The development of condoms made from other materials has been prompted by the epidemics of HIV/AIDS and other STDs, perceived shortcomings of latex condoms, the increasing incidence of allergies to latex condoms, and the advent of new technologies and materials. Various thermoplastic elastomeric materials have been tested, and designs and production techniques have been developed. As of 1997, the FDA had cleared (i.e., approved) five male synthetic condoms and one female synthetic condom for marketing. Several other male and female synthetic condom designs are under development.
This chapter describes the materials, designs, other product attributes and manufacturing processes of synthetic elastomeric male condoms; a synthetic elastomeric (polyurethane) female condom; and natural skin male condoms. It focuses on the condoms approved or under consideration by the FDA for marketing (see Table 7-1).
In the early 1960s, the FDA began requiring efficacy testing for medical devices. As the latex condom was already a proven method of protecting against pregnancy, it was "grandfathered" into the group of contraceptives approved without substantial clinical data on its effectiveness.
In the early 1990s, the FDA began requiring extensive clinical data before approving new medical devices. Hence, most new synthetic elastomer condoms are required to meet much more rigorous standards than latex male condoms. These clinical data requirements have delayed synthetic condoms reaching the market. (Anonymous 1996) The Health Industry Manufacturers Association estimated that the application review time for new medical devices had more than doubled from 81 days in 1991 to 185 days in 1994. (Anonymous 1995) This review process is believed to be even longer now.
Synthetic Elastomeric Condoms
Research on new condoms has focused on synthetic compounds that are commonly called thermoplastic elastomers. The synthetic elastomeric condoms:
- may offer better physical properties than latex and may thus be stronger than latex
- transmit more body heat, hence allowing more sensitivity
- do not usually have an odor as does latex
- generally do not deteriorate with the use of oil-based lubricants and can thus be used with a variety of lubricants
- can be used by people who are sensitive or allergic to latex
- do not deteriorate under adverse storage conditions
- are generally more uniform in their composition than latex, and
- can be formulated to feel like they are thinner than they actually are.
Under its substantial equivalence 510(k) submission process, the FDA has approved five synthetic elastomeric male condoms for marketing. Only one, the Avanti polyurethane condom manufactured by the London International Group, is currently commercially available. The others approved are two synthetic Trojan brand condoms by Carter-Wallace, Inc. and two Tactylon brand condoms from Sensicon (formerly known as Tactyl Technologies, Inc.). Other synthetic male condoms in the development stages are the Ezon condom, made of polyurethane by Mayer Laboratories, Inc., and a polyurethane condom by Ortho-McNeil Pharmaceutical of Canada.
Male synthetic condoms are currently approved by the FDA only for people who are allergic to latex. These condoms are required to have an interim labeling step until the required extensive clinical trials on contraceptive efficacy are completed. In the U.S., the Avanti package labeling currently states:
The risks of pregnancy and sexually transmitted diseases (STDs), including AIDS (HIV infection), are not known for this condom. A study is being done. There are laboratory tests on this polyurethane material. These tests show that organisms even as small as sperm and viruses like HIV cannot pass through it.
Male synthetic elastomeric condoms are manufactured using either a dipping process similar to latex condoms or a cut-and-seal process, which uses extruded synthetic elastomeric films. Currently there are three different types of synthetic elastomers being used: polyester polyurethanes, polyether polyurethanes and styrene-based elastomers.
Avanti Male Condom
Apex Medical Technologies developed the initial design of a polyurethane male condom, then called the Sensation condom. The FDA approved it in March 1989, but the company never marketed it. Working with the London International Group, Apex amended the application, including design and formulation changes. The FDA gave pre-market clearance for this new design, now called the Avanti condom, in March 1991, ahead of a recent FDA ruling that manufacturers of medical devices be required to perform extensive clinical testing prior to marketing. Avanti entered the U.S. market in 1994 and is still the only synthetic male condom available for purchase there.
The Avanti condom is made from Duron, a thermoplastic elastomer in the polyester polyurethane family. The first version on the market, called the "Superthin" Avanti, had relatively high breakage rates in clinical studies conducted in 1994 by the Los Angeles Regional Family Planning Council (now the California Family Health Council), ranging from 4.4 percent to 15 percent. (Anonymous 1996) The high breakage rates may have been due to the thin film (0.037 to 0.042 mm). (For latex condoms, major standards and specifications vary: no requirement; minimum of 0.03 mm; minimum of 0.05 mm; and a range from 0.04 to 0.08 mm.)
