Phenylephrine hydrochloride

Repeated dose toxicity: oral

Administrative data

Endpoint:

chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Non-GLP, non-guideline study, published in peer reviewed literature, limitations in design (neurobehavioural exminations, haematology, clinical chemistry and organ weight measurements not conducted), and reporting, but otherwise adequate for assessment.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Materials and methods

Principles of method if other than guideline:

Groups of 50 rats of each sex were fed diets containing 620 or 1,250 ppm phenylephrine hydrochloride for 2 years. Endpoints to assess toxicity included mortality, clinical observations, ophthalmologic examination, body weight, food consumption, necropsy and histopathology.

GLP compliance:

no

Remarks:

However, the experimental data, pathology materials and tables for the report were examined for completeness, consistency, and accuracy and for procedures consistent with Good Laboratory Practice requirements.

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Phenylephrine hydrochloride

EC Number:

200-517-3

EC Name:

Phenylephrine hydrochloride

Cas Number:

61-76-7

Molecular formula:

C9H13NO2.ClH

IUPAC Name:

phenylephrine hydrochloride

Details on test material:

- Name of test material (as cited in study report): phenylephrine hydrochoride
- Molecular weight: 203.7
- Molecular formula:C9H13NO2HCl
- Appearance: white, microcrystalline powder
- Analytical purity: about 99% by elemental analysis, high-performance liquid chromatography, nonaqueous titration of the amine group, and the USP titration method that uses bromination of three aromatic ring positions
- Impurities: 0.08% water; two impurities (not identified) with a total peak area of 0.09% of that of the major peak detected by HPLC.
- Lot/batch No.: 160-XX-177 (from Ganes Chemical Company, New York)
- Stability under test conditions: stable upon storage for at least 2 weeks at temperatures up to 60°C
- Storage: in the dark at 25ºC

Test animals

Species:

rat

Strain:

other: F344/N

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories (Portage, MI)
- Age at study initiation: 6-7 weeks
- Weight at study initiation: males 139-146 g, females 107-112 (group means)
- Housing: 5 animals of the same sex per cage; polycarbonate cages with Reemay spun-bonded polyester filters and Aspen wood shavings as bedding
- Diet: ad libitum; NIH 07 Rat and Mouse Ration (Zeigler Bros., Gardners, PA)
- Water: ad libitum; public water supply softened with sodium zeolite to 21 grains/gal, then filtered through spun polyethylene; automatic watering system (Edstrom Industries, Waterford, WI)
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22.7 ± 0.4
- Humidity (%): 50 ± 10
- Air changes (per hr): >15
- Photoperiod (hrs dark / hrs light): 12 / 12 (fluorescent light)

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

DIET PREPARATION
- Rate of preparation of diet: once per week (maximum storage time).
- Preparation procedure: a dry premix of feed (NIH 07 Rat and Mouse Ration) and test material was added to the appropriate amount of feed and mixed for 15 minutes in a stainless steel blender
- Storage temperature of food: 4°C

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

- Analytical method: Extraction of diet samples with methanol:acetic acid (99:1 for homogeneity samples, 95:5 for samples to check stability and achieved concentration) followed by HPLC analysis of the filtered extract.
- Homogeneity: Checked by analysis (in duplicate) of samples taken at three different locations from the feed in the blender. All dietary concencentrations measured were within ±10% of the target values (1250 or 2500 ppm).
- Stability: Checked by analysing samples (from an 800 ppm feed blend) after storage at -20, 5, 25 or 45°C for two weeks. The results showed that the test material was stable under these conditions.
- Achieved concentrations: The feed mixtures were analyzed periodically to determine if they contained the correct concentrations of phenylephrine hydrochloride. All of the analyzed feed mixtures were within ± 10% of the target concentrations.

Duration of treatment / exposure:

103 weeks

Frequency of treatment:

daily in feed

Doses / concentrations

Remarks:

Doses / Concentrations:
0 - 620 - 1,250 ppm (mg/kg diet)
Basis:
nominal in diet

No. of animals per sex per dose:

50/sex/dose

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: Based on decreased weight gain (11% decrease in terminal body weight in males at 1,250 ppm) and deaths (at 5,000 ppm and higher) in the 12-week study, doses selected for the 2-year study were 620 and 1,250 ppm.

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice per day

BODY WEIGHT: Yes
- Time schedule for examinations: once per week during the first 12 weeks, once per four weeks thereafter

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption: Measured per cage, once per week
- Calculated compound intake: Yes

OTHER:
- Palpation: once per four weeks from 9 to 24 months
- Ophthalmoscopic examination: 10 control and 10 high-dose animals of each sex at 6, 12 and 18 months

HAEMATOLOGY, CLINICAL CHEMISTRY, URINALYSIS, NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
Necropsy was performed on all animals including those that died before the end of the study (unless they were excessively autolyzed, cannibalized, missexed or found missing).

