above the pKa of a basic analyte generally produces chromatograms with a good symmetrical peak shape. The chromatogram for oseltamivir is shown in Figure 4. Because the pKa of oseltamivir is 7.75 (9), a mobile phase comprising a pH 10 (2 U above the pKa) bicarbonate buffer was chosen. The C18 column used for the HPLC method is designed to operate under basic pH conditions. Injections of aqueous mixtures of aspirin, ampicillin, chloroquine, acetaminophen, amoxicillin, ciprofloxacin, quinine, chloramphenicol, or erythromycin into the HPLC system showed no interfering chromatographic peaks. The limit of detection for oseltamivir phosphate at 220-nm and 254-nm detection wavelengths are 2.2 ng and 4.2 ng, respectively.


Determination of oseltamivir quality by colorimetric and liquid chromatographic methods.

Green MD, Nettey H, Wirtz RA - Emerging Infect. Dis. (2008)

Chromatogram of oseltamivir from Tamiflu purchased over the Internet.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2570928&req=5

Figure 4: Chromatogram of oseltamivir from Tamiflu purchased over the Internet.
Mentions: Intraday and interday accuracy and precision were within ±11% for oseltamivir phosphate concentrations of 0.6 mg/mL to 4.5 mg/mL (Table 1). Mobile phase pH above the pKa of a basic analyte generally produces chromatograms with a good symmetrical peak shape. The chromatogram for oseltamivir is shown in Figure 4. Because the pKa of oseltamivir is 7.75 (9), a mobile phase comprising a pH 10 (2 U above the pKa) bicarbonate buffer was chosen. The C18 column used for the HPLC method is designed to operate under basic pH conditions. Injections of aqueous mixtures of aspirin, ampicillin, chloroquine, acetaminophen, amoxicillin, ciprofloxacin, quinine, chloramphenicol, or erythromycin into the HPLC system showed no interfering chromatographic peaks. The limit of detection for oseltamivir phosphate at 220-nm and 254-nm detection wavelengths are 2.2 ng and 4.2 ng, respectively.

Bottom Line: Hoffmann-La Roche Ltd., Basel, Switzerland) because of a growing concern about counterfeit oseltamivir.Both methods were evaluated for variability and selectivity and subsequently applied to batches of oseltamivir products acquired through the Internet.Colorimetric and chromatographic analysis showed all batches of oseltamivir product were within +/-15% of the stated amount of active ingredient.

View Article: PubMed Central - PubMed

Affiliation: Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. mgreen@cdc.gov

ABSTRACT
We developed a colorimetric and chromatographic assay for oseltamivir to assess the authenticity of Tamiflu (F. Hoffmann-La Roche Ltd., Basel, Switzerland) because of a growing concern about counterfeit oseltamivir. The colorimetric assay is quantitative and relies on an extractable colored ion-pair complex of oseltamivir with Congo red or bromochlorophenol blue. The reverse-phase chromatographic assay uses an alkaline mobile phase with UV detection. Both methods were evaluated for variability and selectivity and subsequently applied to batches of oseltamivir products acquired through the Internet. The Congo red test showed greater assay sensitivity, linearity, and accuracy. Colorimetric and chromatographic analysis showed all batches of oseltamivir product were within +/-15% of the stated amount of active ingredient.

Show MeSH