NO802452L - DEPOT PREPARATION WITH DELAYED ACTIVE SUBSTANCE - Google Patents

Description

! • The present application relates to a method for the production of a veterinary medicinal depot preparation in solid, com-ji 'primed form with delayed release which is suitable for combating tissue parasite insect larvae, especially of the order Di'ptera, ad systemically. in I

The control of insect larvae that live as parasites in the tissues of their host animals is of very great importance because of the considerable damage that can be caused by the parasites in domestic livestock and especially in grazing livestock. j j

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i i '. The dipteran larvae can enter the tissues of their host animals on ; very different way. Thus, the dipteran females can, after egg-j laying, which can take place in different body parts of the j host animal, and the larvae that have come out of the eggs can be taken up by !

in the host animals through licking and bore into the throat or the larvae can bore into the skin of the host animals from the outside. i. However, the eggs can also first be laid on mosquitoes or flies.' The larvae develop in the eggs and emerge as soon as the carrying insect seeks out a suitable host. In the case of the live-bearing dipteran species, the larvae can be introduced directly into the nose or eyes of the host animals from the dipteran females. j i

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After the larvae have entered the host, they can seek out the preferred body parts by migration. The larvae can e.g. appear in or under the skin, in the stomach, intestinal tract or in; nose, throat or dental cavities of their'host animals.

The different forms of appearance of the parasitic dipteran larvae on animals are summarized under the term myiasis.

i • Myiasis can occur in many animal species, e.g. at fe,; horses, donkeys, mules, reindeer, sheep, pigs, dogs and cats.

The host animals can be attacked by the parasite dipter larvae. , alongside other adverse effects lead to a reduction in milk production, wool loss, emaciation and even death. :

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.If the host animals are attacked by main parasites that lead to i j blister formations in the skin, it can also lead to a reduction in value-j I .åspjonning ing sohm udeav n vlead rvpenere förtveridinegs , fdør a dbe lærfoenre latkaen r vhea rteen n lfiotr en > >åi< I>j •li pupate. i j i l ■As the larvae can attack very different and partly difficult i Inaccessible body parts of the host animals, it is very j .problematic to combat them. In addition, a possible infestation of the host animals by the tissue parasite insect larvae is not limited to a short, easily understandable period of time. Thus, in particular: j. the flight times of the female insects that are able to lay eggs or lay larvae extend over long periods of time, depending on the environmental conditions, which, in addition to constant control of the host animals, would require treatment at short intervals. Under practical conditions, however, such a procedure would be very labour-intensive and expensive and hardly possible to carry out in free-ranging herds. j j i i i

i i For effective and long-term control of the tissue parasite; insect larvae therefore require a preparation that provides reliable and long-term protection of the host animals against the parasites without causing adverse side effects. Production of such

preparations are a difficult problem due to the large and varied requirements which they must satisfy. The desired properties of such preparations can only be realized by a multi-component system, in which it must be fulfilled, for example, that the individual component is not toxic to the host animals such as skai; processed, and also not under the influence of other components, digestive juices of the host animals and the food which

these compounds form toxic products.

1. ■ 'i i l The effectiveness of the active substance must not be affected in any way by the other components. IN

Furthermore, after the host animal has received the preparation, an effective concentration in the blood must be achieved which must be maintained over a long period of time without at any time reaching a concentration that is so high that it can harm the host animal. On the other hand, there must also be no premature release of the active substance or preparation through the host animal. '

Through the present invention, a depot is provided

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preparation with extended release of active ingredient which, next to , l an active ingredient of formula I in li j

in which hydrogen, methyl, ethyl or cyclopropyl, R2 means hydrogen or methyl, R-. hydrogen, methyl or cyclopropyl, R 1 hydrogen or methyl and R 1 - ethyl, n-propyl, isopropyl

or cyclopropyl, or one non-toxic for ruminants. acid addition salt thereof, and a common auxiliary substance or several such containing alkylhydroxyalkylcellulose in which the alkyl groups independently contain 2 or 3 carbon atoms, and a higher fatty acid with 15 to 18 carbon atoms in the alkyl part or a calcium or magnesium salt thereof.

