Registration Dossier

Toxicological information

Basic toxicokinetics

Currently viewing:

Administrative data

Endpoint:
basic toxicokinetics
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Report with some details lacking

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1979
Report Date:
1979
Reference Type:
publication
Title:
Absorption, distribution, excretion and metabolism of orally administered 14C-beta-cyclodextrin in rat.
Author:
A. Gerlóczy, A. Fónagy, P. Keresztes, L. Perlaky, J. Szejtli
Year:
1985
Bibliographic source:
Arzneimittelforschung. 1985, 35(7), 1042-7
Reference Type:
publication
Title:
Absorption and Metabolism of beta-Cyclodextrin by Rats
Author:
A. Gerlóczy, A. Fónagy, J. Szejtli
Year:
1981
Bibliographic source:
Proceedings of the first International Symposiums on Cyclodextrins (1981), J. Szetliy (ed.), Reichel, Dordrecht (1982), 101-108.

Materials and methods

Objective of study:
absorption
distribution
excretion
metabolism
Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 417 (Toxicokinetics)
Deviations:
yes
Principles of method if other than guideline:
see Details on study design
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Universally labelled 14C-beta-CD was synthesized in the Department of Agricultural Chemistry and Techniques, University of Technology, Budapest.
Radiolabelling:
yes
Remarks:
universally labelled 14C

Test animals

Species:
rat
Strain:
other: Wistar (Amsterdam) X Long Evans (Chester Beatty) F1 male rats and CFY female rats
Sex:
male/female
Details on test animals and environmental conditions:
Absorption study:
Wistar (Amsterdam) X Long Evans (Chester Beatty),F1 males weighing on average 200 g, were used. They received a standard rat diet and drank water ad lib.
Wistar (Amsterdam) X Long Evans (Chester Beatty),F1 males weighing-on average 160g, were starved for 4-8 h before treatment, and also during it; drinking water was made available ad lib. throughout.

Blood level study:
Intravenous treatment: A female CFY rat weighing 120 g was treated with 13.33 mg/kg 14C-beta-CD (309.32 kBq/kg = 8.36µCi/kg) by intravenous injection into the tail vein; the test substance was dissolved in physiological saline solution and was administered in 0.5 ml volume.
Oral treatment: One CFY female rat weighting 200 g, was staved for 24 h, under ad lib. water supply. It subsequently received a single dose of 313.5 mg/kg 14C-beta-CD (7272.72 kBq/kg = 196.56 µCi/kg) by oral route, through a gastric tube. The test substance was homogenized in 20% dextran solution, and was administered in 2.5 ml volume.

Excretion and distribution study:
A female CFYrat, 150 g in weight was given orally 36.1 mg/kg 14C-beta CD (837.31kBq/kg =22.63 µCi/kg.), homogenized. in 1 ml 20% dextran solution. Another female CFY rat, 200 g in weight, received orally 313.5 mg/kg 14C-beta CD (7272'.72 kBq/kg = 196.56 µCi/kg), homogenized in 2.5 ml 20% dextran solution. Three female CFY rats; on average 150 g in weight, received each a 1.88 mg/kg (43.66kEq/kg = 1.18 µCi/kg) oral dose of chromatographically purified 14C-beta CD, homogenized in 1.5ml 20% dextran solution.
The control rats, one OFY female weighing160g, and one Wistar R (Amsterdam) X Long Evans (Chester Beatty) Fl male, weighing 150 g, were treated orally with 12.8 mg/kg (2006.5 kBq/kg = 54.23 µCi/kg) 14C-glucose, homogenized for administration in 1 ml 20% dextran solution.


No further details available.

Administration / exposure

Route of administration:
other: oral:gavage and intravenous
Vehicle:
other: 20% dextran solution if applied orally and saline solution in case of injection
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: once


DIET PREPARATION
- Rate of preparation of diet (frequency): not applicable
- Mixing appropriate amounts with (Type of food): not mentioned


VEHICLE
- Justification for use and choice of vehicle (if other than water): solubility and non-toxicity
Duration and frequency of treatment / exposure:
once
Doses / concentrations
Remarks:
Doses / Concentrations:
Absorption study:
Orally: 49.6 mg/kg 14C-beta-CD (1150.7 kBq/kg =31.1µ,Ci/ /kg) and 36.7 mg/kg 14C -beta CD (851.37 kBq/kg = 23.01 µCi/kg) (male rats)

Blood level study:
Orally: 313.5 mg/kg 14C-beta CD (7272.72 kBq/kg = 196.56 µCi/kg)
Intravenous: 13.33 mg/kg 14C-beta CD (309.32 kBq/kg = = 8.36 µCi/kg) by intravenous injection into the tail vein

