Airway Delivery of Hydrogel-Encapsulated Niclosamide for the Treatment of Inflammatory Airway Disease

Repurposing of the anthelminthic drug niclosamide was proposed as an effective treatment for inflammatory airway diseases such as asthma, cystic fibrosis, and chronic obstructive pulmonary disease. Niclosamide may also be effective for the treatment of viral respiratory infections, such as SARS-CoV-2, respiratory syncytial virus, and influenza. While systemic application of niclosamide may lead to unwanted side effects, local administration via aerosol may circumvent these problems, particularly when the drug is encapsulated into small polyethylene glycol (PEG) hydrospheres. In the present study, we examined whether PEG-encapsulated niclosamide inhibits the production of mucus and affects the pro-inflammatory mediator CLCA1 in mouse airways in vivo, while effects on mucociliary clearance were assessed in excised mouse tracheas. The potential of encapsulated niclosamide to inhibit TMEM16A whole-cell Cl- currents and intracellular Ca2+ signalling was assessed in airway epithelial cells in vitro. We achieved encapsulation of niclosamide in PEG-microspheres and PEG-nanospheres (Niclo-spheres). When applied to asthmatic mice via intratracheal instillation, Niclo-spheres strongly attenuated overproduction of mucus, inhibited secretion of the major proinflammatory mediator CLCA1, and improved mucociliary clearance in tracheas ex vivo. These effects were comparable for niclosamide encapsulated in PEG-nanospheres and PEG-microspheres. Niclo-spheres inhibited the Ca2+ activated Cl- channel TMEM16A and attenuated mucus production in CFBE and Calu-3 human airway epithelial cells. Both inhibitory effects were explained by a pronounced inhibition of intracellular Ca2+ signals. The data indicate that poorly dissolvable compounds such as niclosamide can be encapsulated in PEG-microspheres/nanospheres and deposited locally on the airway epithelium as encapsulated drugs, which may be advantageous over systemic application.

Strategies to target SARS-CoV-2 entry and infection using dual mechanisms of inhibition by acidification inhibitors

Many viruses utilize the host endo-lysosomal network for infection. Tracing the endocytic itinerary of SARS-CoV-2 can provide insights into viral trafficking and aid in designing new therapeutic strategies. Here, we demonstrate that the receptor binding domain (RBD) of SARS-CoV-2 spike protein is internalized via the pH-dependent CLIC/GEEC (CG) endocytic pathway in human gastric-adenocarcinoma (AGS) cells expressing undetectable levels of ACE2. Ectopic expression of ACE2 (AGS-ACE2) results in RBD traffic via both CG and clathrin-mediated endocytosis. Endosomal acidification inhibitors like BafilomycinA1 and NH4Cl, which inhibit the CG pathway, reduce the uptake of RBD and impede Spike-pseudoviral infection in both AGS and AGS-ACE2 cells. The inhibition by BafilomycinA1 was found to be distinct from Chloroquine which neither affects RBD uptake nor alters endosomal pH, yet attenuates Spike-pseudovirus entry. By screening a subset of FDA-approved inhibitors for functionality similar to BafilomycinA1, we identified Niclosamide as a SARS-CoV-2 entry inhibitor. Further validation using a clinical isolate of SARS-CoV-2 in AGS-ACE2 and Vero cells confirmed its antiviral effect. We propose that Niclosamide, and other drugs which neutralize endosomal pH as well as inhibit the endocytic uptake, could provide broader applicability in subverting infection of viruses entering host cells via a pH-dependent endocytic pathway.

Scalable nanoprecipitation of niclosamide and in vivo demonstration of long-acting delivery after intramuscular injection

The control of COVID-19 across the world requires the formation of a range of interventions including vaccines to elicit an immune response and immunomodulatory or antiviral therapeutics. Here, we demonstrate the nanoparticle formulation of a highly insoluble drug compound, niclosamide, with known anti SARS-CoV-2 activity as a cheap and scalable long-acting injectable antiviral candidate.

Development and evaluation of inhalable composite niclosamide-lysozyme particles: A broad-spectrum, patient-adaptable treatment for coronavirus infections and sequalae

Niclosamide (NIC) has demonstrated promising in vitro antiviral efficacy against SARS-CoV-2, the causative agent of the COVID-19 pandemic. Though NIC is already FDA-approved, administration of the currently available oral formulation results in systemic drug levels that are too low for the inhibition of SARS-CoV-2. We hypothesized that the co-formulation of NIC with an endogenous protein, human lysozyme (hLYS), could enable the direct aerosol delivery of the drug to the respiratory tract as an alternative to oral delivery, thereby effectively treating COVID-19 by targeting the primary site of SARS-CoV-2 acquisition and spread. To test this hypothesis, we engineered and optimized composite particles containing NIC and hLYS suitable for delivery to the upper and lower airways via dry powder inhaler, nebulizer, and nasal spray. The novel formulation demonstrates potent in vitro and in vivo activity against two coronavirus strains, MERS-CoV and SARS-CoV-2, and may offer protection against methicillin-resistance staphylococcus aureus pneumonia and inflammatory lung damage occurring secondary to SARS-CoV-2 infections. The suitability of the formulation for all stages of the disease and low-cost development approach will ensure rapid clinical development and wide-spread utilization.

Repurposing of niclosamide as a STAT3 inhibitor to enhance the anticancer effect of chemotherapeutic drugs in treating colorectal cancer

AIMS

Colorectal cancer (CRC) is the third most common cancer worldwide. Mutation of various cell signaling molecules or aberrant activation of signaling pathways leads to poor response to chemotherapy in CRC. Signal transducer and activator of transcription protein 3 (STAT3) is an important signaling molecule, which plays crucial roles in regulating cell survival and growth. In this study, the potentitation of chemotherapy by putative STAT3 inhibitors for treating CRC was investigated.

