Hemp Therapies Wiki / Liposomal Delivery Systems

Liposomal Quality Testing and Measurement

A finished liposomal product can be characterized through several distinct laboratory measurements, each describing a different physical attribute of the particle.

Measurement Techniques

Particle size in finished liposomal products is commonly measured using dynamic light scattering (DLS). Additional imaging techniques used to examine liposome structure and layer count include transmission electron microscopy (TEM), cryo-TEM, and atomic force microscopy (AFM). “Zeta potential” refers to a measurement of the surface electrical charge of a liposome particle, typically obtained through electrophoretic mobility or DLS-based instruments. Encapsulation efficiency — the percentage of an ingredient that ends up inside the liposome rather than free in solution — can be measured using centrifugation, dialysis separation, or HPLC/spectrophotometric analysis. Lamellarity, the number of bilayers within a given liposome, can be assessed using cryo-TEM imaging or phosphorus-31 nuclear magnetic resonance (31P-NMR). The phase behavior of a lipid membrane can be studied using techniques such as X-ray diffraction or differential scanning calorimetry.

Industry Testing Practices

Some supplement manufacturers report internal batch testing for particle-size uniformity, citing thresholds such as maintaining particle sizes at or below 500 nanometers. Manufacturers in the supplement industry commonly reference third-party laboratory testing, along with cGMP- certified and FDA-registered manufacturing facilities, as part of their quality-control process. In pharmaceutical development literature, a polydispersity index (PDI) below 0.10 is used as one marker of a uniform, narrow particle-size distribution within a liposome batch.

Summary

A liposomal formulation’s quality is characterized across several independent measurements — particle size, zeta potential, encapsulation efficiency, and lamellarity — each requiring its own laboratory technique, and supplement-industry testing practices vary in how many of these measurements are actually reported.