Indian Patents. 240763:"AN IMPROVED MALE CONTRACEPTIVE FORMULATION"

Title of Invention	"AN IMPROVED MALE CONTRACEPTIVE FORMULATION"
Abstract	The present invention relates to an improved contraceptive formulation, and the method of preparation and use thereof, particularly for use by males wherein the contraceptive primarily comprises of an injectable basic compound, a solvent and essentially a magnetic compound.

Full Text	The present application is a divisional application out of Indian Patent Application No. 716/DEL/1996 now Indian Patent No. 190814. The present invention relates to a method for preparing an improved contraceptive formulation. Particularly, the invention relates to an improved contraceptive formulation essentially comprising of magnetic compound, preferably of an oxide of iron having microsized particles, and the method of preparation and use thereof. More particularly, the present invention relates to an improved contraceptive formulation as stated hereinabove, which can be detected externally and evacuated to restore the fertility. The fertility, particularly in males, can be controlled by affecting the flow of the spermatozoa or the quality of the spermatozoa, when they pass through the reproductive duct, called the vas deferens, of the male. The flow of the spermatozoa can be affected by cutting and tying the vas deferens. This technique is widely used and called vasectomy. As a result of this technique the spermatozoa are prevented from flowing in the forward direction and are accumulated in the epididymis. The accumulation of the spermatozoa results in production of enhanced antibodies, which in-turn destroy the accumulated spermatozoa. The major disadvantage of the known vasectomy techniques is that the reversal of the fertility is not effective. The rejoining of the vas deferens does not result in the desired fertility, because the level of generation of antibodies remains high, which in-turn continue to destroy the spermatozoa. Further disadvantage of the vasectomy, as known in the art, is the requirement of micro-surgery. The another known method to affect the flow of the spermatozoa is the occlusion method. Such known methods comprises of implantation of a reversible occlusion device, which on implantation blocks the flow of the spermatozoa in the vas deferens and control the fertility'. This method also has disadvantages, such as, the implanted device has the regulator knob, which stays outside the vas deferens, but within the scrotum and is operated only by the trained medical assistant. In addition this method also has the disadvantages of requirement of surgery and maintaining the higher level of generation of antibodies even after the removal of the implanted device, which inturn continue to destroy the spermatozoa and resulting in poor level of fertility. Still another disadvantage of this method is the imperfect blockage, which will result in the flow of the spermatozoa and hence the complete destruction of the spermatozoa is not resulted. The another known occlusion method comprises of injecting polyurethane at a high pressure in the vas deferens. The injected polymeis further polymerised in-situ to a solid plug by introducing an initiator. The sohd plug thus formed blocks the flow of the spermatozoa in the manner as described herein above. The major disadvantage of such known occlusion methods is the generation of the back pressure in the epididymis. The quality of the spermatozoa is affected by injecting the injectable contraceptiye into the lumen of the vas deferens. The vas deferens is known to be the suitable site for the contraceptive intervention in the males. The disadvantage of such known methods is that the extent of flow and the rate of flow cannot be controlled externally satisfactorily. The main disadvantage, in addition to the disadvantages as described herein above, of the known methods of the prior art for controlling the fertility of males, as described herein above, is that they cannot be detected externally. The basic compound of the contraceptive being a polymer is generally not radioopaque and hence cannot be detected by X-ray imaging. The magnetic resonance imaging also fails to detect the contraceptive mainly due to its poor contrast with the soft tissue. The ultrasound is also incapable of detecting the contraceptive, due to the low percentage of the basic compound. To overcome this disadvantage, if the net percentage of the basic compound is increased, it will have the disadvantages associated with the higher percentage. Furthermore, some of the regions of the vas deferens are so placed that the ultrasonic approach is not practicable. Still another disadvantage of the known methods of controlling the fertility of males by injectable contraceptives, is that, the restoration of the fertility generally calls for an invasive procedure wherein a flushing compound is injected into lumen of the vas deferens, which affects the restoration of the fertility. It is further a disadvantage of the known methods of controlling the fertility, particularly of the vasectomy, that the fertility is not controlled immediately, that is contraceptive and the contraceptive technique is not effective from the day one. Therefore, there is a need to have a contraceptive, which can overcome the disadvantages of the prior art as described herein above and particularly can be detected externally and evacuated conveniently without the requirement of any surgical procedure, further, the fertility is restored fully on evacuation of the contraceptive. This is the main object of this invention to make a complete, disclosure of an improved