Name: multiplex therapeutic drug monitoring by isotope-dilution hplc-ms/ms of antibiotics in critical illnesses
Uploaded: 2018-08-30T15:00:00
Description: Watch this Scientific Journal Video about Multiplex Therapeutic Drug Monitoring by Isotope-dilution HPLC-MS/MS of Antibiotics in Critical Illnesses at JoVE.com

貴重な入力のための博士 Zoller について適切な校正範囲と著者は提案手法を確立する彼の助け博士 Schütze を感謝します。著者はまた質量分析施設の技術的なスタッフを認めます。

注: メタノールなどの有機溶剤を取り扱う際、発煙のフードで動作するようにそれをお勧めします。メスフラスコですべてのバッファーと移動相を準備します。明記のないソリューションは準備の後は、1 ヶ月の室温で保存することができます。
1. 校正器および品質管理サンプルの準備
注: 対応するデータ分析シート ストックとスパイク溶液の調製の<...

<ol>
	<li>Fleischmann, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+Global+Incidence+and+Mortality+of+Hospital-treated+Sepsis.+Current+Estimates+and+Limitations.">Assessment of Global Incidence and Mortality of Hospital-treated Sepsis. Current Estimates and Limitations.</a> American Journal of Respiratory and Critical Care Medicine. 193 (3), 259-272 (2016).</li><li>Dellinger, R. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surviving+Sepsis+Campaign:+international+guidelines+for+management+of+severe+sepsis+and+septic+shock,+2012.">Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock, 2012.</a> Intensive Care Medicine. 39 (2), 165-228 (2013).</li><li>Lodise, T. P., Drusano, G. 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G., Eliasson, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standard+dosing+of+piperacillin+and+meropenem+fail+to+achieve+adequate+plasma+concentrations+in+ICU+patients.">Standard dosing of piperacillin and meropenem fail to achieve adequate plasma concentrations in ICU patients.</a> Acta Anaesthesiologica Scandinavica. 60 (10), 1425-1436 (2016).</li><li>Abdul-Aziz, M. H., Lipman, J., Mouton, J. W., Hope, W. W., Roberts, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applying+pharmacokinetic/pharmacodynamic+principles+in+critically+ill+patients:+optimizing+efficacy+and+reducing+resistance+development.">Applying pharmacokinetic/pharmacodynamic principles in critically ill patients: optimizing efficacy and reducing resistance development.</a> Seminars in Respiratory and Critical Care Medicine. 36 (1), 136-153 (2015).</li><li>Imani, S., Buscher, H., Marriott, D., Gentili, S., Sandaradura, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Too+much+of+a+good+thing:+a+retrospective+study+of+beta-lactam+concentration-toxicity+relationships.">Too much of a good thing: a retrospective study of beta-lactam concentration-toxicity relationships.</a> Journal of Antimicrobial Chemotherapy. 72 (10), 2891-2897 (2017).</li><li>Ventola, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+antibiotic+resistance+crisis:+part+1:+causes+and+threats.">The antibiotic resistance crisis: part 1: causes and threats.</a> Pharmacy &amp; Therapeutics. 40 (4), 277-283 (2015).</li><li>Pulcini, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibiotic+stewardship:+update+and+perspectives.">Antibiotic stewardship: update and perspectives.</a> Clinical Microbiology and Infection. 23 (11), 791-792 (2017).</li><li>Cairns, K. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+impact+of+a+multidisciplinary+antimicrobial+stewardship+team+on+the+timeliness+of+antimicrobial+therapy+in+patients+with+positive+blood+cultures:+a+randomized+controlled+trial.">The impact of a multidisciplinary antimicrobial stewardship team on the timeliness of antimicrobial therapy in patients with positive blood cultures: a randomized controlled trial.</a> Journal of Antimicrobial Chemotherapy. 71 (11), 3276-3283 (2016).</li><li>Baur, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+antibiotic+stewardship+on+the+incidence+of+infection+and+colonisation+with+antibiotic-resistant+bacteria+and+Clostridium+difficile+infection:+a+systematic+review+and+meta-analysis.">Effect of antibiotic stewardship on the incidence of infection and colonisation with antibiotic-resistant bacteria and Clostridium difficile infection: a systematic review and meta-analysis.</a> Lancet Infectious Diseases. 17 (9), 990-1001 (2017).</li><li>Roberts, J. A., Norris, R., Paterson, D. L., Martin, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Therapeutic+drug+monitoring+of+antimicrobials.">Therapeutic drug monitoring of antimicrobials.