Infections with soil-transmitted helminths (Ascaris lumbricoides, hookworm, and Trichuris trichiura) are widespread and often occur concomitantly. These parasitic-worm infections are typically treated with albendazole or mebendazole, but both drugs show low efficacy against T. trichiura. Albendazole is the drug of choice against hookworm.In this double-blind trial conducted on Pemba Island, Tanzania, we randomly assigned children, 6 to 14 years of age, to receive one of four treatments: oxantel pamoate at a dose of 20 mg per kilogram of body weight, plus 400 mg of albendazole, administered on consecutive days; oxantel pamoate at a single dose of 20 mg per kilogram; albendazole at a single dose of 400 mg; or mebendazole at a single dose of 500 mg. We assessed the efficacy and safety profile of oxantel pamoate-albendazole when used in the treatment of T. trichiura infection (primary outcome) and concomitant soil-transmitted helminth infection (secondary outcome). Efficacy was determined by means of assessment of the cure rate and egg-reduction rate. Adverse events were assessed four times after treatment.Complete data were available for 458 children, of whom 450 were infected with T. trichiura, 443 with hookworm, and 293 with A. lumbricoides. The cure rate of T. trichiura infection was significantly higher with oxantel pamoate-albendazole than with mebendazole (31.2% vs. 11.8%, P=0.001), as was the egg-reduction rate (96.0% [95% confidence interval {CI}, 93.5 to 97.6] vs. 75.0% [95% CI, 64.2 to 82.0]). The cure rate with albendazole (2.6%) and the egg-reduction rate with albendazole (45.0%; 95% CI, 32.0 to 56.4) were significantly lower than the rates with mebendazole (P=0.02 for the comparison of cure rates). Oxantel pamoate had low efficacy against hookworm and A. lumbricoides. Adverse events (mainly mild) were reported by 30.9% of all children.Treatment with oxantel pamoate-albendazole resulted in higher cure and egg-reduction rates for T. trichiura infection than the rates with standard therapy. (Funded by the Medicor Foundation and the Swiss National Science Foundation; Current Controlled Trials number, ISRCTN54577342.).
Dissolution and disintegration of solid dosage forms such as multiple-layer tablet with different active ingredients depend on formulation and properties used in the formulations, and it may sometimes result in counterintuitive release kinetics. In this manuscript, we investigate the behavior of combined acetylsalicylic acid and mefenamic acid bi- and triple-layer formulations. We show that the simulation model with a cellular automata predicted the impact of the inert layer between the different active ingredients on each drug release and provide a good agreement with the experimental results. Also, it is shown that the analysis based on the Noyes-Whitney equation in combination with a cellular automata-supported dissolution and disintegration numerical solutions explain the nature of the unexpected effects. We conclude that the proposed simulation approach is valuable to predict the influence of material attributes and process parameters on drug release from multicomponent and multiple-layer pharmaceutical tablets and to help us develop the drug product formulation.
Cardiovascular diseases are the leading causes of death in industrialized countries. Atherosclerotic coronary arteries are commonly treated with percutaneous transluminal coronary intervention followed by stent deployment. This treatment has significantly improved the clinical outcome. However, triggered vascular smooth muscle cell (SMC) proliferation leads to in-stent restenosis in bare metal stents. In addition, stent thrombosis is a severe side effect of drug eluting stents due to inhibition of endothelialization. The aim of this study was to develop and test a stent surface polymer, where cytotoxic drugs are covalently conjugated to the surface and released by proteases selectively secreted by proliferating smooth muscle cells. Resting and proliferating human coronary artery smooth muscle cells (HCASMC) and endothelial cells (HCAEC) were screened to identify an enzyme exclusively released by proliferating HCASMC. Expression analyses and enzyme activity assays verified selective and exclusive activity of the matrix metalloproteinase-9 (MMP-9) in proliferating HCASMC. The principle of drug release exclusively triggered by proliferating HCASMC was tested using the biodegradable stent surface polymer poly-l-lactic acid (PLLA) and the MMP-9 cleavable peptide linkers named SRL and AVR. The specific peptide cleavage by MMP-9 was verified by attachment of the model compound fluorescein. Fluorescein release was observed in the presence of MMP-9 secreting HCASMC but not of proliferating HCAEC. Our findings suggest that cytotoxic drug conjugated polymers can be designed to selectively release the attached compound triggered by MMP-9 secreting smooth muscle cells. This novel concept may be beneficial for stent endothelialization thereby reducing the risk of restenosis and thrombosis.
Recently, a lipopeptide derived from the hepatitis B virus (HBV) large surface protein has been developed as an HBV entry inhibitor. This lipopeptide, called MyrcludexB (MyrB), selectively binds to the sodium taurocholate cotransporting polypeptide (NTCP) on the basolateral membrane of hepatocytes. Here, the feasibility of coupling therapeutic enzymes to MyrB was investigated for the development of enzyme delivery strategies. Hepatotropic targeting shall enable enzyme prodrug therapies and detoxification procedures. Here, horseradish peroxidase (HRP) was conjugated to MyrB via maleimide chemistry, and coupling was validated by SDS-PAGE and reversed-phase HPLC. The specificity of the target recognition of HRP-MyrB could be shown in an NTCP-overexpressing liver parenchymal cell line, as demonstrated by competitive inhibition with an excess of free MyrB and displayed a strong linear dependency on the applied HRP-MyrB concentration. In vivo studies in zebrafish embryos revealed a dominating interaction of HRP-MyrB with scavenger endothelial cells vs xenografted NTCP expressing mammalian cells. In mice, radiolabeled 125I-HRP-MyrBy, as well as the non-NTCP targeted control HRP-peptide-construct (125I-HRP-alaMyrBy) demonstrated a strong liver accumulation confirming the nonspecific interaction with scavenger cells. Still, MyrB conjugation to HRP resulted in an increased and NTCP-mediated hepatotropism, as revealed by competitive inhibition. In conclusion, the model enzyme HRP was successfully conjugated to MyrB to achieve NTCP-specific targeting in vitro with the potential for ex vivo diagnostic applications. In vivo, target specificity was reduced by non-NTCP-mediated interactions. Nonetheless, tissue distribution experiments in zebrafish embryos provide mechanistic insight into underlying scavenging processes indicating partial involvement of stabilin receptors.