MAIN METHODS

A few putative STAT3 inhibitors were investigated. Niclosamide, originally indicated for the treatment of tapeworm infection, was chosen for further investigation in five CRC cell lines (HCT116, HT29, HCC2998, LoVo and SW480). Western blot analysis was used to evaluate the expression of STAT3/phospho-STAT3 and its downstream targets. Sulforhodamine B assay was used to evaluate the cytotoxicity of drug combinations. Flow cytometric assays were used to investigate the apoptotic and cell cycle effect.

KEY FINDINGS

Niclosamide was found to inhibit expression and activation of STAT3 in a concentration- and time-dependent manner, thereby downregulating STAT3 downstream targets including survivin and cyclin-D1 to induce apoptosis and cell cycle arrest. When combined with niclosamide or specific STAT3 inhibitor (C188-9), the cytotoxicity and DNA damage response from SN38 (the active metabolite from irinotecan) were significantly enhanced. The sequential exposure of SN38 followed by niclosamide was found to be the most potent treatment sequence for the drug combination.

SIGNIFICANCE

Niclosamide represents a promising candidate for repurposing to potentiate the anticancer activity of chemotherapeutic drugs.

A phase I study of niclosamide in combination with enzalutamide in men with castration-resistant prostate cancer

BACKGROUND

Niclosamide, an FDA-approved anti-helminthic drug, has activity in preclinical models of castration-resistant prostate cancer (CRPC). Potential mechanisms of action include degrading constitutively active androgen receptor splice variants (AR-Vs) or inhibiting other drug-resistance pathways (e.g., Wnt-signaling). Published pharmacokinetics data suggests that niclosamide has poor oral bioavailability, potentially limiting its use as a cancer drug. Therefore, we launched a Phase I study testing oral niclosamide in combination with enzalutamide, for longer and at higher doses than those used to treat helminthic infections.

METHODS

We conducted a Phase I dose-escalation study testing oral niclosamide plus standard-dose enzalutamide in men with metastatic CRPC previously treated with abiraterone. Niclosamide was given three-times-daily (TID) at the following dose-levels: 500, 1000 or 1500mg. The primary objective was to assess safety. Secondary objectives, included measuring AR-V expression from circulating tumor cells (CTCs) using the AdnaTest assay, evaluating PSA changes and determining niclosamide's pharmacokinetic profile.

RESULTS

20 patients screened and 5 enrolled after passing all screening procedures. 13(65%) patients had detectable CTCs, but only one was AR-V+. There were no dose-limiting toxicities (DLTs) in 3 patients on the 500mg TID cohort; however, both (N = 2) subjects on the 1000mg TID cohort experienced DLTs (prolonged grade 3 nausea, vomiting, diarrhea; and colitis). The maximum plasma concentration ranged from 35.7 to 182 ng/mL and was not consistently above the minimum effective concentration in preclinical studies. There were no PSA declines in any enrolled subject. Because plasma concentrations at the maximum tolerated dose (500mg TID) were not consistently above the expected therapeutic threshold, the Data Safety Monitoring Board closed the study for futility.

CONCLUSIONS

Oral niclosamide could not be escalated above 500mg TID, and plasma concentrations were not consistently above the threshold shown to inhibit growth in CRPC models. Oral niclosamide is not a viable compound for repurposing as a CRPC treatment.

CLINICAL TRIAL REGISTRY

Clinicaltrials.gov: NCT02532114.

Niclosamide, an oral antihelmintic drug, exhibits antimetastatic activity in hepatocellular carcinoma cells through downregulating twist-mediated CD10 expression

Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world, especially, in eastern Asia, and its prognosis is poor once metastasis occurs. Niclosamide, a US Food and Drug Administration-approved antihelmintic drug, was shown to inhibit the growth of various cancers including HCC, but the effect of niclosamide on cell motility and the underlying mechanism have not yet been completely defined. The present study demonstrated that niclosamide, at 0-40 nM, concentration-dependently inhibited wound closure and the migratory/invasive capacities of human Huh7 and SK-Hep-1 HCC cells without exhibiting cytotoxicity. A protease array analysis showed that CD10 was dramatically downregulated in Huh7 cells after niclosamide treatment. Western blot and flow cytometric assays further demonstrated that CD10 expression was concentration-dependently downregulated in Huh7 and SK-Hep-1 cells after niclosamide treatment. Mechanistic investigations found that niclosamide suppressed Twist-mediated CD10 transactivation. Moreover, knockdown of CD10 expression by CD10 small interfering RNA in HCC cells suppressed cell migratory/invasive abilities and overexpression of CD10 relieved the migration inhibition induced by niclosamide. Taken together, our results indicated that niclosamide could be a potential agent for inhibiting metastasis of HCC, and CD10 is an important target of niclosamide for suppressing the motility of HCC cells.

Extracellular pH Modulates Neuroendocrine Prostate Cancer Cell Metabolism and Susceptibility to the Mitochondrial Inhibitor Niclosamide