</a> British Journal of Clinical Pharmacology. 73 (1), 27-36 (2012).</li><li>Paal, M., Zoller, M., Schuster, C., Vogeser, M., Schutze, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+quantification+of+cefepime,+meropenem,+ciprofloxacin,+moxifloxacin,+linezolid+and+piperacillin+in+human+serum+using+an+isotope-dilution+HPLC-MS/MS+method.">Simultaneous quantification of cefepime, meropenem, ciprofloxacin, moxifloxacin, linezolid and piperacillin in human serum using an isotope-dilution HPLC-MS/MS method.</a> Journal of Pharmaceutical and Biomedical Analysis. 152, 102-110 (2018).</li><li>Vogeser, M., Seger, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pitfalls+associated+with+the+use+of+liquid+chromatography-tandem+mass+spectrometry+in+the+clinical+laboratory.">Pitfalls associated with the use of liquid chromatography-tandem mass spectrometry in the clinical laboratory.</a> Clinical Chemistry. 56 (8), 1234-1244 (2010).</li><li>United States Pharmacopeia and National Formulary. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+&#60;621&#62;.">Chapter &#60;621&#62;.</a> CHROMATOGRAPHY (USP 37-NF 32 S1). , 6376-6385 (2014).</li><li>Wong, G., Sime, F. B., Lipman, J., Roberts, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+do+we+use+therapeutic+drug+monitoring+to+improve+outcomes+from+severe+infections+in+critically+ill+patients?.">How do we use therapeutic drug monitoring to improve outcomes from severe infections in critically ill patients?.</a> BMC Infectious Diseases. 14, 288 (2014).</li><li>. Cefepime hydrochloride: Highlights of prescribing information Available from: <a target="_blank" href="https://www.accessdata.fda.gov/drugsatfda_docs/Label/2016/050679s040lbl.pdf">https://www.accessdata.fda.gov/drugsatfda_docs/Label/2016/050679s040lbl.pdf</a> (2016)</li><li>. Meropenem: Highlights of prescribing information Available from: <a target="_blank" href="https://www.accessdata.fda.gov/drugsatfda_docs/Label/2008/050706s022lbl.pdf">https://www.accessdata.fda.gov/drugsatfda_docs/Label/2008/050706s022lbl.pdf</a> (2006)</li><li>. Ciprofloxacin hydrochloride: Highlights of prescribing information Available from: <a target="_blank" href="https://www.accessdata.fda.gov/drugsatfda_docs/Label/2016/019537s086lbl.pdf">https://www.accessdata.fda.gov/drugsatfda_docs/Label/2016/019537s086lbl.pdf</a> (2016)</li><li>. Moxifloxacin hydrochloride: Highlights of prescribing information Available from: <a target="_blank" href="https://www.accessdata.fda.gov/drugsatfda_docs/Label/2010/021277s038lbl.pdf">https://www.accessdata.fda.gov/drugsatfda_docs/Label/2010/021277s038lbl.pdf</a> (2010)</li><li>. Linezolid: Highlights of prescribing information Available from: <a target="_blank" href="https://www.accessdata.fda.gov/drugsatfda_docs/Label/2012/021130s028lbl.pdf">https://www.accessdata.fda.gov/drugsatfda_docs/Label/2012/021130s028lbl.pdf</a> (2011)</li><li>. Piperacillin and Tazobactam: Highlighs of prescribing information Available from: <a target="_blank" href="https://www.accessdata.fda.gov/drugsatfda_docs/Label/2017/050684s88s89s90_050750s37s38s39lbl.pdf">https://www.accessdata.fda.gov/drugsatfda_docs/Label/2017/050684s88s89s90_050750s37s38s39lbl.pdf</a> (2017)</li><li>Zander, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+biobanking+conditions+on+six+antibiotic+substances+in+human+serum+assessed+by+a+novel+evaluation+protocol.">Effects of biobanking conditions on six antibiotic substances in human serum assessed by a novel evaluation protocol.</a> Clinical Chemistry and Laboratory. 54 (2), 265-274 (2016).</li><li>Zander, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantification+of+piperacillin,+tazobactam,+cefepime,+meropenem,+ciprofloxacin+and+linezolid+in+serum+using+an+isotope+dilution+UHPLC-MS/MS+method+with+semi-automated+sample+preparation.">Quantification of piperacillin, tazobactam, cefepime, meropenem, ciprofloxacin and linezolid in serum using an isotope dilution UHPLC-MS/MS method with semi-automated sample preparation.</a> Clinical Chemistry and Laboratory. 53 (5), 781-791 (2015).</li></ol>

