FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:
"Medicated Intrauterine Device"
2. APPLICANT(S)
(a) NAME: Pregna International Limited
(b) NATIONALITY: Indian Company registered under the
Provisions of Companies Act, 1956
(c) ADDRESS: 13, Suryoday Estate,
136, Tardeo Road,
Mumbai -400034, M.S. India
3. PRREAMBLE TO THE DESCRIPTION
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Medicated Intrauterine Device
Field of the invention
The present invention relates to a method of making intrauterine devices. More particularly, the present invention relates to medicated intrauterine device, and a process of preparation thereof.
Background of the invention
It is known that intrauterine devices can provide a system for timed release, local administration of a drug. Various gynecological problem which are treated using other dosage form, can be treated with localized treatment using medicated IUDs. Further, Medicated IUDs are useful for the inhibition of fertility but are also useful in treating and medicating other conditions of the female reproductive system. Various approaches for medicated IUDs have been tried using polymers. However, these IUD's are not effective in controlling bleeding and are not effective.
Accordingly, there exists a need for providing an IUD which overcomes abovementioned drawback and provide effective medicated IUD for timed release and local administration of the drug.
Objects of the invention
An object of the present invention is to provide a process for preparation of a medicated IUD which is effective.
Another object of the present invention is to provide a process for preparation of medicated IUD which provides controlled release of a drug therethrough.

Summary of the invention
According to present invention there is provided a process for preparation of medicated intrauterine device (IUD), the process comprising steps of:
mixing formable silicone with a drug and a cross linker to form a mixture thereof;
moulding the mixture and keeping for a predefined period to prepare a matrix;
immersing the matrix in a solvent and allowed to swell for predefined period, wherein the solvent is selected such that the drug and silicone is insoluble therein;
assembling the swollen matrix on vertical arm of the T shaped IUD by the using a fixture;
drying the matrix and allowing the matrix to shrink on the vertical arm of the T shaped IUD;
covering the matrix mounted on the vertical arm of the T shaped IUD with a membrane; and
attaching a suture to the T shaped IUD to form a medicated IUD.
Typically, wherein the drug is a progestogen selected from the group consisting of progesterone, desogestrel, etonogestrel, gestodene, levonorgestrel, medroxyprogesterone, norethisterone, norgestimate, and norgestrel.
Typically, wherein the solvent is Cyclohexane.
Typically, wherein the membrane is a drug permeable covering which control release of the drug from the matrix.

Detailed description of the invention
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with the prior art techniques and approaches are overcome by the present invention as described below in the preferred embodiment.
The present invention provides a process of preparation of a medicated intrauterine device on preexisting contraceptive intrauterine platform and an attachment formed of a base polymer such as silicone, containing a drug therein. The medicated intrauterine device provides controlled release of a drug therethrough by means of a polymer covered by a membrane which controls the rate of release of the drug.
Accordingly, the present invention provides a process of preparation of medicated intrauterine device (IUD). Specifically, figure 1 shows the process (100). The process starts at (10). At (20), the process (100) includes mixing formable silicone with a drug and a cross linker to form a mixture thereof.
Specifically, a suitable, medically acceptable polymer such as silicone rubber, for example, such as RTV silicone rubbers can be used for forming the base. More specifically, the silicone rubber which can be vulcanized/cured at room temperature is used. Specifically, silicone is mixed with a drug in equal proportion. In an embodiment, the drug is a progestogen. The progestogen is selected from the group consisting of progesterone, desogestrel, etonogestrel, gestodene, levonorgestrel, medroxyprogesterone, norethisterone, norgestimate, and norgestrel.
The drug to be dispensed in the IUD is mixed with the silicone in micronized form by stirring until a smooth paste of the two components is formed. Further, the process of mixing the silicone with the drug and the cross linker is continued for