The active substances of formula I give a systemic effect, which means that an effect against the parasite dipter larvae also occurs in the untreated body parts even when applied locally to the host animal. The depot preparations according to the present invention thus enable an effective fight against the parasite dipter larvae also in such parts of the body where a direct application is extremely difficult or practically impossible. They have a particularly good effect on the larvae of insects of the order | diptera as. causing myiasis, which larvae belong j in the families calliforidae, ostridae, cuterebridae, gaster-ofilidae, sarcofagidae and hypodermatididae, e.g. against j ! larvae of lucilia spee., coklyomyia hominivorax, \ chrysomyia bezziana, hypoderma lineata, hypoderma bovis, . j in dermatobia hominis, odemagena tarandi, gasterofilus spee,

ostrus ovis, rhinoestrus purpureus, wolfårtia vigil and cuterebra spee.<:>I

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Among the compounds of formula I are 2-cyclopropylamino-! I 4,6-diamino-s-triazine, due to its outstanding effect, is particularly suitable for combating the tissue parasite insect larvae, especially those of the order Diptera. j j

i J Under the term acid addition salts of the compounds with

formula I means such salts with pharmaceutically tolerable acids, e.g. with strong mineral acids, such as hydrochloric acid or, sulfuric acid or with organic acids, such as acetic acid, tartaric acid or citric acid.

in the Connection? with formula I can be prepared according to and per se: known methods, e.g.

a) reacts a compound of formula II in which R^, R2•qg R,- has the meaning given for formula I and X means

'li halogen, preferably chlorine, with ammonia or a • primary or secondary amine of formula V, where R 2 and

R^has it for formula. In stated meaning:

b) reacts a 2,4-diamino-6-halo-s-triazine with formula III, where R1R2, R3 and R4 have the meaning given for formula I and X means halogen, preferably chlorine, with a compound of formula VI, in which R has the meaning specified for formula I or .. c) when R^ in the compound of formula I has the same meaning as R^, and R2 has the same meaning as R^ reacts a compound of formula IV, where R^ has the meaning given for formula I, and X means halogen, preferably chlorine, with ammonia or a primary, resp. secondary amine of formula VII, in which R',- , i_ a. j • ' ™ ' 1 has the meaning of R^ = R^as indicated for formula I, and R'2 has the meaning R2= R^as indicated for formula I:

The substitution of the halogen atoms with ammonia, primary and/or secondary amines with formulas V, VI and VII takes place while dissolving the starting materials with formulas II, III and IV in inert solvents, such as e.g. acetone, acetone/water mixtures, methyl ethyl ketone, dioxane or dioxane-water mixtures and reacts these mixtures at normal or possibly higher pressure and at temperatures of 20-150°C, preferably 50-140°C, with ammonia, primary and/or 1

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secondary amines..

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i The starting materials of formulas II, III and IV are for a stori| part known and can be produced analogously by known methods.'

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The production of the active ingredients is explained in more detail; : by the following examples.

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Example 1

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a) 2-cyclopropylamino-4,6-diamino-s-triazine

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A mixture of 100 g of 2-cyclopropylamino-4-amino-6-chloro-s-triazine, 51 g of ammonia and 500 ml of dioxane is heated in an autoclave for 24 hours at 140°C. After cooling, dioxane is distilled off in vacuum, the crystalline residue is washed with water and dried. The crude product is recrystallized from methanol, , m.p. 219-222°C.

b) 2-cyclopropylamino-4,6-djamino-s-triazine, salt with 2 moles of hydrochloric acid. in

Dissolve 25 g of 2-cyclopropylamino-4,6-diamino-s-triazine hot

in 2000 ml abs. ethanol. This solution is cooled to 15°C, cooled further with ice and then hydrochloric acid gas is introduced until saturation. This causes white crystals to fall out. These are filtered off and the crude salt thus obtained is washed with a lot of ether, m.p. 195°C (decomposition).