A subsequent study compared a thicker version of the "Superthin" Avanti condom (0.045 to 0.050 mm) with a latex condom. The study found that the Avanti failed more often than latex, but the pregnancy rates of the two condoms were equivalent. For the Avanti, during intercourse and withdrawal, the breakage rates were 4.0 percent and slippage rates were 4.5 percent. Corresponding rates for the latex study control were 0.4 percent and 1.2 percent, respectively. The study did not address the comparable STD protection of the Avanti condom. (Nelson) Only this thicker version is being marketed.
The Avanti condom looks very similar to a straight-sided, reservoir-tipped latex condom. It is wider than the standard latex condom, measuring about 65 mm in lay-flat width compared to the traditional 52 mm. A retaining ring is made from rolled, pressed polyurethane at the open end of the condom.
Tactylon Male Condom
Sensicon Corporation, a manufacturer of dipped and molded condoms and other medical products, has developed three new designs of male synthetic condoms. All the designs are made from a non-latex elastomer formulation of styrene ethylene butylene styrene (SEBS) called Tactylon, which was developed by Sensicon. Unlike silicone or polyurethane, SEBS can be formulated to mimic the elastic properties of latex.
Tactylon has similar elastic properties to latex but is translucent when non-lubricated and clear with silicone lubricant, compared to the tan, somewhat translucent latex condom. Tactylon condoms are manufactured with a vertical dipping process and have a minimal rim at the open end similar to latex condoms. The three designs are a standard condom, a "baggy" condom and a low-modulus standard condom, which is more elastic and has a higher elongation.
The standard design is cylindrical and nearly identical in specifications to currently marketed reservoir-tipped latex condoms. The FDA has cleared the marketing of the standard condom in both lubricated and unlubricated forms. It will be lubricated with silicone and packaged in foil. At least one form of this condom is expected to be on the market in 1998.
The more elastic, low-modulus design has an elongation in the range of 1000 percent (compared to the usual 800 percent elongation for male latex condoms). This greater elasticity may reduce the incidence of breakage during intercourse. The FDA has cleared this condom for marketing.
The "baggy" condom has an open end similar in lay-flat width (52 mm) to a traditional latex condom but a closed end with a much larger lay-flat width (80 mm). The larger width of the baggy condom design may allow greater comfort and pleasure for users by reducing constriction and increasing frictional forces. At present, this condom design has not been cleared by the FDA for marketing.
Several studies have compared Tactylon and latex condoms for breakage rates and acceptability issues. A study using 250 standard Tactylon and 250 latex condoms found that the Tactylon condom performed as well and was as acceptable to users as the latex condom. (Trussell) In an FHI study comparing approximately 560 condoms of each of the three Tactylon designs with 560 latex condoms, the combined Tactylon breakage rates were slightly higher than the latex control. (Steiner)
Another study compared breakage and slippage rates of about 1,200 of each Tactylon design and about 1,200 latex condoms. The clinical breakage rates for the Tactylon condoms were higher than the latex control, which was 0.9 percent (far lower than most condom studies). The complete slippage rates were lower for the standard and low-modulus Tactylon condoms than the latex control (1.1 percent), while the slippage rate of the baggy Tactylon design was slightly higher. These data are from condoms used only during vaginal intercourse. Regarding acceptability issues, the standard and low-modulus condoms were significantly preferred to latex, with users noting enhanced sensitivity, sensation, fit and comfort. There were also fewer incidences of reaction and genital pain with Tactylon condoms compared to the latex control. The study, conducted by the Contraceptive Research and Development (CONRAD) Program, is not published.
Trojan Male Condom
Two variations of one design of a polyurethane male condom manufactured by Carter-Wallace, Inc. have been cleared by the FDA through the substantial equivalence 510(k) process: one condom lubricated with silicone and one with N-9 and silicone. (Ohye) These condoms will most likely be marketed under the Trojan brand name.
The condom is manufactured through a dipping process of an aliphatic polyurethane material which results in a condom that has a higher tensile strength and break force than a latex condom. (Ohye) This condom measures 59 mm in width, 189 mm in length. Further details on this condom are not available from public records.
Ezon Male Condom
Ezon, a synthetic thermoplastic elastomeric condom developed by FHI, is to be manufactured and marketed by Mayer Laboratories, Inc. It has not yet received FDA approval. The Ezon condom is slipped onto the penis rather than rolled on and represents the first new male condom design since the traditional rolled-rim condom. The condom consists of a baggy sheath attached to a double-layered flange or collar at the open end. This flange is used for gripping and donning the condom and also serves as the retaining mechanism for the condom. The shaft of the condom is rolled up in between the double-layered flange and unrolls automatically as the condom is pulled on. The baggy design of the Ezon condom may increase sensation for men who feel constricted by a tighter-fitting latex condom.
