6-aminopenicillanic acid

Toxicological Summary

Workers - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Acute/short term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Acute/short term exposure

Hazard assessment conclusion:

no-threshold effect and/or no dose-response information available

DNEL related information

Workers - Hazard via dermal route

Systemic effects

Long term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Acute/short term exposure

Hazard assessment conclusion:

no-threshold effect and/or no dose-response information available

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

no-threshold effect and/or no dose-response information available

Acute/short term exposure

Hazard assessment conclusion:

no-threshold effect and/or no dose-response information available

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:

no hazard identified

Additional information - workers

Worker DNEL:

Long-Term exposure -Systemic effects

Dermal:

Assuming that dermal absorption will not be higher than oral absorption (based on low log Pow and MW>100) a worst case assumption is taken:

Dermal DN(M) EL: > 3.3 mg/kg bw day

Assessment Factor: 300. Dose descriptor starting point: 1000 mg/kg bw day (NOAEL -28 day oral RDT)

Derivation of AF:

4 – Allometric scaling (rat to human)

2.5 - interspecies differences

5 - sensitivity of population (workers)

6 – sub-acute to chronic

Inhalation:

Inhalation DN(M) EL: > 23.5 mg/m³

Assessment Factor:75 Dose descriptor starting point: 1000 mg/kg bw day (NOAEL -28 day oral RDT)

Derivation of AF:

2.5 - interspecies differences

5 - sensitivity of population (workers)

6 – sub-acute to chronic

Conversion of oral NOAEL to inhalation NOAEL

1000 mg/kg bw/day ÷ 0.38 m³/kg x 6.7 m³/10 m³

= 1763 mg/m²

General Population - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Acute/short term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Acute/short term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

DNEL related information

General Population - Hazard via dermal route

Systemic effects

Long term exposure

Hazard assessment conclusion:

hazard unknown but no further hazard information necessary as no exposure expected

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

no hazard identified

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

General Population - Hazard via oral route

Systemic effects

Long term exposure

Hazard assessment conclusion:

no hazard identified

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

DNEL related information

General Population - Hazard for the eyes

Local effects

Hazard assessment conclusion:

no hazard identified

Additional information - General Population

Acute Toxicity: Oral

The test substance 6-aminopenicillanic acid was administered to male and female Wistar rats by gavage. The experiment was performed as limit test with a concentration of 2000 mg/kg bw.No animal died during the 14 day observation period. No abnormalities were detected regarding body weight development or gross pathology. Clinical signs attributed to test item administration was piloerection.

The LD50 was determined to be greater than 2000 mg/kg bw.

Acute Toxicity:Inhalation

In accordance column 2 of REACH Annex VIII, testing by the inhalation route is appropriate if exposure of humans via inhalation is likely taking into account the vapour pressure of the substance and/ or the possibility of exposure to aerosols, particles or droplets of an inhalable size. Particle size distribution study for 6-APA has shown that 97.6% of the particle is less than 100 µm (inhalable) and only 0.975%

Acute Toxicity:Dermal

In accordance column 2 of REACH Annex VIII, testing by the dermal is appropriate if the physiochemical and toxicological properties suggest potential for a significant rate of absorption through the skin. The high water solubility of 2.16 g/l and the very low log P value of -3.87, suggest that the substance is too hydrophilic to cross the lipid rich environment of the striatum corneum. Also dermal uptake of the substance will be minimal as the molecular weight of the substance is >100.

Skin Irritation:

Based upon the observations made in the Primary Dermal Irritation Study in rabbits, 6-APA (6-Aminopenicillinic Acid), was determined not to be a dermal irritant.

Eye Irritation:

The test material was determined to be a mild irritant (class 4 in the Modified Kay and Calandra system). The maximum Group mean score was 12.7. However All effects were reversible within 72 hours.

Skin Sensitisation:

The test material was considered to be a non sensitiser under the conditions of the test. The test material did not meet the criteria for classification as a sensitiser according to EU labelling regulations Commission Directive 2001/59/EC. No symbol and risk phrase are required.

