Charles D. Conover

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The current review presents an update of drug delivery using poly(ethylene glycol) (PEG), that focuses on recent developments in both protein and organic drugs. Certainly the past 10 years has resulted in a renaissance of the field of PEG drug conjugates, initiated by the use of higher molecular weight PEGs (M(w)>20,000), especially 40,000 which is(More)
Water soluble 2'-taxol poly(ethylene glycol) (PEG) esters have been synthesized and shown to function in vitro as prodrugs. However, in vivo experiments clearly establish that in order for these prodrugs to behave in a predictable fashion, the molecular weight of PEG must be of such magnitude so as to maintain a t1/2(circulation) > t1/2(hydrolysis). When(More)
An improved synthesis of the hindered PEG-camptothecin diester transport form has been achieved using the Mukaiyama reagent. We have also assessed the effect of changing the electronic configuration of the (d-position of PEG-camptothecin transport forms on the rates of hydrolysis of the pro-moiety, and attempted to correlate these differences to efficacy in(More)
Purpose: This study was designed to assess the circulatory retention, antitumor activity and tissue biodistribution of polyethylene glycol (PEG)-conjugated camptothecin-20-O-glycinate, PEG-β-camptothecin (PEG-β-CPT). PEG-β-CPT is a novel water-soluble transport form (macromolecular prodrug) of the naturally derived antitumor drug, 20-(S )-camptothecin(More)
The primary purpose of this study was to screen individual amino acid spacers in polyethylene glycol (PEG) conjugated camptothecin for their impact on the conjugates' antitumor activity. Secondly, an active member of this series was used to assess the PEG-camptothecin conjugate's efficacy against a battery of solid tumor types. PEG-camptothecin is a novel(More)
BACKGROUND This study was designed to assess the efficacy of polyethylene glycol(PEG) conjugated camptothecin, PEG-alpha-camptothecin, a novel water soluble transport form (prodrug) of the naturally derived antitumor drug, 20-(S)-camptothecin. MATERIAL AND METHODS Circulatory retention studies were performed in non-tumor bearing mice injected(More)
Beta-endorphin (beta-END) is an inhibitory factor in the neuroendocrine control of luteinizing hormone (LH) release and thus, presumably also of hypophysiotropic luteinizing hormone-releasing hormone (LHRH) release. In order to address if the median eminence (ME) is a site of beta-END action, we studied its functional role in ewes by assessing: (a) the(More)
This paper reports on the synthesis and in vivo oncolytic activity of a series of water-soluble acyl derivatives of polyethylene glycol (PEG) conjugated podophyllotoxin. Some analogs of the polymer conjugate showed significantly better activity in a murine leukemia model than native podophyllotoxin suspended in an intralipid emulsion. Additionally, when(More)
This study was designed to assess the morphological effects of a bolus infusion of PEG-hemoglobin on the heart, lung, liver, spleen and kidney of laboratory rats. Of particular interest was the determination of PEG-hemoglobin's potential to form vacuoles in the tissues and whether these were transitory and article specific. One hundred ten female(More)