Distribution and Excretion study:
1.88 (43.66 kBq/kg = 1.18 µCi/kg), 36.1mg/kg (837.31 kBq/kg = 22.63 µCi/kg) or 313.5 mg/kg (7272.72 kBq/kg = 196.56 µCi/kg)(female rats)
No. of animals per sex per dose:
Absorption study:
exp. 1: 5 (+ 3 control)
exp. 2: 2 (+ 2 control)

Blood level:
intravenous: 1
orally: 1

Excretion and distribution study:
low dose: 3
mid dose: 1
high dose: 1
(+ 2 control)
Control animals:
other: yes, concurrent 14C-Glucose
Positive control:
no
Details on study design:
1) Absorption study:
Assay of blood samples for radioactivity:
In the first experiment, Wistar R (Amsterdam) X Long Evans (Chester Beatty) F1 male rats, on average 200 g weight , received food and water ad lib. before and during treatment. Five rats were treated orally, through a gastric tube, with 49.6 mg/kg 14C-beta-CD (1150.7 kBq/kg =31.1µ,Ci/kg). The test substance was homogenized in 20% dextran solution (dextran MW 43000) and administered in 1 ml volume. Three control rats were given 50.9 mg/kg 14C-glucose (376.66 kEg/kg = 10.18 µCi/kg), also by the oral route, through a gastric tube; 14C-glucose was homogenized in 20% dextran solution, and w.as administered in 1 ml volume, as above.
In the second experiment, Wistar R (Amsterdam) X Long Evans (Chester Beatty) F1 males, on average 160 g in weight, were starved for 4-8 h-before treatment, and during the experimental period as well, but received drinking water ad lib. throughout. Two rats received orally, through a gastric tube, 36.7 mg/kg 14C-beta CD (851.37 kBq/kg = 23.01 µCi/kg) homogenized in 1% methylcellulose; the average dose volume was 1.5 ml. Another two rats were treated in the same way with 36.9 mg/kg 14C-g1ucose (1091.5 kBq/kg = 29.5 µCi/kg), dissolved in 196 methylcellulose, and administered on average in 1.5 ml volume.

Blood samples , 50 µl each, were withdrawn from the tail vein of the rats at predetermined time intervals. The samples were solubilized in 0.75 ml of Soluene-100 (Packard):isopropanol = 1:1 (v/v) solution and were bleached with a 25ml hydrogen peroxide for 30min at room temperature. Then 10 ml of Insta Gel (Pack-ard):0.5 M HCI =1:1 (v/v) solution was added to the samples, which were incubated in the dark for 24 h, at room temperature, to prevent light effect. After incubation, the samples were assayed for radioactivity in the first experiment in a Searle Nuclear Chicago Mark III 6880 apparatus , in the second experiment in a Beckman LS 100 C liquid scintillation counter. The radioactivity (dpm) measured was related to 10 ml blood and expressed as thousandth of total administered radioactivity.


2) Blood level study:
Determination of the blood 14C-beta CD level:
Intravenous treatment: A female CFY rat weighing 120 g was treated with 13.33 mg/kg 14C-beta CD (309.32 kBq/kg = 8.36 µCi/kg) by intravenous injection into the tail vein; the test substance was dissolved in physiological saline solution and was administered in 0.5 ml volume.
Oral treatment: A female CFY rat weighing 200 g was starved for 24 h , under ad lib. water supply. It subsequently received a single dose of 313.5 mg/kg 14C-beta CD (7272.72 kBq/kg = 196.56 µCi/kg) by oral route, through a gastric tube. The test sub-stance was homogenized in 20% dextran solution, and was administered in 2.5 ml volume.

3) Excretion and Distribution study:
Quantitative assay of exhaled 14CO2 and radioactivity measurement of urine, faeces and organs:
The rats were starved for 24 h before treatment, but received drinking water ad lib. During the experimental period they were also deprived of water.
One female. OFY rat, weighing 150 g, was given 36.1mg/kg (837.31 kBq/kg = 22.63 µCi/kg) 14C-beta CD orally, through a gastric tube; 14C-beta CD was homogenized in 1 ml 20% dextran solution for administration. Another female CFY rat, 200g in weight, received 313.5 mg/kg 14C-beta CD (7272.72 kBq/kg = 196.56µCi/kg) by the oral route, in 2.5m12096 dextran solution. Three female CFY rats, on average 150 g in weight, were given 1.88 mg/kg chromatographically purified 14C-beta CD (43.66. kBq/kg = 1.18 µCi/kg) orally through a gastric tube, in 1.5 ml 20% dextran solution. Two control rats, a CFY female weighting 160 g, and a Wistar R (Amsterdam) X Long Evans (Chester Beatty) F1 male, weighing 150g, received each 12.8 mg/kg 14C-glucose (2006.5 kBq/kg = 54.23 µCi/kg) orally through a gastric tube , in 1 ml 20% dextran solution.

