Synthetic and photochemical studies of substituted 1-acyl-7-nitroindolines.

A previous study of substituent effects on the photo-cleavage of 1-acyl-7-nitroindolines has been extended to examine the effects of electron-donating and electron-withdrawing substituents. 1-Acetyl-4,5-methylenedioxy-7-nitroindoline was inert to 350 nm irradiation, reinforcing an earlier finding that excessive electron-donation by substituents can divert the excited state into non-productive pathways. By contrast, the 1-acetyl-5,7-dinitro- and 1-acetyl-4-methoxy-5,7-dinitroindolines and respectively both showed improved photolysis efficiency in aqueous solution compared to the 1-acyl-4-methoxy-7-nitro compound . Unlike , both and gave mixed photoproducts, the corresponding dinitroindolines and the 5-nitro-7-nitrosoindoles. These results are interpreted in terms of a previous mechanistic study. Investigation of the 4-methoxy-5,7-dinitroindoline conjugate of L-glutamate showed that the stoichiometry of glutamate release upon photolysis was only 65-77% of the theoretical value, suggesting that photolysis of these dinitro compounds may involve pathways other than the clean photolysis previously observed for mono-nitro compounds such as .     

Novel Biodegradable Polyester Poly(Propylene Succinate): Synthesis and Application in the Preparation of Solid Dispersions and Nanoparticles of a Water-Soluble Drug

Poly(propylene succinate) (PPSu) polymers of average molecular weights from 2,800 to 13,100 g/mol were synthesized and characterized with regard to crystallinity, thermal properties, and cytocompatibility. Higher molecular weight samples exhibited lower degree of crystallinity and melted at lower temperatures. Melting of the polymer appeared to begin at 38°C. PPSu cytocompatibility was investigated based on human umbilical vein endothelial cells viability in the presence of increasing concentrations of polymer, and it was found that PPSu exhibited comparable cytocompatibility with poly(dl-lactide). The feasibility of applying PPSu as a drug carrier was shown for the first time, as solid dispersions and nanoparticles of sodium fluvastatin based in PPSu were prepared. Drug release rates decreased with increasing the molecular weight of PPSu in both solid dispersions and nanoparticles. For dispersions prepared from PPSu of the same molecular weight, drug release rates increased with drug loading. It appears that PPSu applicability as a drug carrier warrants further consideration.     

Multiobjective long-term planning of biopharmaceutical manufacturing facilities

Biopharmaceutical companies with large portfolios of clinical and commercial products typically need to allocate production across several multiproduct facilities, including third party contract manufacturers. This poses several capacity planning challenges which are further complicated by the need to satisfy different stakeholders often with conflicting objectives. This work addresses the question of how a biopharmaceutical manufacturer can make better long-term capacity planning decisions given multiple strategic criteria such as cost, risk, customer service level, and capacity utilization targets. A long-term planning model that allows for multiple facilities and accounts for multiple objectives via goal programming is developed. An industrial case study based on a large scale biopharmaceutical manufacturer is used to illustrate the functionality of the model. A single objective model is used to identify how best to use existing capacity so as to maximize profits for different demand scenarios. Mitigating risk due to unforeseen circumstances by including a dual facility constraint is shown to be a reasonable strategy at base case demand levels but unacceptable if demands are 150% higher than expected. The capacity analysis identifies where existing capacity fails to meet demands given the constraints. A multiobjective model is used to demonstrate how key performance measures change given different decision making policies where different weights are assigned to cost, customer service level, and utilization targets. The analysis demonstrates that a high profit can still be achieved while meeting key targets more closely. The sensitivity of the optimal solution to different limits on the targets is illustrated.     