The Ezon condom can be pulled on using either side, unlike roll-on condoms. It is easy to don, even in the dark, and reduces the interruption of putting on a condom. In contrast, a traditional roll-on condom can be put on correctly in only one direction. Additionally, beginning to don a traditionally rolled condom "inside-out" might contaminate it with bodily fluids. If this happens (and users suspect contamination with bodily fluids has occurred), it is recommended that a new condom be used, but many people simply reuse the original condom and thereby expose the vagina to the side of the condom that may have been contaminated with pre-ejaculatory fluid. Further details on this condom are not available from public records.
Ortho-McNeil Thermoplastic Elastomer Condom
Ortho-McNeil Pharmaceutical of Canada, has developed a synthetic elastomeric condom, with a patent on the manufacturing method, the new condom and the use of the specific polyester polyurethane to make similarly shaped products. From diagrams, it appears that the condom consists of a contoured shaft, a reservoir tip and a rim roll made of solid polyurethane. The entire condom is made of a polyester polyurethane. The film thickness can be set from 0.005 to 0.24 mm, with optimal thickness of 0.01 to 0.10 mm. (Schut)
This condom is manufactured by a thermo-molding process. First, a ribbon of polyurethane measuring 1.0 to 1.9 mm is extruded. The ribbon is then pre-formed into a disk-like shape by a stamping process, then heated and further shaped. It is then re-heated and positioned along the rim of a mold cavity. A pressure plug, air pressure and vacuum are used in combination to draw the shaped polyurethane into the mold cavity without having the polyurethane touch the walls of the mold. (Schut)
The Female Condom
The female condom is manufactured and marketed by The Female Health Company. It was first marketed in Switzerland and the United Kingdom in 1992. In 1993, the FDA approved the condom for marketing in the U.S. The Female Health Company now holds worldwide rights to this condom design, which is manufactured in the United Kingdom.
The FDA has approved the female condom for the prevention of pregnancy and the prevention of STDs. In the U.S., the package labeling for the female condoms states:
Latex condoms for men are highly effective at preventing sexually transmitted diseases, including AIDS (HIV infection), if used properly. If you are not going to use a male latex condom, you can use the Female Condom to help protect yourself and your partner. Reality only works when you use it. Use it every time you have sex. Before you try the Female Condom, be sure to read the directions and learn how to use it properly.
| |
| The FDA has approved the female condom for the prevention of pregnancy and the prevention of STDs. |
As of 1997, the female condom had been marketed in about 20 countries, primarily in North America and Europe, although marketing efforts had begun in Brazil, Canada, Zimbabwe, Zambia and other African countries. It is marketed under various brand names including Reality in the U.S., Femy in Spanish speaking countries, the Care Contraceptive Sheath in Zimbabwe, and Femidom in other countries. WHO and the Joint United Nations Programme on HIV/AIDS (UNAIDS) have negotiated a price with The Female Health Company of less than U.S. $1.00 per condom for the public sector in developing countries. This is helping to broaden its availability.
The female condom consists of a soft, loose-fitting, polyurethane sheath and a flexible polyurethane ring at each end. One ring, which is not attached to the condom, is placed in the closed end of the sheath and serves as an insertion mechanism and anchor inside the vagina. The other ring, which is attached to the open end, forms the external edge of the condom and remains outside the vagina after insertion, thus providing protection to the labia and base of the penis during intercourse. Female condoms do not restrict the penis like most latex male con-doms. As a result, sensitivity may be better for some couples. Additionally, since the condom covers the internal and much of the external genitalia, it may offer greater protection against the transmission of STDs than does the male condom, if used correctly. It can be inserted up to eight hours before intercourse.
The female condom is pre-lubricated with a non-spermicidal, silicone-based dimethicone lubricant and is generally sold with additional water-based, glycerine lubricant. The lay-flat width is about 78 mm at its widest diameter. Its length is approximately 170 mm and the film thickness ranges from 0.042 to 0.053 mm. The condom is packaged in cellophane.
The female condom is manufactured from an extruded polyether polyurethane film. The film is cut to shape and then sealed along the sides and closed end. The inner ring of the condom is manufactured by molding a polyether polyurethane similar to that used in the sheath of the condom. The outer ring at the open end of the condom is made from a pressed polyether polyurethane and is sealed to the sheath of the condom.