Neuroendocrine prostate cancer is a lethal variant of prostate cancer that is associated with castrate-resistant growth, metastasis, and mortality. The tumor environment of neuroendocrine prostate cancer is heterogeneous and characterized by hypoxia, necrosis, and numerous mitoses. Although acidic extracellular pH has been implicated in aggressive cancer features including metastasis and therapeutic resistance, its role in neuroendocrine prostate cancer physiology and metabolism has not yet been explored. We used the well-characterized PNEC cell line as a model to establish the effects of extracellular pH (pH 6.5, 7.4, and 8.5) on neuroendocrine prostate cancer cell metabolism. We discovered that alkalinization of extracellular pH converted cellular metabolism to a nutrient consumption-dependent state that was susceptible to glucose deprivation, glutamine deprivation, and 2-deoxyglucose (2-DG) mediated inhibition of glycolysis. Conversely, acidic pH shifted cellular metabolism toward an oxidative phosphorylation (OXPHOS)-dependent state that was susceptible to OXPHOS inhibition. Based upon this mechanistic knowledge of pH-dependent metabolism, we identified that the FDA-approved anti-helminthic niclosamide depolarized mitochondrial potential and depleted ATP levels in PNEC cells whose effects were enhanced in acidic pH. To further establish relevance of these findings, we tested the effects of extracellular pH on susceptibility to nutrient deprivation and OXPHOS inhibition in a cohort of castrate-resistant prostate cancer cell lines C4-2B, PC-3, and PC-3M. We discovered similar pH-dependent toxicity profiles among all cell lines with these treatments. These findings underscore a potential importance to acidic extracellular pH in the modulation of cell metabolism in tumors and development of an emerging paradigm that exploits the synergy of environment and therapeutic efficacy in cancer.

Altered Gene Expression in the Schistosome-Transmitting Snail Biomphalaria glabrata following Exposure to Niclosamide, the Active Ingredient in the Widely Used Molluscicide Bayluscide

In view of the call by the World Health Organization (WHO) for elimination of schistosomiasis as a public health problem by 2025, use of molluscicides in snail control to supplement chemotherapy–based control efforts is likely to increase in the coming years. The mechanisms of action of niclosamide, the active ingredient in the most widely used molluscicides, remain largely unknown. A better understanding of its toxicology at the molecular level will both improve our knowledge of snail biology and may offer valuable insights into the development of better chemical control methods for snails. We used a recently developed Biomphalaria glabrata oligonucleotide microarray (31K features) to investigate the effect of sublethal exposure to niclosamide on the transcriptional responses of the snail B. glabrata relative to untreated snails. Most of the genes highly upregulated following exposure of snails to niclosamide are involved in biotransformation of xenobiotics, including genes encoding cytochrome P450s (CYP), glutathione S-transferases (GST), and drug transporters, notably multi-drug resistance protein (efflux transporter) and solute linked carrier (influx transporter). Niclosamide also induced stress responses. Specifically, six heat shock protein (HSP) genes from three super-families (HSP20, HSP40 and HSP70) were upregulated. Genes encoding ADP-ribosylation factor (ARF), cAMP response element-binding protein (CREB) and coatomer, all of which are involved in vesicle trafficking in the Golgi of mammalian cells, were also upregulated. Lastly, a hemoglobin gene was downregulated, suggesting niclosamide may affect oxygen transport. Our results show that snails mount substantial responses to sublethal concentrations of niclosamide, at least some of which appear to be protective. The topic of how niclosamide’s lethality at higher concentrations is determined requires further study. Given that niclosamide has also been used as an anthelmintic drug for decades and has been found to have activity against several types of cancer, our findings may be of relevance in understanding how both parasites and neoplastic cells respond to this compound.

Schistosomes are snail-transmitted parasites that continue to infect over 230 million people worldwide and cause the disease schistosomiasis. Currently there is no effective vaccine against the disease. Control programs have relied primarily on use of chemotherapy with praziquantel to eliminate adult worms from infected people. An increasing body of evidence, however, suggests that praziquantel-based control programs are not likely to be sufficient to achieve sustainable transmission control. Snail control achieved by focal use of molluscicides, especially in combination with other methods like chemotherapy, sanitation and health education, offers considerable promise for reduction of disease transmission. Consequently, use of molluscicides in snail control is likely to increase in the coming years. We undertook a microarray study to assess transcriptional responses to niclosamide, the active ingredient in commonly-used molluscicides, in the schistosome-transmitting snail Biomphalaria glabrata. We show that niclosamide activates components in snails’ pathways known to be involved in biotransformation of xenobiotics and stress responses. We suggest that major alterations in vesicle trafficking and interference with oxygen transport also follow niclosamide exposure. The results contribute to our understanding of molecular impacts of niclosamide exposure on snails, and provide a basis for further studies to define the mode of action of niclosamide and other molluscicides in the future.

Taenia solium infection in Peru: a collaboration between Peace Corps Volunteers and researchers in a community based study

Background

Neurocysticercosis is a leading cause of seizures and epilepsy in most of the world, and it occurs when Taenia solium larval cysts infect the central nervous system. T. solium tapeworm infection is endemic in much of Peru, but there are scarce data on the prevalence in many rural highland communities where it is likely to be hyper-endemic. Peace Corps Volunteers live and work in these communities; however, to our knowledge, they have not been used to facilitate public health research.

Materials and Methods

We utilized Peace Corps Volunteers to estimate the prevalence of T. solium tapeworm infection in seven rural communities in northern Peru. A convenience non-random sampling frame was used. Peace Corps Volunteers facilitated the collection of stool samples (N = 2,328), which were analyzed by sedimentation and microscopy. Niclosamide treatment and purgation preceded species identification, which was done by PCR-REA.

Results

Taenia sp. egg-positive stool samples were found in three of the seven communities we surveyed. The overall prevalence of Taenia sp. egg positivity was 2.1% (49/2,328) (95% CI = 1.6–2.8%) with prevalence up to 4.3% (42/977) (95% CI = 3.1–5.8%) by community. All 34 of the specimens tested by PCR-REA were T. solium. The overall prevalence of T. solium tapeworm infection was 1.5% (34/2,328) (95% CI = 1.0–2.0%). Prevalence up to 2.9% (28/977) (95% CI = 1.9–4.1%) by community was observed.

Conclusion/Significance

This study recorded high T. solium tapeworm prevalence, and identified hyper-endemic rural communities. It demonstrates that synergy between researchers and Peace Corps Volunteers can be an effective means to conducting large-scale, community-based studies in remote areas of Peru.

