Agents having a tumor-inhibiting action and their use

The invention relates to pharmaceutical compositions containing, as an active ingredient, a water-soluble polyester or polycarbonate based on one or more polyetherglycols of Formula (I) as defined in the specification. Also included in the invention is the use of said compositions for their tumor-inhibiting action.

The present invention relates to the use of as agents having a 
tumour-inhibiting action of water-soluble polyesters or polycarbonates 
based on polyether-diols, which are in themselves known. 
It has already been disclosed that complex Cu.sup.II and Co.sup.II salts of 
ethylene/maleic acid copolymers are active against Walker's sarcoma [see 
J. Med. Chem., 12 (1969), 1, 180]. 
Furthermore, polycations of various types, for example polyamidoamines, 
poly-N-morpholinoethylacrylamide and N-oxide polymers, have been tested 
for inhibition of the formation of metastases, with the result that only 
the dissemination of tumour cells, but not the growth of metastases in 
situ or metastases in a lymph node, could be influenced [see J. Med. 
Chem., 16 (1973), 496]. 
The activity of polymers with carboxyl groups against 180 sarcoma, as a 
function of the molecular weight, the charge density and also the 
metal-binding capacity of the carboxyl groups, has also been described 
[see Dissertation Abstr. Intern. B 33 (1973), 5,745]. 
Polyanions, for example poly-(ammonium acrylate), acrylic acid/acrylamide 
copolymers and also ethylene/maleic anhydride copolymers, are said to 
have, in connection with their tumour-inhibiting action, a heparin-like 
effect and also a virus inhibition, and moreover to increase the 
immunoreactions [see J. Med. Chem., 17 (1974), 1,335]. 
It is apparent from all this work that the tumour-inhibiting action of the 
polymers investigated hitherto against the experimental tumours used 
frequently only lies at the lower limit of significance and, in a number 
of cases, is restricted to prophylactic or adjuvant effects only. 
Disadvantageously, it is moreover apparent that the investigations cited 
were carried out in many cases on allogenic mouse tumours having a 
tendency towards spontaneous regression, and not systematically and under 
experimental arrangements relevant to clinical conditions. 
Generally, there is a lack of data on the toxicity of the preparations, 
although the administration of high doses of substances having a molecular 
weight of more than 30,000 suggests inadequate elimination, or storage in 
the tissues. 
W. Regelson et al. [see Nature, 186 (1960), 778-780] have investigated the 
tumour-inhibiting action of synthetic polyelectrolytes such as polyacrylic 
acid, polymethacrylic acid and hydrolysed or aminolysed ethylene/maleic 
anhydride copolymers. By comparing the actions of the dicarboxylic acid 
form, the amido-carboxylic acid form and the diamido form of 
ethylene/maleic anhydride copolymers, they found that at least one 
ionisable carboxyl group is necessary for a significant tumour inhibition. 
Experiments carried out by these authors with polyacrylamides in high 
doses (800 mg/kg, MW 60-70,000 and 400 mg/kg, MW 120,000) showed a 
negative tumour-inhibiting action or a non-significant positive action. 
Likewise, agents having a tumour-inhibiting action have been described, 
which are characterised in that they contain at least one water-soluble 
homopolymer or copolymer which contains 1,3-dihydroxy-2-methylenepropane 
and/or derivatives thereof [see DOS (German Published Specification) 
2,705,189]. Similar preparations with a similar action are water-soluble 
homopolymers or copolymers which contains 3,4-dihydroxybut-1-ene or 
hydroxyalkyl (meth)acrylates or derivatives thereof, or also derivatives 
of allyl alcohol, in polymerised or copolymerised form [see DOS (German 
Published Specification) 2,740,082]. 
Moreover, a certain tumour-inhibiting action of emulsifiers which contain 
incorporated polyethylene oxide chains has been disclosed. Thus, 
polyoxyethyleneated sorbitan monooleate ("Tween" 80-Trade Mark) has been 
used for immunisation against hyperdiploid Ehrlich's tumour [see 
Experientia, 29 (1973), 710]. 
A block copolymer of polypropylene oxide and polyethylene oxide ("Pluronic" 
F 68-Trade Mark) has proved to be active against the onset of metastases 
of Walker's 256 Ascites tumour, probably by influencing the blood 
coagulability [see Cancer, 29 (1972), 171]. As is known, these 
preparations are highly active emulsifiers and for this reason are not 
very well tolerated, in particular on parenteral administration. 
