DEVELOPMENT OF A MULTILAYER NATURAL BIOPOLYMER FILM WITH ENHANCED MOISTURE AND OXYGEN BARRIER PROPERTIES FOR PHARMACEUTICAL PACKAGING: A CRITICAL REVIEW.

Pharmaceutical packaging must preserve the quality, safety and performance of medicinal products throughout manufacturing, transport and storage. Moisture and oxygen resistance can be especially important for dosage forms containing moisture-sensitive or oxidation-sensitive ingredients. Conventional polymeric and multilayer packaging systems provide useful mechanical and barrier functions, but their environmental pollution/damage and end-of-life management have encouraged research into renewable and biodegradable materials. This critical narrative review examines natural biopolymers and multilayer design strategies relevant to pharmaceutical packaging, with emphasis on starch, chitosan, cellulose-based reinforcement, glycerol plasticization and hydrophobic lipid coatings such as beeswax. Literature on chitosan–starch blends, cellulose/chitosan nanocomposites, chitosan–beeswax films and starch–beeswax structures suggests that composition and architecture can influence mechanical properties, water uptake and gas transmission. However, findings from food-packaging films cannot automatically be translated to pharmaceutical primary packaging because drug compatibility, extractables and leachables, microbial quality, stability, seal integrity and regulatory qualification require separate evaluation. A key distinction is made between water absorption, water-vapour transmission rate (WVTR), water-vapour permeability (WVP) and oxygen transmission rate (OTR); these parameters are related but not interchangeable. The review proposes a staged research framework for a chitosan–starch–MCC film with a beeswax-based coating, including formulation screening, structural and mechanical characterization, direct barrier testing, model-product protection studies and environmental assessment. Current evidence supports further investigation but does not establish that this specific formulation provides enhanced oxygen barrier or is suitable for commercial pharmaceutical use. Reproducible testing, product-specific qualification and life-cycle evidence are required before any substitution claim can be justified.