Marcin Płaczek, Katarzyna Opęchowska, Lucyna Wolniak, Małgorzata Sznitowska

Buffers in parenteral formulations – technological and biopharmaceutical aspects

 

2025-09-12

Subject of Study. During manufacturing, certain medicinal products require the use of unique environmental conditions and technological operations, as well as the use of specific pharmaceutical excipients. A special group of preparations is, for example, drugs administered parenterally, which must meet unique quality requirements: not only sterility, absence of mechanical impurities, and bacterial endotoxins, but also an appropriate pH value and osmotic pressure. The pH of a solution administered to a patient by injection or infusion is of fundamental importance from the point of view of both drug quality and its efficacy and patient safety.

Aim of Study. The purpose of the study was to gather the most important information on buffers used as excipients in the formulation of parenteral drugs. The authors’ intention was to clarify the mechanism of pH stabilization by buffer solutions, the range of effective buffering action, and the principles of selecting the right buffer system depending on the characteristics of a formulation intended for parenteral administration.

Materials and Methods. The paper is a narrative review, which was prepared based on recognized professional literature and information contained in medical scientific databases (Scopus, PubMed, Ebsco, and Web of Science). When searching these databases, the following keywords were used as filters: “buffers”, “parenteral drugs”, “injections”, “infusions”. The search results were narrowed down to the last 10 years, and more previously published sources were sought if further clarification of an issue was needed.

Results. The publication reviews the buffer systems currently used in parenteral drug formulations, including biopharmaceutics. For detailed description, buffers such as phosphate, acetate, citrate, phosphate-citrate, succinate, Tris, and histidine were selected. Characterization of these buffers includes the range of buffering efficiency and physicochemical compatibility with the other ingredients of the parenteral drug, as well as the technological feasibility of their use in liquid and solid preparations (lyophilized powders). The descriptions are supplemented with examples of practical problems that for professional personnel may sometimes be posed by the need to use a parenteral drug with a specific pH value. Moreover, examples of registered parenteral drugs containing buffers are presented in the form of tabular summaries.

Conclusions. The information presented in the publication shows how important for the quality of a parenteral drug it is to choose the right buffering system. This choice must follow a series of experiments at the stage of preformulation and development. Buffer selection must consider the properties of the drug substance, compatibility with other excipients, and application characteristics related to the route of administration for such specific forms of the drug as parenteral forms.

Keywords: pharmaceutical excipients, infusions, buffers, pharmaceutical technology, injections, parenteral drugs.

© Farm Pol, 2025, 81(1): 3–14