Translational Barriers to Pharmaceutical Excipient Readiness in Marine-Derived Polymers

Marine polymers have attracted a lot of attention as potential alternatives to the traditional animal-derived polymers in pharmaceutical formulation since they are abundant, biocompatible, and versatile in functionality. However, the presence of these materials in dosage-form studies, often in support of proof-of-concept trials, does not mean they are ready to apply as excipients routinely. This review critically evaluates the reasons why three of the most highly researched marine-derived polymers, chitosan, alginate, and carrageenan, continue to encounter significant translational barriers in pharmaceutical excipient development. All three polymers have been demonstrated to have clear pharmaceutical utility; however, their behavior is highly dependent on source, structure, processing history and formulation context. Chitosan explains why functional benefits may be compromised by responses to material requirements; alginate explains why apparent proximity to use may not remove composition-related variability; and carrageenan explains that even seemingly simple rheological functions may be very context-dependent. All of this points to the fact that the major hurdle lies not in the lack of potential, but in the difficulty of achieving the required degree of control, reproducibility, and manufacturability in order to make the reliable use of excipients possible. Future progress in this field will likely require a shift from descriptive exploration toward readiness-focused evidence, including demonstrated control over material attributes, reproducible performance, and feasible qualification pathways.