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Acute toxicity of prostaglandins E2,F2α and 15 (s) 15 methyl prostaglandin E2 methyl ester in the baboon
ACUTE
TOXICITY
OF PROSTAGLANDINS E2,F2o AND 15 (S) 15 METHYL
PROSTAGLANDIN E2 METHYL ESTER IN THE BABOON.
P. Adaikan Ganesan and S. M. M. Karim Department of Obstetrics and Gynaecology, University of Singapore, Kandang Kerbau Hospital, Singapore 8.
SUMMARY The cardiovascular, uterine stimulant and gastrointestinal effects of F and 15 (S) 15 methyl PGE methyl ester in the East 1: these three parameters the Eat%z:$: Ar?&is) have been studied. baboon responds both qualitatively and quantitatively in a similar manner to The lethal doses of the prostaglandins given by bolus intravenous inman. jections have been determined and the human lethal doses estimated.
INTRODUCTION Inspite of high doses employed, the intra-amniotic route of prostaglandin administration for the termination of second trimester pregnancy is associated with fewer side effects compared with the systemic administration of these compounds. This is because after the intra-amniotic injection the prostaglandins diffuse into the placental and hence uterine circulation out of the amniotic fluid. Changes in maternal blood levels are minimal (1). However inadvertant systemic injection of the dose of prostaglandin E 3, F,+o or 15 (S) 15 methyl PGE2 methyl ester intended for intra-amniotic admintstra ton would be expected to produce serious side effects in view of the known cardiovascular, gastrointestinal and respiratory effects of much smaller doses of these compounds. The present investigation was undertaken to study the uterine, cardiovascular and gastrointestinal effects of three prostaglandins in baboon and compare with the data available from human studies. The lethal intravenous dose of the prostaglandins is also determined. Accepted
July
20
PROSTAGLANDINS AUGUST
10, 1974
VOL. 7 NO. 3
215
PROSTAGLANDINS
METHODS Female baboons weighing 10 Kg ( + 1.5 Kg) were used in the investigation. Cardiovascular Studies Four non-pregnant baboons were anaesthetised with Fhencyclidine hydrochloride (Sernylan, -Parke-Davies) injected intramuscularly in doses required to keep the animals under light anaesthesia. Blood pressure measurements were taken from a cannulated femoral artery connected to a Devices recorder via a Statham transducer. Bolus intravenous injections of prosmglandins were given into a cannulated femoral vein. Uterine Effects Nine baboons in the second trimester of pregnancy (12-13 weeks gestation) were used. They were lightly anaesthetised with phencyclidme hydrochloride. Uterine activity was measured using a transabdominally inserted 16 gauge polyethylene catheter into the amniotic sac. The amniotic fluid pressure was recorded on a Devices recorder via a pressure transducer. Prostaglandins were administered through the same catheter. Lethal dose The study was carried out in eighteen non-pregnant female baboons. The animals were individually housed in squeeze cages. No anaesthesia or other pre-medication was used. Each baboon received only one intravenous injection of Prostaglandin. After administering the Prostaglandin the animals were closely observed for a continuous period of three hours and periodically thereafter for the next 24 hours.
RESULTS Cardiovascular The cardiovascular responses of the baboons to the three prostaglandins were qualitatively and quantitatively similar to man. Prostaglandin E2 and 15 (S) 15 methyl PCE methyl ester lowered and PGF20 increased the arterial blood pressure. %Ie results obtained in the baboons are compared with available data in man in Table I.
216
AUGUST
10, 1974
VOL. 7 NO. 3
PROSTAGLANDINS
Uterus On the basis of previous experience (unpublished) the following doses of the three prostaglandins were selected for intra-amniotic administration in order to produce adequate uterine stimulation for the termination of pregnancy in the baboons.