contraceptive formulation, and the method of preparation and use thereof, which can overcome the disadvantages of the prior art as described herein above. Another object of the present invention is to propose for an improved contraceptive formulation, as stated herein above, which can be detected externally by any non-invasive technique, -such as, X-rays, magnetic resonance imaging, ultrasound etc. Further an object of this invention is to propose for an improved contraceptive formulation, as stated herein above, which can be evacuated conveniently without the requirement of any surgical procedure. Further, the evacuation of the proposed contraceptive results in restoration of the fertility fully. Still another object of the present invention is for an improved contraceptive formulation, as stated herein above, of which the flow extent and the flow rate can be controlled conveniently. Still further an object of this invention is to propose an improved contraceptive formulation, as stated herein above and described herein below, which can control the fertility immediately from the day one, that is from the day the proposed contraceptive is injected. Accordingly, this invention provides a complete disclosure of an improved contraceptive formulation, and the method of preparation and use thereof, particularly for use by males, wherein the contraceptive primarily comprises of an injectable base compound, a solvent and essentially a magnetic compound. Accordingly, this invention relates to an improved male contraceptive formulation comprising 35 - 55 % by weight of polymer / copolymer of the kind such as herein described, 5 - 25 % by weight of magnetic compound, which is iron or iron oxide and 20 to 60 % by weight of solvent to obtain the improved contraceptive formulation. According to the preferred embodiment of the present invention the injectable basic compound of the presently disclosed improved contraceptive formulation, as stated herein above, is selected from the group of polymers or the copolymers and the solvent is selected from the group of solvents having the better tissue penetration into the folds of the inner wall of the vas deferens and capable of helping in the retention of the selected polymer or the copolymer. The magnetic compound is preferably an oxide of the magnetic metal. In accordance with this invention the polymer or the copolymer of the presently disclosed improved contraceptive formulation, as stated herein above, is preferably a copolymer of the styrene maleic anhydride or alternatively is acrylic acid comethylmethacrylate or acrylic acid cobutylacrylate or maleic anhydride comethylmethacrylate or itatonic acid comethylmethacrylate or polyacrylic acid or hydroxyethyl methacrylate or polymethylmethacrylate, more preferably is a copolymer of the styrene maleic anhydride. Further, in accordance to the preferred embodiment of this invention the solvent of the presently disclosed improved contraceptive formulation is dimethyl sulfoxide. In accordance to the essential embodiment of the present invention the magnetic compound of the presently disclosed improved contraceptive formulation is the oxide of the magnetic metal, preferably it is the iron oxide, more preferably it is the ferric oxide having composition of Fe304. In accordance to the preferred embodiments, as described herein above, the presently disclosed improved contraceptive formulation comprises 35 to 55% weight by volume of the selected copolymer or the polymer. The specific composition range is selected to have the desired viscosity and the flow characteristics and the molycular weight, so that the copolymer or the polymer can not function merely as an occlusion device and hence having negligible positive charge. Similarly on the other end it cannot have excessive charge with the reduced stability but have a better biological effects. Such as, it should not have the free flowing property, which in turn may be responsible for the flow of the copolymer or the polymer to the vermontenum, which is the sensitive member and the the copolymer or the polymer may cause the irritation, and the injecting of the proposed contraceptive should not become difficult. However, the present invention is not restricted to the method of preparation of and to the selection of the copolymer or the polymer. For the example, without the intention to limit the scope of the present invention, the copolymer or the polymer, preferably may have relative viscosity between 1.2 to 2.5 and molecular weight between 55,000 to 1,00,000 . The pH of the copolymer or the polymer on in-situ hydrolysis is preferably between 4 .0 to 4 .5. However,- the presently disclosed invention is restricted essentially by addition of the magnetic compound during the preparation of the contraceptive. The magnetic compound, as stated herein above, is an oxide of a magnetic metal, preferabaly of iron, more preferably it is an iron oxide having composition of Fe304. The magnetic compound is preferably taken in powder form. The particle size of the powder form of the magnetic compound is preferable microsize, particularly between I to 20 micron, more particularly between 4 to 10 micron. The proposed improved contraceptive formulation comprises essentially of 5 to 25% by weight, preferably between 8 to 15% by weight of overall composition. The presently disclosed contraceptive formulation can be prepared by using the active polymer, such as copolymer of styrene maleic anhydride or the passive polymer, such as polyurethane followed by addition of the initiator to further polymerise the polyurethane. The major difference for selecting the active