Disruption of STAT3 by niclosamide reverses radioresistance of human lung cancer

A major challenge affecting the outcomes of patients with lung cancer is the development of acquired radioresistance. However, the mechanisms underlying the development of resistance to therapy are not fully understood. Here, we discovered that ionizing radiation induces phosphorylation of Janus-associated kinase (JAK)-2 and STAT3 in association with increased levels of Bcl2/Bcl-XL in various human lung cancer cells. To uncover new mechanism(s) of radioresistance of lung cancer, we established lung cancer cell model systems with acquired radioresistance. As compared with radiosensitive parental lung cancer cells (i.e., A549, H358, and H157), the JAK2/STAT3/Bcl2/Bcl-XL survival pathway is significantly more activated in acquired radioresistant lung cancer cells (i.e., A549-IRR, H358-IRR, and H157-IRR). Higher levels of STAT3 were found to be accumulated in the nucleus of radioresistant lung cancer cells. Niclosamide, a potent STAT3 inhibitor, can reduce STAT3 nuclear localization in radioresistant lung cancer cells. Intriguingly, either inhibition of STAT3 activity by niclosamide or depletion of STAT3 by RNA interference reverses radioresistance in vitro. Niclosamide alone or in combination with radiation overcame radioresistance in lung cancer xenografts. These findings uncover a novel mechanism of radioresistance and provide a more effective approach to overcome radioresistance by blocking the STAT3/Bcl2/Bcl-XL survival signaling pathway, which may potentially improve lung cancer outcome, especially for those patients who have resistance to radiotherapy.

Niclosamide overcomes acquired resistance to erlotinib through suppression of STAT3 in non-small cell lung cancer

The emergence of resistance to EGF receptor (EGFR) inhibitor therapy is a major clinical problem for patients with non-small cell lung cancer (NSCLC). The mechanisms underlying tumor resistance to inhibitors of the kinase activity of EGFR are not fully understood. Here, we found that inhibition of EGFR by erlotinib induces STAT3 phosphorylation at Tyr705 in association with increased Bcl2/Bcl-XL at both mRNA and protein levels in various human lung cancer cells. PTPMeg2 is a physiologic STAT3 phosphatase that can directly dephosphorylate STAT3 at the Tyr705 site. Intriguingly, treatment of cells with erlotinib results in downregulation of PTPMeg2 without activation of STAT3 kinases [i.e., Janus-activated kinase (JAK2) or c-Src], suggesting that erlotinib-enhanced phosphorylation of STAT3 may occur, at least in part, from suppression of PTPMeg2 expression. Because elevated levels of phosphorylated STAT3 (pSTAT3), Bcl2, and Bcl-XL were observed in erlotinib-resistant lung cancer (HCC827/ER) cells as compared with erlotinib-sensitive parental HCC827 cells, we postulate that the erlotinib-activated STAT3/Bcl2/Bcl-XL survival pathway may contribute to acquired resistance to erlotinib. Both blockage of Tyr705 phosphorylation of STAT3 by niclosamide and depletion of STAT3 by RNA interference in HCC827/ER cells reverse erlotinib resistance. Niclosamide in combination with erlotinib potently represses erlotinib-resistant lung cancer xenografts in association with increased apoptosis in tumor tissues, suggesting that niclosamide can restore sensitivity to erlotinib. These findings uncover a novel mechanism of erlotinib resistance and provide a novel approach to overcome resistance by blocking the STAT3/Bcl2/Bcl-XL survival signaling pathway in human lung cancer.

[Studies on spray of niclosamide ethanolamine salt II observation on prevention of Schistosoma japonicum infection in bovine]

OBJECTIVE

To investigate the spray of niclosamide ethanolamine salt on prevention of bovine schistosomiasis in the field so as to provide a technical support for the improvement of schistosomiasis control strategy.

METHODS

A total of 160 buffalo were selected as experimental objects marked by ear-mark numbers. All the buffalo were administered with praziquantel and then randomly divided into 3 groups, which were sprayed with niclosamide ethanolamine salt (500 ml per head) every 15 d (Group A), every 30 d (Group B) and an agent without niclosamide ethanolamine salt every 15 d (Group C as the control), respectively. The buffalo's droppings were collected to examine the eggs of schistosome every 30 days during the trial.

RESULTS

Ninety days after the spraying, the prevalence rates of schistosomiasis were 4.00%, 4.08%, and 24.49% in the Group A, Group B, and Group C, respectively. Compared with the control group (Group C), the decline prevalence rates of schistosomiasis were 83.67% and 83.34% in the Group A and Group B, respectively.

CONCLUSIONS

The buffalo spraying with 1% niclosamide ethanolamine salt can reduce schistosomiasis prevalence in bovine, that is this intervention has an obvious protective effect.

[Studies on spray of niclosamide ethanolamine salt. I. development and effect assessment of spray of niclosamide ethanolamine salt]

OBJECTIVE

To develop a spray of niclosamide ethanolamine salt for prevention of bovine from Schistosoma japonicum infection, and explore its characteristics and effect.

METHODS

The solubilizers, penetrating agents, emulsifiers were screened, and the spray of niclosamide ethanolamine salt was formulated according to the screening results. The niclosamide ethanolamine salt was determined by using a HPLC technique, and the stability was observed. The preventive effect of the spray was assessed by in-vitro trials against cercariae and protection trials in mice.