It has now been found, surprisingly, that water-soluble polyesters and 
polycarbonates which have been prepared from polyether-glycols possess 
strong tumour-inhibiting properties or alleviate pain associated with 
tumour afflicted organisms. 
In the molecular weight range from 1,000 to 100,000, the substances show 
statistically significant prophylactic and curative actions against solid 
tumours of syngenic systems, in a broad dosage range of 0.5 to 500 mg/kg, 
preferably 5 to 250 mg/kg, under experimental arrangements and methods of 
administration relevant to clinical conditions. 
The acute toxicity of the purified substances is low; the LD 50 is 
generally above 2,500 mg/kg, for intravenous administration, so that the 
substances possess an unusually large therapeutic range. 
The pharmaceutical compositions according to the invention incorporating 
such substances thus represent an important enrichment of therapy. 
According to the present invention there are, therefore, provided 
pharmaceutical compositions containing as an active ingredient a 
water-soluble polyester or polycarbonate based on one or more 
polyether-glycols, which corresponds to the formula 
##STR1## 
in which A is statistically distributed hydrogen or methyl, 0.1%-50% 
preferably 0.1%-33% of the A groups being methyl, 
the groups B are identical or different and are a hydrogen atom, an 
aliphatic, alicyclic or aromatic radical having up to 8 carbon atoms, 
(preferably a hydrogen atom or a C.sub.1 to C.sub.4 alkyl group), a group 
X--CO, X being a hydrogen atom or an aliphatic, alicyclic or aromatic 
radical (particularly mono- or bi-cyclic carbocyclic) having up to 7 
carbon atoms (preferably a hydrogen atom or a C.sub.1 to C.sub.3 alkyl 
group), a group Y--O--CO--, Y being an aliphatic, alicyclic or aromatic 
radical having up to 7 carbon atoms (preferably a C.sub.1 to C.sub.4 alkyl 
group) or a group Z--NH--CO--, Z being a hydrogen atom or an aliphatic, 
alicyclic or aromatic radical having up to 7 carbon atoms (preferably a 
hydrogen atom or a C.sub.1 to C.sub.4 alkyl group), it being particularly 
preferred for one or both of the B groups to be hydrogen 
Q denotes a group 
##STR2## 
R being an alkylene or arylene having up to 20 carbon atoms (preferably up 
to 6 carbon atoms) and R' being alkylene having 2 to 18 carbon atoms 
(preferably 2 to 6 carbon atoms), 
n denotes a number from 5 to 500 (preferably from 8 to 300), and 
m denotes a number from 1 to 30 (preferably from 1 to 15). 
As used herein and unless otherwise specified, (1) the term "alkyl" 
contains 1 to 7, preferably 1 to 3 carbon atoms, (2) the term "alicyclic" 
is preferably "cycloalkyl" containing 3 to 8, preferably 5 or 6 carbon 
atoms but may also represent "cycloalkenyl" or "cycloalkadinyl" containing 
5 to 8, preferably 5 or 6 carbon atoms; and the term "aromatic" or 
"arylene" is preferably mono- or bi-cyclic carbocyclic aryl or arylene, 
respectively. 
Preferred active ingredients for use in compositions of the present 
invention are those of the general formulae 
##STR3## 
in which A denotes statistically distributed H or CH.sub.3L , 67 to 100 
mol % being H and 0 to 33 mol % being CH.sub.3, 
R denotes an alkylene or arylene group having up to 6 carbon atoms, 
R' denotes an alkylene group having 2 to 6 carbon atoms, 
R" denotes an alkylene or arylene group having up to 6 carbon atoms, 
R"' denotes an alkylene group having 2 to 6 carbon atoms, 
n denotes a number from 8 to 300, and 
m denotes a number from 1 to 15. 
The following compounds are examples of particularly preferred active 
ingredients in compositions according to the present invention: 
##STR4## 
The polyesters to be used according to the invention can be prepared by 
known methods [see Houben-Weyl, Methoden der organischen Chemie (Methods 
of Organic Chemistry), 4th edition (1963), Volume 14/II, page 1 et seq.; 
Ullmanns Enzyklopadie der technischen Chemie (Ullman's Encyclopaedia of 
Chemical Technology), 3rd edition, Volume 14 (1963), pages 80-85]. 