ORGAN WEIGHTS: No

HISTOPATHOLOGY: Yes
Animals examined: all.
Tissues were preserved in 10% neutral buffered formalin, embedded in paraffin, sectioned, and stained with hematoxylin and eosin.
Tissues examined: gross lesions, skin, mandibular lymph nodes, mammary gland, salivary gland, sternebrae or vertebrae or femur including marrow, thymus, larynx and pharynx, trachea, lungs and bronchi, heart and aorta, thyroid gland, parathyroids, esophagus, stomach, duodenum, jejunum, tongue, tissue masses and regional lymph nodes, ileum, colon, cecum, rectum, mesenteric lymph nodes, liver, pancreas, spleen, kidneys, adrenal glands, urinary bladder, seminal vesicles/prostate/testis/epididymus/vaginal tunics/scrotal sac or ovaries/uterus, brain, pituitary gland, and preputial or clitoral glands. The mesovarium was among those tissues taken for histologic assessment only if a gross lesion was noted.

Statistics:

Survival:
The probability of survival was estimated by the product-limit procedure of Kaplan and Meier (1958). Animals were censored from the survival analyses at the time they were found dead of other than natural causes or were found to be missing; animals dying from natural causes were not censored. Statistical analyses for a possible dose-related effect on survival used the method of Cox (1972) for testing two groups for equality and Tarone's (1975) life table test for a dose-related trend. When significant survival differences were detected, additional analyses using these procedures were carried out to determine the time point at which significant differences in the survival curves were first detected. The survival analyses were two-sided.

Other endpoints: no comparative statistical analysis (except for tumour data; details on analysis of these data are given under 7.7 Carcinogenicity)

Results and discussion

Results of examinations

Details on results:

SURVIVAL
Survival was not adversely affected by treatment. After week 98, survival of high-dose males was significantly greater than that of controls.

CLINICAL SIGNS
There were no treatment-related clinical signs of toxicity.

OTHER
There were no treatment-related ophthalmologic findings.
Palpable masses: no data.

BODY WEIGHT AND WEIGHT GAIN
Compared to controls, body weights of dosed animals were slightly lower. This effect was dose-related. In males, mean body weights were 3%-8% (low-dose) or 4%-15% (high-dose) lower throughout of the study. In females, mean weights were about 4%-10% (high-dose) lower compared to controls throughout most of the study. Body weights of low-dose females were similar to controls. NB: the initial mean weight at the high-dose was 5% (males) or 4% (females) lower than that of controls.

FOOD CONSUMPTION
Food consumption was not affected by treatment.

GROSS PATHOLOGY
No results reported.

HISTOPATHOLOGY: NON-NEOPLASTIC
- Liver: increased incidence and severity of chronic focal inflammation in both sexes at both dose levels (males: control 2/50, low-dose 13/50, high-dose 17/50; females control 17/50, low-dose 28/50, high-dose 35/50). The lesion did not differ in character from the lesion that occurs spontaneously in the F344 rat. It was characterized by the presence of mononuclear cells scattered around bile ducts in the portal triad regions of hepatic lobules. Small granulomas were frequently adjacent to or replacing bile ducts in the portal regions. The granulomas appeared to consist entirely of macrophages.
- Prostate: increased incidence and severity of inflammation at both dose levels (control 10/50, low-dose 24/50, high-dose 24/50). These lesions were similar to those that spontaneously arise in the F344 rat but were subjectively judged to be more severe in dosed rats than in control rats.
- Lung: increased incidence of perivascular cuffing (inflammation surrounding the vascular tissue in the lung) in low- and high-dose males (males: control 2/50, low-dose 12/50,high-dose 8/50; females: control 4/50, low-dose 6/50, high-dose 7/50). The association of this lesion with treatment was less clear than that for the inflammation observed in the liver and prostate.

No other compound related non-neoplastic changes were observed.

HISTOPATHOLOGY: NEOPLASTIC
No compound-related increases in neoplastic lesion were observed. Notably, the incidence of proliferative lesions in the haematopoietic system, adrenals and liver was lower in dosed rats than in controls (see details on results under 7.7 Carcinogenicity).

Effect levels

Dose descriptor:

LOAEL

Effect level:

620 mg/kg diet

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Target system / organ toxicity

Critical effects observed:

not specified