Birth control agents

Representative Partial Syntheses. The synthesis of 19-nnr-stcroids was stimulated by the development of orally active progestins as birth control agents. 

Birth Control. A major use of estrogens is for inhibition of ovulation, in eotnbinatiun with progestins. Steroidal birth control agents containing e.strogens arc discassed in the section on chemical eontraception later in this chapicr. 

Birth Control. A significam use or the progcsiins. us of the esimgens. is inhibition of ovuiation. Steroidal birth control agents are discussed in the following section on chemical contraception. 

The hot water and alcohol extracts of the roots of T. wilfordii have shown effects on the reproductive system and this fact has stimulated a great deal of research, particularly relating to the male reproductive system, and their possible use as a birth control agent. Studies in animals and humans have provided considerable encouragement for the development of a novel nonsteroidal male contraceptive agent [173]. In this context, pharmacological... 

Many drugs have been modified by synthesis to contain alkyne substituents, with the aim to increase bioavailabUity and activity, and at the same time reduce potential toxicity. For example, ethynyl estrogens, such as 17-ethynylestradiol, are considerably more potent birth-control agents than are the naturally occurring hormones (see Section 4-7). 

Synthetic estrogens such as 17-ethynylestradiol are birth control agents. Estradiol, the female sex hormone, is a secondary alcohol that cannot be administered orally because it would be rapidly oxidized by the hver. The synthetic estrogens contain an ethynyl group (—C=CH) and are tertiary alcohols that are not oxidized in metabolic reactions. The ethynyl group in these compounds is located so that the hydroxyl group has the same stereochemistry as the natural estradiol. 

Finally, a new class of antispermatogenic agents containing the same fundamental structure cited above has been described (76JMC778). 1-Halobenzyl-l J/-indazole-3-carboxylic acids are potentially useful for birth control, and because they act after a single administration they are of interest for the physiological study of the male reproductive system. 

As discussed later in this chapter, contraindications exist for various forms of contraception. Patients must be evaluated completely by a health care professional to rule out any medical contraindications to certain contraceptives. The physical examination also will allow health care professionals to determine if there are other medical concerns, such as hypertension, diabetes, or liver disease, that need to be considered when determining the appropriate contraceptive agent. Clinicians also should review family history for potential risks with certain forms of birth control. 

RC, a 22-year-old woman, presents to your clinic requesting information on contraception. You begin to take a history and determine that the patient is currently sexually active and is not using any method of birth control. Her past medical history is significant only for acne, and she takes no medications except occasional ibuprofen for menstrual cramps. On further questioning, you discover that she has a positive family history for hypertension and coronary artery disease. As you begin to discuss various contraceptive options with the patient, it is clear that she has a preference for an oral contraceptive agent. 

Few, if any, products are administered via the vagina that are intended for systemic absorption. Thus, this route has not been as widely studied and characterized as others. On the other hand, large numbers of different products (douches, spermicides, antiyeast agents, etc.) have been developed that require introduction into the vagina in order to assert their localized effects. Increased research into different birth control and antiviral prophylaxis will result in more vaginal products in the future. All these must be assessed for vaginal irritation potential, and this serves as an example of the other tissue tolerance issues. 

Gender Men and women differ in their response to agents owing to hormonal influences Female birth control pill is the most obvious... 

Membrane-reservoir systems based on solution-diffusion mechanism have been utilized in different forms for the controlled delivery of therapeutic agents. These systems including membrane devices, microcapsules, liposomes, and hollow fibres have been applied to a number of areas ranging from birth control, transdermal delivery, to cancer therapy. Various polymeric materials including silicone rubber, ethylene vinylacetate copolymers, polyurethanes, and hydrogels have been employed in the fabrication of such membrane-reservoir systems (13). 

In addition to the many hundreds of steroids isolated from plants and animals, thousands more have been synthesized in pharmaceutical laboratories in a search for new drugs. Among the best-known synthetic steroids are the oral contraceptives and anabolic agents. Most birth-control pills are a mixture of two compounds, a synthetic estrogen, such as ethynylestradiol, and a synthetic progestin, such as norethindrone. Anabolic steroids, such as stanozolol and methandrostenolone (Dianabol), are synthetic androgens that mimic the tissue-building effects of natural testosterone. 

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