Vaginal ring
Encyclopedia
Vaginal rings are polymeric drug delivery
devices designed to provide controlled release of drugs for intravaginal administration
over extended periods of time. The ring is inserted into the vagina
and provides contraception protection. Leaving the ring in for 3 weeks slowly releases hormones into the body, mainly vaginally administered estrogens and/or progestogens (a group of hormones including progesterone
). These hormones stop ovulation and thicken the cervical mucus, creating a barrier preventing sperms from fertilizing an egg. Worn continuously for three weeks followed by a week off, each vaginal ring provides one month of birth control. Several vaginal ring products are currently available, including:
A number of vaginal ring products are also in development.
Rings can be removed prior to intercourse, but, in the case of the contraceptive Nuvaring, only for one to three hours to maintain efficacy of birth control.
Drug delivery
Drug delivery is the method or process of administering a pharmaceutical compound to achieve a therapeutic effect in humans or animals. Drug delivery technologies modify drug release profile, absorption, distribution and elimination for the benefit of improving product efficacy and safety, as well...
devices designed to provide controlled release of drugs for intravaginal administration
Intravaginal administration
Intravaginal administration is a route of administration where the substance is applicated inside the vagina. Pharmacologically, it has the potential advantage to result in effects primarily in the vagina or nearby structures with limited systemic adverse effects compared to other routes of...
over extended periods of time. The ring is inserted into the vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...
and provides contraception protection. Leaving the ring in for 3 weeks slowly releases hormones into the body, mainly vaginally administered estrogens and/or progestogens (a group of hormones including progesterone
Progesterone
Progesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species...
). These hormones stop ovulation and thicken the cervical mucus, creating a barrier preventing sperms from fertilizing an egg. Worn continuously for three weeks followed by a week off, each vaginal ring provides one month of birth control. Several vaginal ring products are currently available, including:
- Estring - a low-dose estradiolEstradiolEstradiol is a sex hormone. Estradiol is abbreviated E2 as it has 2 hydroxyl groups in its molecular structure. Estrone has 1 and estriol has 3 . Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect...
-releasing ring, manufactured from silicone elastomer, for the treatment of vaginal atrophy (atrophic vaginitisAtrophic vaginitisAtrophic vaginitis is an inflammation of the vagina due to the thinning and shrinking of the tissues, as well as decreased lubrication...
). - Femring - a low-dose estradiol-acetate releasing ring, manufactured from silicone elastomer, for the relief of hot flashes and vaginal atrophyAtrophyAtrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations , poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself...
associated with menopauseMenopauseMenopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormones that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining...
. - NuvaRingNuvaRingNuvaRing is the trade name for a combined hormonal contraceptive vaginal ring manufactured by Merck that is available by prescription...
- a low-dose contraceptiveBirth controlBirth control is an umbrella term for several techniques and methods used to prevent fertilization or to interrupt pregnancy at various stages. Birth control techniques and methods include contraception , contragestion and abortion...
vaginal ring, manufactured from poly(ethylene-co-vinyl acetate), and releasing etonogestrelEtonogestrelEtonogestrel is a progestin used in hormonal contraceptives, most notably the subdermal implant Implanon and the contraceptive vaginal ring NuvaRing....
(a progestinProgestinA progestin is a synthetic progestogen that has progestinic effects similar to progesterone. The two most common uses of progestins are for hormonal contraception , and to prevent endometrial hyperplasia from unopposed estrogen in hormone replacement therapy...
) ethinyl estradiol (an estrogenEstrogenEstrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
).
A number of vaginal ring products are also in development.
Methods of use
General - Vaginal rings are easily inserted and removed. Vaginal walls hold them in place. Although their exact location within the vagina is not critical for clinical efficacy, rings commonly reside next to the cervix. Rings are typically left in place during intercourse, and most couples report no interference or discomfort. In many cases, neither partner feels the presence of the ring.Rings can be removed prior to intercourse, but, in the case of the contraceptive Nuvaring, only for one to three hours to maintain efficacy of birth control.
- Femring - Femring is inserted into the vagina and left in place for three months, after which it is removed and replaced with a fresh ring.
- NuvaRing - NuvaRing is inserted into the vagina and left in place for three weeks, after which it is removed for a 'ring-free' week to allow menstruationMenstruationMenstruation is the shedding of the uterine lining . It occurs on a regular basis in sexually reproductive-age females of certain mammal species. This article focuses on human menstruation.-Overview:...
to occur.