Respiratory Sensitisation:

Previous literature on skin sensitization have concluded that in rabbits treated with the standard 6- Aminopenicillanic Acid (6-APA) produced high levels of penicilloyl-specific antibodies, but that after purification processes to remove high molecular weight impurities, 6-APA failed to induce these levels of antibodies in rabbits. A similar situation was found with Ampicillin prepared from original processed 6-APA, when injected in rabbits, high levels of penicilloyl specific antibody were found then when the Ampicillin was prepared from 6-APA specially purified by complex adsorption processes to remove protein impurities. Occupational asthma (in section 7.10.4) seen is an old case study with 6-APA, is probably due to the impurities, however since then a change in the manufacturing process of antibiotics has been introduced to remove protein impurities (high molecular weight). This process is said to lower the immunogenicity potential and hence suggest that 6-APA is not any more a respiratory sensitizer. Further evidence to suggest that 6-APA is not a respiratory sensitiser is the negative result in the LLNA assay in section 7.4.1.

14 -Day repeat dose toxicity study:

No clinical signs of toxicity were detected for test or control animals throughout the study period. Isolated instances of increased salivation were evident post dosing, in animals of either sex treated with 1000 mg/kg/day throughout the treatment period and in animals of either sex treated with 500 mg/kg/day on Day 14. Such observations are often recorded following the oral administration of an unpleasant tasting and/or locally irritant test material formulation and are considered of no toxicological importance. The test material administered at doses of 1000, 500 and 250 mg/kg/day resulted in treatment-related effects at 1000 and 500 mg/kg/day. The effects detected in this study were considered not to represent an adverse health effect, therefore a No Observed Adverse Effect Level (NOAEL) and a suitable high dose level for use on a twenty-eight day study were considered to be 1000 mg/kg/day.

28 -Day Repeat dose toxicity study:

The oral administration of 6-aminopenicillanic acid at dose levels of 30, 300 and 1000 mg/kg/day for a period of twenty eight consecutive days did not result in any toxicologically significant effects in animals of either sex treated with 30, 300 or 1000 mg/kg/day. The "No Observed Adverse Effect Level" *NOAEL) was therefore considered to be 1000 mg/kg/day.

In vitro gene mutation in bacteria:

Mutagenic activity of 6-Aminopenicillanic acid was not observed. The study was considered sufficient to fulfil the standard information requirement 8.4.1 in vitro gene mutation study in bacteria. The additional E. coli cross linking strain is anticipated to have no impact on the final conclusions of the study.

In vitro cytogenicity in mammalian cells:

The test material did not induce a toxicologically significant increase in the frequency of cells with chromosome aberrations in either the absence or presence of a liver enzyme metabolising system. The test material was therefore considered to be non-clastogenic to human lymphocytes in vitro.

In vitro gene mutation in mammalian cells:

The test material did not induce any toxicologically significant increases in the mutant frequency at the TK +/- locus in L5178Y cells and is therefore considered to be non mutagenic under the conditions of the test.

Genetic toxicity in vivo:

In vivo somatic cell genotoxicity or germ cell mutagenicity study will be scientifically unjustified as there is no indication of mutagenicity effect of the substance in the following test: In vitro gene mutation study in bacteria, In vitro cytogenicity study in mammalian cells and In vitro gene mutation study in mammalian cells.

Carcinogenicity:

According to Annex X, section 8.9.1, column 2 of Regulation No. 1907/2006 a carcinogenicity study may be proposed if the substance has widespread dispersive use of frequent or long term human exposure and the substance is classified as mutagen category 3, or there is evidence from repeat dose studies that the substance is able to induce hyperplasia and/or pre-neoplastic lesions. 6-Aminopenicillanic acid (6-APA) is not classified as a mutagen category 3 and there is no evidence from the repeat 28-day oral dose study that 6-APA is able to induce hyperplasia or pre-neoplastic lesions. Also results from a valid structural activity relationship model (QSAR) showed no structural alert for carcinogenicity. Therefore a carcinogenicity study is not warranted.

Toxicity to reproduction:

No effects were noted in a one litter prenatal toxicity study in rats dosed with either 200 or 400 mg/kg bw/day of ampicillin anhydrous.

