GB2177913A - Anti malarial compositions - Google Patents

Abstract

Compositions in unit dosage form contain as active principle, from 20 to 200 mg of a mixture comprising: 30 to 60% quinine 20 to 40% quinidine 20 to 40% cinchonine as their bases or salts. v

Description

SPECIFICATION Pharmaceutical Composition for Combating Malaria The present invention relates to a pharmaceutical composition and more particularly to a pharmaceutical composition having antimalarial activity.

Malaria is probably the most widespread of all human diseases. It is estimated that some 300 million people are affected each year, with a mortality rate of 1%.

It is, therefore, essential that there be made available effective means of combating this calamitous afflication and any improvement on existing treatment is to be considered as a valuable contribution to defensive therapy.

Quinine is, at the present time, one of the most widely used and appropriate weapons in the struggle against malaria.

This alkaloid is effective as a means of both suppressing and controlling attacks of malaria caused by Plasmodium falciparum, Plasmodium vivax and Plasmodium malariae.

Other alkaloids closely related to quinine, such as quinidine, cinchonine and cinchonidine, have proved to possess a degree of activity similar to that of quinine in this indication [L. H. Schmidt, Alkaloids, 1955, Vol.

V, p. 141 eft so (1956)] and several associations of quinine with such cincona alkaloids have been described and used.

In these associations, the alkaloids are mixed for example with resorcine to improve solubility.

However, quinine has never been surpassed as a means of treating severe attacks due to P. falciparum.

It has now been discovered that certain therapeutics associations containing quinine, quinidine and cinchonine, in well-defined proportions by weight, possess a higher degree of antimalarial activity than that observed with quinine alone.

It has also been unexpectedly found that such associations not only possess a higher degree of activity than quinine but also exert a marked effect against strains that are resistant to quinine. Thus, the present invention relates to an antimalarial pharmaceutical composition, presented in dosage unit form containing from 20 to 200 mg of a mixture made up as follows: 30 to 60% quinine 20 to 40% quinidine 20 to 40% cinchonine each of these ingredients being in the form of a base or of a pharmaceutically acceptable salt, in association with an appropriate pharmaceutical carrier or excipient.

Preferred compositions according to the invention will include 50 to 1000 mg of a mixture of quinine, quinidine and cinchonine in the proportion of 1:1: 1, each of these ingredients being in the form of a base or of a pharmaceutically acceptable salt.

Other preferred compositions according to the invention will contain from 50 to 1000 mg of a mixture of 50% quinine, 20% quinidine and 30% cinchonine, each of these ingredients being in the form of a base or of a pharmaceutically acceptable salt As examples of pharmaceutically acceptable salts, mention may be made of the hydrochloride, hydrobromide, sulfate, maleate, formiate, fumarate, benzoate, methanesulfonate, carbonate, gluconate and resorcinate.

Pharmacological studies carried out with compositions of the invention have been found to exert a powerful antiparasitic action both in vitro and in vivo. Results of tests so performed are given hereunder.

1 ) In vitro a) Ex vivo tests were made on cultures of P falciparum taken from 25 Thailand patients.

The cultures were exposed for three days to the action of the com position under study after which proliferation was measured by introducing a radio-labeled precursor.

In accordance with this experimental procedure, a test was carried out with a mixture of quinine-resorcine dihydrochloride/quinidine-resorcine dihydrochloride/cinchonine-resorcine dihydrochloride in the proportion of 1:1:1, hereinafter referred to as Composition 1.

For comparison purposes, a similar test was performed with various concentrations of quinineresorcine dihydrochloride alone.

The results obtained are given in the following Table: TABLE 1 Strains sensitive to Strains resistant to quinine quinine IDso (ng/ml) IDso (ng/ml) Quinine salt 63.23 183.12 Composition 1 29.76 60.50 N.B. ID50=dose required to reduce parasitosis by 50% These results show that, on the cultures obtained from the 25 patients in question, Composition 1 is more active than quinine alone not only against strains which are sensitive to this latter compound but also against strains which are resistant to it.

b) Tests were also carried out on P. falciparum strains maintained in continuous culture in a R.P.M.I.

1640 (Roswall Park Memorial Institute) medium to which had been added 35 mM H.E.P.E.S. (2-Nhydroxy-ethyl-piperazino-2-N'-ethanesulfonic acid) and 10% human umbilical cord serum. At the beginning of the test, the level of parasitemia was brought down to 0.2% by addition of human ORh+ red blood corpuscles previously preserved for 8 to 20 days at 4"C.

The upper layer of sediment of the red blood corpuscles was eliminated by washing three times so as to reduce the white blood corpuscles and platelets to negligible quantities. Each composition under study was divided into decreasing concentrations so as to obtain final concentrations ranging from 8000 to 6 pg/ml in the culture dish. The red blood corpuscles with a parasitemia level of 0.2% were placed in suspension in a culture medium containing tritium-treated hypoxathine so as to provide, in each culture, a volume of 250111 of medium,61l1 of corpuscular sediment and 0.8 pCi of H3-hypoxanthine. The platelets were then incubated for3 days at37 C in a moist atmosphere, in a gaseous medium containing 5% carbon dioxide, 18% oxygen and 77% nitrogen.The cells were collected by suction on a glass-fibre filter and, after drying, the incorporated radioactivity was measured on a scintillation counter.

