When preparing biotech products, aseptic technique must be employed as it is with traditional parenteral products. The product should be prepared in a clean room designed for this purpose with laminar air flow hoods, etc. Most of the products require reconstitu-tion with sterile water or bacteriostatic water for injection depending on stability data. The compat-ibility of individual products varies and limited data are available. As mentioned previously, when adding diluent to these products, care should be taken not to shake them, but to swirl the container or roll it between the palms of the hands. In the case of lyophilized products, introduction of the diluent should be directed down the side of the vial and not directly on the powder to avoid denaturing the protein. It is important to mention that stability does not mean sterility. Biotech products require the same precautions as any other parenteral product. Sterility is particularly important when pre-filling and pre-mixing various doses for administration at home. Once the manufacturer’s sterile packaging is entered, sterility can no longer be assured nor will the manufacturer be responsible for any subsequent related problems. Many biotech drugs are not compatible with preservative agents and single use vials do not contain a preservative. Individual manufacturers have not addressed the issue of sterility and each institution or organization must determine its own policy on this issue. Many of the currently available biotechnology-produced products are provided as single-dose vials and should not be reused. This does not, however, prevent preparing batches (“batching”) of unit-of-use doses in order to be efficient. Many of the patients receiving these agents are likely to have suppressed immune systems and are vulnerable to infection. Therefore, a policy involving the maintenance of sterility of biotech products should be developed by each healthcare organization, especially hospitals, and specialty phar-macies. When products are made in a sterile environment under aseptic procedures they should remain sterile until used and thus could be stored for as long as physical compatibility data dictate. However, most institutions have shorter expiration dates, which are generally 72 hours or less, on reconstituted products. These expiration dates have been arbitrarily set due to lack of good sterility data to the contrary. Sterility studies should be performed in order to determine if reconstituted products could be stored for a longer period of time and still maintain sterility. For products reconstituted for home use in the pharmacy sterile products area, a seven day expiration date is used provided the product is stable and can be stored in the refrigerator. The American Society of Health-System Pharmacists has published a technical assistance bulletin on sterile products, which should be consulted for developing policies on storage of reconstituted parenteral pro-ducts (American Society of Hospital Pharmacy, 2000). Patients need to be informed about specific storage requirements and expiration dates to assure sterility and stability.