3β,21-dihydroxy-16α-methylpregn-5-en-20-one 21-acetate

Toxicity to microorganisms

Administrative data

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Dec 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to DIN guideline under GLP

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

DIN 38412-8 (Pseudomonas Zellvermehrungshemmtest)

Deviations:

no

Principles of method if other than guideline:

Not relevant

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

3β,21-dihydroxy-16α-methylpregn-5-en-20-one 21-acetate

EC Number:

214-633-7

EC Name:

3β,21-dihydroxy-16α-methylpregn-5-en-20-one 21-acetate

Cas Number:

1173-09-7

Molecular formula:

C24H36O4

IUPAC Name:

2-[(1S,2R,3aS,3bS,7S,9aR,9bS,11aS)-7-hydroxy-2,9a,11a-trimethyl-1H,2H,3H,3aH,3bH,4H,6H,7H,8H,9H,9aH,9bH,10H,11H,11aH-cyclopenta[a]phenanthren-1-yl]-2-oxoethyl acetate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): 16-Alpha-Acetoxypregnenolon
- Analytical purity: 98.8%
- Lot/batch No.: 14415018

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Pseudomonas putida

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

16 h

Results and discussion

Effect concentrations

Duration:

16 h

Dose descriptor:

EC50

Effect conc.:

> 24 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Any other information on results incl. tables

Table 1: Mean values of turbidity (expressed as TE/F) and growth inhibition as a function of the concentration

Concentration	TE/F ± standard deviation		Growth inhibition (%)
( mg/L)	[mean value (16 hours)]
Control	315	± 7,1	0
1 :1000 diluted	307	± 15,3	2,5
1:100 diluted	350	± 79,4	-11,1
1 :10 diluted	337	± 25,2	-7
saturated, not diluted	403	± 5,8	-27,9

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

16-Alpha-Acetoxypregnenolon in a saturated solution (approximately 24 mg/I) had no inhibitory effect on the growth of Pseudomonas putida.
The slight increase of growth is not considered to be relevant in terms of aquatic toxicity. Furthermore, the test method is not designed for the
evaluation of growthstimulating
effects.

Executive summary:

The test substance 16-Alpha-Acetoxypregnenolon (ZK 29211) was incubated in an aqueous solution including nutrients with a bacterial population of Pseudomonas putida for a test duration of approximately 16 hours. The nutrient solution was made up of mainly nitrate, phosphates, carbohydrates, some trace elements and vitamins. A stock solution with a concentration of 1000 mg/L was prepared, stirred for 24 hours and filtered. This filtered stock solution was used for the highest test concentration. For the rest of the test concentrations the stock solution was diluted 1:10, 1:100 and 1 :1000. Additionally, one control without the test substance was used. Furthermore, for each test concentration one test vessel was incubated without addition of the inoculum in order to analyse the inherent turbidity of the test compound. All test solutions including the control were incubated in triplicate. As a parameter for the grawth of the bacterial population, the turbidity of the test and contral solutions was analysed photometrically at a wave-Iength of 436 nm. The concentration of the saturated, filtered solution was estimated by TOC-analysis and subsequent calculation based on the structural formula. It was estimated with approximately 24 mg/L.

The measurements showed that there is no growth inhibition of the bacterial population. On the contrary, there is a slight growth increase particularly at the highest test concentration in comparison with the control group.