INTRA UTERINE DRUG DELIVARY

INTRAUTERINE DRUG DELIVERY SYSTEM:

INTRAUTERINE DRUG DELIVERY SYSTEM Prepared by: Murari Pavan M.Pharm(Pharmaceutics) Gautham college of pharmacy( bangalore)

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What is an Intrauterine Contraceptive Devices (IUD)? An IUD is a small soft T-shaped device with a nylon string attached. How Does an IUD Work? An IUD prevents sperm from meeting an egg. An IUD may stop a fertilized egg from growing inside the uterus.

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How Effective is an IUD? Nova T (copper wrapped IUD) is about 98.7% effective in preventing pregnancy. Mirena (hormone wrapped IUD) is about 99% effective in preventing pregnancy.

Types of IUD’s::

Types of IUD’s: Most common: T-shaped, copper bands on plastic stem/arms Inserted in uterus through vagina and cervical opening Strings: assure IUD is in place; facilitate removal Most common copper IUD: TCu-380A Less common: hormonal IUDs

Copper bearing IUD’s::

Copper bearing IUD’s: The first clinical studies were conducted using T-shaped polyethylene plastic device wound with 30mm 2 copper wire(Cu.T-30). The pregnancy rate was found to be reduced to 5% from 18% attained by non-medicated T-shaped IUD. A) 7-Shaped IUD : Further development of the concept of intra-uterine contraception by metallic copper has resulted in copper barring IUD, which contains 89mg copper wire, wound around the vertical limb of a 7-shaped polypropylene device, to give an effective surface of approximately 200mm 2 used for 3years as intra-uterine contraceptive treatment.

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This device release copper ion at a mean daily dose of 9.87µg/day continuously in the uterine cavity for upto 40months. The Cu-7 appears to be substantially smaller then other. It can be easily inserted because of it’s special 7-configuration in addition to its small size. Insertion can usually be accomplished without the need for cervical dilation and further more removal is generally painless.

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B) T-Shaped IUD’s : T-shaped IUD containing 200mm 2 contraceptive copper wire winding around the vertical leg of a T-shaped polyethylene device in the manner as copper-7 device. It is used for 3years of contraceptive treatment. This T-shaped device has a volume of 0.16cm 3 ,which is almost twice as large as the 7-shaped device Copper T 380 Efficacy 0.3% Copper T-Safe 380A No pregnancies beyond 8yrs (effective than copper-T 380)

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C) New development of copper bearing IUD’s : The Cu-T-380A with 2 collars of copper positioned on the transverse arms of the letter T. Each collar provides an additional surface area of 30mm 2 . it has relatively small surface area of copper (2×30mm 2 ) but effective than Cu-T-200. Another new version of copper bearing IUD: The combined multi load copper IUD (MLCU-250) was also introduced. It is a compromise between Cu-T IUD, but without the central plastic membrane and has a surface area of 250mm 2 copper wire. The blunt apex of the device fits into the vault of the uterine cavity without penetrating the endometrial walls and its two arms studded side arms fully adapt to the contours of the uterine cavity.

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Multi-load copper bearing IUD’s with variation in copper surface area and size which make adaption of the IUD to the size of the individual uterine cavity possible are available in various types. They are, MLCU-250 MLCU-250short MLCU-250standard MLCU-250mini MLCU-325 MLCU-375SL

Potential development:

Potential development 1) Membrane controlled reservoir-type drug delivery system: These drug delivery devices consist of a polymeric membrane that both encapsulates and controls the release of contraceptive agent a) Single component system : In this system the contraceptive agent is encapsulated in its pure solid form in a capsule fabricated form bio-compatible polymeric materials (silicon elastomers and polyethylene-polymers) The release of contraceptive agent such as progesterone follows essentially zero-order kinetics.

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b) Multi component system : In this system a constant drug release profile is maintained by encapsulating a liquid medium saturated with excess drug profiles in a rate-controlling polymeric membrane. 2) Polymer matrix diffusion controlled drug delivery devices : This drug delivery device is prepared by homogenously dispersing the drug particles in a crossed linked polymeric matrix. a) Retrievable matrix device : This drug delivery system is designed for feasibility of retrieval at termination of treatment. It can be easily fabricated from silicone elastomers by premixing a drug in powder form with a semisolid silicone elastomers before vulcanization at room or low temperature or from polyethylene by dry mixing. The rate of drug relesse is not constant but time dependent.

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b) Bio-degradable matrix device : This drug delivery system is designed to eliminate the need for retrieving at the end of treatment it can be prepared by dissolving such a poly (lactic acid), in a common organic solvent to dryness, to produce drug dispersing biodegradable matrix devices of varyng shapes and sizes, The rate of drug-release from this type of drug delivery system is a combination of polymer hydrolysis and drug diffusion.

MECHANISM OF ANTIFERTILITY ACTION OF COPPER::

MECHANISM OF ANTIFERTILITY ACTION OF COPPER : Copper is known to be cytotoxic in high concentration it enhances the spermatocidal and spermato depressive action of an IUD. The copper concentration in endometrial epithelium and superficial stromata inhibits the binding of steroids of their receptors. Cupric ion inhibits the binding of 17- β - estradiol to human endometrial cytosol. Cupric ions shows only little effect on sperm motility. Copper wire was also “Blastocystocidal”. This blastocystocidal activity may be due to interference with the active transport of ions and lysosome of the blastocyst incorporated with the copper, thus releasing lysosomal enzymes and causing cellular autolysis and death.

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A copper bearing IUD was reported to produce significant effects like: Increased alkaline phosphate activity in uterine fluids and endometrium tissue. No change of acid phosphate activity in uterine fluid but its concentration in endometrium tissue increases.

Advantages of the IUD:

Advantages of the IUD Provides long-term birth control. Cost effective. Can be removed when a woman would like to become pregnant. Convenient - a woman does not need to remember it daily or weekly.

Disadvantages of an IUD:

Disadvantages of an IUD Between 2 and 10% fall out, most commonly in the first year of use. Increased risk of miscarriage if an IUD is left in the uterus during pregnancy. In rare cases, the IUD may attach to or perforate the wall of the uterus. With the copper IUD, a woman may experience heavier bleeding and cramping with periods.