Analysis of amoxicillin and five impurities on the Agilent 1220 Infinity LC System

Transcription

1 Analysis of amoxicillin and five impurities on the Agilent Infinity LC System LC analysis of impurities down to the.% level with long sub--µm columns, high flow rates and back pressure greater than bar Application Note Drug Development and Pharmaceutical QA/QC Authors A. Koeberlein Frankenthal, Germany A.G. uesgen Agilent Technologies Waldbronn, Germany mau 8 Impurity A Impurity C Impurity B Impurity D Impurtity E min Abstract is an antibacterial drug widely used against gram-positive and gram-negative organisms. In pharmaceutical drug discovery and development, it is crucial to analyze impurities due to their potential for toxic effects on humans. and its impurities were analyzed on the Agilent Infinity LC System on a 5 mm. mm column with.8 µm particles. When using a flow rate of ml/min (at 55 bar), the analysis was completed within seven minutes. Under these conditions, impurities down to a level of.% could be detected. The Agilent Infinity LC System is an ideal instrument for impurity analysis in a pharmaceutical quality control laboratory.

2 Introduction In pharmaceutical drug discovery and development, it is crucial to analyze for impurities due to their potential for toxic effects on humans. An impurity could be the active pharmaceutical substance itself, a minor byproduct from the production process, a secondary substance in a drug isolated from a natural source, a metabolite created in the human body, or a degradation product of the pharmaceutical agent created under storage conditions. Regulatory agencies stipulate that in the final drug, the amount of an impurity is below.% of the main compound. Recently, a number of publications have dealt with the analysis of amoxicillin and its impurities by PLC with UV or MS detection.,, is an antibacterial drug widely used against gram-positive and gram-negative organisms. It can degrade to several different byproducts, as illustrated in the pathways in Figure. is a polar substance, and its separation requires a high amount of water in the mobile phase. In this Application Note, we use a gradient method in combination with UV detection for the determination of amoxicillin and related impurities. Precision of areas and retention times as well as limits of detection (LD) and limits of quantitation (LQ) for the impurities were evaluated. Linearity in the low nanogram range (trace level) was evaluated for impurities. The Agilent Infinity LC System is an ideal instrument for impurity analysis in a pharmaceutical quality control laboratory. Experimental Instrumentation The instrument used in this application is the Agilent Infinity LC System in the following configuration: Gradient Pump, Autosampler, Column ven and Variable Wavelength Detector. Analyzing amoxicillin requires a column that can tolerate % water as a starting condition. The Agilent ZRBAX SB- Aq column, which is compatible with the highest percentages of water in the mobile phase was used for all experiments. The software used was ChemStation, revision B... N N N S C C C N N N S C C C N N S C C C N C N N N C C S C N N N C C S C penicillinoic acid penilloic acid -ydroxy-phenylglyl amoxicillin 5 Diketopiperazine amoxicillin 5 Figure Degradation pathways of amoxicillin.

3 Chromatographic conditions Sample: diluted in pure water Column: Agilent ZRBAX SB-Aq. mm 5 mm,.8 µm p/n Mobile phase: A: Water phosphate buffer (. mol/l), p=.8 B: ACN Gradient: Time Component A Component B [min] [%] [%] Flow rate:. ml/ min, max pressure 55 bar Stop time: 7 min Post time: min Detector: VWD 9 nm Peak width: PW >.5 min, z Injection Vol: µl Column temp: C Sample preparation Sample compounds: Level 5 Amount Amount Amount Amount Amount Amount (ng/µl) (ng/µl) (ng/µl) (ng/µl) (ng/µl) (ng/µl) Impurity A Impurity B Impurity C Impurity D Impurity E Table Concentratiion levels of impurities. Results and discussion Precision of retention times and areas Precision of areas and retention times was evaluated with concentration level (Figure ). The injection volume was µl. The resolution for impurity B is.97. ther impurities and degradation products are observed in the chromatogram, but in Figure, only the impurities and degradation products shown in Table were determined. Table shows the precision of retention times and areas of amoxicillin impurities. trihydrate Impurity A, p-hydroxy-phenylglycine Impurity B, Penicilloic acid mau 8 Impurity A Impurity C, -Aminopenicillanic acid Impurity D, p-hydroxy-phenylglycyl Impurity E, Diketopiperazine- A stock solution of amoxicillin was prepared in water with a concentration of mg/ml. Solutions for the evaluation of impurity data were prepared in water (Table ). Different concentration levels were used for testing the precision of retention times and areas for the evaluation of LD, LQ and linearity. Impurity C Impurity B Figure Concentration level for testing precision of retention times and areas over eight runs, µl injected, maximum pressure of 55 bar at ml/min flow rate. Impurity D Impurtity E min