Each test was performed twice for each concentration. Each culture contained the following controls: non-infested red blood corpuscles, infested red blood corpuscles without any antimalarial agent. A graphic evaluation was then carried out of the inhibitory doses and of the slope of the inhibition curve.

The results obtained in these in vitro tests were similar to those given above for the ex vivo tests.

In addition, tests similar to those described above were carried out using a composition of the invention containing quinine monohydrochloride, quinidine monohydrochloride and cinchonine monohydrochloride in a proportion of 1:1:1, in comparison with quinine monohydrochloride. In both ex vivo and in vivo tests, the results were similar to those given above.

2) In vivo The following test was carried out in vivo using a Plasmodium berghei strain as parasitic agent.

White male mice (Swiss Albino F1), weighing 18 to 22 g were inoculated by intravenous route with 107 red blood corpuscles infested with a strain of Plasmodium berghei N. The infected red blood corpuscles came from a donor mouse sacrificed by inhalation of chloroform with its parasitemia had reached 20%. The red blood corpuscles were taken up in a syringe containing a small quantity of heparin and the blood was then diluted in NCTC medium 199 (National Cancer Tissue Culture) so that 0.2 ml contained approximately 107 red blood corpuscles. The composition under study was then dissolved or suspended in Tween 80 and sterile distilled water after which it was administered subcutaneously.

The compositions under study were given once a day for four days and, on the day following the last administration, the blood was spread in a thin layer to enable the level of parasitemia to be measured. The IDso and IDgo were then determined (i.e. the doses of composition required to reduce parasitosis by 50% and 90% respectively).

The following results were obtained with the compositions indicated hereunder: Composition 1: As defined above Composition 2: Quinine-resorcine dihydrochloridelquinidine-resorcine dihydrochloride/cinchonine-resorcine dihydrochloride in the proportion of 50%, 20% and 30%.

These compositions were compared to the three ingredients used alone.

TABLE 2 IDso (mg/kg) ID90 (mg/kg) Quinine salt 100 380 Quinidine salt 107 280 Cinchoninesalt 70 128 Composition 1 35 160 Composition 2 39 165 These results show clearly that the compositions of the invention are much more active than their ingredients used alone. Similar results to those given above were obtained with compositions identical to Compositions 1 and 2 but in which there was no resorcine.

The pharmaceutical compositions of the invention may be presented in any form suitable for administration in human and veterinary medicine for the treatment of malaria.

As modes of administration, there may be cited oral, sublingual, subcutaneous, intramuscular, intravenous, transdermic and rectal. The dosage unit may take the form of, for example, a tablet, coated-tablet, hard- or soft-gelatin capsule, powder, granules, suspension or syrup for oral administration, of a suppository for rectal administration or of a sterile solution or suspension for parenteral administration.

The total quantity of active principle, i.e. the mixture of quinine, quinidine and cinchonine or of their pharmaceutically acceptable salts, will be from 20 to 2000 mg per dosage unit depending on the mode of administration. The dosage unit will preferably contain 50 to 500 mg of active principle for oral administration, from 100 to 150 mg for rectal administration and from 20 to 2000 mg for parenteral administration, for example by infusion.

Daily dosage will depend on the administration route employed. In general, one dosage unit will be required 1 to 4 times per day. In this way, this daily amount of active principle may vary between 1 and 30 mg per kilo of body-weight. Preferably, it will be in the region of 25 mg/kg.

Generally speaking and taking into account the mode of administration desired, the pharmaceutical compositions of the invention will be prepared by associating the active principle defined above with an appropriate pharmaceutical carrier or excipient. This latter may be selected from substances such as distilled water, starches, talc, magnesium stearate, polyvinylpyrrolidone, alginic acid, colloidal silica, sodium chloride, titanium dioxide, cocoa butter, sweetening agents etc. A more detailed but non-limitative description is given hereunder of various methods of preparing the compositions of the invention.

For example, a composition is prepared in tablet form by forming a powdery mixture from the above-described active principles and a diluent or a base such as starch, saccharose, kaolin, dicalcic phosphate etc. and subsequently transforming the mixture into granules or fragments after adding a lubricant and finally compressing into tablets.

Granulation of the powdery mixture may be performed by wetting with a binding agent such as syrup, starch paste or acacia mucilage and forcing through a screen.

Another method of granulation consists in fragmenting the powdery mixture by passing it th rough a tabletting machine and breaking the resulting imperfectly formed tablets into small pieces. To prevent sticking, these pieces may be lubricated by adding a stearate in salt form, talc or a mineral oil and then forming cubes.

The lubricated mixture is then compressed to provide the desired tablets.

If required, the tablets may be coated, enteric-varnished or covered in such a way that the active principle is only gradually released.