本稿で報告する ICU の19セフェピム、メロペネム、シプロフロキサシン, モキシフロキサシン、リネゾリドの頻繁に使用される抗生物質の定量化のためのシンプルで堅牢なタンデム質量分析を用いた方法のためのプロトコルとピペラシリン14。スプレッドシートは、抗生物質の純度と、ポリマーの分子量を考慮して、品質管理、キャリブレータ、抗生の貯蔵?...

抗生物質は、医学の実践に革命をもたらしたが重篤な細菌感染症罹患率と重大な病気の1の死亡率の主要な原因のまま。この点で、適切な用量で適切な対策のプロンプトの管理は病気制御2の最重要です。
証拠の成長するボディは、広域スペクトル抗生物質による経験的治療が患者集団は複雑な問題がより深刻になっているを示します。これは集中治療室 (ICU)、特に重要な薬物動態 (PK) パラメーターの途方もない個体間変動はよく3,4を観察しました。したがって、ICU 患者不足治療成功5,6の危険とサブ治療レベルの差し迫った危険があります。再度、患者は臨床的利点7で重篤な有害事象があります過度の抗生物質濃度に不必要に公開されます。抗生物質の誤用と不十分な投与の両方はまた公衆衛生8に増え脅威となりつつある抗生の抵抗の普及を煽っています。
抗生物質の使用を改善するために、彼らの effectivenessas を維持するためには、可能な限り世界保健機関は 2015年9抗菌剤耐性に関する地球的行動計画を立ち上げた。抗菌薬の管理プログラムは、国立公衆衛生戦略10臨床医が患者ケア11のと同時に品質の大幅向上を支援に慎重な抗菌薬使用の本質的な基礎を構成します。12抗生物質耐性を削減します。抗菌治療薬のアプリケーションを通じて個々 の患者の投薬モニタリング (TDM) はこのコンテキスト13キー楽器です。
までに、市販の TDM アッセイ、糖ペプチド抗生物質やアミノグリコシド系抗生物質の利用のみ。他のクラスの物質の定量化は、社内法の開発や検証が面倒なことに通常必要です。、したがって、提案の詳細、臨床関連性の高い濃度の範囲14内 ICU で最も関連性の高い抗生物質の定量化のために使用できる堅牢な質量分析を用いた試金のためのプロトコル。メソッドは、最近私たちの質量分析施設で確立されたし、以来 ICU における TDM のルーチンに適用されています。手順は、質量分析機能を備えた多くの施設における抗菌薬の TDM の迅速な実装を可能にする均一サンプル クリーンアップ簡単解析設定を使用します。
ここで説明されているプロトコルはセフェピム、メロペネム、シプロフロキサシン, モキシフロキサシン、リネゾリドのタンデムとの組み合わせで同位体希釈液体クロマトグラフィー (LC) を用いる血清中ピペラシリンの定量化のために最適化された質量分析 (MS/MS)。同位体希釈 - LC/MS MS 方法論、安定同位体標識化合物が特定のマトリックス (例えば血清) と利子のサンプルに追加されます。同位体標識の基準は、そのラベルのない相手、すなわち天然分子と親イオン-娘イオン転移と呼ばれる、その断片化製品の異なる分子量のための興味の analyte と区別できます。同位体標識化合物があると比べて、そのラベルのないほぼ同じ全体的な物理化学的現象は、彼らがの高度でほぼ行列に依存しない試料の定量を許可する MS/MS の理想的な社内基準精度15。最近では、市販されている多く安定同位体標識内部標準小分子の定量化, 抗菌薬の TDM を含めて使用することができます。
分析 C8 アルキル鎖長逆相カラム (100 mm x 2.1 mm、3 μ m 粒子径) と抗生物質の分析記述プロトコルにクロマト グラフの分離が実行されます。メソッド開発時にすべての検体の内部標準正規化行列因子は 94.6%、105.4%、≤8.314の変動係数との間でした。

