6-Piperidino-2,4-Diaminopyrimidine-3-Oxide Salt of 3-Carboxypyridine N-Oxide and Topical, Related Compositions

Object of the present invention is the 6-piperidine-2,4-diaminio-pyrimidine-3-oxide salt of 3-carboxypyridine N-oxide according to formula (I) ##STR2##

The compound (I) is active in promoting the growth of hairs and of other body piles and can therefore be employed in cosmetic, pharmaceutical and veterinary field in the form of appropriate topical formulations.

Said 2,4-diaminopyrimidine derivate, which is the basic component of the salt of formula (I), is known also under the common international name of Minoxidil: it is already employed as anti-hypertensive drug in human therapy and its use by topical application in the treatment of the common baldness and spotted alopecia has been described.

As a consequence of Minoxidil being insoluble in water, the resulting liquid formulations are glycol or polyalcohol-based and their topical applications are therefore unpleasant, tending to grease the scalp.

On the contrary, the salt object of the invention, being soluble in water, can therefore be easily formulated as water-based composition.

The acid component of salt (I), 3-carboxypyridine N-oxide, known also as oxyniacic acid, is already employed in systemic therapy as lipemia-controlling drug, particularly the cholesterol and tryglyceride fraction, and as vaso-activating agent, free from particular side-effects.

These very properties of oxyniacic acid allow to reasonably assume that the higher activity of the novel compound of formula (I), compared to Minioxidil alone. is to be ascribed, as far as hair growth is concerned, to a synergistic mechanism whereby the lipidic component of the scalp, the altered composition of which is regarded as responsible for some forms of baldness, is favourably controlled and an effective micro-circulation, considered also very important for the optimum preservation of hair health, is restored.

The novel compound object of the invention is, moreover, remarkably soluble in water and, for this peculiar property, particularly suitable for the utilization in formulations based only, or prevailingly, on water, which are particularly appropriate in the trichological field.

Both the systemic toxicity and the cutaneous endurableness fall within the ranges already known for topically administered Minoxidil.

Compound (I) can therefore the advantageously formulated as lotion, cream, spry, shampoo, gel, brilliantine, bandoline, preferably based only, or prevailingly, on water. The formulations object of the invention can include, besides the compound of formula (I), other complementary active ingredients in addition to the usual carriers and excipients, such as perfumes, stabilizers, drystuffs, etc.

The invention obviously concerns those formulations too, wherein oxyniacic acid and Minoxidil do not meet stechiometric ratios; in this case the non salified portion of either component has activity complementary to the compound of formula (I).

The formulations of the invention include the active ingredient in concentration ranging from 0,1% to 10% and are to be generally applied on the interested area once or more per day.

The preparation of the novel compound is carried out according to techniques well-known in the art; f.i. it can be prepared in water by reacting nearly stechiometric amounts of Minoxidil and 3-carboxypyridine N-oxide.

The compound of the invention can be easily prepared by employing other suitable solvents, such as anhydrous or partly dehydrated methanol, ethanol, isopropanol, etc.

The compound of formula (I) is isolated according to usual techniques, such as, for example, the solvent evaporation, the precipitation by non-solvents, etc.

The following exemples are only aimed at illustrating the invention and not at limiting it.

To a suspension of 2,0 g of Minoxidil in 50 ml of water 1,39 g of 3-carboxypyridine N-oxide areadded. The resulting solution can be employed as such to form compositions for topical application. Alternatively, the compound can be isolated as a solid, for example by evaporating the water, preferably under reduced pressure.

According to this procedure, the compound of formula (I) is obtained preferably pure, in theoretical yield. I.R. Spectrum (KBr)

2,09 g of Minoxidil and 1.39 g of 3-carboxypyridine N-oxide are dissolved in 100 ml of 95% ethanol. The resulting solution can be employed as such or suitably diluted and/or added with adjuvants or complementary materials.

Alternatively, the solid compound can be isolated by thoroughly evaporating the solvent or by adding ethyl ether as precipitating agent to a partially evaporated solution.

The solid compound, no matter how it was obtained, chemically conforms with that of Example 1.

In the following are reported compositions of formulations of the compound according to formula (I).