Details on dosing and sampling:
High performance liquid chromatography
Conditions: Varian 8500 apparatus, Knauer UV-RI double detector; temperature: 25°C; Knauer column (4.6 x 25 cm); column packing: LiChrosorb NH2 5 µm; injection volume: 25 µl; eluant: acetonitril : water 74:26 (v/v); flow rate 1.5 ml/min; fraction volume: 0.19 ml (10 drops): there were 2 µm thick metal filter pads on top of th column, and on these were mounted three GF/F glass filter pads, to which the blood sample was applied. 14C-beta CD was detected by refraction index detector. A mixture of non-labelled ri-bose, glucose, maltose and beta CD was chromatographed as reference standard.

Measurement of radioactivity
The radioactivity of the chromatographic fractions of 14C-beta CD was measured by the liquid scintillation technique. After measurement of the fractions the filters and the radioactivity of the contaminated (about 0.5 cm thick) top layer of the column packing was also measured. The samples, 0.19 or 0.5.ml in volume, were transferred each to 2 ml Bray's solution (600 ml toluene, 1800 ml dioxane, 1800 ml methylcellosolve, 42 g PPG, 2.1 g POPOP, 336 g naphtalene).

Determination of 14C-beta CD in blood in vitro
One hundred µl 3.8% Na-citrate solution and subsequently 43 µg (60000 dpm) 14C-beta CD was added to 100 µI of blood. The sample was mixed, for overnight then hydrolysed with 50 µl 3M KOH by continuous stirring for further 12 h at room temperature. Then it was neutralized with 40 µl 4M HCl and 25 µl aliquot was used for liquid chromatography.

Determination of 14C-beta CD in blood, after intravenous administration
A 13.33 mg (309.32 kBq/kg = 8.36 µlCi/kg) dose of 14C-beta OD , dissolved in 0.5 ml physiological saline solution, was injected into the tail vein of a female CFY rat weighing 120 g. Two min later a blood sample was withdrawn from the tail vein. One hundred µl Na-citrate, and subsequently 50 µI 3 M KOH was added to 100 µl blood. The sample was then hydrolysed for 12 h, neutralized with 40 µl 4 M HCl, and 25µl of it was used for liquid chromatography.
Statistics:
not reported