<table>
	<tbody>
		<tr>
			<td>cefepime hydrochloride</td>
			<td>Sigma-Aldrich</td>
			<td>1097636</td>
			<td>USP Reference Standard</td>
		</tr>
		<tr>
			<td>meropenem trihydrate</td>
			<td>Sigma-Aldrich</td>
			<td>Y0001252</td>
			<td>EP Reference Standard</td>
		</tr>
		<tr>
			<td>ciprofloxacin</td>
			<td>Sigma-Aldrich</td>
			<td>17850</td>
			<td></td>
		</tr>
		<tr>
			<td>moxifloxacin hydrochloride</td>
			<td>Sigma-Aldrich</td>
			<td>SML1581</td>
			<td></td>
		</tr>
		<tr>
			<td>linezolid</td>
			<td>Toronto Research Chemicals</td>
			<td>L466500</td>
			<td></td>
		</tr>
		<tr>
			<td>piperacillin sodium salt</td>
			<td>Sigma-Aldrich</td>
			<td>93129</td>
			<td></td>
		</tr>
		<tr>
			<td>cefepime-13C12D3 sulfate</td>
			<td>Alsachim</td>
			<td>C1297</td>
			<td>Isotope labelled internal standard for cefepime</td>
		</tr>
		<tr>
			<td>meropenem-D6</td>
			<td>Toronto Research Chemicals</td>
			<td>M225617</td>
			<td>Isotope labelled internal standard for meropenem</td>
		</tr>
		<tr>
			<td>ciprofloxacin-D8</td>
			<td>Toronto Research Chemicals</td>
			<td>C482501</td>
			<td>Isotope labelled internal standard for ciprofloxacin</td>
		</tr>
		<tr>
			<td>moxifloxacin-13C1D3 hydrochloride</td>
			<td>Toronto Research Chemicals</td>
			<td>M745003</td>
			<td>Isotope labelled internal standard for moxifloxacin</td>
		</tr>
		<tr>
			<td>linezolid-D3</td>
			<td>Toronto Research Chemicals</td>
			<td>L466502</td>
			<td>Isotope labelled internal standard for linezolid</td>
		</tr>
		<tr>
			<td>piperacillin-D5</td>
			<td>Toronto Research Chemicals</td>
			<td>P479952</td>
			<td>Isotope labelled internal standard for piperacillin</td>
		</tr>
		<tr>
			<td>methanol</td>
			<td>JT Baker</td>
			<td>8402</td>
			<td></td>
		</tr>
		<tr>
			<td>HPLC grade water</td>
			<td>JT Baker</td>
			<td>4218</td>
			<td></td>
		</tr>
		<tr>
			<td>formic acid</td>
			<td>Biosolve</td>
			<td>6914132</td>
			<td></td>
		</tr>
		<tr>
			<td>acetic acid</td>
			<td>Biosolve</td>
			<td>1070501</td>
			<td></td>
		</tr>
		<tr>
			<td>ammonium formate</td>
			<td>Sigma-Aldrich</td>
			<td>70221-25G-F</td>
			<td></td>
		</tr>
		<tr>
			<td>tert-Butyl methyl ether</td>
			<td>Merck</td>
			<td>101845</td>
			<td></td>
		</tr>
		<tr>
			<td>Fortis 3 &#956;m C8 100 * 2.1 mm</td>
			<td>Fortis</td>
			<td>F08-020503</td>
			<td></td>
		</tr>
		<tr>
			<td>Ti-PEEK-encased Prifilter (2 &#956;m)</td>
			<td>Chromsystems</td>
			<td>15011</td>
			<td></td>
		</tr>
		<tr>
			<td>2795 Alliance HPLC system</td>
			<td>Waters</td>
			<td>176000491</td>
			<td></td>
		</tr>
		<tr>
			<td>Quattro micro API Tandem Quadrupole System</td>
			<td>Waters</td>
			<td>720000338</td>
			<td></td>
		</tr>
		<tr>
			<td>QuanLynx 4.1 software</td>
			<td>Waters</td>
			<td>/</td>
			<td>Data evaluation software provided by the mass spectrometer manufacturer</td>
		</tr>
	</tbody>
</table>

