An In-Depth Analysis of pH-Independent Controlled Drug Delivery Systems and Prospects for the Future

Significant advancements have been made in controlled drug delivery systems in recent years, especially for oral administration. Conventional methods, although groundbreaking, encounter significant constraints when handling drugs with weak acidity or alkalinity because of their solubility being influenced by pH. The release rates of these ionizable drugs are subject to variability, which is influenced by factors such as the pH of the gastrointestinal tract (GIT), patient-specific conditions, and whether the patient is in a fed or fasted state. As a result, there is often a lack of correlation between in vitro and in vivo data. Therefore, it is imperative to develop drug delivery systems that are not affected by changes in pH in order to address these limitations. This review delves into different strategies that have been developed to achieve drug release that is not affected by changes in pH. These strategies include the utilisation of Diffucaps technology, the incorporation of pH modifiers and surfactants, the combination of non-ionic and ionic polymers, the implementation of supersaturating techniques with nucleation inhibitors, and the utilisation of osmotic drug delivery systems. We assess the efficacy of these methods in reducing the influence of pH fluctuations on the solubility and release rates of drugs. In addition, we explore the potential of these innovative techniques to enhance the reliability and predictability of drug delivery, ultimately leading to better therapeutic results. This review provides an in-depth information of various pH independent controlled drug delivery based formulation and By summarizing the existing technologies and looking into the future, the importance of innovation in pH independent delivery systems is emphasised, laying a good foundation for the future design of simple drug delivery systems, which will be conducive to achieving a wider range of applications in oral drug delivery system.