polymer or the passive polymer is the requirement of the clinician to have the flowing injectable contraceptive which can also affect the fertility ability of the spermatozoa, which can be met by using the active polymer, or the requirement of the clinician is to have a contraceptive capable of forming the plug or blockage to prevent the flow of the spermatozoa, which on-turn can be met by using the passive polymer. The contraceptive can also incorporate the polymer base, which can hydrolise in the spermatic fluid and/or can develop a positive charge and may result in the decrease of pH in-situ. The performance of the contraceptive formulation prepared in accordance to the preferred embodiment of this invention essentially comprising of the magnetic compound will not be affected. However, the use of presently disclosed formulation is suitable with bom the polymers, i.e. active and passive polymer. The range of viscosity, flow characteristics, molecular weight and of pH are to suggest the preferable values of these properties of the selected polymer, which does not mean that the use of the presently disclosed formulation of the contraceptive will alter the said - properties of the selected polymer. On the other end the solvent carrier of the contraceptive may incorporate the reactive moiety, such as sulphur. The example of such colvent is the dimethyl sulphoxide. According to one of the preferred embodiment of the present invention, contraceptive formulation when prepared in accordance to the present invention, comprising of copolymer of styrene maleic anhydride, dimethyl sulphoxide and the iron oxide results in die formation of the styrene maleic anhydride-dimethyl sulphoxide complex, which in-turn is injected in the vas deference. This complex in-turn enters in the folds of the vas deferens inner wall which promotes the anchorage and retention of the contraceptive. The complex breaks only when the reaction is complete. The dimethyl sulphoxide gets absorbed into the surrounding tissue and the blood stream for ultimate excretion. The presently disclosed formulation incorporating the magnetic compound facilitates the detection of the pathway of the excretion in addition to the detection of the location and movement of the protein (of spermatic fluid) -polymer complex, particularly the polar amino acid-styrene maleic anhydride copolymer complex, which was formed before the breakage of the styrene maleic anhydride copolymer-dijnethyl sulphoxide complex. The protein-polymer complex has positive charge and the protein layer around the copolymer in this complex protects the dissolution of the copolymer, which in turn definetly has the advantage of long - term retention and effective action of the contraceptive in the vas deferens and as well as of its long term detection. The contraceptive as described herein above can also be converted to give the performance as occlusion device by forming the plug to block the flow of the spermatozoa. This action is acheived by increasing the percentage of the basic polymer with respect to the solvent, that is, by increasing the percentage of the styrene maleic anhydride copolymer with reference to dimethyl sulphoxide. The protein-copolymer complex, as stated herein above, can be broken by injecting the extra dose of the solvent, particularly of the dimethyl sulphoxide or sodium bicarbonate, which in-tum breaks the protein-copolymer complex and allows the removal of the contraceptive. This reaction of breaking the protein-copolymer complex definetly has the advantage of reversibility of the proposed contraceptive. The present invention is not limited by the method of preparation of the polymer or the copolymer, as stated herein above. However, the present invention is described by way of the example without any intention to restrict the scope of this invention. In accordance to one of the preferred embodiments of the present invention the basic copolymer is prepared by - copolymerising styrene and maleic anhydride monomers in ethyl acetate in the nitrogen atmosphere and subjected to a step of irradiation at a dose of 0.2 megarad for every_ 40 grams of the polymer and a dose rate of 30 to 40 rad/sec. Preferably the dose is 0.22 megarad and at a dose rate of 30 rad/sec. The source of irradiation is cobalt 60 gamma radiation. This step is followed by addition of ether to precipitate the copolymer and to wash with hot water to remove the traces of the unreacted homopolymers and maleic anhydride monomer. The copolymer is aried and dissolved in 1.2 dichloro-ethane for removal of styrene monomer by soxhiet extraction. The polymeric solution is filtered to remove the styrene monomer and the polymer is precipitated again from this solution by the addition of ether. The precipitated polymer is again washed with hot water, dried and stored. The molecular weight of the copolymer thus formed is between 55000 to 100000, preferably between 85000 to 93000, having relative viscosity between 1.2 to 2.4. preferably between 1.3 to 2.0. The selected quantity of the polymer thus prepared is dissolved in the selected quantity of the pure solvent to which the selected quantity of the magnetic compound is added. The selected quantity as referred herein means the quantity as stated herein above. The formulation is made homogenised and has the advantage of providing uniform distribution after the injection. The magnetic compound, as stated herein above, is an oxide of a magnetic metal, preferabaly of iron, more preferably it is an iron oxide having composition of Fe304. - The magnetic compound is preferably taken in powder form having the microsize particles, particularly