multiplex therapeutic drug monitoring by isotope-dilution hplc-ms/ms of antibiotics in critical illnesses

特に病院抗菌薬の管理プログラムの実施に関し、多くの臨床施設における抗生物質の治療薬物モニタリングのためにますます需要があります。
現在の仕事で提案するセフェピム、メロペネム、シプロフロキサシン, モキシフロキサシン、リネゾリド、ピペラシリン、一般的に使用されるの定量化のための多重化、高性能液体クロマトグラフィー-タンデム質量分析 (hpcl ペ ・ MS/MS) プロトコル集中治療室における抗生物質。メソッドは、欧州医薬品庁のガイドラインによると総合的に検証以前されました。
急速なサンプルのクリーンアップ後、検体を 4 分以内 C8 逆相 HPLC カラムに分離して対応する安定同位体標識内部基準に複数反応におけるエレクトロ スプレー イオン化 (ESI +) 質量分析法で定量時間 (MRM) を監視します。提案手法は、制服のクロマト グラフ条件設定、臨床検査の毎日で堅牢な抗生物質薬剤モニタリングを可能にする単純なインストルメンテーションを使用してください。検量線にまたがる感受性菌と、食塊が得られるピーク濃度 (Cmax) の最小発育阻止濃度 (MIC) に近い抗生物質の量を含む薬物濃度範囲投与レジメン。サンプルのクリーンアップ前に、血清の希釈の必要のない複数の測定値を投与した抗生物質の曲線下面積が得られます。

記述のプロトコルを使用して、典型的なクロマト グラムは図 2で描かれています。米国薬局方 (USP) クロマトグラフィーのガイドライン16によると現在のシステムで列のデッド ボリュームが ~0.22 mL ~0.08 ml、余分な列ボリューム (インジェクター、チューブ、コネクタを含む) と決定されたこと~0.30 mL のホールド アップ量。すべて?...

Watch this Scientific Journal Video about Multiplex Therapeutic Drug Monitoring by Isotope-dilution HPLC-MS/MS of Antibiotics in Critical Illnesses at JoVE.com

Multiplex Therapeutic Drug Monitoring by Isotope-dilution HPLC-MS/MS of Antibiotics in Critical Illnesses

治療薬物モニタリング同位体希釈高速液体クロマトグラフィー-MS/質量分析法による重要な病気で抗生物質の多重化します。

ここで集中治療室、すなわちセフェピム、メロペネム、シプロフロキサシン, モキシフロキサシン, リネゾリドのピペラシリンで頻繁に使用される抗生物質の定量化のためのタンデム質量分析を用いたプロトコルを提案する.