RESULTS

The screened formulation was presented as following: 1% niclosamide ethanolamine salt was dissolved in 18% dimethyl sulfoxide, and then added with 1% azone and 2% span, together with 78% ethanol, to yield a 1% spray of niclosamide ethanolamine salt. The spray appeared golden flowing liquid, with 1% niclosamide ethanolamine salt in content (W/W), pH 7.4-7.8, and good thermal and cold stability. All cercariae died (100%) while exposed to the spray at a concentration of 1.00 mg/L for 2 min, and the similar effect was achieved while exposed to 0.50 mg/L of the spray for 5 min or 0.10 mg/L for 30 min. The spray at concentrations less than 0.05 mg/L had no evident toxicity to cercariae. A volume of 0.5 ml of the 1% spray was sprayed on the abdomen of mice, 1-3 d later, the mice were infected with S. japonicum cercariae on the spraying sites, no mice were infected, with a protection rate of 100%. Five days post-spraying, the protection rate was 40%, and the worm burden reduction rate was 65.87%. Ten days later, all the mice were infected, however, the worm burden reduction rate was 51.98%. The worm burdens on days 5 or 10 post-spraying were significantly lower than those of the control (P < 0.01). The spray exhibited a good preventive efficacy to mice from S. japonicum infection in lab.

CONCLUSIONS

The spray of niclosamide ethanolamine salt has stable physical and chemical property, and is a novel liquid preventive agent against bovine schistosomiasis. In addition, it has a rapid activity against S. japonicum cercariae, so can prevent bovine from S. japonicum infection.

[Toxicity of niclosamide with plastic film mulching to fish]

OBJECTIVE

To observe the toxicity of niclosamide with plastic film mulching to fish.

METHODS

A ditch with Oncomelania snails was selected as the study site, and it was divided into a control group and a molluscicide group. After the river closure, the molluscicidal group was sprayed with niclosamide with a dosage of 2 g/m2, and then covered with plastic film; no molluscicide measure was implemented in the control group. The toxicity of the molluscicide to carp fish in resting and flowing water environment was observed.

RESULTS

In flowing water, the death rates of carp fry of the molluscicidal and control groups showed no statistical difference 7 d after the film mulching (P = 0. 680), and no carp fry died in the 2 groups after plastic film taking off for 4 d. The death rates of carp fry between the 3 sites (with a distance of 50, 100 and 150 m from the molluscicidal group, respectively) and the control group had no statistical difference 7 d after film mulching (P = 0.955), and no dead fry was discovered 4 d after taking off the film. In downstream, for the death rates of carp fry, there was no difference between the molluscicidal group and the control group (P = 0.376). The death rates of snails before and after the molluscicidal experiment showed a significant difference (P < 0.01).

CONCLUSIONS

The technology of niclosamide molluscicide with plastic film mulching can not only improve the molluscicidal effect, but also avoid the toxicity to fish, which is suitable for special environment such as a fish pond.

[Evaluation on molluscicidal effect of suspension concentrate of metaldehyde and niclosamide]

OBJECTIVE

To evaluate the molluscicidal effect of suspension concentrate of 26% metaldehyde and niclosamide (MNSC) in laboratory and field.

METHODS

The experiment of MNSC against Oncomelania snails were performed by immersion and spray methods with different time in laboratory and field, and the wettable powder of 50% niclosamide ethanolamine salt (WPN) and fresh water were set as the controls.

RESULTS

In laboratory, by immersion method (immersion for 24 h), LC50 of MNSC was 0.058 3 mg/L, which was lower than 0.094 7 mg/L of WPN. For the concentrations of 2.0 mg/L and 1.0 mg/L of MNSC by immersion method (immersion for 24, 48 h and 72 h, respectively), the death rates of snails were all 100%. In laboratory, by the spray method, the snail death rates were higher than 97% on the 3rd and 7th day when the dosage of MNSC was higher than 1.0 g/m2. In the field, by the immersion method, the snail death rates of MNSC (2 g/m3) for 24, 48 h and 72 h were 97.78% -100% in Hubei Province and 97.50% - 100% in Anhui Province, respectively, the rates of WPN were 98.89% - 100% and 97.56% - 100%, respectively, and the snail death rates of MNSC and WPN were both 100% in Jiangsu Province. In the field, by the spray method, the snail death rates of MNSC for 1, 3 d and 7 d were 83.12% - 94.64% in Jiangsu Province, 67.81% - 86.67% in Hubei Province and 72.80% - 100% in Anhui Province, respectively. The snail death rates of WPN for 1, 3 d and 7 d were 78.40% - 86.11%, 77.27% - 87.50% and 83.81% - 98.51%, respectively. In Hunan Province, the snail death rates of MNSC and WPN after spraying for 7 d were 94.94% and 94.20%, respectively, after spraying for 15 d, the rates were 86.67% and 89.38%, respectively.

CONCLUSIONS

The molluscicidal effect of MNSC is as the same as WPN by immersion and spray methods in laboratory and field. MNSC has the characteristics of good water solubility, quick dispersing and easy using. In addition, the efficiency component of MNSC is half of WPN. So MNSC is a novel form of molluscicide which is worthy of promotion in field.

A novel method for oral delivery of apolipoprotein mimetic peptides synthesized from all L-amino acids

Administered subcutaneously, D-4F or L-4F are equally efficacious, but only D-4F is orally efficacious because of digestion of L-4F by gut proteases. Orally administering niclosamide (a chlorinated salicylanilide used as a molluscicide, antihelminthic, and lampricide) in temporal proximity to oral L-4F (but not niclosamide alone) in apoE null mice resulted in significant improvement (P < 0.001) in the HDL-inflammatory index (HII), which measures the ability of HDL to inhibit LDL-induced monocyte chemotactic activity in endothelial cell cultures. Oral administration of L-[113-122]apoJ with niclosamide also resulted in significant improvement (P < 0.001) in HII. Oral administration of niclosamide and L-4F together with pravastatin to female apoE null mice at 9.5 months of age for six months significantly reduced aortic sinus lesion area (P = 0.02), en face lesion area (P = 0.033), and macrophage lesion area (P = 0.02) compared with pretreatment, indicating lesion regression. In contrast, lesions were significantly larger in mice receiving only niclosamide and pravastatin or L-4F and pravastatin (P < 0.001). In vitro niclosamide and L-4F tightly associated rendering the peptide resistant to trypsin digestion. Niclosamide itself did not inhibit trypsin activity. The combination of niclosamide with apolipoprotein mimetic peptides appears to be a promising method for oral delivery of these peptides.