Toxicity to Reproduction, Developmental toxicity and Teratogenicity:

The following substances are considered to be similar in order to facilitate read-across for systemic toxicity endpoints: Ampicillin and Penicillin. The read-across justification is based on the very high water solubility of the substances; they all contain the β- lactam ring and have low acute toxicity.

A literature review of available human and animal data on reproductive toxicity to 6-Aminopenicillanic Acid (6-APA) and its read-across substances showed no unequivocal evidence of reproductive/ developmental toxicity. Penicillin G, V and Ampicillin have been used at all stages during pregnancy. As a general principle, pregnant women should not take any drugs, but if an antibiotic must be prescribed, the doctor can choose from Penicillin G, V and Ampicillin, as they have never been shown to cause harmful adverse effects. It has therefore been concluded that beta-lactams are the preferred antibiotic for use against bacterial infection in pregnancy.

The pharmacokinetics of Ampicillin during human pregnancy has been studied in detail and the placental transfer of Ampicillin has been well characterized. Ampicillin and other Penicillins accumulate in amniotic fluid in large amounts after maternal ingestion. This accumulation is caused by fetal urinary excretion of the antibiotic into the amniotic fluid, which continues until the mother stops ingesting the drug. Thereafter, the fetus gradually reabsorbs the antibiotic (probably by swallowing the amniotic fluid) and clears the drug by passage across the placenta to the mother. No adverse fetal effects have been associated with this process.

Primary studies have been conducted in rats with anhydrous Ampicillin (oral dosing by incorporation into diet, 200 or 400 mg/kg/day for 60 days before mating, through pregnancy and nursing for a minimum of either 15 weeks (1 litter study) or 21 weeks (2 litter study) and in rats with Ampicillin sodium (subcutaneous dosing, 200 mg/kg/day for the first 14 days of gestation and then through end of lactation). In both the 1 and 2 litter oral dose studies (20 maternal animals per Ampicillin treatment group) the authors reported no difference between control and Ampicillin-treated groups with respect to fertility (Ampicillin-treated male rats were used along with females), gestation period, litter size or ratio of sex of offspring, length or weight of pups at birth, weaning, or 3 weeks after weaning; pup morphology (by gross observation and alizarin red-stained skeletal examination) was also unaffected by treatment. In addition, dams from the 2 litter study were euthanised and reproductive organs examined; no Ampicillin-related effects of toxicological significance were observed. With subcutaneous administration, the authors reported no effect of Ampicillin treatment of reproductive success or outcomes.

Overall 6-APA is of low toxicological activity (no evidence of toxicity seen in any of the test available) and the very low log Pow suggests that there is unlikely to be any accumulation of test material in body fat.

Therefore, taking into account the low toxicity and animal welfare, this test is not considered scientifically necessary in accordance with Annex XI, section 1.1.

References:

Bray R et al: Transfer of ampicillin into fetus and amniotic fluid from maternal plasma in late pregnancy. Am J Obstet Gynecol 96:9328-42, 1966.

Greselin E, Herr F, Charest MP, Sadeek M, Vlielander L & Hajdu A. Toxicology studies of R-12, 101-5 (Penbritin oral, 6 (D(-)- α-Aminophenylacetamido) penicillanic acid –Type W.2/B (anhydrous).Beecham Research Laboratories Ltd. 1964

 Jordhein O, Hagen AG: Study of ampicillin levels in maternal serum, umbilical cord serum and amniotic fluid following administration of ampicillin. Acta Obstet Gynecol Scand 59:315-7, 1980.

Knothe N & G.A Dette .Antibiotics in Pregnancy: Toxicity and Teratogenicity.. Infection (1985) 13.Nr.2

 

Kraybill EN et al: Transplacental ampicillin: inhibitory concentrations in neonatal serum.Am J Obstet Gynecol 138:793-6, 1980.

MacAulay M et al: Placental transfer of ampicillin. Am J Obstet Gynecol 96:943-50, 1966.

 

 Philipson A: Pharmacokinetics of ampicillin during pregnancy. J Infect Dis 136:370-6, 1977.