between 1 to 20 micron, more particularly between 4 to 10 micron. The proposed improved contraceptive formulation comprises essentially of 5 to 25% by weight of the magnetic compound, preferably between 8 to 15% by weight of the magnetic compound. In accordance to one of the preferred embodiments of this invention the proposed contraceptive is first injected only in the vas deferens by an incision in the scrotal skin or by a percutaneous method. According to preferred embodiment of this invention the proposed contraceptive is injected into vas deferens only in the complex form comprising of complex of copolymer/polymer-solvent complex and magnetic compound. The proposed contraceptive will result in the fertility control immediately from the day it is injected. If the fertility, control is desired for a certain period of time the dose of the proposed contraceptive is selected so that the injected contraceptive itself develops the free flowing property on expiry of the non-fertility period, as the presently disclosed contraceptive is effective from the day it is injected into the vas deferens. However, the presently disclosed contraceptive can also be injected into vas deferens by any such known method of the art. The magnetic compound definetly has the advantage of overcoming the disadvantages of the known such contraceptive formulations. The flow of the contraceptive after injection can be controlled by applying the magnetic field, which inturn generates the drag force* on the contraceptive comprising the magnetic compound and this result in control of the flow of the contraceptive. The contraceptive prepared in accordance to the presently invention, comprising of the magnetic compound produces the magnetic field, which can be sensed on the body surface, which in-turn offers an advantage of detection of the proposed contraceptive externally and without employing any invasive technique. In case the magnetic field intensity of the magnetic compound of the proposed contraceptive formulation reduces over a period of time, the same can be improved by magnetising the contraceptive of the present invention internally by applying an external magnetised field. This remagnetisation process, that is application of the external magnetising field, will not result in any remanent magnetic field on the body surface, thus will not have adverse effect to the subject but will have an advantage of permitting the detection of the injected contraceptive even for a longer time. The injected contraceptive can be set to the circular, spiral and rotation movements by applying the rotating magnetic field externally. This circulation, spiral and rotational movement as a result of the application of the external rotational magnetic field produces the churning action and the protein-polymer complex, formed after injecting the contraceptive as stated herein above, or the matrix of the injected polymeric contraceptive also gets churned and the big flakes formed of the contraceptive gets fragmented, which inturn leads to the evacuation of the injected contraceptive even after the complex has been formed. The evacuation will lead to the restoration of the fertility and gives an advantage of the reversibility of the proposed contraceptive, which again is acheived without employing any invasive technique. It is understood from the foregoing description that the proposed contraceptive formulation comprising of the magnetic compound as one of the essential component results in convenient means of detecting the presence of the injected contraceptive and the movement of the same, that is to have the advantage of the static and the dynamic detection without exposing the body to any harmful energies. In addition it helps to control externally the flow path and the flow rate of the injected contraceptive and as well as convenient evacuation without employing any invasive technique, thus avoiding any trauma to the patient. I Claim : 1. An improved male contraceptive formulation comprising 35 - 55 % by weight of polymer / copolymer of the kind such as herein described, 5 -25 % by weight of magnetic compound, which is iron or iron oxide and 20 to 60 % by weight of solvent to obtain the improved contraceptive formulation. 2. An improved contraceptive formulation as claimed in claim 1, wherein said polymer / copolymer is a copolymer of the styrene maleic anhydride or acrylic acid comethylmethacrylate or acrylic acid cobutylacrylate or maleic anhydride comethylmethacrylate or itatonic acid comethylmethacrylate or polyacrylic acid or hydroxyethyl methacrylate or polymethylmethacrylate. 3. An improved contraceptive formulation as claimed in claim 2, wherein said copolymer is a copolymer of the styrene maleic anhydride. 4. An improved contraceptive formulation as claimed in any of the preceding claims, wherein the molecular weight of the copolymer is between 55000 to 100000, preferably between 85000 to 93000. 5. An improved contraceptive formulation as claimed in claim 1, wherein said solvent is dimethyl sulfoxide or sodium bicarbonate. 6. An improved contraceptive formulation as claimed in claim 1, wherein said iron oxide is of ferric oxide. 7. An improved contraceptive formulation as claimed in claims 1 to 6, wherein the said magnetic compound has the microsized particles, preferably between 1 to 20 micron, more preferably between 4 to 10 micron. 8. An improved contraceptive formulation as claimed in claims 1 to 7, wherein the said formulation comprises between 8 to 15 % by weight of overall composition of said magnetic compound. 9. An improved contraceptive formulation substantially as herein described.

