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Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
July 23, 1994 - July 29, 1994
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report date:
1994

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
EU Method B.1 (Acute Toxicity (Oral))
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
Deviations:
no
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
(R)-α-phenylethylammonium (-)-(1R, 2S)-(1,2-epoxypropyl)phosphonate monohydrate
EC Number:
418-570-8
EC Name:
(R)-α-phenylethylammonium (-)-(1R, 2S)-(1,2-epoxypropyl)phosphonate monohydrate
Cas Number:
25383-07-7
Molecular formula:
C11H20NO5P
IUPAC Name:
(R)-α-phenylethylammonium (-)-(1R, 2S)-(1,2-epoxypropyl)phosphonate monohydrate
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material (as cited in study report): Fosfomycin PEA salt
- Physical state: white crystalline powder
- Lot/batch No.: 4177
- Expiration date of the lot/batch: at least 3 years from the manufacturing date
- Stability under test conditions: at least 3 years
- Storage condition of test material: plastic bag in a cartboard box, at room temperature protected from the light.
- Other: manufacturing date: June 10, 1994

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Italia S.p.A.
- Age at study initiation: 7/9 weeks
- Weight at study initiation: Males: 225-250 g. Females: 200-225 g
- Fasting period before study: 16 hours
- Housing: 5 animals/sex/cage in T11C air-conditioned room in grill cages 40.5x38.5x18h cm with stainless feeder.
- Diet (e.g. ad libitum): Ad libitum (GLP 4RF21 top certificate pellet diet)
- Water (e.g. ad libitum): Ad libitum (from the municipal water main system, filtered).
- Acclimation period: Five days before the start of the test

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2 ºC
- Humidity (%): 55 ± 10 %
- Air changes (per hr): 20 per hour (filtered on HEPA 99.97 %)
- Photoperiod (hrs dark / hrs light): 12 h dark/12 h light (7 a.m - 7 p.m)

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: Methocel (methylcellulosae aqueous solution)
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 100 mg/ml

MAXIMUM DOSE VOLUME APPLIED: 20 ml/kg
Doses:
2000 mg/kg bw
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Clinical signs and mortality: at 30 minutes, 2, 4 and 6 hours on the first day after the administration (day 1) and then twice a day up to termination of the observation period.
Weighing: twice pre-trial (at randomization and on day 1 just before administration) and on days 3, 8 and 14.
- Necropsy of survivors performed: Yes. All surviving animals (fasted overnight) were killed by excision of the femoral arteries, after i.p. overdosage anesthesia with 5% sodium pentobarbital.
- Other examinations performed: clinical signs, body weight, organ weights, histopathology, other: Clinical signs and behaviour, body weight and gross pathology examinations.

Results and discussion

Effect levels
Key result
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
No animals died during the observation period.
Clinical signs:
Signs involving the CNS (hypoactivity, muscular tremors, palpebral closure and hypothermia), the respiratory apparatus (shallow breathing) and piloerection, hunched posture and salivation were clinically observed in the treated rats starting from 30 minutes - 4 hours and lasting up to 6-24 hours after the test article administration. Sporadic cases of ataxia, reddish nasal discharge and chromodacryorrhea were also observed in some animals during the first days of the study. Recovery of all treated rats was achieved within 24 (females) - 48 hours (males) of treatment.
Body weight:
Low body weight gain was observed in some animals only at the day 3 weighing. Body weight gain returned to normal at the subsequent weighings.
Gross pathology:
No appreciable macroscopic findings were evident in any treated rat.

Any other information on results incl. tables

Table 1. Clinical signs frequency (cumulative)

Clinical signs

No. of rats affected

Signs observed (time)

From*

To**

Hypoactivity

10

30 m

6 h

Ataxia

2

2 h

6 h

Reddish nasal discharge

2

2 d

-

Shallow breathing

3

2 h

2 d

Piloerection

10

30 m

2 d

Hunched posture

10

30 m

2 d

Muscular tremors

6

30 m

6 h

Salivation

6

30 m

6 h

Chromodacryorrhea

1

2 d

-

Palpebral closure

4

4 h

6 h

Hypothermia

3

2 h

2 d

Recovery

10

2 d

3 d

* first observation in one or more animals; ** last observation in one or more animals.

(day of treatment = day 1)

 

Table 2. Body weight (g). Dose: 2000 mg/kg.

Day

1 M

2 M

3 M

4 M

5 M

6F

7F

8F

9F

10F

Pre-trial

269

260

269

274

267

242

228

224

228

236

1*

247

235

248

250

238

220

209

209

210

214

3

258

251

269

260

249

226

209

214

215

224

8

298

287

305

285

301

248

229

236

261

248

14

362

344

352

353

344

263

252

253

281

270

 

Table 3. Gross pathology examination.

Dose

(mg/kg)

Animals

Macroscopic findings

2000

Males No. 1-5

No appreciable macroscopic findings

 

Females No. 6-10

No appreciable macroscopic findings

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Remarks:
EU criteria.
Conclusions:
The oral LD50 of the test article in rats was higher than 2000 mg/kg bw.
Executive summary:

A toxicity study in Sprague Dawley Crl:CD (SD) rats (5 males and 5 females) with a single oral administration of the test article Fosfomycin PEA salt at the dosage of 2000 mg/kg bw (limit dose) was performed in accordance with EU Method B.1 and OECD Guideline 401. The test article was administered as a suspension in 0.4% methylcelllulosae aqueous solution at the constant volume of 20 ml/kg. All rats were treated after a 16 hour fasting period. The day of treatment was considered day 1 of the study. The animals were weighed twice before treatment (at randomization and on day 1 just before treatment) and on days 3, 8 and 14. They were clinically observed for 14 days following the treatment. On day 15 all treated rats were killed by excision of the femoral arteries, after i.p. overdosage anesthesia with 5% sodium pentobarbital and they were submitted to a thorough autopsy.

No animals died during the observation period.

The main clinical signs observed were: hypoactivity, muscular tremors, palpebral closure and hypothermia), the respiratory apparatus (shallow breathing) and piloerection, hunched posture starting from 30 minutes - 4 hours and lasting up to 6-24 hours after the test article administration. Sporadic cases of ataxia, reddish nasal discharge and chromodacryorrhea were also observed in some animals during the first days of the study. Recovery of all treated rats was achieved within 24 (females) - 48 hours (males) of treatment.

Low body weight gain was observed in some animals only at the day 3 weighing. Body weight gain returned to normal at the subsequent weighings. No appreciable macroscopic findings were evident in any treated rat.

In conclusion, the oral LD50 of the test article in rats was higher than 2000 mg/kg bw and transient clinical signs involving the CNS and the respiratory apparatus were the main findings.