: 100 pg/Kg
PGE2 PGF2cY 15 (S) 15 methyl PGE2 methyl ester
single dose (3 animals)
: 500 pg/ Kg single dose (3 animals) :
1 pg/Kg single dose (3 animals)
The above doses of the Prostaglandins produced an elevation of uterine tonus lasting for 15-30 minutes followed by regular and rhythmic contractions lasting for more than 10 hours (Fig. 1). All baboons aborted between 12 and 18 hours after Prostaglandin administration. In a previous study (Karim and Ganesan - unpublished results) half the above doses of PGE and PGF to produce abortion in all four baboons (2 with each Prostag ? andin). %efailed baboon given 0. 5 pg/kg 15 (S) 15 methyl PGE2 methyl ester aborted forty nine hours after drug administration. Lethal dose Prostaglandin
E2
Seven baboons were given bolus intravenous injection of PGE2 in a dose ranging from 0.4 - 12.8 mg /Kg. Each baboon received only one dose of Prostaglandin. Doses of 0.4, 0.8, 1.6 and 3.2 mg/Kg were not lethal. Diarrhoea, vomitt ing, salivation and increase in respiration rate were recorded ln all animals during the three hours observation period. The two baboons receiving 6.4 mg/Kg PGE2 had several episodes of vomitting and diarrhoea and died twelve and fourteen hours after prostaglandin administration. One baboon receiving 12.8 mg/ Kg died 90 minutes after the dose of prostaglandin (Table II). Prostaglandin
F20
A single intravenous dose of 128 mg/ Kg of PGF20 given to one baboon resulted in respiratory distress followed by death within 4 minutes of drug administration. Fifteen minutes later when the chest was opened the heart was still beating. With doses of 2-64 mg/Kg all (six) baboons survived. The only noticeable effects were urination, salivation, diarrhoea and vomitting (Table II). 15 (S) 15 methyl PGE2 methyl ester Doses of 10, 20, 40 and 80 pg/Kg given to four baboons were not lethal. Salivation, shivering, vomitting and diarrhoea were observed in all animals (Table II).
AUGUST
10, 1974
VOL. 7 NO. 3
217
PROSTAGLANDINS
Table I Comparison
of the effect of three Prostaglandins
arterial
I
blood pressure
in man and baboon.
Baboon (4 animals) Response Intravenous mm Hg dose
DRUG
on the mean
Man+ Dose pg/Kg Response mm Hg
i’g/Kg 2.0
PGE2
10.0
PGF20 15 (S) 15 methyl PGE2 methyl ester
+ -
0. 5
-6 (2-8)
1. 8
-6 (2-10)
+16 (8-18)
8
+20 (12-24)
-7 (4-10)
0.4
-9
Data from Karim, Somers and Hillier (1971) Refers to decrease and + increase in mean arterial blood pressure. The figures in parenthesis refers to range of blood pressure effect.
Fig.
1
LI--_.
I,mm
5 mim
,.., ; Baboon
hours Weight:
4 hours 10 1 kg
Gestation:
13 Weeks
Effect of Intra-amniotic
injection of PGE2
on the uterine activity in a baboon.
218
AUGUST
10, 1974
VOL. 7 NO. 3
PROSTAGLANDINS
Table Effect of intravenous
administration
II of three prostaglandins
in baboons.
T
li
u~imal No
Prostaglandin
Effects
and Dose+
PGE2
0.4 mg /Kg
PGE2
0.8 mg /Kg
PGE2
1.6 mg /Kg
Salivation
PGE2
3.2 mg/Kg
Salivation,
PGE2
6.4 mg /Kg
Salivation, watery diarrhoea, died 12 hrs. after injection
6
PGE2
6.4 mg /Kg
Salivation, watery diarrhoea, died 14 hrs. after injection
7
PGE2
12.8 mg /Kg
8
PGF2a
2.0 mg)Kg
Urination
9
PGF20!
