As a bile-acid substance, ursodeoxycholic acid can be utilized as a pharmaceutical excipient to improve the dissolution performance of poorly-soluble drugs. This paper describes the action mechanisms and effects of ursodeoxycholic acid in increasing the solubility of poorly-soluble drugs, and summarizes its application value in pharmaceutical formulation development, so as to provide references for the development of poorly-soluble drug preparations.
1 Introduction
Drug solubility is a critical factor determining in-vivo bioavailability and clinical therapeutic efficacy. Numerous drug candidates and active pharmaceutical ingredients are inherently characterized by low aqueous solubility due to their physicochemical properties. This drawback directly restricts drug dissolution and absorption in the gastrointestinal tract, leads to insufficient in-vivo exposure, and hinders formulation development and clinical outcomes.
As a typical bile-acid compound, ursodeoxycholic acid possesses intrinsic pharmacological activity as well as solubilizing properties. It can modify the dissolution behavior of poorly-soluble drugs through multiple pathways. Its solubilizing mechanisms and applications in formulation development are analyzed in the following sections.
2 Mechanisms of Ursodeoxycholic Acid for Improving Solubility of Poorly-Soluble Drugs
2.1 Solubilization via formation of bile salt complexes
Ursodeoxycholic acid can interact with poorly-soluble drugs to form bile-salt complexes. Such complexes remarkably raise the dissolution capacity of active pharmaceutical ingredients in aqueous media, optimize drug dissolution profiles, and thereby facilitate drug absorption within the gastrointestinal tract. This mode of action is especially applicable to drugs suffering from solubility bottlenecks for the purpose of bioavailability improvement.
2.2 Modulation of bile secretion and cholesterol metabolism to alter drug solubility in bile phase
Ursodeoxycholic acid modulates physiological processes including cholesterol metabolism and bile secretion, and participates in hepatic bile acid synthesis, bile formation and excretion. By regulating these physiological pathways, it changes the solubility of poorly-soluble drugs in the bile environment, enhances their chemical stability in bile systems, and indirectly elevates the overall drug bioavailability.
3 Application Value of Ursodeoxycholic Acid in Formulation Development
For formulation design of poorly-soluble drugs, ursodeoxycholic acid can be incorporated into formulation recipes as a solubilizing excipient. Relying on its solubilizing capacity, it ameliorates the dissolution properties of active pharmaceutical ingredients, addresses the common problem of low bioavailability for poorly-soluble drugs, improves the in-vivo pharmacodynamic performance of preparations, and supports better clinical application of drugs.
4 Conclusion
Ursodeoxycholic acid represents a promising solubilizing pharmaceutical excipient and is of great significance in the research and development of poorly-soluble drug preparations. It improves drug solubility and boosts bioavailability mainly through two core mechanisms: formation of bile-salt complexes and regulation of bile secretion. It offers new technical insights for formulation development and clinical application of poorly-soluble drugs.
