Drug – bio-affecting and body treating compositions – Plant material or plant extract of undetermined constitution... – Containing or obtained from azadirechta
Reexamination Certificate
1998-01-15
2001-12-25
Pak, John (Department: 1616)
Drug, bio-affecting and body treating compositions
Plant material or plant extract of undetermined constitution...
Containing or obtained from azadirechta
C424SDIG001, C424SDIG001, C514S450000, C514S453000, C514S783000, C514S841000, C514S842000, C514S843000
Reexamination Certificate
active
06333058
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for the preparation of a spermicidal agent from neem oil or extractives. Though reference is made to a spermicidal agent, it is to be understood that such an agent also contains an antifertility agent.
2. Description of the Related Art
It is generally known that antifertility activity can be effected by three methods. One such method is that of a spermicidal activity by a spermicidal agent. Sperms from the male organism are killed or prevented from reaching the uterus of a female organism so as to prevent any fertilization. Yet another method is that the sperms are allowed to reach the uterus of a female organism. Such sperms are fertilized, and the fertilized ovum starts developing, and that the developing embryo travels to the wall of the uterus of a female organism and gets implanted.
In such a method the implantation is prevented. The third method is to allow the implantation and the uterine milieu is altered and embryo separated and aborted.
The present invention relates to a spermicidal agent so as to prevent a fertilization. Neem oil is known to have spermicidal activity, but its shelf life is short, and the activity too low to be of practical use. Thus, it is known to subject neem oil to the step of steam distillation to obtain a spermicidal agent. A disadvantage is that the process is time consuming, and the neem oil residues required for spermicidal activity are the residues obtained by the method of steam distillation become a waste.
Australian Patent No. 9,468,667 A discloses a method of blocking fertility in a male mammal by injecting neem oil or an active compound into the vas deferens of the male. U.S. Pat. No. 5,196,197 discloses an antifertility agent comprising neem oil and a reetha extract.
An object of this invention is to propose a process for the preparation of a spermicidal agent from neem oil and extractives.
Another object of this invention is to propose a process for the preparation of a spermicidal agent from neem oil and extractives which obviates the disadvantages associated with those of the prior art.
Yet another object of this invention is to propose a process for the preparation of a spermicidal agent from neem oil and extractives which has the required level of activity.
SUMMARY OF THE INVENTION
According to this invention there is provided a process for the preparation of a spermicidal agent from neem oil obtained from neem seeds comprising the steps of subjecting neem oil to the step of precipitation in the presence of an aliphatic hydrocarbon solvent, such as n-hexane, to obtain a precipitate containing essentially bitter constituents and a miscible solution containing odoriferous constituents, subjecting the miscible solution to the step of enrichment in the presence of a polar solvent to obtain a fraction comprising said solvent and said odiferous constituents, and distilling the polar solvent to obtain a concentrated extract enriched with spermicidal agent. The term neem oil used herein is intended to imply neem oil and neem extractives.
In accordance with this invention, neem oil is mixed with a solvent having a boiling point of up to 120° C. Preferably, the solvent comprises an aliphatic hydrocarbon such as n-hexane. The ratio of neem oil to solvent is 0.5:1 to 3:1. The solvent added to neem oil can be of light, middle or heavy fraction. Though all three fractions may be employed in the process of the present invention, it is preferred that the middle fraction be employed as the loss is less and the solvent can be recycled. If the light fraction is used, the boiling point is less than 60° C. and, consequentially, the cost is more in comparison to that of the middle fraction. The heavy fraction has a boiling point of 110 to 120° C. and, hence, greater energy is required for recovery of the solvent.