Inhibition of rabbit muscle glycogen phosphorylase by D-gluconohydroximo-1,5-lactone-N-phenylurethane

The effect of the beta-glycosidase inhibitor D-gluconohydroximo-1,5-lactone-N-phenylurethane (PUG) on the kinetic and ultracentrifugation properties of glycogen phosphorylase has been studied. Recent crystallographic work at 2.4 A resolution [D. Barford et al. (1988) Biochemistry 27, 6733-6741] has shown that PUG binds in the catalytic site of phosphorylase b crystals with its gluconohydroximolactone moiety occupying a position similar to that observed for other glucosyl compounds and the N-phenylurethane side chain fitting into an adjacent cavity with little conformational change in the enzyme. In solution, PUG was shown to be a potent inhibitor of phosphorylase b, directly competitive with alpha-D-glucopyranose 1-phosphate (glucose-1-P) (Ki = 0.40 mM) and noncompetitive with respect to glycogen and AMP. When PUG was tested for synergistic inhibition in the presence of caffeine, the Dixon plots of reciprocal velocity versus PUG concentration at different fixed caffeine concentrations provided intersecting lines with interaction constant (alpha) values of 0.95-1.38, indicating that the binding of one inhibitor is not significantly affected by the binding of the other. For glycogen phosphorolysis, PUG was noncompetitive with respect to phosphate, suggesting that it can bind to the central enzyme-AMP-glycogen-phosphate complex. PUG was shown to inhibit phosphorylase alpha (without AMP) activity (Ki = 0.43 mM) in a manner similar to that of the b form. However, in the presence of AMP, PUG exhibited complex kinetics, acting as a noncompetitive inhibitor with respect to glucose-1-P, while a twofold decrease of PUG binding to the enzyme-AMP-glycogen complex was observed. Ultracentrifugation experiments demonstrated that PUG does not cause any significant dissociation of phosphorylase alpha tetramer. Furthermore the dimerization of phosphorylase alpha by glucose is completely prevented in the presence of PUG. These observations are consistent with PUG binding to both the R and the T conformations of phosphorylase.     

New Method for Evaluation of Virucidal Activity of Antiseptics and Disinfectants

Counting culturable viruses adsorbed to cellulose nitrate filters (the VIRADEN method) is proposed as a simple procedure for the evaluation of the virucidal activity of antiseptics and disinfectants. The virucidal activities of two different doses of iodine, chlorine, glutaraldehyde, and chlorhexidine digluconate on poliovirus 1 were tested with a standardized procedure and with the VIRADEN method. The two procedures assayed provided similar results.     

Role of ERK1/2 activation in microtubule stabilization and glucose transport in cardiomyocytes

We previously demonstrated that microtubule disruption impairs stimulation of glucose uptake in cardiomyocytes and that 9-cis retinoic acid (9cRA) treatment preserved both microtubule integrity and stimulated glucose transport. Herein we investigated whether 1) activation of the extracellular signal-regulated kinases (ERK1/2) is responsible for microtubule destabilization and 2) ERK1/2 inactivation may explain the positive effects of 9cRA on glucose uptake and microtubule stabilization. Adult rat cardiomyocytes in primary culture showed increased basal ERK1/2 phosphorylation. Cardiomyocytes exposed to inhibitors of the ERK1/2 kinase mitogen/extracellular signal-regulated kinase (MEK) 1/2 had preserved microtubular scaffold, including microtubule-organizing centers (MTOC), together with increased insulin and metabolic stress-stimulated glucose transport as well as signaling, thus replicating the effects of 9cRA treatment. Although 9cRA treatment did not significantly reduce global ERK1/2 activation, it markedly reduced perinuclear-activated ERK1/2 at the location of MTOC. 9cRA also triggered relocation of the ERK1/2 phosphatase mitogen-activated protein kinase phosphatase-3 from the cytosol to the nucleus. These results indicate that, in cardiomyocytes, microtubule destabilization, leading to impaired stimulation of glucose transport, is mediated by ERK1/2 activation, impacting on the MTOC. 9cRA acid restores stimulated glucose transport indirectly through compartmentalized inactivation of ERK1/2.