Hydrogels in Pharmaceutical Formulation: Properties, formulation strategies, and drug delivery applications.

OBJECTIVES

This review aims to provide a systematic overview of hydrogel systems as pharmaceutical excipients for drug delivery. It focuses on their classification, formulation strategies, physicochemical properties, and applicability across different routes of administration.

SIGNIFICANCE: Hydrogels have progressed into multifunctional excipients capable of modulating drug release, enhancing residence time, and improving patient compliance. This review consolidates formulation-oriented knowledge while addressing translational, manufacturing, and regulatory considerations.

KEY FINDINGS: Hydrogels are classified based on source, polymer type, network charge, physical form, and cross-linking methods. Key excipient properties-including swelling, porosity, mechanical strength, biodegradability, and environmental responsiveness-govern performance. Diverse fabrication techniques support tailored design for oral, topical, transdermal, ocular, rectal, and injectable delivery. Challenges such as scalability and reproducibility persist, while stimuli-responsive and composite hydrogels offer promising solutions.

CONCLUSION

This review highlights a formulation-driven framework for the rational design and clinical translation of hydrogel-based pharmaceutical excipients in advanced drug delivery systems.