two to three hour to achieve thorough mixing until a whitish transparent mixture is formed.
At step (30), the process (100) includes moulding the mixture into a mould cavity and keeping for a predefined period to prepare a matrix. Before, pouring the mixture in the mould cavity, air bubbles from the mixture are removed. In an embodiment, the mixture is kept in a vacuum chamber for removing of air bubbles. The mixture is then injected into mould by manual injector. Thereafter, the mould is allowed to cure for at least 24 hrs to form matrix inside the mould. For ease of withdrawal of the matrix from the mould cavity, any suitable lubricant known in the art may be used.
Further, an apparatus for making the drug-containing matrix includes a multicavity mold that facilitates the molding of multiple IUD attachments simply and for easy removal for application to an available platform of the IUD. The mould cavity can be chosen to provide the matrix with dimensions that give the desired drug release rate. The medicated IUD of the present invention may be inserted into the uterus by means of a loading means known in the art.
At step (40), the process (100) includes immersing the matrix in a solvent which is then allowed to swell for predefined period. The solvent is selected such that the drug and silicone are insoluble therein. In an embodiment, the solvent is cyclohexane. The matrix is swollen, slipped onto the IUD stem and permitted to shrink thereon, again as described hereinbelow. Specifically, length of the matrix is sufficiently long to cover the length of the stem.
At step (50), the process (100) includes assembling the swollen matrix on vertical arm of a T shaped IUD by the using a fixture.

At step (60), the process includes drying the matrix and allowing the matrix to shrink on the vertical arm of the T shaped IUD. In an embodiment, drying of the matrix is done to evaporate the solvent cyclohexane from the matrix and matrix shrinks on the T shaped IUD frame.
At step (70), the process includes covering the matrix mounted on the vertical arm of the T shaped IUD with a membrane to slow the rate of release of drug, and to impart greater structural integrity to the IUD. Specifically, the membrane is a drug permeable covering which control release of the drug from the matrix. More specifically, the membrane using membrane cutting fixture is swollen similar to the matrix and mounted over the matrix. In an embodiment, a commercially available silicone rubber tube can be swollen in a non-destructive solvent, and the tubing can be easily slipped onto the matrix and allowed to shrink in place. Any one of a number of solvents can be used to swell the silicone rubber and drug sleeve and the silicone rubber tubing. Cyclohexane is chosen for its quickness in swelling these members, the greater extent to which it swells them, and for its safety. However, any of the hexanes, straight-chain parafins, and normal hydrocarbons that are fully saturated may be used. However, the solvent should dissolve neither the drug nor the silicone rubber. In this relation, ether, toluene or chloroform may not be suitable.
At step (80), the process includes attaching a suture is to the IUD. The formed medicated IUD assembly is then provided with a proper length of suture. The process (100) ends at step (90).
The combination IUD and drug release attachment made of polymer such as silicone described above gives good contraceptive benefit. It acts as a known,

unmedicated IUD, and as a controlled dosage, directly administering contraceptive drug dispensing device. Another advantage from the use of the matrix described above is a decrease in menstrual blood loss.
Drugs delivered with devices of the kind described above may be any of those useful for treatment of any condition of the uterus or endrometrium thereof, as well as drugs useful in providing contraceptive effects, whether of local or of systemic activity. Although only the room temperature vulcanizing silicone rubber has been used so far in forming the matrix, many other polymer and drug mixtures may be useful in forming the matrix. Likewise, only silicone rubber tubing as described above has been used to control the release rate and impart greater structural integrity, but the other membrane, may, as well, be composed of other biocompatible polymers that may be applied in a variety of ways, such as by dip-coating, heat-sealing, spraying, or otherwise.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

We claim
1. A process for preparation of medicated intrauterine device (IUD), the
process comprising steps of:
mixing formable silicone with a drug and a cross linker to form a mixture thereof;
moulding the mixture and keeping for a predefined period to prepare a matrix;
immersing the matrix in a solvent and allowed to swell for predefined period, wherein the solvent is selected such that the drug and silicone is insoluble therein;
assembling the swollen matrix on vertical arm of the T shaped IUD by the using a fixture;
drying the matrix and allowing the matrix to shrink on the vertical arm of the T shaped IUD;
covering the matrix mounted on the vertical arm of the T shaped IUD with a membrane; and
attaching a suture to the V shaped IUD to form a medicated IUD.
2. The process as claimed in claim 1, wherein the drug is a progestogen selected from the group consisting of progesterone, desogestrel, etonogestrel, gestodene, levonorgestrel, medroxyprogesterone, norethisterone, norgestimate, and norgestrel.
3. The process as claimed in claim 1, wherein the solvent is Cyclohexane.

4. The process as claimed in claim 1, wherein the membrane is a drug permeable covering which control release of the drug from the matrix.