Background: The efficacy and safety of photodynamic therapy for superficial bladder cancer depend on tumor-selective accumulation of the photosensitizer. Bladder transitional-cell carcinoma cells overexpress the transferrin receptor on their surface. We examined whether transferrin-mediated liposomal targeting of the photosensitizer aluminum phthalocyanine tetrasulfonate (AlPcS 4 ) is an effective strategy to attain tumor-selective accumulation of this compound when applied intravesically. Methods: AlPcS 4 was stably encapsulated in unconjugated liposomes (Lip-AlPcS 4 ) or transferrin-conjugated liposomes (Tf-Lip–AlPcS 4 ). The accumulation of free AlPcS4, Lip-AlPcS 4 , and Tf-Lip–AlPcS 4 in human AY-27 transitional-cell carcinoma cells and in an orthotopic rat bladder tumor model was visualized by fluorescence microscopy. In vitro AlPcS 4 accumulation was quantified by fluorescence measurements following drug extraction, and the photodynamic efficacy of AlPcS 4 was measured in a clonogenic assay. All statistical tests were two-sided. Results: AY-27 cells incubated with Tf-Lip–AlPcS 4 had much higher intracellular AlPcS 4 levels than AY-27 cells incubated with Lip-AlPcS 4 (384.1 versus 3.7 μM; difference = 380.4 μM, 95% CI = 219.4 to 541.3; P = .0095). Among rats bearing AY-27 cell–derived bladder tumors, intravesical instillation with Tf-Lip–AlPcS 4 resulted in mean AlPcS 4 fluorescence in tumoral tissue, normal urothelium, and submucosa/muscle of 77.9 fluorescence units (fu) (95% CI = 69.1 to 86.8 fu), 4.3 fu (95% CI = 4.0 to 4.5 fu), and 1.0 (95% CI = 0.1 to 1.9 fu), respectively, whereas instillation of free AlPcS 4 resulted in nonselective accumulation throughout the whole bladder wall, and Lip-AlPcS 4 instillation resulted in no tissue accumulation. Photodynamic therapy of AY-27 cells incubated with Lip-AlPcS 4 resulted in cell viabilities greater than 90% for all concentrations and incubation times tested; photodynamic therapy of cells incubated with 1 μM Tf-Lip–AlPcS 4 or AlPcS 4 resulted in cell viabilities of 0.19% (95% CI = 0.02% to 0.36%) and 1.32% (95% CI = 0.46% to 2.19%), respectively. Higher concentrations of either AlPcS 4 or Tf-Lip–AlPcS 4 resulted in cell kills of more than 3 logs. Conclusions: Transferrin-mediated liposomal targeting of photosensitizing drugs is a promising potential tool for photodynamic therapy of superficial bladder tumors.
A monospecific antibody (anti‐CF 3 CO antibody) was obtained by affinity chromatography on a N ɛ ‐trifluoroacetyl‐ l ‐lysine (CF 3 CO‐Lys) matrix of a rabbit polyclonal antiserum, directed against trifluoroacetylated protein adducts (CF 3 CO‐proteins). The anti‐CF 3 CO antibody recognized distinct CF 3 CO‐proteins on immunoblots of a liver biopsy obtained from a human individual 10 h after halothane anaesthesia. Cross‐reactive proteins of 52 kDa and 64 kDa were recognized on immunoblots of livers obtained from human individuals not exposed to halothane. Recognition of both CF 3 CO‐proteins and the 52‐kDa and 64‐kDa cross‐reactive proteins was abolished in the presence of 1 mM CF 3 CO‐Lys. Anti‐CF 3 CO antibody, affinity‐adsorbed to the 52‐kDa or the 64‐kDa cross‐reactive proteins of human liver, recognized the majority of target CF 3 CO‐proteins on immumoblots of the human liver biopsy of an individual exposed to halothane. Liver biopsies of 5 out of 7 (71%) patients with halothane hepatitis exhibited an absence or low amounts of immuno‐recognizable 52‐kDa and/or 64‐kDa cross‐reactive proteins. In contrast, of 22 control human individuals tested, all liver tissue samples were positive for the 52‐kDa and/or the 64‐kDa cross‐reactive proteins. These data indicate that epitopes on the cross‐reactive proteins of 52 kDa and 64 kDa of human liver bear strong immunochemical resemblance to epitopes on human liver CF 3 CO‐proteins. Low‐level expression of the cross‐reactive proteins of 52 kDa and 64 kDa is discussed as one possible factor in human susceptibility to halothane hepatitis.