Cream formulations protecting against cercarial dermatitis by Trichobilharzia

Dermatitis caused by penetrating bird schistosome cercariae is an emerging global public health problem. Infections may be prevented by the use of topical formulations that inhibit cercarial skin penetration. We evaluated nine water resistant formulations by exposing treated arms of volunteers to Trichobilharzia szidati cercariae. Six formulations protected from cercarial invasion. However, after immersion of the treated skin in water (2 x 20 min), only two formulations offered full protection: (1) Safe Sea, a cream protecting against jelly fish, (2) niclosamide in water resistant sun protecting cream formulations at concentrations as low as 0.05%. In an in vitro system Safe Sea and a 0.1% niclosamide formulation caused a high damage rate in T. szidati (92% and 99% after 5 min; only niclosamide with lethal effect) but not in Schistosoma mansoni (1% and 72%; both formulations with lethal effect). However, a 1% niclosamide formulation damaged S. mansoni sufficiently (100% after 5 min) and might offer full penetration protection.

The Hymenolepis diminuta–Golden Hamster (Mesocricetus auratus) Model for the Evaluation of Gastrointestinal Anticestode Activity

A novel laboratory anticestode assay was developed using Hymenolepis diminuta in the hamster. The commercial anticestode compounds, praziquantel, bunamidine, and niclosamide were active against patent infections of Hymenolepis diminuta in golden hamsters (Mesocricetus auratus) when given orally at 3.125, 100, and 200 mg/kg, respectively. The gastrointestinal nematode anthelmintics, cambendazole and mebendazole, were active at 50 mg/kg. Rafoxanide (fasciolicide) was active at 25 mg/kg, the lowest level tested. The coccidiostat, nicarbazin, was active at experimental levels (800 mg/kg and up). The anthelmintic-ectoparasiticide (endectocide), ivermectin, was inactive against the tapeworm at 0.5 mg/kg, as expected.

Development of bait formulations for control of intermediate hosts of African schistosome species

Exploration of methods of snail control indicated a need for a new method because many failures in control programmes are due to lack of contact between molluscicides and the target snail population. The incorporation of molluscicides inside food pellets that are attractive to and ingestible by the target snails is suggested. Different concentrations of alcoholic extracts of Ambrosia maritima, Cucumis prophetarum and Rhynchosia minima-molluscicides of plant origin-were compared with niclosamide (Bayluscide) which is a strong synthetic molluscicide. They were incorporated into attractive food pellets and the lethal doses were determined. The results showed that Biomphalaria alexandrina snails are sensitive to only bait formulations with low concentrations of molluscicides. Laboratory and semi-field trials were conducted to study the efficacy of the prepared bait formulations on Biomphalaria alexandrina snails. The stability of these bait formulations was studied and it was observed that their effectiveness was reduced after long storage periods (> 3 weeks). The results revealed that Ambrosia maritima was the most effective molluscicide.

Field tests of a village-based mollusciciding programme for the control of snail hosts of human schistosomes in Cameroon

The feasibility of using unskilled workers at the district or village level to perform mollusciciding activities in arid regions of northern Cameroon was investigated. A simplified procedure for application to temporary ponds, the principal sites of schistosomiasis transmission in that region, was tested. This consisted of mixing the required quantity of niclosamide (Bayluscide, Bayer AG, Leverkusen) with pond water in a plastic watering can and applying the mixture around the circumference. To aid dispersion, the can was repeatedly swept from the perimeter toward the centre of the pond. Two ponds each were treated once near the end of the rainy season at 1 of 3 concentrations: 0.5, 1.0 and 1.5 p.p.m. Following treatment, 100% snail mortality was recorded at all concentrations. A simple, rapid method for determining the quantity of niclosamide needed to treat temporary ponds was also devised. Physical characteristics were determined for 16 potential schistosomiasis transmission sites in the region. An integration of those characteristics was used to develop a simplified scale indicating the quantity of niclosamide needed to treat ponds based on their circumference. The operational feasibility of a village based mollusciciding programme using those simplified procedures was then evaluated in 2 villages. Village health workers demonstrated a high accuracy (87%) in identifying potential schistosomiasis transmission foci and snail host populations were virtually eliminated from treated sites.

Evaluation of a twice-a-week application of 1% niclosamide lotion in preventing Schistosoma haematobium reinfection

A randomized double-blind trial was conducted to assess the efficacy of a twice-a-week application of 1% niclosamide lotion for prevention of Schistosoma haematobium reinfection. Six hundred farmers in Fayoum, Egypt, 18-40 years of age, were treated to cure their S. haematobium infection, then randomly assigned to self-apply niclosamide or placebo lotion to their limbs, neck, and torso. Subjects were exposed to schistosomal-infested water during routine irrigation activities from April to October 1992. Three hundred fifty subjects met the inclusion criteria and completed the trial, 169 (48.3%) in the niclosamide group and 181 (51.7%) in the placebo group. The subjects assigned to the niclosamide-treated group were comparable with those in the placebo group in age (27.2 versus 27.8 years), total water contact (101.9 versus 109.0 hr), lotion application compliance (93.5% versus 90.6%), and avoidance of whole body water contact (94.7% versus 96.7%). The reinfection rate with S. haematobium was 30.8% in the niclosamide-treated group and 28.2% in the placebo group. Niclosamide lotion applied to the limbs and trunk twice a week failed to prevent S. haematobium reinfection.