Similarly, a composition of the invention may be obtained in the form of a hard- or soft-gelatin capsule by simply mixing the active principle with a pharmaceutical carrier. The resulting powdery mixture is then introduced into a hard- or soft-gelatin sheath, preferably after adding to the mixture a lubricant such as talc, magnesium stearate or calcium stearate.

Powders for oral administration may be prepared by crushing the active principle to a suitably fine consistency and mixing it with a diluent similarly treated which may be an edible glucide derivative such as starch. Preferably, a sweetening agent or sugar together with a flavouring oil will be included.

To obtain a liquid composition for oral administration, granules are prepared by wetting the active principle and a water-soluble diluent such as saccharose, glucose etc..., with a binding agent such as acacia mucilage, gelatin solution or methylcellulose solution and forcing the resulting product through a screen to form granules which are then dried. Preferably, the composition will contain a suspension agent such as gum tragacanth. Liquid compositions for oral administration can subsequently be prepared in dosage-unit form, such as a syrup, in which each teaspoonful will contain a pre-determined amount of active principle.

A composition in the form of a syrup or elixir may contain, in addition to the active principle, an appropriate sweetening agent, antiseptic such as methylparaben or propylparaben, colouring agent and sweetener.

A composition for rectal administration may also be prepared in the form of a suppository by pouring, into a suitable mold, a mixture comprising the active principle and a binding agent melting at rectal temperature, such as cocoa butter, polyethyleneglycol or lanolin.

For parenteral administration, aqueous suspensions, isotonic saline solutions or sterile injectable solutions may be prepared which contain the active principle together with, if required, a solubilizing agent, for example polysorbate 80, suitable wetting agents, for example propyleneglycol or butyleneglycol, and a preservative such as benzyl alcohol.

The following non-limitative Examples illustrate pharmaceutical compositions according to the invention: EXAMPLE 1 Compositions for Oral Administration I. Tablet Tablets having the following composition were prepared: Quininemonohydrochloride2H2O 25.2 mg Quinidine monohydrochloride 1 H20 24.8 mg Cinchonine monohydrochloride 2H,O 25.6 mg Corn starch 56.4 mg Polyvidone excipient 5.0 mg Sodium carboxymethyl starch 7.5 mg Talc 4.5 mg Magnesiumstearate 1.0 mg in accordance with the procedure described hereunder: All the ingredients, with the exception of the lubricant (talc, magnesium), were thoroughly mixed in a mixinglkneading machine for 15 minutes. The mixture was further kneaded while water was gradually added and then passed through a 1.25 mm-mesh screen. The resulting granules were dried in an oven with forced ventilation until a relatively low level of residual humidity was obtained. The granules were rendered uniform and the lubricant added.

Tablets, each weighing 150 mg and containing 75.6 mg active principle, were then prepared by compression.

II. Soft-gelatin capsule Soft-gelatin capsules having the following composition were prepared: Quinine sulfate 2H2O 49.7 mg Quinidinesulfate2H2O 51.2 mg Cinchonine sulfate 2H2O 50.4 mg Mill sugar 19.2 mg Colloidal silica 0.2 mg Talc 5.0 mg EXAMPLE 2 Composition for Parenteral Administration A sterile injectable aqueous composition was prepared having the following formulation: Quininemonohydrochloride2H2O 25.2 mg Quinidine monohydrochloride 1H2O 24.8 mg Cinchonine monohydrochloride 2H,O 25.6 mg Methane 75.5 mg Sodium chloride 7.0 mg Hydrochloric acid, water sufficient for 1 ml.

Claims (9)

1. Pharmaceutical composition in dosage unit form having anti-malarial activity and containing 20 to 2000 mg of a mixture comprising: 30 to 60% quinine 20 to 40% quinidine 20 to 40% cinchonine each of these ingredients being in the form of a base or pharmaceutically acceptable salt, the said mixture being associated with an appropriate pharmaceutical carrier or excipient.

2. Pharmaceutical composition according to Claim 1 containing 50 to 1000 mg of a mixture of quinine or one of its pharmaceutically acceptable salts, quinidine or one of its pharmaceutically acceptable salts and cinchonine or one of its pharmaceutically acceptable salts, in the proportion of 1:1:1.

3. Pharmaceutical composition according to Claim 1 containing 50 to 1000 mg of a mixture of 50% quinine or one of its pharmaceutically acceptable salts, 20% quinidine or one of its pharmaceutically acceptable salts and 30% cinchonine or one of its pharmaceutically acceptable salts.

4. Pharmaceutical composition according to any one of Claims 1 to 3 presented in a form suitable for oral administration.

5. Pharmaceutical composition according to any one of Claims 1 to 3 presented in a form suitable for rectal administration.

6. Pharmaceutical composition according to any one of Claims 1 to 3 presented in a form suitable for parenteral administration.

7. Pharmaceutical composition according to Claim 4 presented in the form of tablets, coated-tablets, hard- or soft-gelatin capsules, powder, granules, suspension or syrup.

8. Pharmaceutical composition according to Claim 5 presented in the form of a suppository.

9. Pharmaceutical composition according to Claim 6 presented in the form of a solution or suspension.