Pharmaceutical suspensions: micro electrophoretic properties.

The microelectrophoretic properties of the drugs griseofulvin, betamethasone, nalidixic acid and thiabendazole in aqueous dispersion have been examined and the zeta potentials calculated from the measured mobilities. Variation in magnitude of particle charge with pH of dispersion is reported and related to the chemical structure and the surface characteristics. The effect of adding anionic (sodium dodecyl sulphate) cationic (dodecyl trimethyl bromide) and non-ionic (polyoxyethylene glycol monoethers of hexadecanol) surface-active agents, and mixtures of these ionic and non-ionic species, on the electrophoretic properties of the drug dispersions has been measured. The results reported agree with those found previously for a model polystyrene latex suspension system under the same conditions.