Piperazine, compound with phosphoric acid

Toxicity to reproduction

Administrative data

Endpoint:

two-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Piperazine (CAS No 110-85-0) is the parent molecule from which piperazine, compound with phosphoric acid or piperazine phosphate (CAS No 1951-97-9) is synthesized. In medicine piperazine is used in the form of the hexahydrate or as the citrate, tartrate, phosphate (1951-97-9) or adipate. Thus, piperazine and piperazine phosphate can be considered as belonging to the same category. No conclusive evidence of reproductive effects have been demonstrated in feeding studies with phosphoric acid or phosphate salts in various species of laboratory animal although limited studies have suggested testicular effects and reduced fertility in rats. No carcinogenic potential was demonstrated in limited feeding studies in rats treated with phosphoric acid or several of its salts, however, in rodents treated orally, several phosphates have been shown to promote the effects of known carcinogens. A wide range of genotoxicity assays (including the Ames bacterial test) have yielded essentially negative results with the acid or its salts. Based on the above, it is has been considered that the properties of piperazine (parent molecule) shall have an important influence on the toxicological properties of piperazine phosphate. Thus, Piperazine (CAS No 110-85-0) has been used as a read across substance, especially for the toxicological end points in this dossier preparation.

Data source

Reference

Reference 1

Reference Type:

other: study report

Title:

Piperazine hydrochloride: Dietary two generation reproduction study in the rat.

Author:

Wood and Brooks PN

Year:

1994

Bibliographic source:

Report to Akzo Nobel from Safepharm Laboratories Ltd., Derby.

Reference 2

Reference Type:

other: study report

Title:

European Union Risk Assessment Report : Piperazine

Author:

European Chemicals Bureau

Year:

2005

Bibliographic source:

3rd Priority List Volume: 56;Final Report, 2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Piperazine

EC Number:

203-808-3

EC Name:

Piperazine

Cas Number:

110-85-0

IUPAC Name:

piperazine

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Administration / exposure

Route of administration:

oral: feed

Type of inhalation exposure (if applicable):

not specified

Vehicle:

not specified

Details on exposure:

The F0 males and females (32 per dose and sex) were dosed for 73 days for males and 17 days for females and paired within their respective dosage groups for up to 21 days.F1 animals were given piperazine in the diet for 80 days.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

For F0 males and females - 73 days for males and 17 days for females.
F1 animals - for 80 days

Frequency of treatment:

daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 5,000, 12,000, or 25,000 ppm (250, 600, or 1,250 mg/kg/day)
Basis:
no data

No. of animals per sex per dose:

32 per dose and sex

Details on study design:

Groups of male and female animals were administered 0,5,000, 12,000, or 25,000 ppm (250, 600, or 1,250 mg/kg/day) piperazine dihydrochloride in
the diet throughout maturation, mating, gestation and lactation phases for two successive generations.

Expressed as piperazine base, the doses represent 125,300, and 625 mg/kg/day. The F0 males and females (32 per dose and sex) were dosed for
73 days for males and 17 days for females and paired within their respective dosage groups for up to 21 days. Subsequent exposure to diets continued throughout the breeding, gestation and lactation periods for both generations.

F1 animals were given piperazine in the diet for 80 days, and all animals were observed for sexual development. Males and females were paired for up to 21 days and pregnant females allowed to deliver their offspring that were observed for growth and development. The adult F0 animals as well as the F1 males and females were sacrificed and examined macroscopically post mortem.

Examinations

Parental animals: Observations and examinations:

Parental animals were observed daily for clinical signs, and the body weights and food consumption recorded weekly during the maturation phase, which was continued for males after the mating phase. Mated females were weighted and food consumption recorded on specific days post coitum and post partum.

Litter observations:

Reduced litter size at birth for both generations (59% and 32% of control values in F1 and F2, respectively)

Postmortem examinations (parental animals):

The adult F0 animals was sacrificed and examined macroscopically post mortem.

Postmortem examinations (offspring):

The F1 males and females were sacrificed and examined macroscopically post mortem.