The preparation by means of azeotropic condensation or by means of solution 
condensation is particularly preferred; in this process, a 
polyether-glycol and a dicarboxylic acid (particularly an alkane 
dicarboxylic acid, such as are used as the starting materials, the 
esterification is carried out in the presence of an acid catalyst and the 
water of reaction formed is distilled off azeotropically, for example with 
toluene. The degree of polymerisation "m" depends on the molar ratio of 
diol to dicarboxylic acid and on the extent of the reaction (degree of 
completion of the reaction). If the reaction is carried out with a molar 
excess of polyether-glycol, polyesters with predominantly OH end groups 
are obtained. Of course, apart from dicarboxylic acids, it is also 
possible to use dicarboxylic acid dichlorides and to react these with the 
polyether-glycols in the presence of tertiary amines. 
The polycarbonates to be used according to the invention can be prepared 
either by phosgenation in an anhydrous medium, in the presence of an inert 
base, or by reaction of a bis-chloroformate of a low-molecular dihydroxy 
compound or of a polyether-glycol with a polyether-glycol, in the presence 
of an inert base [see Houben-Weyl, Methoden der organischen Chemie 
(Methods of Organic Chemistry), 4th edition, Volume 14/II (1963), pages 53 
and 54]. In this case again, the degree of polycondensation "m" depends on 
the molar ratio of diol to phosgene or bis-chloroformate. 
Of course, it is also possible to use mixtures of polyether-glycols of 
different average molecular weights or also mixtures of 2 or more 
dicarboxylic acids or of 2 or more bis-chloroformates, for the preparation 
of polyesters or polycarbonates to be used according to the invention. 
The hydroxyl end groups of the polyesters or polycarbonates can be 
converted by known methods to ether groups, carboxylic acid ester groups, 
carbonic acid ester groups, or urethane groups. In the preparation of 
polyesters, ester end groups can be introduced by the concomitant use of 
corresponding amounts of a monocarboxylic acid, and in the case of the 
preparation of polycarbonates by the addition of a chloroformate of a 
monoalcohol. 
The polyether-diols which are necessary for the preparation of the 
polyesters or polycarbonates to be used according to the invention are 
known to those skilled in the art. They are used in large amounts for the 
manufacture of polyurethane plastics. They are manufactured by the 
polymerisation or copolymerisation, with ring opening, of ethylene oxide 
and propylene oxide [see Houben-Weyl, Methoden der org. Chemic (Methods of 
Organic Chemistry), 4th edition, Volume XIV/2, 1963, page 427 et seq., 
Ullmanns Encyklopadie der technischen Chemie (Ullmann's Encyclopaedia of 
Chemical Technology), 3rd edition, Volume 14 (1963, pages 49-52)]. 
Copolymerisates of ethylene oxide and propylene oxide contain 0.1%-50%, 
preferably 0.1%-33% propylene oxide. Starting from ethylene oxide, the 
polyethylene glycols are obtained, which are very water-soluble from 
diethylene glycol up to products having molecular weights above 10.sup.6. 
Of the polypropylene glycols formed from propylene oxide, only the 
relatively low-molecular representatives are water-soluble. The solubility 
in water of the polypropylene glycols and of the ethylene oxide/propylene 
oxide copolymers can be improved by the incorporation of ionic groups. 
Ethylene oxide/propylene oxide random copolymers are water-soluble to a 
greater or lesser extent, depending on their molecular weight and content 
of propylene oxide units. 
The agents according to the invention can be dissolved in physiologically 
isotonic sodium chloride solution, at temperatures of 
20.degree.-40.degree. C., to give solutions of 0.5%-30% strength by 
weight. It is, however, possible to incorporate them into tablets, 
capsules and other preparation for the peroral administration. In addition 
to exceptionally low toxicity, they possess a strong tumour-inhibiting 
action against tumours in warm-blooded animals and are therefore intended 
for use in combating diseases caused by tumours. 
As stated above, the invention also relates to the use in medicine as 
antitumorial agents of the compounds of the invention. 
This invention further provides a method of combating the above-mentioned 
diseases in warm-blooded animals, which comprises administering to the 
animals a compound of the invention in admixture with an inert 
pharmaceutical carrier, e.g. a diluent. For parenteral administration such 
solutions should be sterile and, if appropriate blood isotonic. 