Example 2

a) 2-cyclopropylamino-4-methylamino-6-amino-s-triazine

A mixture of 12.7 g of 2-cyclopropylamino-4-methylamino-6-chloro-s-triazine, 17.4 g of 28% aqueous ammonia solution and 30 ml of dioxane is heated in an autoclave for 4 hours at 140°C.

After cooling, the reaction mixture is poured into 350 ml

of a solution of potassium carbonate in water cooled to 0°C and extracted with benzene/ether 1:1. After drying with sodium sulfate, the solvent is removed in vacuo and the residue is recrystallized from isopropanol/hexane, m.p. 159-162^.

b) 2-cyclopropylamino-4-methylamino-6-amino-s-triazine, salt with 2 moles of hydrochloric acid. 38 . g 2-cyclopropylamino-4-methylamino-6-amino-s-triazine: dissolve in 280 ml of chloroform. This solution is cooled with ice to 0-5°C and hydrochloric acid gas is introduced until saturation. Thereby [

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white crystals fall out. To obtain complete precipitation, mix with 280 ml of ether. The crude hydrochloride is filtered off and<1>recrystallized from methanol, m.p. 197-199°C. ■

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Example 3

l 2, 4, 6-tris-cyclopropylamino-s-triazine

A mixture of 20 g of 2-chloro-4, 6-bis-cyclopropylamino-s-triazine, 10.1 g of cyclopropylamine and 80 ml of dioxane is heated for 22 hours in an autoclave at 14 0 o C. The reaction mixture is evaporated. in vaku1u<m>to half and mix with 300 ml of water. Extract with ethyl acetate, dry with sodium sulphate and remove the solvent in vacuo. The residue is recrystallized from dioxane/petroleum ether, m.p. 75-77 C. " '

In an analogous way as in examples 1 to 3, the following compounds of formula I can also be prepared:

The depot preparations can be prepared in a simple way by first stirring alkylhydroxyalkylcellulose in a suitable swelling substance, such as e.g. ethanol and leave to swell for a few hours. Underneath, a mass with a honey-like consistency is formed into which the fatty acid or a calcium or magnesium salt thereof is stirred. The active ingredient is then added. and an auxiliary substance or several auxiliary substances after dry mixing. The resulting mixture is processed while stirring into a plastic mass and granulated. After drying the granulate, it is broken through a suitable sieve and pressed into a fixed dosage form.

Among alkylhydroxyalkyl cellulose, one can advantageously e.g. use ethyl hydroxyethyl cellulose. Water-insoluble ethylhydroxyethylcellulose has proven particularly suitable with a viscosity of 10 to 250 cP (centipoise) measured in a 5% solution in 80 parts toluene and 20 parts 95% ethanol at 25°C. The ethyl-hydroxyethyl cellulose, which is hereinafter called low-viscosity, has a viscosity of 20 to 35 cP measured under the same conditions.

As higher fatty acids, e.g. stearic acid and palmitic acid as well as their calcium and magnesium salts in question, especially stearic acid.

As excipients, above all fillers, which have a high specific gravity, are suitable, such as e.g. barium sulphate, bismuth subnitrate, iron(n) salts and especially iron powder.

As it is above all alkylhydroxyalkylcellulose. in conjunction with the fatty acid or its salts, which affect the rate of release of the active ingredient, you can set the total j ! the active ingredient content in the depot preparation with an advantage through corresponding adaptation of the content of filler material, i.e. by increasing the active ingredient content, the proportion of filler material can be reduced, and by reducing the active ingredient content, the content can be increased.

As granulation media, you can use ordinary granulation

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liquid such as e.g. carbon tetrachloride, dichloromethane or

in preferably ethanol.

The granulation can take place in a manner known per se, e.g. using a sieve rasp whereby elongated bodies are produced.

The obtained granules are preferably dried.ca. 2 4 hours at room temperature and then broken through a suitable sieve. The subsequent pressing of the granulate can be carried out using a suitable tablet press. As fixed dosage forms, boli in particular comes into consideration.

When producing the solid dosage form, granules containing the same ingredients in different proportions can be pressed. When using such mixed granules, the course of the active substance indication can very well be adapted to the relevant objective.