Results and discussion

Preliminary studies:
not reported

Toxicokinetic / pharmacokinetic studies

Details on absorption:
Determination of radioactivity level of blood
The blood radioactivity levels of 14C-beta CD and 14C-glucose were compared after oral administration. In the first experiment we used rats given food and water ad lib. before and during the experiment. Five rats received orally 49.6 mg/kg (1150 kBq/kg) 14C- beta CD, and three control rats received 50.9 mg/kg (376.66 kBq/kg) 14C-glucose,
also orally.
The individual radioactivity values (dpm) related to 10 ml blood and expressed as thou-sandths of the total administered radioactivity. The radioactivity of blood increased slowly up. to the 4th h after 14C-beta CD treatment, then it remained almost constant until the 8th h when the radioactivity found in the blood corresponded to 0.5% of the administered radioactivity. After that radioactivity level of blood decreased continuously, 96 h after the treatment about 0.3% of the administered radioactivity was still present in the blood. Treatment with 14C-glucose was followed by a rapid increase of radioactivity.
The radioactivity peak, corresponding to 1.5% of the administered radioactivity, was measured within half an hour after glucose administration. The radioactivity level of blood decreased to about 0.3% by 96 h.
The rats used in the second experiment were starved for 48 h before treatment, and .further during the experimental period. Two rats each received 36.7 mg/kg (851.37 kBq/kg) 14C-beta CD and 36.9 mg/kg (1091.5 kBq/kg) 14C-glucose, resp., by the oral route. The radioactivity peak, 1.2-1.7% of administered radioactivity, appeared 5-11 h after 14C- beta CD treatment. The 14-C-glucose peak, 8.2% of administered radioactivity appeared within 30min after administration.
The slopes of the curves for blood radioactivity levels were similar to those found in un-fasted rats, but 14C-beta CD and14-C-glucose equally reached higher levels in the fasting condition. Radioactivity appeared in the blood of rat following per os 14C-beta CD treatment. A protracted, low radioactivity maximum appeared between 4-8 or 5-11 h after treatment, the radioactivity peak corresponded to 0.5 or 1.7% of the administered radioactivity, resp.
Details on distribution in tissues:
Determination of blood 14C-beta CD level
The 14C-beta CD level was determined in whole blood both in vitro and in vivo, after intravenous and oral administration. We used the method of Zsadon and colleagaes (Zsadon, B., Otta, K.H., Tildes, F. and Szejtli, J.: J. Chromatogr. 172, 490, 1979) for high performance liquid chromatography.
For in vitro chromatographic analysis, 60000 dpm (43 µg) 14C-beta CD was added to 200 µl citrated blood, the sample was hydrolized in alkanine medium, neutralized, and an aliquot of 512 dpm radioactivity was applied on the column, 2162 dpm of it was re-tained on the top of the column and on a total 2065 dpm appeared in the beta CD peak.
Similar results were obtained after intravenous administration of 14C-beta CD; it was injected in 13.33 mg/kg dose ( 309.32 kBq/kg) into the tail vein of a female CFY rat, which was killed by bleeding after treatment. After appropriate treatment of the sample, 4500 dpm was applied on the column, of which1800dpm was retained on the top of the column, and 2000 dpm appeared in the beta CD peak.
For oral treatment 313.5 mg/kg 14C-beta CD (7272.72 kBq/kg) was fed to a female CFY rat weighing 200g. The following results were obtained on analysis at Shafter treatment. The radioactivity of 50 µI blood was assessed as 5000 dpm by liquid scintillation tech-nique. After processing of the sample, 1017 dpm (corresponding to 10.17 µl blood) was applied on the column; 700dpm was retained on top, 47 dpm appeared in the beta CD peak, and 269 dpm detected in the fraction preceding beta CD, was regarded as me-tabolized beta CD. If the unidentified radioactivity of 700 dpm, retained on the top of the column, is regarded as deriving from 14C-beta CD, the maximum radioactivity attributable to 14C-beta CD is 700+47 dpm = 747 dpm in 10.17 µl blood, i.e. 73451 dpm (52.7 µg 14C-beta CD) in 1 ml blood. Since the specific gravity of the blood is 1.06 g/ml, the 14C-beta CD content of 1 g blood should be 49.7 µg, this, however, is an overestimated value, because the unidentified activity retained on the filter (700 dpm), which was also included in the calculation amounts to 93.796 of the total dpm measured (747 dpm). If only the amount detected in the beta CD peak (47 dpm) is considered, the beta CD con-tent of the blood amounts to 3.1 µg/g, i.e. 3.1 ppm.
Organ distribution of label
After the finishing of assays for exhaled 14CO2 (24 h at the low and intermediate dose level, and 10 h at the high dose level), the rats were killed, autopsied, and the liver, kidney, spleen, lung, heart, brain, gonads, adrenals, thymus, stomach, small and large in-testine were assayed for radioactivity. Appropriate samples were also secured from the fat and muscle tissue. Organ radioactivity (dpm) was expressed as per cent of total ad-ministered radioactivity (dpm).
A considerable difference was, however, found between the radioactivities of the colon contents of experimental (36.1 and 1.88 mg/kg 14C-beta CD) and control rats (12.8 mg/kg 14C-glucose) 24 h after treatment. In the experimental series 9-15% of the total label in the control series about 2% of it (with the faecal radioactivity included) appeared in the colon within the above time period.
At the highest level of treatment (313.5 mg/kg 14C-beta CD) about 55% of total admin-istered radioactivity was detected in the colon 10 h after administration of the labelled compound. Organ radioactivities did not appreciably differ between 14C-beta CD treated experimental rats and the 14C-glucose treated controls. No specific cumulation of label derived from 14C-beta CD was observed in any organ.
Details on excretion:
Assay of urine and faeces for radioactivity
The amount of label (dpm) excreted in the urine and faeces within 24 h - in the case of the 313.5 mg/kg dose within 10 h - was reported in per cents related to total urine vol-ume or faecal weight, and to total administered radioactivity (dpm) as 100%. The amount of label excreted with urine did not differ appreciable between the experimental and control rats, having been 4.2-4.8 % and 2-3.6 %, resp. A similar comparison of the faecal samples was not possible as the experimental animals had no faeces.

