Stability Studies: A Scientific Mission of the Hospital Pharmacist

Abstract

The preparation of medications is a fundamental part of the pharmacist’s profession. Today, hospital pharmacists prepare mainly sterile products i. e. anticancer drugs, antibiotics, medications for intensive care units in Centralized Intravenous Additive Services (CIVAS), eye-drops or parenteral nutrition especially for pediatrics. Oral solutions are prepared for patients who have difficulties to swallow such as pediatric or elderly patients. The more traditional preparations (such as capsules or unguents) are still carried out but today represent a small part of the activity of pharmacotechnics. Nevertheless, for all these preparations, hospital pharmacists need stability data to assign a shelf life to their compounded products. The need for stability studies is huge and this field of activity is a part of our mission defined in the official Good Manufacturing Practices (GMP) for compounding pharmacies. These GMP guidelines are similar in many countries. For example, in the French guidelines, the text makes it clear in chapter 1 that “The shelf life of the preparations can be determined by using bibliographic references or by performing stability studies.” and in chapter 2 “Control”: The hospital pharmacist has various missions including ... “the control of stability” [1]. Here is a non-exhaustive list of examples of stability studies which can be performed by hospital or university teams: – intravenous (IV) mixtures used in intensive care units or oncology, – parenteral (IV or subcutaneous) new monoclonal antibodies that are often prepared in advance or can be conserved if the prescription is cancelled after the preparation, – oral solutions for pediatrics or geriatrics, – very expensive drugs in the case of limited stability data provided by the manufacturers, to save money, – dilutions of antibiotics in unusual solvents such as peritoneal dialysis solutions, – anticancer drugs at elevated temperatures for intraperitoneal hyperthermic chemotherapy, – leaching of plasticizers into the solutions from containers. Diethylhexylphtalate (DEHP) is a well-known example of potentially toxic additive used in polyvinyl chloride containers but other less known products can leach into the solution and be potentially harmful to the patient, – etc.