A further possibility for regulating the release of the active ingredient consists in partially providing the depot preparation's surface with a coating of a water-insoluble substance which is common for enclosing preparations.

Depot preparations containing 0.1 to

60% by weight active substance with formula I, 2 to 15% by weight, preferably 3 to 8% by weight alkylhydroxyalkylcellulose and 0.1 to' 5% by weight, preferably 0.5 to 2% by weight fatty acid or calcium or magnesium salt thereof, calculated on the total weight of the depot preparation.

The use of ethyl hydroxyethyl cellulose together with stearic acid works very well in the quantity ranges indicated above.

The following examples illustrate the preparation and composition of depot preparations according to the present invention. In addition, water-insoluble ethylhydroxyethyl cellulose is used

a viscosity in the range from 20 to 35 cP.

Example 4

12.5 g of low-viscosity ethyl hydroxyethyl cellulose is stirred into 30 ml of ethanol. After swelling overnight, stir 7.5 g of stearic acid powder into the mixture. 50.0 g of 2-cyclopropylamino-4,6-diamino-s-triazine and 180.0 g of iron powder which have previously been mixed dry are added to this mixture while stirring. A plastic mass is produced which, for the further production of fine, elongated bodies, is pressed manually through a sieve of 6M/cm.

The granules thus obtained are dried for 24 hours at room temperature and then pressed with a tablet press into 10 boli with a weight of 25 g each and a specific weight of 2.95.

Example 5:

According to the method described in example 4, 10 balls with a weight of 25 g each and a specific gravity of 3.01 are produced from 12.5 g of low-viscosity ethylhydroxy ethyl cellulose, .30 ml of ethanol, 2.5 g of stearic acid powder, 50.0 g 2-cyclopropylamino-4,6-diamino-s-triazine. and 185.0 g of iron powder.'

Example 6:

750 ml of ethanol with a proportion of 5% isopropyl alcohol are placed in a plate tube plant with rotating brushes. The alcohol is added while stirring with 375 g of low-viscosity ethyl hydroxyethyl cellulose.

It is stirred further until sedimentation can no longer occur.. After swelling for a few hours, e.g. overnight, stir 75 g of stearic acid powder into the resulting honey-like mass. This mass is processed while stirring into a plastic mass in a planetary tube plant with agitators with a mixture of 1500 g of 2-cyclopropylamino-4,6-diamino-s-triazine and 5550 g of iron powder which has been premixed dry in a planetary tube plant with agitator wings for approx. 10 minutes This mass is finely granulated with a sifter. The thus formed granulate is dried for 24 hours at room temperature and then crushed with a dry granulation sieve with 6M/cm. The finished granulate is pressed with a suitable tablet press to boli each 56 mm length, 12 mm width and maximum 12 mm height, and a total weight of each 30 g.

Example 7:

According to the method described in example 6, boli is produced with a total weight of 26.5 g each from 312.5 g of low-viscosity ethylhydroxyethyl cellulose, 1000 ml of ethanol with a proportion of 5% isopropyl alcohol, 125.0 g of stearic acid powder, 1875.0 g 2-cyclopropylamino-4,6-diamino-s-triazine and

.4 312.5 g iron powder.

Example 8:

According to the method described in example 6, boli is produced with a total weight of 25 g each from 31.2 5 g ■ low-viscosity ethylhydroxyethyl cellulose, 100 ml ethanol with a proportion of 5% isopropyl alcohol, 12.5 g stearic acid powder, 187.5 g 2-cyclopropylamino-4,6-diamino-s-triazine and 393.75 g of iron powder.

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In a similar way as described in the previous examples

i can also produce depot preparations with other active ingredient concentrations. The active substance content of the preparations should preferably be chosen so that the host animals to be treated daily receive a dose in the range from 1 to 100 mg/kg body weight. The total weight of the preparation, which is preferably provided in the form of boli, is preferably in a range from 10 to 100 g.

The depot preparations according to the present invention can be given by means of suitable application devices such as e.g. a bolus applicator for ruminants to be treated, above all cattle and sheep.