There is an ever-increasing demand for the therapeutic drug monitoring of antibiotics in many clinical facilities, particularly with regard to the ...

Therapeutic drug monitoring of antibiotics is increasingly recognized as an important element for the implementation of national and local antibiotic stewardship programs. To meet this increasing demand of antibiotic therapeutic drug monitoring in medical facilities, we present a protocol for the quantification of antibiotics in circulation that aims to adjust the dosage to the susceptibility of the involved pathogens. The presented mass spectrometry-based protocol was optimized for the quantification of the most commonly used antibiotics in intensive care units, namely cefepime, meropenem, ciprofloxacin, moxifloxacin, linezolid, and piperacillin.Due to the broad calibration range, the method can also be used to calculate the pharmacokinetic area under the curve for an administered antibiotic. With a total turnaround time of approximately 30 minutes, the presented protocol is suitable for daily antibiotic therapeutic drug monitoring in clinical laboratories. First spike nine volumes of drug-free serum with one volume of previously prepared 10-fold concentrated spike solutions to obtain the serum calibrators zero through seven and quality controls A through D.For example, add 0.5 milliliters of spike solution to 4.5 milliliters of serum in a 10-milliliter polypropylene tube and incubate it for 15 minutes at four degrees Celsius on a roller mixer at 50 rpm.Use a repetitive pipette to generate 100-microliter aliquots of the calibrators and quality controls in 1.5-milliliter polypropylene tubes. Store the calibrators, quality controls, and previously prepared antibiotic stock solutions at minus 80 degrees Celsius for up to six months. After preparing six internal standard stock solutions, combine them in a 1.5-milliliter polypropylene tube to yield a five-fold concentrated internal standard mix.Add the desired internal standards to 965 microliters of 25%methanol in water. Store the internal standard stock solutions and the five-fold concentrated internal standard mix at minus 80 degrees Celsius. To prepare mobile phase A, add approximately 500 milliliters of HPLC grade water to a 1, 000-milliliter volumetric flask.Add one milliliter of formic acid, 10 milliliters of one-molar ammonium formate, and fill the flask to 1, 000 milliliters with HPLC grade water. Then transfer the mobile phase solution to a clean glass bottle. To prepare mobile phase B, add HPLC grade absolute methanol to a clean glass bottle.To prepare the purge solvent, add approximately 500 milliliters of distilled water to a 1, 000-milliliter volumetric flask. Add 70 milliliters of absolute methanol, one milliliter of formic acid, and fill the flask to 1, 000 milliliters with distilled water. Transfer the solvent to a clean glass bottle.Connect the bottles with mobile phases A and B and the purge solvent to the HPLC system. Make sure that the needle wash solvent tube is connected to the bottle containing mobile phase B.To prepare the precipitation agent, add 2.5 milliliters of methyl tert-butyl ether to a 25-milliliter volumetric flask and fill to 25 milliliters with absolute methanol. Place a C8 reversed phase column into the column chamber, then connect the column to the HPLC and mass spectrometer in the direction of the flow.In order to generate the sample list, open the corresponding sample measurement master file template and add the patient samples to be processed. Generate groups of up to 20 patient samples and flank them with the corresponding quality control pair. Using the Inlet file control software, set the Wet Prime function to 50%mobile phase A and 50%mobile phase B and wet prime for two minutes with a flow rate of one milliliter per minute.Next, refresh the syringe by executing six strokes of 600 microliters in the control software. To equilibrate the C8 reversed phase column, turn on the the flow in the inlet file and flush it with 7%mobile phase B and 93%mobile phase A for a minimum of five minutes, using a flow rate of 0.4 or 0.5 milliliters per minute. Visually verify the column temperature of 30 degrees Celsius.With a repetitive pipette, add 25 microliters of the internal standard mix to the thawed calibrator, QC sample, or patient serum in a 1.5-milliliter polypropylene tube and vortex the tube for a few seconds. Then incubate the mixture for five minutes at room temperature on a benchtop shaker. After incubation, add 150 microliters of the precipitation reagent to the sample internal standard mix with a repetitive