Galenic ophthalmic medicines may be useful for patients who cannot use commercially available products or for whom no product is available. This circumstance occurs when, for example, a patient is allergic to an excipient contained in the commercial product, or if the available dose or concentration is not suitable for administering the prescribed dose, or if the drug is not very stable and must be prepared at the time of administration.
The extemporaneous preparation of eye medication is considered a complex practice during which the suitability, efficacy and safety of the drug for each individual patient must be assessed. For each compound, the pharmacist must also pay attention to the formulation and physical, chemical and microbiological stability. Collaboration with the physician is, therefore, essential and the pharmacist can be a useful source of information for the ophthalmologist on the availability of alternatives for patient treatment.
The process of creating a galenic drug ophthalmic
The compounding of ophthalmic products is best performed in specialised aseptic facilities with appropriate equipment, including air filtration systems. Laboratories where ophthalmic galenic drugs are produced are required to have a robust quality management system that complies with the guidelines. ISO 9001 is the international standard for quality management system and is used by organisations to demonstrate their ability to consistently provide products and services that meet regulatory requirements.
When the compounding is subdivided into batches, is subject to additional regulations, and the premises for preparation must comply with the Therapeutic Goods Administration for Good Manufacturing Practice (GMP), which is outside the scope of work of typical compounding.
When submitting a prescription, it is necessary to collect all relevant information about the patient, including medical history, information on allergies and adverse drug effects, information on previous use of eye preparations.
The pharmacist will review the prescription and check the known safety and efficacy of the active ingredient, dose, frequency, route of administration and duration of treatment. In addition, a check will be made to ensure that the suggested formulation and dosage of the drug are appropriate and that there are no commercially available products that are the same or very similar to be used.
In the case of ophthalmic eye drops, the active substance may be added to a neutral eye drop base. It is preferable for the pharmacist to use a published formula for which safety and stability data are available.
The compounded prescription drug must also have an expiry date, generally no more than 28 days after manufacture (although for some preparations this may be up to six months). In particular, for eye drops and ophthalmic ointments, the expiry date may be up to 28 days depending on the chemical and/or physical stability of the components.
In the case of eye drops, intraocular injections or ointments for ophthalmic use, the products are prepared using appropriate standardised aseptic techniques and, if necessary, dispensed in single doses. In addition, the products are mixed in a specially designed room with a laminar flow hood, using special equipment and a controlled air flow, which is regularly monitored for compliance.
Finally, an integral part of the formulation of ophthalmic galenic medicines is patient information. It is important for the patient to have the necessary information for safe and effective use of the prescribed medicine and to be able to rely on the advice of the pharmacist, as well as the doctor, in case of need.
Bibliography:
Lynn Weekes, Iqbal Ramzan, Prescription of compounded ophthalmic medications-a pharmacy perspective, Clin Exp Optom. 2021 Apr;104(3):406-411. doi: 10.1111/cxo.13066. Epub 2021 Mar 23.
Dr. Carmelo Chines
Direttore responsabile