The measurement of the active substance release from the depot preparations can be done in vivo and in vitro. In in vitro studies, the release of the active substance from the boli in an artificial medium is measured at specific time intervals. In in vivo investigations, parasites in the egg or larval stage are applied to the ruminants to be treated and the time until the parasite larvae are completely killed is measured.

Attempt 1:

Out of 6 sheep, 3 receive a bolus prepared according to example 4, and

3 a bolus prepared according to example 5 by means of a bolus applicator. That the housing remains in the sheep is checked daily using an electro-iron detector. For in vivo investigations, from 24 hours after application of the boli daily approx. 50 to 100 newly hatched larvae and newly laid eggs of Lucilia sericata on the back of the sheep and a check for mortality (complete killing of the parasite larvae) is carried out 24, 48, 72 and 96 hours after application.

The application of the host animals takes place by scratching the animals' back skin with a scalpel. The cutting site■is moistened by spraying. of water and the larvae respectively the eggs are .brought to this place. The first application takes place on the animal's instep. Each further application is carried out approx. 10 cm. closer to the body than the previous one. The application sites are characterized using different color markings.

The table below shows the results:

The results show that over a period of approx. 1 month, the parasite larvae are killed within 48 hours. In the further course, the shelters produced according to example 4 prove to be particularly advantageous, as the larvae are killed within 72 hours over a period of more than 6 weeks.

Attempt 2:

In an experimental apparatus, the release of the active substance is investigated

a bolus which: is prepared according to example 6. As experimental apparatus, essentially the apparatus for tablet-explosion studies which is described in The United States Pharmacopeia (USP) XIX, United States Pharmacopeial Convention Inc., 1975, page 650, serves.

The apparatus consists of a wire basket, a container for an immersion liquid and a suitable device which makes it possible to raise and lower the basket in the immersion liquid with a constant frequency. The frequency is between 28 and 32 cycles/min. over a height difference of 5 to 6 cm. The volume of the immersion liquid is chosen so that the wire braid of the basket at the highest point for the upward movement remains at least 2.5 cm below the liquid surface and for the downward movement at least 2.5 cm from the bottom of the liquid container. The time required for the upward movement is equal to that for the downward movement. The transition at the change of direction is smooth and not abrupt. The device also contains a thermostatic device for heating the liquid to a range between 35 and 39°C.

In contrast to the device described in the USP, the bolus to be examined is not placed in a tube which is in the basket, but directly in the basket. 1000 ml beaker-glass serves as liquid container, which is filled with 750 ml of demineralized water. During the first 8 hours of the examination, the water is renewed every hour. Later, the renewal takes place every 12 hours and finally with a 24-hour rhythm. The test temperature is 37°C. The quantitative determination of the active substance content in the water samples is carried out spectrophotometrically at a wavelength of 207 nm. . In the following diagram (Fig. 1), the active substance release from the bolus to the surrounding medium is shown expressed as a percentage of the total active substance content in the bolus at the start of the experiment and depending on time.

Attempt 3:

The release of the active substance to a bolus prepared according to example 8 was investigated with the temperature described in experiment 2 over a longer period of time.

The active substance release in the first 24 hours after the start of the experiment is shown in fig. 2. In the first 2 hours, the measurement of the released amount of active substance expressed in mg takes place at intervals of 20 minutes. In the following 3 hours, measurements were taken at half-hour intervals, and in the next 4 hours at 1-hour intervals. Further measurements then took place after 7 and 8 hours.

In fig. 3, the measurement results from 24 hours after the beginning of the experiment until the 10th day are indicated.-First 3, then 2 measurements were made per day.

Fig. 4 shows the active substance release expressed as a percentage of the total active substance content at the beginning of the experiment over a period of 61 days, with 2 measurements being taken daily from. 4th to 21st day. Then it was measured once a day.;

In the results of experiments 2 and 3, the amounts of active substance are indicated cumulatively, i.e. the total amount of active substance released up to the time of measurement is indicated.