Detection of exhaled 14-CO2
One rat received orally 36.1 mg/kg 14C-beta CD (837.31 kBq/kg), another rat 313.5 mg/kg 14C-beta CD (7272.72 kBq/kg), and three rats were treated, also by the oral route, with 1.88 mg/kg (43.66 kBq/kg) chromatographically purified14C-beta CD. The control rats received 12.8 mg/kg 14C-glucose (2006.5 kBq/kg), orally. (For further de-tails see Chapters 11.1. and 11.3. of this Report.) The rats were caged individually in metabolic cages, and the exhaled air was assayed for radioactivity every other hour over a 24h (36.1 and 1.88mg/kg)or a 10 h period (313.5 mg/kg). The radioactivity (dpm) found was expressed in percents related to total administered radioactivity (dpm). The results show changes in the radioactivity of exhaled 14CO2 after treatment with 36.1 and 313.5 mg/kg 14C-beta CD. Detectable radioactivity appeared 2 h after treatment at both dose levels; it corresponded to 3.8-5% of administered radioactivity. The radioac-tivity peak appeared between 6 and 8 h after treatment; it corresponded to 20 and 5% of administered radioactivity at the 36.1 and 313.5mg/kg dose level, resp. At the interme-diate level of treatment (36.1 mg/kg) 1.46% of the administered radioactivity was de-tected between 22 and 24 h; the total 14CO2 radioactivity detected in 24 h was 64.1% of the administered radioactivity. Fifty per cent of the total exhaled radioactivity was measured within 7.3 h. The latter value could not be given for the 313-5 mg/kg dose, at which observation lasted only 10 h.
Changes in radioactivity of exhaled 14CO2 following oral administration of chromato-graphically purified 14C-beta CD in a dose of 1.88 mg/kg show after the first 2 h, 2.4% of the total label was detected in the form of exhaled 14CO2. The 14CO2 peak ap-peared between 4 and 6 h in two of three rats, and represented 19-20%•of the total la-bel. The third rat showed a peak of about 11% between 6 and 8 h. On the average 55%•of the total administered radioactivity was eliminated as exhaled 14CO2 within 24 h, and 50% of the total exhaled radioactivity appeared within 6.35 h. For exhaled 14CO2 levels of the control rats treated with 14C-gIucose, peak radioactivity, on the average 26.4%, was detected 2h after treatment. Subsequently the exhaled 14CO2 concentration tended to decrease on the average to 2% between 10 and 12 h and on the average to 0.45% between 22 and 24 h. During 24 h observation 58.5% of the total administered radioactivity was eliminated in the exhaled air. The 50% of the total ex-haled radioactivity appeared within 2.5h. Thus 14C-beta CD was metabolized by the rats in a similar degree to 14C-glucose within the 24h of the study. After 14C-beta CD treatment 55 to 64% of total administered radioactivity, after 14C-glucose treatment on the average 58% of it was eliminated with exhaled 14CO2. The elimination peak - 11-20% of total label - appeared 4-6 or 6-8 h after administration in the case of the 14C-beta CD treated rats, and within the first 2 h, amounting to 26%, in the case of the 14C-glucose treated control rats.

Metabolite characterisation studies

Metabolites identified:
no

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): no bioaccumulation potential based on study results
The studies show that beta-Cyclodextrin is metabolized at a percentage of at least 50 % to yield CO2 and only minor fractions are present in organs, urine or faeces after 10 or 24 h respectively.
Executive summary:

The absorption, distribution, excretion and metabolism of orally administered universally labelled 14C-beta-cyclodextrin and 14C-glucose were compared in rat. The maximum radioactivity of the blood derived from 14C-beta-cyclodextrin was observed between 4th and 11th h and the value of the maximum in different experiments ranged between 5 and 17 % of the total administered radioactivity. Following 14C-glucose treatment radioactivity reached the maximum within half-an-hour, with values of 15 to 82 %. In the 8th h after a high dose (313.5 mg/kg) of beta-cyclodextrin no more than 3-50 ppm beta-cyclodextrin was detectable in the blood by HPLC. After 14C-beta-cyclodextrin treatment 4.2-4.8% of the administered total radioactivity was excreted by the urine and about the same quantity (2-3.6%) in case of 14C-glucose. No specific accumulation was observed after 14C-beta-cyclodextrin treatment in the different organs. The large intestine contained 10-15% of the cyclodextrin radioactivity while this value was only 2% in case of 14C-glucose. Following p.o. administration of different doses of 14C-beta-cyclodextrin the radioactivity peak was detected in the exhaled air between the 4-6th and 6-8th h, respectively, depending on the administered doses, while in case of 14C-glucose treatment it was observed within 2 h. The total radioactivity exhaled by 14C-beta-cyclodextrin treated animals in 24 h was 55 to 64% of the administered radioactivity and 58% in case of 14C-glucose. It is assumed that beta-cyclodextrin is metabolized in rats slower but similarly to glucose, therefore p.o. administered beta-cyclodextrin cannot induce toxic symptoms.