Pharmacokinetic characteristics, pharmacodynamic effect and in vivo antiviral efficacy of liver-targeted interferon alpha

Visualizing and quantifying antimicrobial drug distribution in tissue

The biodistribution and pharmacokinetics of drugs are vital to the mechanistic understanding of their efficacy. Measuring antimicrobial drug efficacy has been challenging as plasma drug concentration is used as a surrogate for tissue drug concentration, yet typically does not reflect that at the intended site(s) of action. Utilizing an image-guided approach, it is feasible to accurately quantify the biodistribution and pharmacokinetics within the desired site(s) of action. We outline imaging modalities used in visualizing drug distribution with examples ranging from in vitro cellular drug uptake to clinical treatment of microbial infections. The imaging modalities of interest are: radio-labeling, magnetic resonance, mass spectrometry imaging, computed tomography, fluorescence, and Raman spectroscopy. We outline the progress, limitations, and future outlook for each methodology. Further advances in these optical approaches would benefit patients and researchers alike, as non-invasive imaging could yield more profound insights with a lower clinical burden than invasive measurement approaches used today.

Functionally engineered 'hepato-liposomes': Combating liver-stage malaria in a single prophylactic dose

Primaquine continues to remain the gold standard molecule with an incumbent toxicity profile, as far as radical treatment of malaria is concerned. Better molecules are available at experimental level but their targeted delivery is a challenge. The present work identifies 'Decoquinate (DQN)' as a repurposed, safer drug molecule with a potential to function as an appealing replacement for primaquine active against liver-stage malaria. The work focuses on delivering the highly lipophilic DQN (log P ~ 5) in a liposomal carrier system to 'sporozoite infested hepatocytes' using two different in-house synthesized hepatotropic ligands. Functionally engineered 'hepato-liposomes' exhibit differences in their DQN loading capacities but no significant change in morphology or particle size and are also not affected by freeze drying. Two ligands, targeting different receptors on hepatocytes, have been compared for their in vitro and in vivo drug delivery efficiency in liver stage malaria. The studies reveal superior antimalarial efficacy of differently designed DQN loaded liposomes and demonstrate antimalarial efficacy at a low dose of 0.5 mg/kg for a repurposed molecule like DQN. The in vivo studies successfully discriminate the functional efficiency of the carriers and establish the importance of design in liposomal drug delivery for malarial prophylaxis.

Elimination half-lives of interleukin-6 and cytokine-induced neutrophil chemoattractant-1 synthesized in response to inflammatory stimulation in rats

The elimination half-lives of in Interleukin-6 (IL-6) and cytokine-induced neutrophil chemoattractant-1 (CINC-1) in rats after inflammatory stimulation were investigated. Five male Sprague-Dawley rats were used (age, 9 weeks; body weight, 235-375 g). Turpentine oil was intramuscularly injected at a dose of 2 mL/kg body weight to induce acute inflammation. Blood was collected pre-injection and 6, 12, 24, 36, 48, 60, 72, 84, and 96 h after the turpentine oil injection. Serum concentrations of IL-6, CINC-1, and α2-macroglobulin (α2M) were measured by enzyme-linked immunosorbent assay. Half-lives were calculated as 0.693/elimination rate constant. The serum concentration of α2M peaked at 48 h after turpentine oil injection. Serum concentrations of IL-6 and CINC-1 increased and peaked at 12 and 24 h, respectively. The terminal elimination half-lives of IL-6 and CINC-1 were 15.5 and 29.9 h, respectively. The half-life of CINC-1 was significantly longer than that of IL-6 (P=0.006). These results suggested that these cytokines synthesized in response to inflammatory stimulation were rapidly eliminated in rats. The serum concentrations of these cytokines should be measured at an early stage if these cytokines will be used as surrogate inflammatory markers instead of acute-phase proteins.

Conjugated polyelectrolytes with galactose-containing side chains for targeted hepatoma cell imaging

Three cationic conjugated polyelectrolytes (CPEs) with a common poly(p-phenylene ethynylene) backbone and different galactose-containing side chains were designed and synthesized.