Field trial of 1% niclosamide as a topical antipenetrant to Schistosoma mansoni cercariae

A randomized, double-blind, placebo-controlled field trial of a topical antipenetrant lotion, 1% niclosamide, applied daily to the upper and lower limbs of farmers occupationally exposed to Schistosoma mansoni cercarial-infested water, was conducted in the Nile Delta to assess its safety and efficacy in preventing reinfection. Farmers aged 18-40 years were treated to cure their S. mansoni infections three months prior to the onset of the trial. Subjects were randomly assigned to receive niclosamide or placebo lotion that was self-applied daily for five months. A total of 186 subjects met the inclusion criteria and completed the trial. The exposure to schistosomal-infested water occurred during routine irrigation activities from June to November 1991. Stool specimens were evaluated monthly during and for two months following the lotion application period. The subjects applying the niclosamide lotion were comparable to those applying placebo lotion in age (mean 30 years for both), total water contact (184.5 hr versus 173.8 hr), reported lotion application compliance (88% versus 92%), and reported water contact involving skin exposure other than upper and lower limbs (23% versus 27%). The schistosomal reinfection rate was lower in the niclosamide group (53.3%) compared with the placebo lotion group (71.3%), (P < 0.02). Increased protection might be obtained with total body application for shorter, less intense, water contact exposures.

[The characteristics of the clinical course of taeniarhynchiasis and its combination with enterobiasis and lambliasis and fenasal treatment]

A total of 276 patients with taeniasis alone and taeniasis associated with enterobiasis or lambliasis were involved in the study. The most prevalent features in patients of all the three groups were combinations of the painful, dyspeptic and astheno-vegetative syndromes, the least so--an isolated astheno-vegetative syndrome. Combinations of these syndromes more frequently occur in taeniasis concomitant with enterobiasis (61% vs. 51% in taeniasis alone). Associations of taeniasis with enterobiasis or lambliasis are more frequently diagnosed in children. Combinations of the three syndromes were revealed in the patients with taeniasis coursing against the background of chronic gastritis, duodenal ulcer, cholepathies: in 79% vs. 33.3% in an uncomplicated course. Fenasal therapy for 3 days in a daily dose of 3 g proved fairly effective: 85.7 +/- 6.3% of adults and 82.6 +/- 6.4% of children recovered.

Efficacy of niclosamide as a potential antipenetrant (TAP) against cercariae of Schistosoma mansoni monkeys

A 1% (W/V) formulation of Niclosamide (2', 5-Dichloro-4-nitrosalicylanilide) (TAP) was tested on Cebus apella monkeys as a topical prophylactic against schistosomiasis mansoni. Two experiments were conducted using the same formulation. In the first experiment, the TAP provided complete protection against schistosomiasis for 3 days. Of the 4 monkeys treated with TAP 7 days before exposure to Schistosoma mansoni cercariae, 2 were completely protected. The remaining 2 monkeys of the 7 day treatment group had a 78% or greater reduction in adult worm burdens when compared to the placebo treated monkeys. The second experiment was designed to determine the time between day 3 and 7 when the TAP no longer provided complete protection. However, all of the TAP treated monkeys in this experiment were completely protected, even the monkeys treated 7 days earlier. In both experiments, all monkeys used as infection controls and those receiving only the placebo became infected and showed typical experimental schistosomiasis. These results demonstrate that the TAP could provide fast acting, short-term protection to people who must enter cercariae infested water.

Dermal absorption of niclosamide in rats and minipigs

The dermal absorption of niclosamide, a drug shown to prevent Schistosomiasis by blocking the dermal penetration of cercariae, has been examined in Sinclair minipigs and rats. Radioactivity in the urine and feces collected daily for 7 days after application of 14C-niclosamide accounted for less than 2 per cent and 10 per cent of the labelled compound applied to pig and rat skin, respectively. Approximately 20 per cent of the radioactivity from the dose solution was recovered on the skin excised from the area of application in both minipigs and rats. No radioactivity was detected in organs removed from the pig 7 days after application of radiolabelled drug while less than 6 per cent of the dose could be accounted for in the rat organs/carcass. Radioactivity in swine blood, removed 0.5, 1, 2, 4 and at 24 h intervals after dosing, was at or below three times background in all of the samples. Total recovery of the applied radioactivity was 78 per cent in pigs and 57 per cent in rats. These studies indicate that niclosamide is very poorly absorbed after dermal application. The results are consistent with earlier comparative studies showing that dermal penetration of xenobiotics in rats is generally higher than in swine.

Studies on the comparative efficacy of mebendazole, flubendazole and niclosamide against human tapeworm infections

The efficacy of Mebendazole and Niclosamide was studied in two groups of 24 and 38 cases, respectively of patients suffering from taeniasis. Mebendazole with dose schedule of 200 and 300 mg twice daily for 3 consecutive days showed a cure rate of 71.42% and 92.30%, whereas Niclosamide at the dose rate of 200mg per patient was 94.76% effective. Flubendazole showed a cure rate of 66.66% only. Mebendazole and Niclosamide possess high taeniacidal activity, ability to reduce the clinical symptoms of taeniasis without any side effects. Niclosamide with high activity and excellent tolerance, is a drug of choice for the treatment of taeniasis in single dose treatment while for hymenolepsiasis it needs extended course.