In more than 40 acceptability studies, a large proportion of women and men say they would use it if they could get it at an affordable price. However, the female condom currently is expensive and can be used only once. Researchers are investigating product integrity, safety and acceptability issues associated with multiple use of the female condom. Clearly, if safe and effective, multiple uses would reduce the effective cost of the device and thus make it more affordable to a wider range of couples. (FHI) The FDA approved shelf life is five years from date of manufacture.
Natural Skin Male Condoms
A natural skin condom is made from the cecum (a part of the intestines) of lambs. These condoms are loose-fitting on the penis and are supposed to conduct heat better than latex condoms and provide more sensitivity during intercourse. Because these condoms are made of natural membranes, oil-based lubricants may not be as damaging to them as they are to latex condoms. Natural skin condoms do not have reservoir tips.
The cecum is a blind pouch of intestine found near the opening of the large intestine there is only one cecum in each lamb. Lambs are the only plentiful domestic animals with ceca that are the proper size and shape for a condom. The age of the lamb is also important, since skin condoms are too thin or tender if made from the ceca of very young lambs, and too thick or tough if made from the ceca of older lambs.
Ceca are removed from the lambs at the slaughterhouse and preserved in salt. Condom manufacturers then sort the fresh ceca and reject any that are too big, too small or damaged. The selected ceca are then cleaned of fats and debris by washing them with a caustic detergent. After washing, they are dried gently in hot air and are flattened. The membranes at that stage look like translucent parchment. A retaining device is needed to keep the condom on the penis because natural skin condoms are not elastic and simply drape around the erect penis. The retaining device is incorporated by placing an elastic band over the open end of the cecum and folding the lip of the cecum over the elastic band. The folded end is then sealed by either gluing or sewing. Once the elastic retaining ring has been added, the condoms are rehydrated and tested for quality assurance.
Because skin condoms are natural products, they do not conform to standard sizes as do synthetic condoms. Skin condoms range from 160 to 180 mm in length and 63 to 80 mm in lay-flat width. Skin condoms are packaged with a water-based lubricant designed to prevent the animal membrane from drying out. Skin condoms are sold in foil packets or hard plastic capsules and come in a rolled or a flat, unrolled form. (Brackett)
Natural skin condoms contain small pores that can measure up to 0.0015 mm across and have been shown in laboratory tests to permit the passage of hepatitis B virus, herpes simplex virus and HIV. However, they have been shown to prevent the passage of sperm and are considered effective contraceptives. The FDA permits natural skin condoms to be labeled only for the prevention of pregnancy and not for the prevention of STDs.
by Caroline E. Gilmore
References
- Arnonymous. Barriers to better condom 'killing people': regulatory, political hurdles stifle development. Contracept Tech Update 1995;16(1):1-6.
- Anonymous. Review of company data shows Avanti breaks less often than latex. Contracept Tech Update 1996;17(4):37-41.
- Brackett J. Condom Information Guide. Durant, OK: Essential Medical Information Systems, Inc. 1988.
- Family Health International, AIDSCAP Women's Initiative. The Female Condom: From Research to the Marketplace. Arlington, VA: Family Health International, 1997.
- Holden G, Legge N, Quirk R, et al. Thermoplastic Elastomers, 2nd edition. New York: Hanser Publishers, 1996.
- Nelson A, Bernstein GS, Frezieres R, et al. Study of the efficacy, acceptability and safety of a non-latex (polyurethane) condom -- final report for NIH project N01-HD-1-3109. Unpublished paper. National Institutes of Health, 1997.
- Ohye GH. Trojan® polyurethane condom with spermicidal lubricant 510(k) summary. Unpublished paper. U.S. Food and Drug Administration Center for Devices and Radiological Health, 1995.
- Schut JH. TPE condom sets new technology standard. Plastics World 1996;(54):16-20.
- Steiner M, Joanis C, Taylor B, et al. Final Report -- Functionality and Acceptability of Three Lubricated TACTYLON® Condoms and a Standard Lubricated Latex Condom. Durham, NC: Family Health International, 1993.
- Trussell J, Warner DL, Hatcher R. Condom performance during vaginal intercourse: comparison of Trojan-Enz® and TACTYLON® condoms. Contraception 1992; 45(1):11-19.
- UNDP/UNFPA/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction. The Female Condom: A Review. Geneva: World Health Organization, 1997.
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