Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Nitrogen containing other than solely as a nitrogen in an...
Reexamination Certificate
1998-10-09
2001-07-03
Dees, Jose G. (Department: 1616)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Nitrogen containing other than solely as a nitrogen in an...
C424S405000, C504S116100, C504S118000, C504S189000, C504S358000, C514S065000, C514S183000, C514S506000, C514S557000, C514S631000, C514S646000, C514S675000, C514S706000, C514S715000, C514S740000, C514S741000, C514S769000, C514S770000, C514S772000, C514S788000, C514S937000, C514S938000, C514S939000, C514S943000, C514S970000, C514S975000
Reexamination Certificate
active
06255350
ABSTRACT:
DEFINITION OF TERMS
For the purposes of this disclosure, the following terms are defined as follows. The miniemulsion herein employed is a microemulsion having a micellular droplet size less than 400 nm which miniemulsion is derived from the dilution of the present water free concentrate composition. This miniemulsion is employed as a clear o/w liquid which is stabilized for extended storage or immediate use.
The active aza compounds referred to herein are active herbicidal or pesticidal compounds containing the aza group
and includes compounds having the structure
R
1
—(X)—R
2
wherein one of R
1
and R
2
is a sulfur- and/or nitrogen-containing heterocyclic radical containing 3 to 5 carbon atoms in a 4 to 6 membered heterocyclic ring and alkenylphenyl, and the other of R
1
and R
2
is the same or is amidosulfuron, phenyl, sulfonylphenyl, phenyloxy, phenoxysulfonyl, or phenylamino where said phenyl radicals and heterocyclic radicals are optionally substituted with lower alkyl, halo, haloalkyl, cyano, C
1
to C
4
alkyl ether, C
1
to C
4
ester, carboxy, ketone, and/or amino and X is
where R
3
, R
4
, R
5
and R
6
are each individually selected from the group of hydrogen, lower alkyl, cyano and amino. Specific examples of some aza compounds are disclosed in U.S. Pat. No. 5,731,264 and are incorporated herein by reference.
Lower alkyl is the radical containing 1 to 4 carbon atoms.
The hydrophilic/hydrophobic balance is expressed as HLB and the HLB of the present miniemulsion is between 7 and 20.
The molecular sieve is a zeolite having an open network structure and pore openings sufficient to absorb water molecules.
The emulsifying agent or surfactant emulsifier mixture is amphipathic containing hydrophilic and hydrophobic portions which can be adjusted by the degree of alkoxylation to meet the needs of the active ingredient selected. In general, the lower the degree of alkoxylation, the more hydrophobic the emulsifier; conversely, the higher the degree of alkoxylation, the more hydrophilic the emulsifier.
BACKGROUND OF THE INVENTION
Formulations of various types, including standard emulsions, suspensions, dispersions and dusts have been developed for delivery of biologically active components on animals and plants for control of insects and weeds. For ecological reasons, liquid, sprayable formulations are most sought after. However, many highly active and desirable aza compounds are totally unstable in water and hydrolyze to inactive metabolites. The high reactivity of Amitraz and sulfonyl urea are cases in point.
Accordingly, the use of these valuable chemicals has been limited to dusts or solutions employing expensive hydrophobic solvents or solvent mixtures. In the search for water stabilized Amitraz concentrate formulations, the use of 1,5-di(2,6-diisopropylphenyl) carbodiimide and or dicyclohexyl carbodiimide have shown some stabilizing affect (see U.S. Pat. No. 4,438,137). However, upon dilution of the concentrate with water in amounts useful for spraying or “pour on” solutions, a significant amount of inactive metabolites are formed; hence, economical use of these active ingredients in a water base is not achieved.
Accordingly, it is an object of this invention to provide a stabilized, water based miniemulsion of a hydrolyzable, biologically active aza compound which can be stored for extended periods without degradation.
Another object of this invention is to provide an aqueous solution of a concentrate containing a high load of the hydrolyzable aza compound.
Still another object is to provide a water solution containing stabilized aza compounds which employ biodegradable and environmentally safe carriers.
Yet another object concerns the preparation of a non-aqueous concentrate of the said hydrolyzable compound which has unique properties and produces miniemulsions of improved efficacy.