It is envisaged that these active compounds will be administered 
parenterally (for example intramuscularly, intraperitoneally, 
subcutaneously and intravenously)-systemically or locally-preferably 
intraperitoneally, intravenously or intramuscularly. Preferred 
pharmaceutical compositions and medicaments are therefore those adapted 
for administration such as intraperitoneal; intravenous or intramuscular 
administration. Administration in the method of the invention is 
preferably intraperitoneal; intravenous or intramuscular administration. 
However, peroral administration can also be used. 
In general it has proved advantageous to administer amounts of from 0.5 mg 
to 500 L mg/kg, preferably 5 mg to 250 mg/kg, of body weight per day to 
achieve effective results. Nevertheless, it can at times be necessary to 
deviate from those dosage rates, and in particular to do so as a function 
of the nature and body weight of the human or animal subject to be 
treated, the individual reaction of this subject to the treatment, the 
type of formulation in which the active ingredient is administered and the 
mode in which the administration is carried out, and the point in the 
progress of the disease or interval at which it is to be administered. 
Thus it may in some cases suffice to use less than the above-mentioned 
minimum dosage rate, whilst in other cases the upper limit mentioned must 
be exceeded to achieve the desired results. Where larger amounts are 
administered it can be advisable to divide these into several individual 
administrations over the course of the day. 
The agents according to the invention are prepared by dissolving the active 
ingredients in physiological sodium chloride solution or by manufacturing 
tablets, capsules and other preparations for the peroral administration. 
The unusual breadth of the administration range mentioned above is a 
result of the unusual non-toxicity of the active ingredient. 
The substances were tested for the induction of tumour inhibiting actions 
in numerous experiments, under various test conditions, against carcinoma 
EO 771 or against mouse sarcoma MCS 4. 
The methodology of the investigations on both these experimental tumours 
can be seen from experiment descriptions (a) and (b). 
DESCRIPTION OF EXPERIMENTS (A) 
Tumour tests against carcinoma EO 771 on C 57 BL/6 mice 
Animal strain: 
C 57 BL/6 mice, inbred (SPF) 
Methods: 
Maintaining the tumor strain: 14-20 days after the last transplantation, 
subcutaneous inoculation of a suspension of cells of carcinoma EO 771 in 
0.5 ml of 0.9% phosphate-buffered NaCl solution (PBS) into C 57 BL/6 mice. 
Preparation of screening tests: Same procedure as in maintaining the strain 
of the tumour, but subcutaneous incoluation of a suspension of 
5.times.10.sup.4 tumour cells in 0.5 ml of 0.9% PBS. 
Treatment: Single intramuscular injecttion of the required solution of 
substances 6 days prior to or 2 days after the tumour transplantation. 
Duration of experiments: 18-22 days after the tumour transplantation. 
Thereafter, sacrificing of the animals, preparation and weighing of the 
subcutaneous tumours. 
Evaluation parameters: Inhibition of the tumour growth by determination of 
the average tumour weight of control animals and groups of treated animals 
and calculation of the tumour weight (TW) index according to the formula: 
##EQU1## 
Assessment of the test results 
TW index 
0.8-0.6=marginal activity 
0.6-0.4=moderate activity 
&lt;0.4=good activity. 
DESCRIPTION OF EXPERIMENTS (B) 
Tumour tests against sarcoma MCS 4 on C 57 BL/6 mice 
Maintaining the tumor strain: 10-14 days after the last transplantation, 
subcutaneous inoculation of a suspension of cells of sarcoma MCS 4 in 0.5 
ml of 0.9% phosphate-buffered NaCl solution (PBS) into C 57 BL/6 mice. 
Preparation of screening tests: Same procedure as in maintaining the strain 
of the tumour, but subcutaneous inoculation of a suspension of 
2.times.10.sup.5 tumour cells in 0.5 ml of 0.9% phosphate-buffered NaCl 
solution. 
Treatment: Single intravenous injection of the required solution of 
substances 2 days prior to or 2 days after the tumour transplantation. 
Duration of experiments: 18-22 days after the tumour transplantation. 
Thereafter, sacrificing of the animals, preparation and weighing of the 
tumours. 
Evaluation and assessment of the results are carried out analogously to 
description of experiments (a). 
TABLE 1 
__________________________________________________________________________ 
Test results against carcinoma EO 771 
Dose 
Administration 
Compound No. 
mg/kg 
1 .times. 
