Zaffaroni system

Nonaqueous partition systems are for compounds which are slightly water-soluble but too polar for reversed-phase systems. The Bush and Zaffaroni systems for separation of steroids are included here. Polar stationary phases such as methanol-water [28], DMF, formamide or propylene glycol [29,30] combined with a suitable less polar mobile phase such as benzene, cyclohexane or CHCI3 are examples. 

Zaffaroni, A., Therapeutic systems the key to rational drug therapy, Drug Metab. Rev., 8,191, 1978. 

B.B. Pharriss, R. Erickson, J. Bashaw, S. Hoff, V.A. Place and A. Zaffaroni, Proges-tasert A Uterine Therapeutic System for Long-term Contraception, Fert. Steril. 25, 915 (1974). 

A. Zaffaroni, Selective Administration of Drug with Ocular Therapeutic System, U.S. Pat. 4,186,184 (Jan 29, 1980) to Alza Corp. through Chem. Abstr. 92 185937b (1980). 

Cellulose and kieselguhr are the carriers which first come into consideration for partition TLC impregnation with the stationary phase is carried out by spraying, or, better, immersion [15, 30, 129, 173, 186], using the Zaffaroni or Bush-type system, known in PC [129]. Smaller spots are obtained with cellulose powder than with kieselguhr or filter paper, due to its very fine structure. Silica gel is, however, also excellently suited as a support for partition chromatography with various PC solvent systems [24, 65, 118, 131]. The carriers mentioned can be used equally well for reversed phase TLC, e. g., after impregnating with paraffin [96, 125] or undecane [40—42, 183]. Information about the properties and capacity of such systems may be found in the PC review of Nehee [129]. Standard size plates are satisfactory for routine work in special cases, microplates [84,137] or sheets [103,223] can be serviceable. 

An early system presented by ZafFaroni et cd. (58) has proved adequate for the routine checks necessary in column separations. New techniques and improved equipment frequently appear in the literature but serve primarily only to streamline the basic design and process. 

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