Pharmacists are frequently called on to prepare sterile products intended for ophthalmic administration when a suitable sterile ophthalmic product is not available from a licensed manufacturer. These products may be administered topically or by subconjunctival or intraocular (e.g., intravitreal and intracameral) injection and may be in the form of solutions, suspensions, or ointments.
The sterility of these products, as well as accuracy in the calculation and preparation of doses, is of great importance. Ocular infections and loss of vision caused by contamination of extemporaneously prepared ophthalmic products have been reported.1,2 Drugs administered by subconjunctival or intraocular injection often have narrow therapeutic indices. In practice, serious errors in technique have occurred in the preparation of intravitreal solutions, which resulted in concentrations up to double the intended amounts.3 To ensure adequate stability, uniformity, and sterility, ophthalmic products from licensed manufacturers should be used whenever possible.
The following guidelines are intended to assist pharmacists when extemporaneous preparation of ophthalmic products is necessary. These guidelines do not apply to the manufacturing of sterile pharmaceuticals as defined in state and federal laws and regulations. Other guidelines on extemporaneous compounding of ophthalmic products also have been published.4,5
1. Before compounding any product for ophthalmic use, the pharmacist should review documentation that substantiates the safety and benefit of the product when administered into the eye. If no such documentation is available, the pharmacist must employ professional judgment in determining suitability of the product for ophthalmic administration.
2. Important factors to be considered in preparing an ophthalmic medication include the following:6
c. pH, buffering.
d. Inherent toxicity of the drug.
e. Need for a preservative.
g. Stability in an appropriate vehicle.
i. Packaging and storage of the finished product.
3. A written procedure for each ophthalmic product compounded should be established and kept on file and should be easily retrievable. The procedure should specify appropriate steps in compounding, including aseptic methods, and whether microbiologic filtration or terminal sterilization (e.g., autoclaving) of the finished product is appropriate.
4. Before preparation of the product is begun, mathematical calculations should be reviewed by another person or by an alternative method of calculation in order to minimize error. This approach is especially important for products, such as intraocular injections, for which extremely small doses are frequently ordered, necessitating multiple dilutions. Decimal errors in the preparation of these products may have serious consequences.