Day of treatment* 
Tumour weight index 
__________________________________________________________________________ 
I (Example 1) 
250 intramuscular 
-6 0.36 
250 intramuscular 
+2 0.38 
II (Example 2) 
50 intramuscular 
-6 0.39 
50 intramuscular 
+2 0.43 
III (Example 3) 
250 intramuscular 
-6 0.23 
250 intramuscular 
+2 0.42 
__________________________________________________________________________ 
*Days of treatment -6 = 6 days before tumour transplantation 
+2 = 2 days after tumour transplantation 
TABLE 2 
__________________________________________________________________________ 
Test results against sarcoma MCS4 
Dose 
Administration 
Compound No. 
mg/kg 
1 .times. 
Day of treatment* 
Tumour weight index 
__________________________________________________________________________ 
I (Example 1) 
0.5 intravenous 
-2 0.45 
5 intravenous 
+2 0.39 
III (Example 3) 
50 intravenous 
-2 0.24 
50 intravenous 
+2 0.32 
IV (Example 4) 
2.5 intravenous 
-2 0.37 
10 intravenous 
+2 0.32 
__________________________________________________________________________ 
*Day of treatment -2 = 2 days before tumour transplantation 
+2 = 2 days after tumour transplantation 
The tumour weight indices of the preparations listed in Tables 1 and 2 show 
that the substances at various doses, for various methods of 
administration, and also on various days of treatment are capable of 
inducing distinct tumour-inhibiting activity both against carcinoma EO 771 
and against sarcoma MCS4.

The following Examples illustrate the production of active ingredients used 
in the compositions of the present invention. 
EXAMPLE 1 
200 g of polyethylene glycol having an average molecular weight M.sub.n of 
1,550 were dissolved in 1 liter of toluene. For drying, 200 ml of toluene 
were distilled off under normal pressure. After cooling to room 
temperature, 20 g of dry pyridine were added, 20 g of butanediol 
bis-chloroformate were then added dropwise, whilst stirring, and the 
reaction mixture was subsequently stirred for 3 hours at room temperature. 
The pyridine hydrochloride was filtered off and washed thoroughly with 
toluene and the toluene solution was evaporated in vacuo on a rotary 
evaporator. The residue was recrystallised twice from 2:1 ethyl 
acetate/diethyl ether, rinsed with diethyl ether and dried in vacuo. 
Yield: 180 g, M.sub.n =5,200 (determined by membrane osmometry in DMF). 
EXAMPLE 2 
200 g of polyethylene glycol having a molecular weight M.sub.n =6,000 were 
dissolved in 1 liter of toluene and dried by distilling off 200 ml of 
toluene. After cooling to room temperature, 4 g of dry pyridine were added 
and a solution of 3.6 g of butanediol bis-chloroformate in 50 ml of 
toluene was added dropwise. The reaction mixture was stirred overnight at 
room temperature. The batch was then diluted with 1 liter of toluene and 
stirred for a further 1 hour. After the pyridine hydrochloride had been 
separated off, the polycarbonate was then isolated as described in Example 
1. 
Yield: 185 g, M.sub.n =1.35.times.10.sup.4 (determined by membrane 
osmometry in DMF). 
EXAMPLE 3 
200 g of polyethylene glycol having a molecular weight M.sub.n =2,000, 8.85 
g of succinic acid and 1 g of p-toluenesulphonic acid were dissolved in 
500 ml of toluene. Toluene was distilled off at about 50 ml/hour, with the 
exclusion of moisture. As soon as 150 ml had distilled, 150 ml of absolute 
toluene were added. As soon as no more water passed over (after about 12 
hours), the toluene was removed in vacuo on a rotary evaporator and the 
residue was recrystallised twice from 2:1 ethyl acetate/diethyl ether. 
Yield: 177 g, M.sub.n =7,300 (determined by membrane osmometry in DMF). 
EXAMPLE 4 
250 g of polyethylene glycol having a molecular weight M.sub.n =4,000, 6.1 
g of adipic acid and 1 g of p-toluenesulphonic acid were dissolved in 500 
ml of toluene. Analogously to Example 3, toluene was distilled off for 24 
hours and the polyester formed was purified by double recrystallisation. 
Yield: 227 g, M.sub.n =10,500 (determined by membrane osmometry in DMF).