Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Nitrogen containing other than solely as a nitrogen in an...
Reexamination Certificate
2000-12-14
2002-10-08
Pak, John (Department: 1616)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Nitrogen containing other than solely as a nitrogen in an...
C514S612000, C514S724000, C514S739000, C514S970000, C422S029000, C422S037000
Reexamination Certificate
active
06462088
ABSTRACT:
SPECIFICATION
The present invention concerns a disinfecting preparation containing chlorine in alcohol. More specifically, the invention relates to a liquid germicidal formulation containing, as the active ingredients, a combination of an alcohol and an organic N-chloroamine, which combination shows a high bactericidal activity and an unexpected stability in time, while maintaining its effectiveness substantially unchanged even after a prolonged storage.
The bactericidal properties of alcohols, known since ancient times, have been studied on a scientific basis starting from the beginning of this century. Some of such products, firstly ethyl alcohol and isopropyl alcohol, have reached in the field of disinfectants a quite remarkable diffusion, also in view of the advantages connected with their water solubility, with the ease of evaporation and with their reduced toxicity. Actually, some higher aliphatic alcohols are more effective than the lower ones as antimicrobial agents, the highest effectiveness being reached by alcohols having 6-8 carbon atoms. However, the low volatility and the unpleasant odor of these compounds have greatly limited their use. Also some aromatic alcohols find some limited application as disinfectants, among which benzyl alcohol and phenethyl alcohol. The latter, however, suffer from the disadvantage of being more toxic.
Ethanol shows its maximum potency as a 60-75% aqueous solution (weight percentage), while solutions of lower or even higher concentration take a longer time to exert the same germicidal effects. Both alcohols with three carbon atoms, i.e. n-propanol and isopropanol, show a higher activity than ethanol, with a maximum level at concentrations around 60% by weight. In spite of their unquestioned antibacterial activity, from the point of view of the activity spectrum aliphatic alcohols have the drawback of being totally ineffective against spore-forming micro-organisms.
Another product the use of which as disinfectant is well established since the last century is chlorine. Chlorine was employed, in the form of calcium chloride, for treating the sewage of the city of London in the mid-XIX century. In the same period, chlorine was used as a disinfectant in the hospital of Dr. Semmelweis in Vienna, to fight the puerperal fever. Although the mechanism of action of chlorine has not yet been fully clarified, it is believed that chlorine performs its disinfecting action by releasing in water hypochloric acid (HClO), which is responsible for the destruction of microorganisms. The concentrations of active chlorine required to kill most of the bacterial species may be of the order of 1 ppm, while higher concentrations are normally required to destroy spores and mycobacteria.
In the current practice, the term chlorine disinfectant is generically employed to refer to any disinfectant consisting in an aqueous solution of chlorine, hypochlorite or hypochlorous acid and also, in many cases, to other organic or inorganic chlorine-releasing compounds, such as, e.g., chloroamines (ClNH
2
, Cl
2
NH, Cl
3
N), N-chlorosulfonamides (e.g., sodium N-chloro-p-toluenesulfonamide or chloramine-T, and sodium N-chlorobenzenesulfonamide or chloramine-B), N-chloroisocyanuric acids. Such compounds are also employed, at the same time, in view of their activity as chemical oxidants, and are consequently the most widely used products for the treatment of drinking water, for sanitizing swimming pools and for water treatment in the food industry.
In view of the foregoing, the interest in formulating a disinfectant containing, as the active ingredients, both alcohol and chlorine is quite clear. A similar preparation would join the antiseptic properties typical of each one of these two classes of compounds, thereby resulting in a product with an enhanced potency and a wider activity spectrum. Although the known art includes many disinfectants that combine the antibacterial activity of alcohols with the activity of other agents, such as, e.g., iodine, phenols or chlorhexidine, no preparations consisting of combinations of chlorine and alcohol appear to be presently on the market. This is apparently due to the strong oxidizing action exerted by chlorine on such organic products, that are known to be relatively easily oxidizable.
As it is known, the power of a compound as an oxidant is measured on one hand by thermodynamic factors, in particular by the standard oxidation potential of the compound, and on the other hand by kinetic factors, which govern the rate of the oxidation reaction. As a matter of fact, although in the absence of information on the reaction kinetics it is impossible to precisely foresee the performance of an oxidizing system, a first valuable indication is always found in the standard oxidation potentials. It is, actually, the high standard oxidation potential for the reduction of molecular chlorine to chloride ion (Cl
2
+2e
−
2Cl
−
) and that for the reduction of hypochloric acid to chloride ion (HOCl+H
+
+2e
−
Cl
−
+H
2
O)— respectively, E
0
=1.36 V and E
0
=1.49 V—that give the most immediate indication of the potency of the chlorine-based agents as chemical oxidants (see, e.g., R. G. Rice and M. Gomez-Taylor, Environmental Health Perspectives, 69, 31-44, (1986)).
In this connection, it has been shown experimentally (D. Coates and J. E. Death, Journal of Clinical Pathology, 31, 148-152, (1978)) that mixtures of various alcohols or glycols (i.e., methanol, n-propanol, isopropanol, ethanol and ethanediol) in aqueous solution at various concentrations (from 10 to 50% by weight) with sodium hypochlorite at a level of available chlorine of 2000 ppm, although having an interesting sporicidal activity when freshly prepared, had lost practically all available chlorine after few hours. In order to exploit the advantageous biological activity discovered, therefore, the concerned publication suggests to store the solutions of alcohol and hypochlorite in separate containers, and to mix them just before use.
A first measure aimed at limiting as much as possible the reactivity between alcohols and chlorine disinfectants may be to use, in a possible preparation, a chlorine source characterized by an oxidation potential lower than sodium hypochlorite, which is able to supply chlorine much more slowly than the common hypochlorites. Products particularly suitable to this end are the chloroamines, as it may be inferred from the following table. The table shows the standard oxidation potentials at 25° C. in aqueous solution (according to two different literature references, i.e. a): R. G. Rice and M. Gomez-Taylor, loc. cit.; b): Ullmann's Encyclopedia of Industrial Chemistry, 5
th
ed., VCH Verlagsellschaft A 28, 87 (1996)).
E
0
, V-Ref.
a)
E
0
, V-Ref.
b)
Chlorine
1.36
1.36
Hypochlorous acid
1.49
1.50
Hypochlorite ion
—
0.90
Chlorine dioxide
1.275
1.71
Monochloroamine
1.16
0.75
Although they are not as powerful as chlorine, chloroamines have the advantage of being more stable, since they are less rapidly reactive. In water, chloroamines slowly hydrolyze, generating hypochloric acid according to the general reaction RR′NCl+H
2
O
RR′NH+HOCl. In view of the fact that the bactericidal activity of these compounds is due to the release of hypochloric acid, the value of the equilibrium constant of the above reaction is used to express the activity of chloroamines as disinfectants. Since hypochloric acid is released gradually from these compounds, the latter may keep their disinfecting activity for longer periods of time, compared to hypochlorites.
Among the possible organic and inorganic compounds belonging to the family of chloroamines, the present invention is concerned with two specific agents, already mentioned in the foregoing, consisting in the monosodium salts of two N-chlorosulfonamides, i.e. N-chloro-p-toluenesulfonamide sodium salt or chloramine-T,
and N-chlorobenzenesulfonamide sodium salt or chloramine-B
Both these compounds are known as topical antiseptics and for water steri
Dannan Hana
Russo Antonello
Eurospital S.p.A.
Nixon & Vanderhye P.C.
Pak John
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