Results and discussion

Results: P0 (first parental generation)

Details on results (P0)

At 625 mg/kg/day piperazine base there was clear evidence of toxicity to the adult animals as judged by a statistically significant reduced body weight increase in both sexes for the F0 as well as F1 animals, an effect that was more pronounced in the second generation (F0 females,3%; F0 males 9%; F1 females 17%, F1 males 20%). Further, there was a reduction in number of pregnancies, reaching statistical significance only in F1 (81.5% vs100% in controls), and a reduced litter size at birth for both generations (59% and 32% of control values in F1 and F2, respectively) (Table 4.18), but no effects on live birth index,viability during lactation, or offspring physical development were noted when subjected to a set of reflexological tests. However, there was a delay in sexual maturation (appearance of vaginal opening for females and preputial separation for males) in both F1 males and females (not investigated in F2), but no significant differences in offspring sex ratios were noted at any dose level. However, it is likely that the delayed sexual observation could be related to the decreased body weights observed as from week 2 and onwards (roughly 25%, respectively).

At 300 mg/kg/day piperazine base, the effects on body weight gain were smaller, although statistically significant in F0 males (9%), but not in F0 females. In the F1 parental generation, bodyweights were significantly reduced in both males and females from week 2, and there was also a slight reduction in food consumption (F1 females, 9%; F1 males 9%). However, the food conversion ratios were similar to control values. There was no effect on the number of pregnancies, but a statistically significant reduced litter size at birth was noted in both generations.

Effect levels (P0)

1

Dose descriptor:

NOAEL

Effect level:

125 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: effects observed mainly on fertility (i.e., reduced pregnancy index and decreased number of implantation sites).

Remarks on result:

other: not specified

2

Dose descriptor:

LOAEL

Effect level:

300 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: the effects on body weight gain were smaller, although statistically significant in F0 males (9%), but not in F0 females.

Remarks on result:

other: not specified

3

Dose descriptor:

dose level:

Effect level:

625 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: there was clear evidence of toxicity to the adult animals as judged by a statistically significant reduced body weight increase in both sexes for the F0 as well as F1 animals.

Remarks on result:

other: not specified

Target system / organ toxicity (P0)

Critical effects observed:

not specified

System:

other: not specified

Organ:

not specified

Results: F1 generation

Details on results (F1)

The offspring were observed daily for clinical signs and the body weights recorded. During the lactation period the offspring were observed
for intra-litter onset and duration of landmarks of physical development. On specific days of lactation, reflexological assessment of offspring was performed. These tests included investigation of the surface-righting reflex (day 1 post partum), mid-air righting reflex (day 17 post partum), startle reflex (day 21 post partum) and pupil reflex (day 21 post partum).

Effect levels (F1)

1

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

125 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: effects observed mainly on fertility (i.e., reduced pregnancy index and decreased number of implantation sites).

Remarks on result:

other: not specified

2

Dose descriptor:

LOAEL

Generation:

F1

Effect level:

300 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Remarks on result:

other: not specified

3

Dose descriptor:

dose level:

Generation:

F1

Effect level:

625 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: there was clear evidence of toxicity to the adult animals as judged by a statistically significant reduced body weight increase in both sexes for the F0 as well as F1 animals.

Remarks on result:

other: not specified

Target system / organ toxicity (F1)

Critical effects observed:

not specified

System:

other: not specified

Organ:

not specified

Overall reproductive toxicity

Reproductive effects observed:

not specified

Treatment related:

not specified

Applicant's summary and conclusion

Conclusions:

For reproductive effects, a NOAEL of 125 mg/kg/day and a LOAEL of 300 mg/kg/day piperazine base can be established, with decreased litter size as the main effects. The NOAEL for the adult animals is estimated to be 125 mg/kg/day piperazine base, with body weight decreases (<10%) at 300 mg/kg/day in the F1-generation and in males of F0.

Executive summary:

For reproductive effects, a NOAEL of 125 mg/kg/day and a LOAEL of 300 mg/kg/day piperazine base can be established, with decreased litter size as the main effects. The NOAEL for the adult animals is estimated to be 125 mg/kg/day piperazine base, with body weight decreases (<10%) at 300 mg/kg/day in the F1-generation and in males of F0.