The synthesis of a new PEG 3 -solubilized gadolinium texaphyrin (Gd-Tex) conjugate containing a malonate-Pt(NH 3 ) 2 moiety is described. The effect of the tumor localizing Gd-Tex macrocycle on platinum activity was evaluated in cell culture. The malonate moiety, analogous to that present in carboplatin, is expected to release Pt(NH 3 ) 2 under physiological conditions. The half-life in phosphate-buffered saline was found to be ca. 3 days at room temperature, and the hydrolytic product released from the conjugate was collected and confirmed as Pt-based by flameless atomic absorption spectrophotometry. Anti-proliferative activity was tested using A549 human lung cancer and A2780 human ovarian cancer cell lines. In both cell lines, the activity of the Gd-Tex conjugate was found to be similar to that of carboplatin. Efficacy against a Pt-resistant ovarian cell line greater than that displayed by carboplatin was also observed.

227ChemInform Abstract Reactions of Mo carbonyl compounds (I) or (IV) with the homoatomic ring compounds (II) or (V) in sealed tubes in toluene, produce clusters containing catenated RAs units. Neither the products nor yields are significantly dependent on which metal precursor compound is used, but are strongly dependent on the R at As. With (II), in the absence of O2, the only isolable product is (III), which crystallizes in the space group Pnnm with Z=2. In reactions with (V) the products obtained depend on the reaction conditions. (VI) (space group P21/c, Z=4) is obtained at 70 rc C and can be converted to (III) (toluene, 120 rc C, 24 h, 72% yield), which is directly obtained at 120 rc C. The catena-complex (VII) crystallizes in the space group P21/n with Z=4.

Microalgae are being developed as a source of fuels and/or chemicals. A processing challenge is dewatering the algae. Electrical approaches to dewatering include exploiting electrophoresis or electroflocculation. The reported experiments show that electrophoresis does occur but is complicated by the effects of the fluid motion. It appears that the coupling of the algal cell and the fluid can be sufficiently strong such that fluid motion effects can influence or dominate behavior. Electroflocculation appears to be a robust process. It does, however, inherently leave electrically induced trace metal flocculants in the dewatered algae.

Conjugates between methotrexate (MTX, Matrex, N-[4-[[(2,4-diamino-6-pteridinyl)methyl]methylamino]benzoyl]-l-glutamic acid), an antifolate cancer chemotherapeutic to which resistance is often observed, and motexafin gadolinium (MGd), an experimental agent demonstrating selective tumor localization, are described. These systems were prepared in order to test whether linking these two species would produce agents with enhanced activity relative to MTX alone. Both ester- and amide-linked conjugates were synthesized starting from MGd and MTX. The ester conjugate showed greater in vitro anti-proliferative activity against the A549 lung carcinoma cell line at short incubation times than did MTX alone. Neither the amide conjugate, nor MGd, showed any observable activity under these in vitro conditions. These results are rationalized in terms of enhanced cellular uptake of both the ester and amide conjugates that is coupled with an effective rate of release (e.g., inherent or enzyme-mediated hydrolysis) in the case of the ester-linked conjugate, but not the corresponding amide system.

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