Taeniasis unresponsive to a single dose of niclosamide: case report of persistent infection with Taenia saginata and a review of therapy

A patient infected in Ethiopia with the beef tapeworm Taenia saginata was unsuccessfully treated with 2 g of niclosamide on four separate occasions over four months. clinical and parasitologic cures were effected by a regimen of 2 g of niclosamide given on three consecutive days. Niclosamide is the drug of choice for treatment of T. saginata and Taenia solium (pork tapeworm) infection; cure rates are approximately 90%. It is not absorbable and thus is nontoxic. Alternative treatments of taeniasis vary in the degree of safety; tin compounds and Aspidium extracts often are toxic. Paromomycin sulfate, which is also nonabsorbable, is effective, although adverse gastrointestinal effects are common with multiple-dose regimens. A relatively safe therapy is with mebendazole, a broad-spectrum anthelmintic agent, although efficacy has varied in different trials. A number of benzimidazoles, as well as nitazoxamide, have been effective against tapeworms. Praziquantel is the best alternative to niclosamide in terms of cost, efficacy, availability, and safety.

Specific health problems of Southeast Asian refugees in middle Tennessee

Three diseases representative of specific health conditions affecting the Southeast Asian refugees living in middle Tennessee are leprosy (chronic bacterial infections), liver fluke infection (parasitic diseases), and hemoglobin E-beta-thalassemia (hematologic disorders). In this paper we discuss incidence, causative agent, mode of transmission, metabolic abnormalities, and management of these conditions.

3,5-dibromo-2'-chloro-4'-isothiocyanato salicylanilide in the control of Hymenolepis nana in rats--a pilot study

The efficiency of a new anticestode compound, 3,5-dibromo-2'-chloro-4'-isothiocyanato salicylanilide (GUPTA et al. 1980) for mass eradication of hymenolepiasis from rat colonies was assessed in a pilot study. The drug was administered with milk or food. For effective eradication, depending on the size of animals, single or multiple doses of 100 to 500 mg of the drug/kg body-weight, mixed in milk, or 50 mg/kg in feed were necessary. Better results were obtained when the compound was given in feed as it ensured effective consumption irrespective of the seasonal variations. The efficacy of the compound was also assessed on cysticercoids in intermediate hosts (Tribolium confusum) by feeding them on flour medicated at 5%, 1% and 0.1% levels. None of the concentrations killed the larvae or arrested their development.

[Pharmacology of a new drug form, fenasal granules]

Experiments on mice and rats were made to study a new medicinal form, fenasal granules given per os and to compare it with ground tablets and powder of fenasal as regards the intestinal content, absorption capacity, anthelminthic activity and toxicity. The intestinal content and absorption capacity of fenasal were medicinal form-dependent. The highest anthelminthic activity was exhibited by fenasal granules. Acute toxicity of powder, ground tablets and granules of fenasal administered to mice and rats per os remained the same.

The efficacy of anthelmintics against Thysaniezia giardi in South Africa

Two field cases of apparent inefficacy of albendazole against cestodes in lambs were investigated. In both farms Thysaniezia giardi was identified and 2 critical controlled trials were conducted to determine the efficacy of 5 anthelmintics against T. giardi. Albendazole dosed at 3,8 mg/kg or 7,6 mg/kg live mass, mebendazole at 15 mg/kg were totally ineffective against T. giardi. Treatment with resorantel at 65 mg/kg or niclosamide at 50 mg/kg however, caused expulsion of the strobilae within 16--24 hours after treatment and at autopsy, lambs were free of scoleces of T. giardi.

Taeniacidal efficacy of SQ 21,704 in dogs by various types of oral administration and in comparison with niclosamide and bunamidine hydrochloride

The streptothrinin antibiotics SQ 21,704 was evaluated against naturally occurring Taenia pisiformis and Dipylidium caninum infections in dogs when they were given at a dose level of 37.5 mg/kg of body weight in four different rations: loaf-type canned meat; chunk-type canned meat; dry (gravy-type) meal; and dry (pelleted) meal. The SQ 21,704 was 100% efficacious against both T pisiformis and D caninum infections when given with the chunk, gravy, and pelleted rations. When given with the loaf-type canned meat, it was 100% effective against T pisiformis and 60% efficacious against D caninum. The SQ 21,704 was effective against both tapeworm species when given orally as a liquid at a dose level of 37.5 mg/kg, formulated as an aqueous suspension containing 94 mg of activity per milliter. The SQ 21,704 was also tested in dogs when given orally in gelatin capsules at a dose level of 37.5 mg/kg without fasting, and was 100% efficacious against both tapeworm species. The results of a comparative taeniacidal study demonstrated that SQ 21,704 was 100% effective in removing both T pisiformis and D caninum when administered orally at a dose level of 37.5 mg/kg, whereas niclosamide and bunamidine hydrochloride were only partially effective at their recommended dose levels. One of five dogs treated with niclosamide at a dose level of 157 mg/kg was positive at necropsy, giving an orally efficacy of 80%. Three of five dogs treated with bunamidine hydrochloride at a dose level of 49 mg/kg were positive at necropsy, giving an overall efficacy of 40%.

The effect of niclosamide on Echinococcus granulosus, Taenia hydatigena and Taenia ovis infections in dogs

The effect of niclosamide (particle size 1 micron m) and its piperazine salt (particle size 5-10 micron m) on Echinococcus granulosus and Taenia hydatigena has been investigated. The piperazine salt of niclosamide was also tested for activity against Taenia ovis. These trials involved 326 dogs. Irrespective of particle size, the drug was found to be virtually inactive against 28-day-old E granulosus. Some evidence was found indicating that there may be a low degree of activity against 70-day-old worms. The drug was found to be effective at 32 mg/kg and 64 mg/kg against T hydatigena and 50 mg/kg against T ovis. Some evidence was obtained that milk decrease the efficiency of the piperazine salt against T hydatigena at the lower dose rates. Micronisation of the drug did not increase the efficiency against this parasite. Vomiting and diarrhoea were common sequelae.