4.0 mg/Kg
Restless
8.0 mg (Kg
Shivering, salivation
16.0 mg /Kg
Lethargic
32.0 mg /Kg
Loose stool,
64.0 mg kg
Salivation,
10 11 12 13 14
PGF2* PGF2tY PGF20 PGF2cY PGF2c,
loose stool
Salivation, died 90 minute after injection
128.0 mg /Kg
Ioose stool,
salivation diarrhoea
Died 4 minutes injection
after
15
15 (S) 15 me PGE2 me ester
10.0 pg/Kg
Salivation, shivering, loose stool, urination
16
15 (S) 15 me PGE2 me ester
20.0 pg/Kg
Loose stool
17
15 (S) 15 me PGE2 me ester
40.0 pg/Kg
Vom itt ing
18
15 (S) 15 me PGE2 me ester
80.0 pg /Kg
Urination,
+
AUGUST
Prostaglandin
10, 1974
given by bolus intravenous
VOL. 7 NO. 3
diarrhoea
injection.
219
PROSTAGLANDINS
Table III Comparison
of intra-amniotic
termination
doses of three Prostaglandins
in baboon and human.
r
Estimation
of human lethal dose.
1
I
I BABOON
MAN _-.-lY1^--ll_ Int ra-amniot ic dose for abortion pg/Kg
+t
_ E2 92 1
Lethal dose Lethal dose Ratio: Therapeutic dose (Intra-amniotic
F
2o! 460
15 (S) E2
R2
0.93
100
Estimated Lethal Dose
5888
/‘g/Kg
for pregnancy
64
_..--
i F2a! _ 1 500‘
15 (S) E 1 1
Lethal Dose
-.
-.-
117760
74.4
6400
128000
80+
256
8O+
64
256
80+
abortion dose) +
*
4
For 15 (S) 15 me PCE2 me ester, given was not lethal. It is the maximal dose tested.
the dose
Data from Karim (1972)
DISCUSSION Replacement of part or all of the amniotic fluid with hypertonic saline as a method of terminating second trimester pregnancy has been in use for In experienced hands the technique has proved to be safe and many years. reliable. However, cases of maternal brain damage and deaths as a result of inadvertant entry of the hypertonic saline into the systemic circulation have been reported (2). It is estimated that Prostaglandins E2, F20 and 15 (S) 15 methyl PCE2 methyl ester in single intra-amniotic doses of 5 mg, 25 mg and 100 pg respectively (or similar doses) have been used for the termination of second trimester pregnancy in over five thousand women. Because of the wide range of pharmacological actions of these compounds such large doses are expected to produce severe side effects should the intra-amniotic dose be inadvertantly injected into the maternal circulation. Fortunately, to date, no fatalities or serious complications have been reported.
220
AUGUST
10,1974 VOL. 7 NO. 3
PROSTAGLANDINS
and 15 (S) 15 methyl PGE methyl The abortifacient doses of PGE , F ester administered, intra amniotically21n 2% and baboon are in the Ggion of The lethal doses for PGE2 and 100 pg/Kg, 500 pg /Kg and 1 pg/Kg respectively. Assummg in the baboon were 6.4 mg/Kg and 128 mg /Kg respectively. the et 1 dose for man to be the same as the baboon, for PGE2 it is 64 times PGF120ha and for PGF2a 256 times higher than the therapeutic (intra amniotic dose) - a comfortable safety factor (Table III). 15 (S) 15 methyl PGE2 methyl ester in dose 80 times higher than the intra amniotic abortifacient dose was not lethal in the baboon.
ACKNOWLEDGEMENTS The work was carried Pha-C-73 /36. Prostaglandins
out under U. S.A. I. D. grant contract No. AID/Cmwere supplied by The Upjohn Company of Canada.
REFERENCES 1.
Karim, S. M. M. Prostaglandins and Human Reproduction: Physiological Roles and Clmical Uses of Prostaglandins in relation to Human Reproduction. In : Karim, S. M. M. Prostaglandins Progress in Research P. 71 (M. T. P. Oxford 1972)
2.
Gennser, G. , S. Kullander and N. Lundgren Studies of therapeutic abortions induced by injection of hypertonic J. Obstet. Gynaec. Brit. Cwlth. Vol. 75 P. 1058-1062 0968)
3.
Karim, S. M. M. , Somers, K. and Hillier, K. Cardiovascular and other effects of Prostaglandins Cardiovascular Research 2 255-259 0971)
AUGUST
10, 1974
VOL. 7 NO. 3
saline.
