61-33-6 | Benzylpenicillin (C₁₆H₁₈N₂O₄S)

Chemical type

• β-lactam antibiotic (natural penicillin)

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• β-lactam antibiotic antigen (diagnostic reagent)

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• Natural penicillin compound

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Key properties

• Used as internal analytical standard
• Similar structure to ampicillin
• Detectable by LC-MS/MS
• Stable reference compound in quantitative assays

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• Used in prick and intradermal skin testing
• Freshly prepared crystalline form
• Positive reaction defined by wheal >3 mm
• Acts as biomarker for predicting desensitization reaction

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• Administered intravenously (IV).
• Produced via fermentation of Penicillium chrysogenum using phenylacetic acid as a precursor.
• Unstable in the acidic environment of the stomach, hence administered parenterally.

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• Internal standard in LC-MS/MS quantification
• Analytical calibration compound

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• Immediate-reading skin testing
• Identification of high-risk allergic patients

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• Treatment of bacterial infections, such as community-acquired pneumonia.
• Referenced as a Single Standard Dose (SSD) of 1 million International Units (mil. IU) for IV treatment.

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Classification by use

• Chemicals used as analytical reference standards
• Chemicals used in pharmaceutical quantitative analysis

A trustworthy factory and manufacturer

1. [Cite:1] Transplacental passage of ampicillin: Implications for antenatal therapy, Placenta, Volume 175, 6 March 2026, Pages 66-72
2. [Cite:2] Effectiveness and safety of algorithm for treating pregnant women with syphilis and history of immediate allergy to penicillin, Journal of Allergy and Clinical Immunology: Global, Volume 4, Issue 4, November 2025, 100572
3. [Cite:3] The greener prescription: Life cycle environmental impact of oral and IV penicillin treatments, Sustainable Chemistry and Pharmacy, Volume 50, April 2026, 102346