The results of the measurements of the release of the active substance show that the release of the active substance first occurs quickly, then more slowly and continuously. This means that with the depot preparations according to the present invention, it is possible to achieve very quickly

a sufficient concentration for enrichment of the active substance in the blood of the animals being treated and that a steady subsequent delivery of the active substance is achieved over a longer period of time. . The depot preparations according to the present invention show an excellent and long-lasting effect of the active substance used.

With these allows an effective concentration. in the blood until the treated animals are maintained over a period of time up to approx.

6 weeks.

Claims (17)

1. Method. for the production of a veterinary medicinal depot preparation in "solid, compressed form with extended, prolonged active substance release which, next to an active substance of formula I wherein R^ means hydrogen, methyl or cyclopropyl, R2 hydrogen or methyl, R^ hydrogen, methyl or cyclopro pyl, R^ hydrogen or methyl and R^ ethyl, n-propyl, isopropyl or cyclopropyl, or an acid addition salt thereof that is non-toxic to ruminants, and a common excipient or several such excipients contain alkylhydroxyalkyl cellulose in which the alkyl groups independently contain 2 or 3 carbon atoms, and a higher fatty acid with 15 - 18 carbon atoms in the alkyl part or a calcium or magnesium salt thereof, characterized by stirring alkylhydroxyalkyl cellulose in which the alkyl groups. independently of each other contains 2 or 3 carbon atoms into a swelling substance, after swelling stirs in a higher fatty acid with 15 - 18 carbon atoms in the alkyl part or a calcium or magnesium salt thereof, adds a through dry mixture of an active substance of formula I with a auxiliary substance or several auxiliary substances prepared mixture, processes the combined mixture under stirring into a plastic mass, granulates and presses this. 2. Method according to claim 1, characterized in that a compound of formula I is used as active ingredient, in which R - to R^ have the meanings specified in claim 1 and Rj. means cyclopropyl. 3. Method according to claim 2, characterized in that 2-cyclopropylamino-4,6-diamino-s-triazine is used as active ingredient. 4. Process according to claim 1, characterized in that a compound of formula I is used as the active substance, in which R^ to R 4 have the meanings given in claim 1 and Ri- means ethyl, n-propyl or isopropyl. 5. Method according to one of claims 1-4, characterized in that 0.1 to 60% by weight of active ingredient with formula I, 2 to 15% by weight of alkylhydroxyalkyl cellulose and 0.1 to 5% by weight of fatty acid or calcium or magnesium salt thereof, calculated on the total weight of the depot preparation. 6. Method according to claim 5, characterized in that 3 to 8% by weight of alkylhydroxyalkyl cellulose and 0.5 to 2% by weight of fatty acid or calcium or magnesium salt thereof are used, calculated on the depot preparation's .total weight. 7. Method according to one of claims 1-4, characterized in that ethylhydroxyethylcellulose is used as alkylhydroxyalkylcellulose. 8. Method according to claim 7, characterized in that an ethylhydroxyethyl cellulose with a lower viscosity is used. 9. Method according to one of claims 1-4, characterized in that stearic acid, palmitic acid or a calcium or magnesium salt thereof is used as fatty acid or a calcium or magnesium salt thereof. ■ 10. Method according to claim 9, characterized in that stearic acid is used as fatty acid. : 11. Method according to one of claims 1-4. characterized in that, in addition to an active substance of formula I and an auxiliary substance or several such auxiliary substances, ethyl hydroxyethyl cellulose and stearic acid are used. 12. Method according to one of claims 1-4, characterized in that a filler with a high specific gravity is used as an auxiliary substance. 13. Method according to claim 12, characterized in that barium sulphate, bismuth subnitrate, iron (II) salts or iron powder are used as fillers. 14. Method according to claim 13, characterized in that iron powder is used as filler. 15. Method according to one of claims 1-4, characterized in that granulation is carried out in the presence of a liquid granulation medium. 16. Method according to claim 15, characterized in that the granulation is carried out in the presence of carbon tetrachloride, dichloromethane or ethanol. 17. Method according to claim 16, characterized in that the granulation is carried out in the presence of ethanol.