E2 and FZa! in man.
221
TOXICITY
OF PROSTAGLANDINS E2,F2o AND 15 (S) 15 METHYL
PROSTAGLANDIN E2 METHYL ESTER IN THE BABOON.
P. Adaikan Ganesan and S. M. M. Karim Department of Obstetrics and Gynaecology, University of Singapore, Kandang Kerbau Hospital, Singapore 8.
SUMMARY The cardiovascular, uterine stimulant and gastrointestinal effects of F and 15 (S) 15 methyl PGE methyl ester in the East 1: these three parameters the Eat%z:$: Ar?&is) have been studied. baboon responds both qualitatively and quantitatively in a similar manner to The lethal doses of the prostaglandins given by bolus intravenous inman. jections have been determined and the human lethal doses estimated.
INTRODUCTION Inspite of high doses employed, the intra-amniotic route of prostaglandin administration for the termination of second trimester pregnancy is associated with fewer side effects compared with the systemic administration of these compounds. This is because after the intra-amniotic injection the prostaglandins diffuse into the placental and hence uterine circulation out of the amniotic fluid. Changes in maternal blood levels are minimal (1). However inadvertant systemic injection of the dose of prostaglandin E 3, F,+o or 15 (S) 15 methyl PGE2 methyl ester intended for intra-amniotic admintstra ton would be expected to produce serious side effects in view of the known cardiovascular, gastrointestinal and respiratory effects of much smaller doses of these compounds. The present investigation was undertaken to study the uterine, cardiovascular and gastrointestinal effects of three prostaglandins in baboon and compare with the data available from human studies. The lethal intravenous dose of the prostaglandins is also determined. Accepted
July
20
PROSTAGLANDINS AUGUST
10, 1974
VOL. 7 NO. 3
215
PROSTAGLANDINS
METHODS Female baboons weighing 10 Kg ( + 1.5 Kg) were used in the investigation. Cardiovascular Studies Four non-pregnant baboons were anaesthetised with Fhencyclidine hydrochloride (Sernylan, -Parke-Davies) injected intramuscularly in doses required to keep the animals under light anaesthesia. Blood pressure measurements were taken from a cannulated femoral artery connected to a Devices recorder via a Statham transducer. Bolus intravenous injections of prosmglandins were given into a cannulated femoral vein. Uterine Effects Nine baboons in the second trimester of pregnancy (12-13 weeks gestation) were used. They were lightly anaesthetised with phencyclidme hydrochloride. Uterine activity was measured using a transabdominally inserted 16 gauge polyethylene catheter into the amniotic sac. The amniotic fluid pressure was recorded on a Devices recorder via a pressure transducer. Prostaglandins were administered through the same catheter. Lethal dose The study was carried out in eighteen non-pregnant female baboons. The animals were individually housed in squeeze cages. No anaesthesia or other pre-medication was used. Each baboon received only one intravenous injection of Prostaglandin. After administering the Prostaglandin the animals were closely observed for a continuous period of three hours and periodically thereafter for the next 24 hours.
RESULTS Cardiovascular The cardiovascular responses of the baboons to the three prostaglandins were qualitatively and quantitatively similar to man. Prostaglandin E2 and 15 (S) 15 methyl PCE methyl ester lowered and PGF20 increased the arterial blood pressure. %Ie results obtained in the baboons are compared with available data in man in Table I.
216
AUGUST
10, 1974
VOL. 7 NO. 3
PROSTAGLANDINS
Uterus On the basis of previous experience (unpublished) the following doses of the three prostaglandins were selected for intra-amniotic administration in order to produce adequate uterine stimulation for the termination of pregnancy in the baboons.
