ZETA POTENTIAL: A KEY FACTOR IN DRUG DELIVERY

This review article deals with measurement and applications of zeta potential, zeta potential in pharmaceutical formulation, Role of zeta potential in stability, material design and preparation. Zeta potential (ζ) is a measure of the magnitude of the repulsion or attraction between particles. Its measurement brings detailed insight into the dispersion mechanism and is the key to electrostatic dispersion control. Stability of colloidal dispersions directly depends upon the zeta potential of system. When a particle is immersed in a fluid, a range of processes causes the interface to become electrically charged. Some of the most commonly found charging mechanisms include adsorption of charged surfactants to the particle surface (for example in an emulsion stabilized by an ionic surfactant), loss of ions from the solid crystal lattice (silver halide particles used in photographic emulsions) and ionization of surface groups (carboxylate in polymer microspheres) . The zeta potential indicates the degree of repulsion between adjacent, similarly charged particles in dispersion. For molecules and particles that are small enough zeta potential will exhibit stability, i.e., the solution or dispersion will resist aggregation. The zeta potential is measured by some methods they are electrophoresis, electro osmosis, sediment potential and streaming potential. When the zeta potential is low, the dispersion will break and flocculate. In pharmaceutical field measurement of zeta potential is used to understand dispersion and aggregation processes and also used to determine the presence or absence of charged groups on the surface of materials. In this review, the significance of zeta potential including its method of measurement and zeta potential in pharmaceutical formulation and their stability were discussed.