Full Text

The present application is a divisional application out of Indian Patent Application No. 716/DEL/1996 now Indian Patent No. 190814.
The present invention relates to a method for preparing an improved contraceptive formulation.
Particularly, the invention relates to an improved contraceptive formulation essentially comprising of magnetic compound, preferably of an oxide of iron having microsized particles, and the method of preparation and use thereof. More particularly, the present invention relates to an improved contraceptive formulation as stated hereinabove, which can be detected externally and evacuated to restore the fertility.
The fertility, particularly in males, can be controlled by affecting the flow of the spermatozoa or the quality of the spermatozoa, when they pass through the reproductive duct, called the vas deferens, of the male. The flow of the spermatozoa can be affected by cutting and tying the vas deferens. This technique is widely used and called vasectomy. As a result of this technique the spermatozoa are prevented from flowing in the forward direction and are accumulated in the epididymis. The accumulation of the spermatozoa results in production of enhanced antibodies, which in-turn destroy the accumulated spermatozoa.
The major disadvantage of the known vasectomy techniques is that the reversal of the fertility is not effective. The rejoining of the vas deferens does not result in the desired fertility, because the level of generation of antibodies remains high, which in-turn continue to destroy the spermatozoa. Further disadvantage of the vasectomy, as
known in the art, is the requirement of micro-surgery.

The another known method to affect the flow of the spermatozoa is the
occlusion method. Such known methods comprises of implantation of a reversible
occlusion device, which on implantation blocks the flow of the spermatozoa in the vas
deferens and control the fertility'. This method also has disadvantages, such as, the
implanted device has the regulator knob, which stays outside the vas deferens, but
within the scrotum and is operated only by the trained medical assistant. In addition
this method also has the disadvantages of requirement of surgery and maintaining the
higher level of generation of antibodies even after the removal of the implanted
device, which inturn continue to destroy the spermatozoa and resulting in poor
level of fertility.
Still another disadvantage of this method is the imperfect blockage, which will result in the flow of the spermatozoa and hence the complete destruction of the spermatozoa is not resulted.
The another known occlusion method comprises of injecting polyurethane at a high pressure in the vas deferens. The injected polymeis further polymerised in-situ to a solid plug by introducing an initiator. The sohd plug thus formed blocks the flow of the spermatozoa in the manner as described herein above. The major disadvantage of such known occlusion methods is the generation of the back pressure in the epididymis.
The quality of the spermatozoa is affected by injecting the injectable contraceptiye into the lumen of the vas deferens. The vas deferens is known to be the suitable site for the contraceptive intervention in the males. The disadvantage

of such known methods is that the extent of flow and the rate of flow cannot be controlled externally satisfactorily.
The main disadvantage, in addition to the disadvantages as described herein above, of the known methods of the prior art for controlling the fertility of males, as described herein above, is that they cannot be detected externally. The basic compound of the contraceptive being a polymer is generally not radioopaque and hence cannot be detected by X-ray imaging. The magnetic resonance imaging also fails to detect the contraceptive mainly due to its poor contrast with the soft tissue. The ultrasound is also incapable of detecting the contraceptive, due to the low percentage of the basic compound. To overcome this disadvantage, if the net percentage of the basic compound is increased, it will have the disadvantages associated with the higher percentage. Furthermore, some of the regions of the vas deferens are so placed that the ultrasonic approach is not practicable.
Still another disadvantage of the known methods of controlling the fertility of males by injectable contraceptives, is that, the restoration of the fertility generally calls for an invasive procedure wherein a flushing compound is injected into lumen of the vas deferens, which affects the restoration of the fertility.
It is further a disadvantage of the known methods of controlling the fertility, particularly of the vasectomy, that the fertility is not controlled immediately, that is contraceptive and the contraceptive technique is not effective from the day one.
Therefore, there is a need to have a contraceptive, which can overcome the disadvantages of the prior art as described herein above and particularly can be

detected externally and evacuated conveniently without the requirement of any surgical procedure, further, the fertility is restored fully on evacuation of the contraceptive.
This is the main object of this invention to make a complete, disclosure of an improved contraceptive formulation, and the method of preparation and use thereof, which can overcome the disadvantages of the prior art as described herein above.
Another object of the present invention is to propose for an improved contraceptive formulation, as stated herein above, which can be detected externally by any non-invasive technique, -such as, X-rays, magnetic resonance imaging, ultrasound etc.
Further an object of this invention is to propose for an improved contraceptive formulation, as stated herein above, which can be evacuated conveniently without the requirement of any surgical procedure. Further, the evacuation of the proposed contraceptive results in restoration of the fertility fully.
Still another object of the present invention is for an improved contraceptive formulation, as stated herein above, of which the flow extent and the flow rate can be controlled conveniently.
Still further an object of this invention is to propose an improved contraceptive formulation, as stated herein above and described herein below, which can control the