: 100 pg/Kg
PGE2 PGF2cY 15 (S) 15 methyl PGE2 methyl ester
single dose (3 animals)
: 500 pg/ Kg single dose (3 animals) :
1 pg/Kg single dose (3 animals)
The above doses of the Prostaglandins produced an elevation of uterine tonus lasting for 15-30 minutes followed by regular and rhythmic contractions lasting for more than 10 hours (Fig. 1). All baboons aborted between 12 and 18 hours after Prostaglandin administration. In a previous study (Karim and Ganesan - unpublished results) half the above doses of PGE and PGF to produce abortion in all four baboons (2 with each Prostag ? andin). %efailed baboon given 0. 5 pg/kg 15 (S) 15 methyl PGE2 methyl ester aborted forty nine hours after drug administration. Lethal dose Prostaglandin
E2
Seven baboons were given bolus intravenous injection of PGE2 in a dose ranging from 0.4 - 12.8 mg /Kg. Each baboon received only one dose of Prostaglandin. Doses of 0.4, 0.8, 1.6 and 3.2 mg/Kg were not lethal. Diarrhoea, vomitt ing, salivation and increase in respiration rate were recorded ln all animals during the three hours observation period. The two baboons receiving 6.4 mg/Kg PGE2 had several episodes of vomitting and diarrhoea and died twelve and fourteen hours after prostaglandin administration. One baboon receiving 12.8 mg/ Kg died 90 minutes after the dose of prostaglandin (Table II). Prostaglandin
F20
A single intravenous dose of 128 mg/ Kg of PGF20 given to one baboon resulted in respiratory distress followed by death within 4 minutes of drug administration. Fifteen minutes later when the chest was opened the heart was still beating. With doses of 2-64 mg/Kg all (six) baboons survived. The only noticeable effects were urination, salivation, diarrhoea and vomitting (Table II). 15 (S) 15 methyl PGE2 methyl ester Doses of 10, 20, 40 and 80 pg/Kg given to four baboons were not lethal. Salivation, shivering, vomitting and diarrhoea were observed in all animals (Table II).
AUGUST
10, 1974
VOL. 7 NO. 3
217
PROSTAGLANDINS
Table I Comparison
of the effect of three Prostaglandins
arterial
I
blood pressure
in man and baboon.
Baboon (4 animals) Response Intravenous mm Hg dose
DRUG
on the mean
Man+ Dose pg/Kg Response mm Hg
i’g/Kg 2.0
PGE2
10.0
PGF20 15 (S) 15 methyl PGE2 methyl ester
+ -
0. 5
-6 (2-8)
1. 8
-6 (2-10)
+16 (8-18)
8
+20 (12-24)
-7 (4-10)
0.4
-9
Data from Karim, Somers and Hillier (1971) Refers to decrease and + increase in mean arterial blood pressure. The figures in parenthesis refers to range of blood pressure effect.
Fig.
1
LI--_.
I,mm
5 mim
,.., ; Baboon
hours Weight:
4 hours 10 1 kg
Gestation:
13 Weeks
Effect of Intra-amniotic
injection of PGE2
on the uterine activity in a baboon.
218
AUGUST
10, 1974
VOL. 7 NO. 3
PROSTAGLANDINS
Table Effect of intravenous
administration
II of three prostaglandins
in baboons.
T
li
u~imal No
Prostaglandin
Effects
and Dose+
PGE2
0.4 mg /Kg
PGE2
0.8 mg /Kg
PGE2
1.6 mg /Kg
Salivation
PGE2
3.2 mg/Kg
Salivation,
PGE2
6.4 mg /Kg
Salivation, watery diarrhoea, died 12 hrs. after injection
6
PGE2
6.4 mg /Kg
Salivation, watery diarrhoea, died 14 hrs. after injection
7
PGE2
12.8 mg /Kg
8
PGF2a
2.0 mg)Kg
Urination
9
PGF20!
4.0 mg/Kg
Restless
8.0 mg (Kg
Shivering, salivation
16.0 mg /Kg
Lethargic
32.0 mg /Kg
Loose stool,
64.0 mg kg
Salivation,
10 11 12 13 14
PGF2* PGF2tY PGF20 PGF2cY PGF2c,
loose stool
Salivation, died 90 minute after injection
128.0 mg /Kg
Ioose stool,
salivation diarrhoea
Died 4 minutes injection
after
15
15 (S) 15 me PGE2 me ester
10.0 pg/Kg
Salivation, shivering, loose stool, urination
16
15 (S) 15 me PGE2 me ester
20.0 pg/Kg
Loose stool
17
15 (S) 15 me PGE2 me ester
40.0 pg/Kg
Vom itt ing
18
15 (S) 15 me PGE2 me ester
80.0 pg /Kg
Urination,
+
AUGUST
Prostaglandin
10, 1974
given by bolus intravenous
VOL. 7 NO. 3
diarrhoea
injection.
