Ophthalmics sterile, compounding

Several guidelines are available in the literature for the pharmacist who must extemporaneously prepare an ophthalmic solution. The USP contains a section on ophthalmic solutions, as do other compendia and several standard textbooks. Since the pharmacist does not have the facilities to test the product, he or she should dispense only small quantities, with an expiration date of no more than 30 days. Refrigeration of the product should also be required as a precautionary measure. To reduce the largest potential source of microbial contamination, only sterile purified water should be used in compounding ophthalmic solutions. Sterile water for injection, USP, from unopened IV bottles or vials is the highest-quality water available to the pharmacist. Prepackaged sterile water with bacteriostatic agents should not be used. 

When an ophthalmic ointment is manufactured, all raw material components must be rendered sterile before compounding unless the ointment contains an aqueous fraction that can be sterilized by heat, filtration, or ionizing radiation. The ointment base is sterilized by heat and appropriately filtered while molten to remove extraneous foreign particulate matter. It is then placed into a sterile steam-jacketed kettle to maintain the ointment in a molten state under aseptic conditions, and the previously sterilized active ingredients) and excipients are added aseptically. While still molten, the entire ointment may be passed through a previously sterilized colloid mill for adequate dispersion of the insoluble components. 

The USP recognizes six methods of achieving a sterile product (i) steam sterilization, (if) dry-heat sterilization, (Hi) gas sterilization, (iv) sterihzation by ionizing radiation, (v) sterilization by filtration, and (vi) aseptic processing (67). For ophthalmic products packaged in plastic containers, t5rpical for ophthalmic products, a combination of two or more of these six methods is routinely used. For example, for a sterile ophthalmic suspension, bottles, dropper tips, and caps may be sterilized by ethylene oxide or y-radiation the suspended solid may be sterilized by dry heat, y-radiation, or ethylene oxide and the aqueous portion of the composition may be sterilized by filtration. The compounding is completed under aseptic conditions. 

For sterile Filtration of ophthalmics and small-volume parenteral products it is not unusual to Find several Filters mounted in series. For instance a compounded bulk product may be Filtered through the wall from a dean area into an aseptic filling room. In these cases there are usually two filters mounted in... 

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