fertility immediately from the day one, that is from the day the proposed contraceptive is injected.
Accordingly, this invention provides a complete disclosure of an improved
contraceptive formulation, and the method of preparation and use thereof, particularly
for use by males, wherein the contraceptive primarily comprises of an injectable base
compound, a solvent and essentially a magnetic compound.
Accordingly, this invention relates to an improved male contraceptive formulation comprising 35 - 55 % by weight of polymer / copolymer of the kind such as herein described, 5 - 25 % by weight of magnetic compound, which is iron or iron oxide and 20 to 60 % by weight of solvent to obtain the improved contraceptive formulation.
According to the preferred embodiment of the present invention the injectable basic compound of the presently disclosed improved contraceptive formulation, as stated herein above, is selected from the group of polymers or the copolymers and the solvent is selected from the group of solvents having the better tissue penetration into the folds of the inner wall of the vas deferens and capable of helping in the retention of the selected polymer or the copolymer. The magnetic compound is preferably an oxide of the magnetic metal.
In accordance with this invention the polymer or the copolymer of the presently disclosed improved contraceptive formulation, as stated herein above, is preferably a copolymer of the styrene maleic anhydride or alternatively is acrylic acid comethylmethacrylate or acrylic acid cobutylacrylate or maleic anhydride comethylmethacrylate or itatonic acid comethylmethacrylate or polyacrylic acid or hydroxyethyl methacrylate or polymethylmethacrylate, more preferably is a copolymer of the styrene maleic anhydride. Further, in accordance to the preferred embodiment of this invention the solvent of the presently disclosed improved contraceptive formulation is dimethyl sulfoxide.

In accordance to the essential embodiment of the present invention the magnetic compound of the presently disclosed improved contraceptive formulation is the oxide of the magnetic metal, preferably it is the iron oxide, more preferably it is the ferric oxide having composition of Fe304.
In accordance to the preferred embodiments, as described herein above, the presently disclosed improved contraceptive formulation comprises 35 to 55% weight by volume of the selected copolymer or the polymer. The specific composition range is selected to have the desired viscosity and the flow characteristics and the molycular weight, so that the copolymer or the polymer can not function merely as an occlusion device and hence having negligible positive charge. Similarly on the other end it cannot have excessive charge with the reduced stability but have a better biological effects. Such as, it should not have the free flowing property, which in turn may be responsible for the flow of the copolymer or the polymer to the vermontenum, which is the sensitive member and the the copolymer or the polymer may cause the irritation, and the injecting of the proposed contraceptive should not become difficult. However, the present invention is not restricted to the method of preparation of and to the selection of the copolymer or the polymer. For the example, without the intention to limit the scope of the present invention, the copolymer or the polymer, preferably may have relative viscosity between 1.2 to 2.5 and molecular weight between 55,000 to 1,00,000 . The pH of the copolymer or the polymer on in-situ hydrolysis is preferably between 4 .0 to 4 .5.
However,- the presently disclosed invention is restricted essentially by addition of the magnetic compound during the preparation of the contraceptive. The magnetic

compound, as stated herein above, is an oxide of a magnetic metal, preferabaly of iron, more preferably it is an iron oxide having composition of Fe304. The magnetic compound is preferably taken in powder form. The particle size of the powder form of the magnetic compound is preferable microsize, particularly between I to 20 micron, more particularly between 4 to 10 micron. The proposed improved contraceptive formulation comprises essentially of 5 to 25% by weight, preferably between 8 to 15% by weight of overall composition.
The presently disclosed contraceptive formulation can be prepared by using the active polymer, such as copolymer of styrene maleic anhydride or the passive polymer, such as polyurethane followed by addition of the initiator to further polymerise the polyurethane. The major difference for selecting the active polymer or the passive polymer is the requirement of the clinician to have the flowing injectable contraceptive which can also affect the fertility ability of the spermatozoa, which can be met by using the active polymer, or the requirement of the clinician is to have a contraceptive capable of forming the plug or blockage to prevent the flow of the spermatozoa, which on-turn can be met by using the passive polymer. The contraceptive can also incorporate the polymer base, which can hydrolise in the spermatic fluid and/or can develop a positive charge and may result in the decrease of pH in-situ. The performance of the contraceptive formulation prepared in accordance to the preferred embodiment of this invention essentially comprising of the magnetic compound will not be affected. However, the use of presently disclosed formulation is suitable with bom the polymers, i.e. active and passive polymer. The range of viscosity, flow characteristics, molecular weight and of pH are to suggest the preferable values of these properties of the selected polymer, which does not