4 Impurity A Impurity B Impurity C Impurity D Impurity E Ret Time Ret Time Ret Time Ret Time Ret Time Ret Time n=8 (min) (mau s) (min) (mau s) (min) (mau s) (min) (mau s) (min) (mau s) (min) (mau s) Mean: S.D.:.89E- 9.59E-.E-.5E-.5E- 9.8E-.E-.88E- 7.8E-.E-.E-.8E- RSD: Table Precision of RT and areas of amoxicillin and impurities for level concentration. The precision of retention times is between.% and.% RSD for all peaks. The precision of areas is between.5% and.9% RSD for impurities with area counts between.9 and mau s. Linearity Linearity was tested over all six concentration levels (Figure ). The linearity is better than.999 for the factor of correlation. 8 5 Impurity A, =.5*Amt +.7 Rel. Res%():.59e Correlation: Impurity B, =.9*Amt +.7 Rel. Res%(): _.85e- Correlation: Impurity C, =.77*Amt +.98 Rel. Res%():.99 5 Correlation: Impurity D, =.8*Amt +.85 Rel. Res%(): _. 5 Correlation: Impurity E, =.757*Amt +.9 Rel. Res%():.7 5 Correlation: Figure Linearity of impurities over all six concentration levels.

5 The limit of detection for the impurities was between. ng and.7 ng injected amount with a signal-to-noise ratio of (Figure red trace). Level was used to determine the minimum detectable level. The limit of quantitation was times higher, close to concentration level, (Figure 5 blue trace). mau.8... Impurity A Concentration level (LQ blue) and (LD red) Impurity C Impurity B Impurity D Impurity E In Table, the results for LD and LQ are combined. _ Noise range min Figure Concentration level (blue trace) and level (red trace), µl injected. Concentration LQ Concentration LD level (times LD) level amount (ng/µl) amount (ng/µl) amount (ng/µl) amount (ng/µl) Impurity A Impurity C Impurity B Impurity D Impurity E Table Results for LD and LQ. 5

6 Analysis of the amoxicillin sample Figure 5 shows the chromatogram of the amoxicillin sample. The sample was dissolved in water to a final concentration of mg/ml. The results are presented in Table, showing that impurities in the.% range can be detected. is present at a percentage level of 9%. The percentage levels for the impurities are calculated in relation to this level. mau 8 Sample amount: mg/ml test sample Impurity A Impurity C Impurity B Impurity D Impurtity E min Figure 5 sample, µl injected. (mau s) ng/µl Percentage Impurity A Impurity C..87. Impurity B Impurity D Impurity E Table Results of real life sample.

7 Conclusion and its impurities were analyzed on the Agilent Infinity LC System using a 5 mm. mm column with.8 µm particles. At a flow rate of ml/min (at 55 bar) the analysis was completed within seven minutes. Under these conditions, impurities down to a level of.% could be detected. This shows that the Agilent Infinity LC System is an ideal instrument for impurity analysis in a pharmaceutical quality control laboratory. References. Ch.B.V.N.Raju, et al., RP-PLC method for analysis of related substances in Amoxicllin Drug substance, Acta Chromatographia,, 57 7, 9. Edgar Naegele et al., Structure elucidation of degradation products of the antibiotic drug, Agilent Technologies publication EN, 5. Edgar Naegele, Statistic evaluation of mass accuracy measurements by ESI TF with a sample of degradation products from the antibiotic drug, Agilent Technologies publication EN, 5 7

8 Agilent Technologies, Inc., July, Publication Number 599-9EN