It is generally known that neem oil consists of glycerides, bitter and odiferous constituents. Only odiferous constituents are employed in the process of the present invention. Certain of such odiferous constituents that can be identified are 2-methyl-pentanal, ethyl propyldisulfide, 3,4-dimethylthiophene, Di-n-propyldisulfide, 2-phenylethanol, 1,2,3-trithracycle, hexane, 5-methyl-2-furturylfuran, trithiacyclononane, longifolene, (7) 8,9,10 (111)-tetrahydron, naptho (2,1-B)-thia, naphthene, 2-methyldecalm, nona-2,4-dienal, n-Propyl-cis-1-propenyl tetrasulfide, n-propyl-trans- 1-propenyl tetrasulfide, 2-Undecanone, 1,2-Bis (isopropyl-mercapto)ethane, Hexahydrofarnesol, methylpalmitate, ethylpalmitate, palmitic acid, farnesylacetate, methyl stearate, stearic acid, and ethyloleate.
The process of the present invention broadly consists in the steps of precipitation and enrichment. As described herein above, the step of solvent partition consists in adding an aliphatic hydrocarbon solvent to neem oil in the ratio of 1:1. The addition of solvent to neem oil provides a miscible solution consisting of glycerides, odoriferous and certain of the biter constituents. Such bitter constituents are removed by the step of precipitation, the remainder of the bitter constituents remaining in the solution.
The step of precipitation is carried out at room temperature. However, lower temperatures are preferred as this enhances the number of bitter constituents that precipitate from the solution. Thus, if the step of precipitation is effected at 10° C., it is estimated that as much as 50% of the bitter constituents are removed by precipitation. Preferably, the step of precipitation is carried out at a temperature of 0 to 15° C. The step of precipitation is carried out for a period of 15 to 60 minutes and preferably from 15 to 30 minutes.
After removal of the precipitation, the filtrate is subjected to the step of enrichment. For this purpose, the ratio of hydrocarbon solvent to the neem oil residue, after precipitation, is adjusted to a level so that the residue contains 0 to 75% for hydrocarbon solvent. The filtrate is either distilled off to remove excess hydrocarbon solvent or fresh excess hydrocarbon solvent is added to obtain the aforesaid condition. A polar extractant such as ethanol or methanol each containing 0 to 10% water is added to the filtrate.
Such a polar extractant is added to the filtrate in the ratio of 1:1 to 1:5 and preferably 1:3, and shaken to effect enrichment. The step of enrichment is carried out at a temperature of 10 to 40° C. and, for exarnple, in a separating vessel. Two layers are produced in the separating vessel. The upper layer is a hydrocarbon layer and contains most of the glycerides, which are not required in the spermicidal agent of the present invention. The lower layer is an alcohol layer containing the odiferous constituents and the remaining bitter constituents.
The lower layer is removed and fresh polar extractant is added to the upper layer. This step may be further repeated several times. Such a step of adding a polar solvent to the upper layer is repeated as a certain amount of odoriferous components are still retained in the upper layer. Thus, treatment with polar extractant allows a further separation of the odoriferous constituents from the upper layer. Alternatively, and in the instance where such a step of enrichment is carried out in a counter flow column, the extractant layer is recycled several times.
The lower layer obtained from the step of enrichment is then subjected to the step of distillation for removal of extractant under atmospheric pressure or moderate vacuum to obtain a concentrated extract.
Reference made herein above to a polar extractant is intended to imply a polar solvent containing 0 to 10% water.
REFERENCES:
patent: H1541 (1996-06-01), Holla
patent: 4946681 (1990-08-01), Walter
patent: 5196197 (1993-03-01), Talwar et al.
patent: 5395951 (1995-03-01), Nagasampagi et al.
patent: 6083506 (2000-07-01), Ilavazhagan et al.
patent: 2184564 A (1997-03-01), None
patent: 2188110 A (1997-04-01), None
patent: 3912059 A (1990-10-01), None
patent: 0436257 A (1991-07-01), None
patent: 0472791 A (1992-03-01), None
pate
Devakumar Chakra
Ilavazhagan Govindaswamy
National Research Development Corporation
Pak John
Venable
Wells Ashley J.
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