Quality Control and Quality Assurance of Topical Gel Formulations: Critical Quality Attributes, Evaluation Parameters and Regulatory Considerations

Topical gels are semisolid dosage forms used to deliver active pharmaceutical ingredients to the skin or other accessible tissues. Their quality depends on the active ingredient, gelling polymer, solvent system, pH, manufacturing process, packaging and storage conditions. Quality control (QC) evaluates materials and products against defined requirements, while quality assurance (QA) provides the wider system of procedures, documentation and review that supports consistent manufacture. This narrative review summarises QA and QC considerations for topical gels, including critical quality attributes, raw-material control, manufacturing variables, finished-product evaluation, microbiological quality, stability and regulatory guidance. Common evaluations include appearance and homogeneity, pH, rheological behaviour, assay, microbial quality and, when appropriate, in-vitro release testing. No single test can establish overall quality; methods and acceptance criteria must be justified for the particular formulation and intended use. Quality-by-design principles and risk-based thinking help connect material and process variables with measurable product attributes. ICH guidance provides general frameworks for pharmaceutical development, quality risk management, analytical procedure validation and pharmaceutical quality systems. Regulatory expectations differ by product, application pathway and jurisdiction; therefore, this review offers a practical framework rather than a universal specification for all topical gels.