HEALTH AND MEDICAL PRODUCTS:EAR DROPS.

EAR DROPS

The human external (outer) ear includes the external auditory canal (ear canal) and the surrounding auricle or pinna (fleshy cartilaginous shell-shaped projection). The external auditory canal is a short tube (about 2.5 centimeters long by 0.6 centimeters wide) that serves as a passage- way between the auricle and the tympanic membrane (eardrum). Near the auricle, the canal consists mostly of elastic cartilage, whereas the remainder of its framework is carved into the temporal bone of the skull. The entire canal is lined with skin bearing hairs, sebaceous (oil) glands, and modified apocrine sweat glands called ceruminous glands that secrete a yellow-brown waxy product called cerumen. Cerumen consists of nearly 50 percent lipids, with additional proteins and carbohydrates. In general, the combination of cerumen, oily secretions from sebaceous glands, squamous epithelial cells from the ear canal lining, and dust and other debris constitutes earwax. The combination of hairs and cerumen naturally assists in slowing the growth of microorganisms (reducing the chances of infection) and in preventing water and damaging debris and foreign objects from entering the ear. Different individuals vary considerably in the amount and consistency of their earwax. In many individuals, the ear is naturally cleansed as the cerumen dries and falls out of the external ear canal. However, some individuals experience excessive ceru- men buildup, possibly attributable to abnormal cerumen production. Other predisposing factors leading to an overproduction of cerumen include hairy ear canals, narrow ear canals, and the presence of in-the-ear hearing aids. The excess cerumen may become impacted and cause dis- comfort, pain, and hearing impairment by the muffling of incoming sounds. The treatment for mildly impacted cerumen is usually periodic ear irrigation, but severe cases can require treatment by trained medical personnel, including ear syringing, physical removal of wax using a blunt instrument (ear curette), and/or suction.

Over-the-counter ear drops used to soften and loosen small to moderate amounts of earwax are all basically oil and peroxide solutions, generally containing active ingredients called ceruminolytics. The drops are placed into the ear canal using a specialized applicator when the head is tilted sideways. The drops remain in the ear by keeping the head tilted or by placing cotton loosely in the ear. A commonly used ceruminolytic includes carbamide peroxide suspended in an organic base (e.g., anhydrous glycerin). Hydrogen peroxide does not directly dissolve earwax, but it may be present for a mechanical effect. “Enzyme”-based ceruminolytic preparations (e.g., containing triethanolamine polypeptide oleate) act as cerumen-lysing surfactants but are seldom chosen by consumers because of their potential to elicit allergic reactions. Other substances often used as “home-remedy” ceruminolytics include a 10 percent aqueous sodium bicarbonate solution (advertised as early as 1860 as an ideal ceruminolytic), glycerin, and olive oil or almond oil warmed to room temperature.