US Pharm. 2017;42(8):47-48.
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. Accurately weigh or measure each ingredient. Aseptically, add the chlorhexidine digluconate to sufficient 0.9% Sodium Chloride Irrigation solution to final volume; mix well. Sterile-filter into sterile containers. Package and label.
Use: This preparation has been used to treat bladder infections by bladder instillation.
Packaging: Package in sterile containers suitable for bladder irrigation.
Labeling: Keep out of reach of children. For professional use. Protect from light. Discard after ____ [time period].
Stability: Check the current edition of the U.S. Pharmacopeia 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: Chlorhexidine is available as chlorhexidine acetate, chlorhexidine gluconate, and chlorhexidine hydrochloride. The acetate and hydrochloride are used as white, crystalline powders, but the gluconate is mostly used as an almost colorless or pale yellow–colored aqueous solution. The aqueous concentration of chlorhexidine that is normally recommended for contact with mucosal surface is 0.05% w/v, as there is no irritant effect on soft tissues and healing is not delayed.4
Chlorhexidine gluconate (chlorhexidine digluconate, Hibiclens, Hibistat, Peridex, Prevacare, C22H30Cl2N10.2C6H12O7, MW 897.88) is ordinarily used as an almost colorless or pale yellow–colored aqueous solution. The pH of a 5% w/v aqueous dilution is between 5.5 and 7.0. Chlorhexidine gluconate is miscible with water and soluble in acetone and 95% ethanol. Chlorhexidine and its salts are widely used for their antimicrobial properties as disinfectants and preservatives. Chlorhexidine exhibits antimicrobial activity against both gram-positive and gram-negative microorganisms. Optimal antimicrobial activity occurs at pH values between 5 and 7. Above pH 8, the chlorhexidine base may precipitate from aqueous solutions. Chlorhexidine base has a melting range of 132°C to 134°C.4
Chlorhexidine and its salts are stable in the dry, powdered form. Chlorhexidine gluconate may undergo hydrolysis when catalyzed by heating and an alkaline pH. Following autoclaving of a 0.02% w/v chlorhexidine gluconate solution at pH 9 for 30 minutes at 120°C, 1.56% of the initial chlorhexidine content was converted to 4-chloroaniline. Solutions should be protected from light. Chlorhexidine salts and their solutions should be stored in well-closed containers, protected from light, and kept in a cool, dry place.4
Incompatibilities include soaps and other anionic materials because chlorhexidine salts are cationic in solution. Additional incompatibilities include acacia, sodium alginate, sodium carboxymethyl cellulose, starch, tragacanth, brilliant green, chloramphenicol, copper sulfate, fluorescein sodium, formaldehyde, silver nitrate, and zinc sulfate. Chlorhexidine salts are compatible with most cationic and nonionic surfactants.4
Sodium Chloride Irrigation, USP, is Sodium Chloride Injection that has been suitably packaged, and it contains no antimicrobial agents. It contains not less than 95.0% and not more than 105.0% of the labeled amount of sodium chloride. It has a pH between 4.5 and 7.0, and it contains no added antimicrobial agents. Sodium chloride solutions are chemically and physically stable. They can be sterilized by filtration or autoclaving. Aqueous sodium chloride solutions will react to form precipitates with silver, lead, and mercury salts. Chlorine can be liberated from acidified sodium chloride solutions when they are mixed with strong oxidizing agents. Sodium chloride will lessen the solubility of some organic compounds; methylparaben is not as soluble in sodium chloride solutions as it is in water. Sodium chloride is soluble in water to the extent of 1 g in 2.8 mL water, and it is slightly soluble in alcohol (1 g in 250 mL of 95% ethanol).1,5
REFERENCES
1. U.S. Pharmacopeia/National Formulary [current revision]. Rockville, MD: U.S. Pharmacopeial Convention, Inc; July 2017.
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. Peltonen I. Chlorhexidine. In Rowe RC, Sheskey PJ, Cook WG, Fenton ME, eds. Handbook of Pharmaceutical Excipients. 7th ed. London, England: Pharmaceutical Press; 2012:175-179.
5. Maximilien JS. Sodium chloride. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook of Pharmaceutical Excipients. 6th ed. London, England: Pharmaceutical Press; 2009:729-732.
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