mean that the use of the presently disclosed formulation of the contraceptive will alter the said - properties of the selected polymer. On the other end the solvent carrier of the contraceptive may incorporate the reactive moiety, such as sulphur. The example of such colvent is the dimethyl sulphoxide.
According to one of the preferred embodiment of the present invention, contraceptive formulation when prepared in accordance to the present invention, comprising of copolymer of styrene maleic anhydride, dimethyl sulphoxide and the iron oxide results in die formation of the styrene maleic anhydride-dimethyl sulphoxide complex, which in-turn is injected in the vas deference. This complex in-turn enters in the folds of the vas deferens inner wall which promotes the anchorage and retention of the contraceptive. The complex breaks only when the reaction is complete. The dimethyl sulphoxide gets absorbed into the surrounding tissue and the blood stream for ultimate excretion. The presently disclosed formulation incorporating the magnetic compound facilitates the detection of the pathway of the excretion in addition to the detection of the location and movement of the protein (of spermatic fluid) -polymer complex, particularly the polar amino acid-styrene maleic anhydride copolymer complex, which was formed before the breakage of the styrene maleic anhydride copolymer-dijnethyl sulphoxide complex. The protein-polymer complex has positive charge and the protein layer around the copolymer in this complex protects the dissolution of the copolymer, which in turn definetly has the advantage of long - term retention and effective action of the contraceptive in the vas deferens and as well as of its long term detection.

The contraceptive as described herein above can also be converted to give the performance as occlusion device by forming the plug to block the flow of the spermatozoa. This action is acheived by increasing the percentage of the basic polymer with respect to the solvent, that is, by increasing the percentage of the styrene maleic anhydride copolymer with reference to dimethyl sulphoxide.
The protein-copolymer complex, as stated herein above, can be broken by injecting the extra dose of the solvent, particularly of the dimethyl sulphoxide or sodium bicarbonate, which in-tum breaks the protein-copolymer complex and allows the removal of the contraceptive. This reaction of breaking the protein-copolymer complex definetly has the advantage of reversibility of the proposed contraceptive.
The present invention is not limited by the method of preparation of the polymer or the copolymer, as stated herein above. However, the present invention is described by way of the example without any intention to restrict the scope of this invention.
In accordance to one of the preferred embodiments of the present invention the
basic copolymer is prepared by - copolymerising styrene and maleic anhydride
monomers in ethyl acetate in the nitrogen atmosphere and subjected to a step of
irradiation at a dose of 0.2 megarad for every_ 40 grams of the polymer and a dose rate
of 30 to 40 rad/sec. Preferably the dose is 0.22 megarad and at a dose rate of 30
rad/sec. The source of irradiation is cobalt 60 gamma radiation. This step is followed
by addition of ether to precipitate the copolymer and to wash with hot water to
remove the traces of the unreacted homopolymers and maleic anhydride monomer.

The copolymer is aried and dissolved in 1.2 dichloro-ethane for removal of styrene monomer by soxhiet extraction. The polymeric solution is filtered to remove the styrene monomer and the polymer is precipitated again from this solution by the addition of ether. The precipitated polymer is again washed with hot water, dried and stored. The molecular weight of the copolymer thus formed is between 55000 to 100000, preferably between 85000 to 93000, having relative viscosity between 1.2 to 2.4. preferably between 1.3 to 2.0. The selected quantity of the polymer thus prepared is dissolved in the selected quantity of the pure solvent to which the selected quantity of the magnetic compound is added. The selected quantity as referred herein means the quantity as stated herein above. The formulation is made homogenised and has the advantage of providing uniform distribution after the injection. The magnetic compound, as stated herein above, is an oxide of a magnetic metal, preferabaly of iron, more preferably it is an iron oxide having composition of Fe304. - The magnetic compound is preferably taken in powder form having the microsize particles, particularly between 1 to 20 micron, more particularly between 4 to 10 micron. The proposed improved contraceptive formulation comprises essentially of 5 to 25% by weight of the magnetic compound, preferably between 8 to 15% by weight of the magnetic compound.
In accordance to one of the preferred embodiments of this invention the proposed contraceptive is first injected only in the vas deferens by an incision in the scrotal skin or by a percutaneous method. According to preferred embodiment of this invention the proposed contraceptive is injected into vas deferens only in the complex form comprising of complex of copolymer/polymer-solvent complex and magnetic compound. The proposed contraceptive will result in the fertility control immediately

from the day it is injected. If the fertility, control is desired for a certain period of time the dose of the proposed contraceptive is selected so that the injected contraceptive itself develops the free flowing property on expiry of the non-fertility period, as the presently disclosed contraceptive is effective from the day it is injected into the vas deferens. However, the presently disclosed contraceptive can also be injected into vas deferens by any such known method of the art.
The magnetic compound definetly has the advantage of overcoming the disadvantages of the known such contraceptive formulations. The flow of the contraceptive after injection can be controlled by applying the magnetic field, which inturn generates the drag force* on the contraceptive comprising the magnetic compound and this result in control of the flow of the contraceptive. The contraceptive prepared in accordance to the presently invention, comprising of the magnetic compound produces the magnetic field, which can be sensed on the body surface, which in-turn offers an advantage of detection of the proposed contraceptive externally and without employing any invasive technique.
In case the magnetic field intensity of the magnetic compound of the proposed contraceptive formulation reduces over a period of time, the same can be improved by magnetising the contraceptive of the present invention internally by applying an external magnetised field. This remagnetisation process, that is application of the external magnetising field, will not result in any remanent magnetic field on the body surface, thus will not have adverse effect to the subject but will have an advantage of permitting the detection of the injected contraceptive even for a longer time.

