Hetacillin

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Cat Number

API0232088

CAS Number

3511-16-8

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Product Detail Description Customer Q&A

CAS Number

3511-16-8

EINECS

222-512-5

Storage

Store at 2-8°C

Synonyms

Hetacilina; Hetacilline; Hetacillinum; Versapen; Phenazacillin; Hetacillin acid; BL-P 804; BRL-804

Molecular Formula

C19H23N3O4S

Molecular Weight

389.5

Smiles

CC1([C@@H](N2[C@H](S1)[C@@H](C2=O)N3C(=O)[C@H](NC3(C)C)C4=CC=CC=C4)C(=O)O)C

General Description

Hetacillin is a semisynthetic penicillin prodrug derived from ampicillin and acetone via a condensation reaction, forming a stable 2,2‑dimethyl‑5‑oxazolidinecarboxylic acid ring. This heterocyclic structure is acid‑stable and reverts to ampicillin upon hydrolysis in the body. The molecule was developed to improve oral absorption and reduce gastrointestinal side effects compared to ampicillin.

Mechanism of Action

Hetacillin itself has minimal antibacterial activity; it serves as a reservoir that releases ampicillin both in the gut and systemically. The released ampicillin inhibits bacterial cell wall synthesis by binding to penicillin‑binding proteins (PBPs), disrupting peptidoglycan cross‑linking. This leads to cell lysis and death of susceptible gram‑positive and gram‑negative organisms. The prodrug approach does not confer resistance to beta‑lactamases.

Application

Hetacillin was indicated for infections caused by susceptible organisms, including respiratory tract infections, urinary tract infections, and skin/soft tissue infections. It has a spectrum identical to ampicillin, covering Streptococcus species, Enterococcus faecalis, E. coli, and Proteus mirabilis.

Does Hetacillin require refrigerated storage as a semisynthetic penicillin?

Yes, it must be stored at 2-8°C. The beta-lactam ring and the hetacillin structure are highly susceptible to hydrolysis at room temperature.

Is Hetacillin extremely sensitive to moisture, and how is this prevented?

Yes, it is hygroscopic and rapidly hydrolyzes to ampicillin. Our packaging includes moisture-barrier foil bags with desiccant; open only in low-humidity environments.

What is the stability of Hetacillin after reconstitution for oral or injectable use?

Reconstituted solutions degrade rapidly (within 24 hours under refrigeration). We provide detailed in-use stability data for various vehicles and storage conditions.

How is the impurity ampicillin (the hydrolysis product) monitored during stability?

This primary degradation product is specifically quantified using a stability-indicating HPLC method, ensuring it remains within pharmacopoeial limits.