HEALTH AND MEDICAL PRODUCTS:SPERMICIDE (BIRTH CONTROL PRODUCT).

SPERMICIDE (BIRTH CONTROL PRODUCT)

The human reproductive system is the only organ system in both males and females that is not essential to the life of the individual. Although the reproductive systems of the human male and female possess many differences, their common purpose is to produce offspring and thus perpetuate the species. In general, the role of the human reproductive system is to synthesize, maintain, nourish, and transport functional male and female reproductive cells called gametes. The reproductive system includes gonads, or reproductive organs that produce the gametes and secrete steroid-based sex hormones; ducts that receive and transport the gametes; accessory glands and organs that secrete fluids into the ducts or other accessory structures to allow for adequate lubrication and gamete functioning; and perineal structures collectively called external genitalia that enhance the human sexual response and allow for efficient reproductive functioning during a copulation event between males and females. Male gametes, called sperm, are produced in gonads called the testes, and female gametes, called ova (eggs), are produced in gonads called the ovaries. When a male and a female gamete unite, fertilization, also known as con- ception, occurs. In sexual reproduction, fertilization results in the formation of a completely new and genetically unique organism. Specifically, the single cell resulting from the union and fusion of the male and female gametes, called a zygote, contains a mixture of chromosomes (DNA) from the two parents. Through a development process of repeated mitotic cell divisions and differentiation (specialization), the zygote undergoes grad- ual transformation and maturation within the female uterus into a complex multicellular new human being.

Sperm are specialized cells produced in the male testes, which are paired oval glands measuring approximately five centimeters (two inches) in length and two and a half centimeters (one inch) in diameter that are supported externally by a cutaneous outpouching of the male abdomen consisting of loose skin and connective tissue called the scrotum. Within the testes, septal tissue extensions divide the testes internally into 200 to 300 wedge- shaped compartments called lobules. Each lobule contains one to four tightly coiled tubules called seminiferous tubules. Within the seminiferous tubules, sperm are produced by a unique cellular division process called spermatogenesis. Controlled by hormones including testosterone, the process of spermatogenesis begins during puberty within males and normally continues throughout life. A healthy adult human male produces approximately 400 million sperm daily.

A sperm is a highly adapted and mobile cell capable of reaching and penetrating a female ovum (egg). Each sperm has three distinct regions: the head (genetic region), the midpiece (metabolic region), and the tail (locomotor region). The head is a flattened ellipse containing a nucleus with densely packed chromosomes (DNA) and a dense membranous granule (actually a specialized lysosome organelle) at the tip called the acrosomal cap that contains enzymes, including proteinases and hyaluronidase, which aid in the penetration of the sperm cell into the ovum. A short neck attaches the head to the midpiece, a region containing organelles called mitochondria that absorb nutrients from the surrounding fluid (called semen) and produce energy (in the form of adenosine tri- phosphate) for sperm locomotion. The tail consists of an organelle called a flagellum, which allows the sperm to propel through the female repro- ductive tract in a unique whiplike corkscrew motion.

Contraception (contra = against, cept = taking) and birth control are synonymous terms. While many individuals use various birth control strategies during their reproductive years, readily available OTC chemical methods of contraception containing spermicide chemicals are frequently chosen. Various foams, creams, jellies, vaginal suppositories, sponges, and douches that contain spermicidal agents make the female vagina and cervix unfavorable for sperm survival and thus decrease the likelihood of a successful fertilization event during intercourse. Once the sperm-killing chemicals are inserted into the female vagina to coat the vaginal surfaces and cervical opening into the uterus, relative contraception protection is provided for approximately one hour. Spermicides can be effective when used alone but are significantly more effective when used with physical barrier devices, including condoms, vaginal pouches, diaphragms, cervical caps, or sponges.

For approximately thirty years, one of the most widely used Food and Drug Administration-approved active ingredient spermicides in various OTC contraceptive products has been nonoxynol-9 (N-9). N-9 is an al- most colorless liquid nonionic detergent (surfactant, a surface-active agent) that inactivates sperm via disruption and disaggregation of the outer protective plasma membrane. Thus, the number of active and viable sperm decreases significantly. This activity stems from the ability of nonionic surfactants, which lack a specific charge and possess a hydrophilic head region and a hydrophobic tail region, to dissolve lipid-containing membranes. A nonoxynol [a-(4-nonylphenyl)-w-hydroxypoly(oxy-1,2-ethanediyl) or poly- ethyleneglycol mono(nonylphenyl) ether] is a nonionic surfactant mixture prepared by reacting nonylphenol with ethylene oxide. The hydrophilic (or water-soluble) portion of the molecule contains the polyethylene ox- ide group. The average number of ethylene oxide units (n) per molecule is indicated by the number after nonoxynol (e.g., nonoxynol-9 for n = 9). A multicomponent mixture of oligomers (at least seventeen are known as characterized by high-performance liquid chromatography) in the com- mercially available form, N-9 is used as a spermicidal ingredient in sper- micidal lubricants, both preapplied to spermicidal condoms and packaged separately.