pipette.Vortex the tube for a few seconds and then incubate for five minutes at room temperature on a benchtop shaker. Following this, centrifuge the suspension at 20, 000 times gravity in a tabletop centrifuge for 10 minutes at four degrees Celsius. Dilute the supernatant one in three with HPLC grade water in a glass vial with a micro insert.Then, place the sample in the HPLC autosampler. Manually start the HPLC-MS/MS analysis in the sample measurement control file. To process the samples, open the corresponding sample measurement control file, select the calibrators, quality controls, and patient samples and evaluate them with the antibiotics quantification method.Check whether the peaks for a specific analyte are properly integrated. Inspect the peaks for each calibrator, QC, and patient sample and manually reintegrate them at the baseline if necessary. Study the calibration curve and examine whether it fulfills linearity over the entire calibration range, a calibration coefficient greater than 0.99, a deviation of each calibration standard within plus or minus 15%of the nominal value except for the lower limit of quantification where a plus or minus 20%is required.Reject a calibration standard not complying with the above-mentioned criteria and reevaluate the calibration curve, including the regression analysis. Now, study the quality controls and examine whether the deviations are within plus or minus 15%of the nominal value. If the quality controls for a specific batch do not fulfill the quality criteria, the samples must be reinjected or even be reprocessed if significant deviations persist.Measured concentrations of a batch must also be evaluated whether they are plausible or not. If the concentration of a patient's sample exceeds the concentration of the highest calibrator, dilute the sample with distilled water up to one in five before the sample cleanup. Repeat the previous cleanup steps for that specific sample and reprocess it.The calculated retention factors for all analytes were 2.8 to 4.2. A sample chart list for the processed samples is shown here. The key parameter is the response gradually increasing with the analyte concentration due to the constant amount of added isotope-labeled internal standard.The calibration curve and quality controls for the example shown here fulfill all quality criteria. The coefficient of determination r-squared is greater than 0.995 and the deviation of the calibrators and the QC samples is within plus or minus 15%of the nominal value. The measured parent-to-daughter ion transitions show four peaks at the same retention time.The two upper peaks depict two transitions that are measured for the analyte of interest and the lower two peaks represent the transitions for the corresponding isotope-labeled internal standard. The first patient has a high serum trough level of 83.4 milligrams per liter of piperacillin that is also sufficient for problem pathogens. The second patient has a concentration of approximately 0.2 milligrams per liter, which is below the lowest calibrator.The third patient has low piperacillin trough concentration of only 5.3 milligrams per liter that is not sufficient for the majority of pathogens. The presented protocol is suitable for isotope dilution HPLC-tandem mass spectrometry-based quantification of cefepime, meropenem, ciprofloxacin, moxifloxacin, linezolid, and piperacillin in human serum. The method uses a rather simple instrument setup and will be there transferable to various mass spectrometry-based platforms.Chromatographic separation of the analytes of interest can also be obtained with a flow rate of 0.4 milliliters per minute as given in the present video. The described method can be used for pharmacokinetic studies as the calibration range allows both the quantification of concentrations close to the minimal inhibitory concentration of a susceptible pathogen as well as peak concentrations that are obtained with bolus administration regimens. After its development this method has been implemented in a mass spectrometry-based care facility for the antibiotic therapeutic drug monitoring in critically ill patients.Due to the fact that beta-lactam antibiotics are chemically unstable once they are dissolved, the quality of the pre-analytical phase such as sample storage plays a vital role in obtaining reliable quantification results. Don't forget that working with organic solvents is hazardous and precautions such as working in a fume should always be taken while preparing chromatography solvents and the precipitation reagent.

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