219
PROSTAGLANDINS
Table III Comparison
of intra-amniotic
termination
doses of three Prostaglandins
in baboon and human.
r
Estimation
of human lethal dose.
1
I
I BABOON
MAN _-.-lY1^--ll_ Int ra-amniot ic dose for abortion pg/Kg
+t
_ E2 92 1
Lethal dose Lethal dose Ratio: Therapeutic dose (Intra-amniotic
F
2o! 460
15 (S) E2
R2
0.93
100
Estimated Lethal Dose
5888
/‘g/Kg
for pregnancy
64
_..--
i F2a! _ 1 500‘
15 (S) E 1 1
Lethal Dose
-.
-.-
117760
74.4
6400
128000
80+
256
8O+
64
256
80+
abortion dose) +
*
4
For 15 (S) 15 me PCE2 me ester, given was not lethal. It is the maximal dose tested.
the dose
Data from Karim (1972)
DISCUSSION Replacement of part or all of the amniotic fluid with hypertonic saline as a method of terminating second trimester pregnancy has been in use for In experienced hands the technique has proved to be safe and many years. reliable. However, cases of maternal brain damage and deaths as a result of inadvertant entry of the hypertonic saline into the systemic circulation have been reported (2). It is estimated that Prostaglandins E2, F20 and 15 (S) 15 methyl PCE2 methyl ester in single intra-amniotic doses of 5 mg, 25 mg and 100 pg respectively (or similar doses) have been used for the termination of second trimester pregnancy in over five thousand women. Because of the wide range of pharmacological actions of these compounds such large doses are expected to produce severe side effects should the intra-amniotic dose be inadvertantly injected into the maternal circulation. Fortunately, to date, no fatalities or serious complications have been reported.
220
AUGUST
10,1974 VOL. 7 NO. 3
PROSTAGLANDINS
and 15 (S) 15 methyl PGE methyl The abortifacient doses of PGE , F ester administered, intra amniotically21n 2% and baboon are in the Ggion of The lethal doses for PGE2 and 100 pg/Kg, 500 pg /Kg and 1 pg/Kg respectively. Assummg in the baboon were 6.4 mg/Kg and 128 mg /Kg respectively. the et 1 dose for man to be the same as the baboon, for PGE2 it is 64 times PGF120ha and for PGF2a 256 times higher than the therapeutic (intra amniotic dose) - a comfortable safety factor (Table III). 15 (S) 15 methyl PGE2 methyl ester in dose 80 times higher than the intra amniotic abortifacient dose was not lethal in the baboon.
ACKNOWLEDGEMENTS The work was carried Pha-C-73 /36. Prostaglandins
out under U. S.A. I. D. grant contract No. AID/Cmwere supplied by The Upjohn Company of Canada.
REFERENCES 1.
Karim, S. M. M. Prostaglandins and Human Reproduction: Physiological Roles and Clmical Uses of Prostaglandins in relation to Human Reproduction. In : Karim, S. M. M. Prostaglandins Progress in Research P. 71 (M. T. P. Oxford 1972)
2.
Gennser, G. , S. Kullander and N. Lundgren Studies of therapeutic abortions induced by injection of hypertonic J. Obstet. Gynaec. Brit. Cwlth. Vol. 75 P. 1058-1062 0968)
3.
Karim, S. M. M. , Somers, K. and Hillier, K. Cardiovascular and other effects of Prostaglandins Cardiovascular Research 2 255-259 0971)
AUGUST
10, 1974
VOL. 7 NO. 3
saline.
E2 and FZa! in man.
221