These and other objectives of the invention will become apparent from the following description and disclosure.
SUMMARY OF THE INVENTION
The above objects are achieved by instant emulsifiable concentrate composition and by the stabilized water diluted miniemulsion prepared therefrom. In accordance with this invention, there is provided an anhydrous liquid concentrate composition of (a) between about 0.05 and about 25 wt. % of a pesticidally active aza compound; (b) between about 2 and about 40 wt. % of a lactam selected from the group of N-methyl pyrrolidone (NMP), N-methyl caprolactam, a C
8
to C
18
alkyl pyrrolidone, a C
8
to C
18
alkyl caprolactam and a mixture thereof; (c) between about 2 and about 20 wt. % of a water scavenging agent selected from the group consisting of a hindered carbopolyimide compound and a molecular sieve and mixtures thereof and (d) between about 10 and about 80 wt. % of a mixture of at least two non-ionic surface active emulsifiers having an HLB of from about 7 to about 20, most preferably having an HLB of from about 7.5 to 11. The preferred composition of the concentrate contains from about 8 to about 15 wt. % (a); from about 15 to about 30 wt. % C
8
and/or C
12
alkyl pyrrolidone optionally containing up to 14 wt. % NMP, most preferably not more than 5 wt. % NMP; from about 5 to about 15 wt. % (c) and from about 65 to about 78 wt. % (d).
The concentrate, when diluted with up to 99.99 wt. % water (a dilution of 10
−4
of the active component), is ideally contained in a miniemulsion having a droplet size below 450 nm. In particular, the Amitraz miniemulsion undergoes no hydrolyzation for more than the 3 day period observed and is a clear water white liquid as opposed conventional emulsions observed over the same period having varying degrees of opacity associated with larger suspended particles. Optionally, other additives or excipients can be included in the above compositions, either as concentrate additives or as miniemulsion additives.
For example when needed to maintain an acidic medium, i.e. at a pH of 3-5, up to about 5 wt. % of a hydrophobic, surface active acid, such as an ethoxylated phosphate ester or e.g. citric acid, can be added as a buffer to the concentrate composition or the subsequently formed o/w miniemulsion. A wetting and spreading agent such as a silicone based surfactant, e.g. Heptamethyl trisiloxane (SILWET® L77, Osi Specialties Inc.) can also be added in an amount up to about 10%, preferably not more than 5%. Other additives, can also be incorporated in the mixtures, such as for example a stabilizer and/or a cosolvent to promote the solubility of the active component in the hydrophobic portion of the emulsion in cases where high load of active is desired. Examples of suitable cosolvents include butyrolactone (BLO), propylene carbonate, furfural, furfural ether, the acetic acid ester with a C
7
rich oxoalcohol (EXXATE® 700), and the like.
The anhydrous Amitraz concentrate of this invention is remarkably stable and undergoes less than 10% decomposition for at least the observed period of 2 weeks when stored at 25° C. over or in the presence of a molecular sieve or a carbodiimide. The miniemulsion of Amitraz is also stable for at least 12 days which is unexpected since prior aqueous formulations show appreciable decomposition of this compound within 6 hours.
DETAILED DESCRIPTION OF THE INVENTION
The clear, water white o/w liquid owes its clarity and stability to the formation of the miniemulsion containing micelle droplets having an average particle size less than about 0.1 micron (&mgr;), preferably less than 0.05&mgr; at 35° C.
Upon dilution of the present concentrate, the lipophilic pyrrolidone component, in the absence of N-methyl pyrrolidone, interacts in the micelle formation so as to orient the water soluble portions of the emulsifying mixture to the surface of the droplet while itself forming a distinct intermediate, water resistant layer or interface around the encapsulated active ingredient. The strong lipophilic nature of the pyrrolidone component, employed at the interfacial layer, enforces isolation of the active species and provides longer protection against hydrolysis during storage of the o/w miniemulsion.
Benning Matthew J.
Ianniello Robert M.
Jon Domingo I.
Narayanan Kolazi S.
Prettypaul Donald I.
Choi Frank I
Davis William J.
Dees Jos,e G.
ISP Investments Inc.
Katz Walter
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