US Pharm. 2015;40(6):53-54.
Method of Preparation: Note—This formulation should be prepared according to strict aseptic compounding technique in a laminar airflow hood in a cleanroom or via isolation barrier technology by a compounding pharmacist who is validated in aseptic compounding. This is a high-risk preparation.
Calculate the quantity of each ingredient for the amount to be prepared. Aseptically, accurately measure the chlorhexidine gluconate and add to sufficient Sterile Water for Injection to final volume and mix well. Sterile-filter into a sterile ophthalmic container. Package and label.
Use: This preparation has been used as an alternative to polyhexamethylene biguanide in the treatment of Acanthamoeba keratitis.
Packaging: Package in tight, light-resistant containers.
Labeling: Keep out of reach of children. Discard after ____ [time period]. For the eye. Store at room temperature.
Stability: Refer to the current edition of the U.S. Pharmacopoeia for the appropriate beyond-use date.1
Quality Control: Quality-control assessment can include weight/volume, physical observation, pH, specific gravity, osmolality, assay, color, clarity, particulate matter, and sterility.2,3
Discussion: Although this preparation is approved for the treatment of dental infections and/or inflammatory conditions as a mouth rinse and topical disinfectant, its off-label uses include ophthalmic applications in the treatment of Acanthamoeba keratitis.4,5
Acanthamoeba keratitis, which is somewhat rare, occurs when amoebae invade the cornea of the eye; it can result in permanent visual impairment or blindness. The condition is most often associated with contact lens use, as Acanthamoeba can survive in the space between the lens and the eye. This supports the recommendations that contact lenses be properly disinfected before they are worn and that they be removed before swimming or surfing.
Pharmacists can also make the following recommendations: 1) Always wash hands before handling contact lenses; 2) rub and rinse the surface of the contact lens before storing; 3) use only sterile products recommended by your optometrist to clean and disinfect your lenses; 4) use fresh solution each time the lens is placed in the case; 5) do not sleep in contact lenses unless prescribed by your doctor, and never wear them after swimming; 6) never exchange lenses with anyone else; and 7) never put contact lenses in your mouth.
Treatment of Acanthamoeba keratitis has included polyhexamethylene biguanide, propamidine isethionate, and chlorhexidine, as well as a combination of propamidine, miconazole nitrate, and neomycin. In some cases, keratoplasty may be required.
Chlorhexidine gluconate (Hibiclens, Periogard, C22H30Cl2N10.2C6H12O7, MW 897.76) is a cationic bisbiguanide used as a topical anti-infective agent. Chlorhexidine gluconate solution occurs as an almost colorless or pale yellow, clear liquid that is miscible with glacial acetic acid and with water; it is miscible with five times its volume of dehydrated alcohol.1 Its solutions generally have a pH in the range of 5 to 7, and it is light-sensitive. Chlorhexidine gluconate should be protected from light and stored at controlled room temperature.1
Sterile Water for Injection is water for injection that has been sterilized and suitably packaged; it contains no added substances. Water for injection is water purified by distillation or by reverse osmosis, and it contains no added substances. Note that water for injection is not prepared by an ion-exchange process. The term water is used to describe potable water from a public water supply that is suitable for drinking and is the beginning point of the official waters. It is a clear, colorless, odorless, and tasteless liquid. Purified water is water that is obtained by distillation, ion exchange, reverse osmosis, or some other suitable process. Water has a specific gravity of 0.9971 at room temperature, a melting point of 0°C, and a boiling point of 100°C. It is miscible with most polar solvents and is chemically stable in all physical states (ice, liquid, and steam).6
REFERENCES
1. U.S. Pharmacopeia 38/National Formulary 33. Rockville, MD: U.S. Pharmacopeial Convention, Inc; 2014:559-611,1928.
2. Allen LV Jr. Standard operating procedure for particulate testing for sterile products. IJPC. 1998;2:78.
3. Allen LV Jr. Standard operating procedure: quality assessment for injectable solutions. IJPC. 1999;3:406-407.
4. Tirado-Angel J, Gabriel MM, Wilson LA, Ahearn DG. Effects of polyhexamethylene biguanide and chlorhexidine on four species of Acanthamoeba in vitro. Curr Eye Res. 1996;15:225-228.
5. Awwad ST, Petroll WM, McCulley JP, Cavanagh HD. Updates in Acanthamoeba keratitis. Eye Contact Lens. 2007;33:1-8.
6. Dubash D, Shah U. Water. In: Rowe RC, Sheskey PJ, Cook WG, Quinn ME. Handbook of Pharmaceutical Excipients. 7th ed. Washington, DC: American Pharmaceutical Association; 2012:880-884.
To comment on this article, contact rdavidson@uspharmacist.com.