The injected contraceptive can be set to the circular, spiral and rotation movements by applying the rotating magnetic field externally. This circulation, spiral and rotational movement as a result of the application of the external rotational magnetic field produces the churning action and the protein-polymer complex, formed after injecting the contraceptive as stated herein above, or the matrix of the injected polymeric contraceptive also gets churned and the big flakes formed of the contraceptive gets fragmented, which inturn leads to the evacuation of the injected contraceptive even after the complex has been formed. The evacuation will lead to the restoration of the fertility and gives an advantage of the reversibility of the proposed contraceptive, which again is acheived without employing any invasive technique.
It is understood from the foregoing description that the proposed contraceptive formulation comprising of the magnetic compound as one of the essential component results in convenient means of detecting the presence of the injected contraceptive and the movement of the same, that is to have the advantage of the static and the dynamic detection without exposing the body to any harmful energies. In addition it helps to control externally the flow path and the flow rate of the injected contraceptive and as well as convenient evacuation without employing any invasive technique, thus avoiding any trauma to the patient.

I Claim :
1. An improved male contraceptive formulation comprising 35 - 55 % by weight of polymer / copolymer of the kind such as herein described, 5 -25 % by weight of magnetic compound, which is iron or iron oxide and 20 to 60 % by weight of solvent to obtain the improved contraceptive formulation.
2. An improved contraceptive formulation as claimed in claim 1, wherein said polymer / copolymer is a copolymer of the styrene maleic anhydride or acrylic acid comethylmethacrylate or acrylic acid cobutylacrylate or maleic anhydride comethylmethacrylate or itatonic acid comethylmethacrylate or polyacrylic acid or hydroxyethyl methacrylate or polymethylmethacrylate.
3. An improved contraceptive formulation as claimed in claim 2, wherein said copolymer is a copolymer of the styrene maleic anhydride.
4. An improved contraceptive formulation as claimed in any of the preceding claims, wherein the molecular weight of the copolymer is between 55000 to 100000, preferably between 85000 to 93000.
5. An improved contraceptive formulation as claimed in claim 1, wherein said solvent is dimethyl sulfoxide or sodium bicarbonate.
6. An improved contraceptive formulation as claimed in claim 1, wherein said iron oxide is of ferric oxide.

7. An improved contraceptive formulation as claimed in claims 1 to 6, wherein the said magnetic compound has the microsized particles, preferably between 1 to 20 micron, more preferably between 4 to 10 micron.
8. An improved contraceptive formulation as claimed in claims 1 to 7, wherein the said formulation comprises between 8 to 15 % by weight of overall composition of said magnetic compound.
9. An improved contraceptive formulation substantially as herein described.

Documents:

762-del-2000-abstract.pdf

762-del-2000-claims.pdf

762-del-2000-complete specification (granted).pdf

762-del-2000-correspondence-others.pdf

762-del-2000-correspondence-po.pdf

762-del-2000-description (complete).pdf

762-del-2000-form-1.pdf

762-del-2000-form-13.pdf

762-del-2000-form-18.pdf

762-del-2000-form-2.pdf

762-del-2000-gpa.pdf

762-del-2000-pa.pdf

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Patent Number

240763

Indian Patent Application Number

762/DEL/2000

PG Journal Number

23/2010

Publication Date

04-Jun-2010

Grant Date

28-May-2010

Date of Filing

25-Aug-2000

Name of Patentee

SUJOY KUMAR GUHA

Applicant Address

PROFESSOR OF BIOMEDICAL ENGINEERING, SCHOOL OF MEDICAL SCIENCE & TECHNOLOGY, INDIAN INSTITUTE OF TECHNOLOGY (IIT), KHARAGPUR-731302, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	SUJOY KUMAR GUHA	PROFESSOR OF BIOMEDICAL ENGINEERING, SCHOOL OF MEDICAL SCIENCE & TECHNOLOGY, INDIAN INSTITUTE OF TECHNOLOGY (IIT), KHARAGPUR-731302, INDIA.

PCT International Classification Number

A61K 9/16

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA