Physical stability of sulfaguanidine suspensions

Preliminary evaluation of shilajit as a suspending agent in antacid suspensions

The efficacy of shilajit, a gummy exudate of the plant Styrax officinalis Linn (Family: Styraceae), was evaluated as a suspending agent for the formulation of antacid preparations. Shilajit produced effects on sedimentation volume similar to those produced by sodium carboxymethyl cellulose (CMC), but at lower concentrations. It induced better flocculation with a moderate increase in viscosity compared to CMC. It did not interfere with the acid-consuming capacity of the suspensions.

Bile acid binding and hypocholesterolemic activity of a new anion exchange resin from 2-methylimidazol and epichlorohydrin

A new anion exchange resin with an imidazolium salt on a epoxide polymer skeleton was synthesized. This white powder material was odorless and tasteless. The in vitro sodium cholate binding of this resin was much more potent than that of cholestyramine. The hypocholesterolemic activity of this resin in cholesterol-fed rabbits proved to be 4.3 times more potent than that of cholestyramine. These results suggest that effective reduction of plasma cholesterol may be achieved with lower doses of this resin.

Nonaqueous cephalosporin suspension for parenteral administration: cefazolin sodium

The flocculation-deflocculation behavior of cefazolin sodium (I) in nonaqueous media and the effect of surfactants as measured by zeta potential, sedimentation, and porosity were studied. A significant difference in zeta potential was observed when the particles were suspended in different nonaqueous media. The addition of surfactant produced a deflocculated state. The surfactant deflocculated the particles by a process of supersaturation and crystallization involving a surfactant-cefazolin complex. The shielding effect of the surfactant on the surface of the particles also apparently affected their electrophoretic properties. Kinetic studies on the stability of the drug as a function of temperature were conducted; it appears that the chemical stability in ethyl oleate at room temperature is adequate for a reasonable shelf life. The efficiency of absorption of the drug from the ethyl oleate suspension was evaluated after intramuscular administration in dogs. The area under the plasma concentration versus time curve and urinary recovery indicated that cefazolin was 100% bioavailable from this nonaqueous preparation.

Pharmaceutical suspensions: relation between zeta potential, sedimentation volume and suspension stability

The effect of added surface-active agents of various ionic types on the sedimentation volume of drug suspensions of betamethasone, griseofulvin, nalidixic acid and thiabendazole has been investigated, and the results correlated with previously measured zeta potentials. Study of the zeta potential/sedimentation volumes versus concentration plots showed that apparently only coagulated, deflocculated or sterically stabilized systems were formed. In most cases the sterically stabilized systems were produced from mixtures of ionic/non-ionic surfactants. These are examples of controlled coagulation, although non-ionic surfactant alone conferred stability against caking. Secondary minimum flocculation was not apparent but this may have been due to the method of examination of suspensions. The work confirmed that the DLVO theory of colloid stability and its modification to include a steric term can be applied to coarse suspension systems.