From hydroxychloroquine to ivermectin: what are the anti-viral properties of anti-parasitic drugs to combat SARS-CoV-2?

BACKGROUND: Nearly a year into the COVID-19 pandemic, we still lack effective anti-SARS-CoV-2 drugs with substantial impact on mortality rates except for dexamethasone. As the search for effective antiviral agents continues, we aimed to review data on the potential of repurposing antiparasitic drugs against viruses in general, with an emphasis on coronaviruses. METHODS: We performed a review by screening in vitro and in vivo studies that assessed the antiviral activity of several antiparasitic agents: chloroquine, hydroxychloroquine (HCQ), mefloquine, artemisinins, ivermectin, nitazoxanide (NTZ), niclosamide, atovaquone and albendazole. RESULTS: For HCQ and chloroquine we found ample in vitro evidence of antiviral activity. Cohort studies that assessed the use of HCQ for COVID-19 reported conflicting results, but randomized controlled trials (RCTs) demonstrated no effect on mortality rates and no substantial clinical benefits of HCQ used either for prevention or treatment of COVID-19. We found two clinical studies of artemisinins and two studies of NTZ for treatment of viruses other than COVID-19, all of which showed mixed results. Ivermectin was evaluated in one RCT and few observational studies, demonstrating conflicting results. As the level of evidence of these data is low, the efficacy of ivermectin against COVID-19 remains to be proven. For chloroquine, HCQ, mefloquine, artemisinins, ivermectin, NTZ and niclosamide, we found in vitro studies showing some effects against a wide array of viruses. We found no relevant studies for atovaquone and albendazole. CONCLUSIONS: As the search for an effective drug active against SARS-CoV-2 continues, we argue that pre-clinical research of possible antiviral effects of compounds that could have antiviral activity should be conducted. Clinical studies should be conducted when sufficient in vitro evidence exists, and drugs should be introduced into widespread clinical use only after being rigorously tested in RCTs. Such a search may prove beneficial in this pandemic or in outbreaks yet to come.

Extended duration local anesthetic agent in a rat paw model.

Encapsulated local anesthetics extend postoperative analgesic effect following site-directed nerve injection; potentially reducing postoperative complications. Our study aim was to investigate efficacy of our improved extended duration formulation - 15% bupivacaine in poly(DL-lactic acid co castor oil) 3:7 synthesized by ring opening polymerization. In vitro, around 70% of bupivacaine was released from the p(DLLA-CO) 3:7 after 10 days. A single injection of the optimal formulation of 15% bupivacaine-polymer or plain (0.5%) bupivacaine (control), was injected via a 22G needle beside the sciatic nerve of Sprague-Dawley rats under anesthesia; followed (in some animals) by a 1cm longitudinal incision through the skin and fascia of the paw area. Behavioral tests for sensory and motor block assessment were done using Hargreave's hot plate score, von Frey filaments and rearing count. The 15% bupivacaine formulation significantly prolonged sensory block duration up to at least 48 h. Following surgery, motor block was observed for 48 h following administration of bupivacaine-polymer formulation and rearing was reduced (returning to baseline after 48 h). No significant differences in mechanical nociceptive response were observed. The optimized bupivacaine-polymer formulation prolonged duration of local anesthesia effect in our animal model up to at least 48 h.

Dynamics of PEGylated-dextran-spermine nanoparticles for gene delivery to leukemic cells.

Leukemic cells are hard-to-transfect cell lines. Many transfection reagents which can provide high gene transfer efficiency in common adherent cell lines are not effective to transfect established blood cell lines or primary leukemic cells. This study aims to examine a new class of cationic polymer non-viral vector, PEGylated-dextran-spermine (PEG-D-SPM), to determine its ability to transfect the leukemic cells. Here, the optimal conditions of the complex preparation (PEG-D-SPM/plasmid DNA (pDNA)) were examined. Different weight-mixing (w/w) ratios of PEG-D-SPM/pDNA complex were prepared to obtain an ideal mixing ratio to protect encapsulated pDNA from DNase degradation and to determine the optimal transfection efficiency of the complex. Strong complexation between polymer and pDNA in agarose gel electrophoresis and protection of pDNA from DNase were detected at ratios from 25 to 15. Highest gene expression was detected at w/w ratio of 18 in HL60 and K562 cells. However, gene expression from both leukemic cell lines was lower than the control MCF-7 cells. The cytotoxicity of PEG-D-SPM/pDNA complex at the most optimal mixing ratios was tested in HL60 and K562 cells using MTS assay and the results showed that the PEG-D-SPM/pDNA complex had no cytotoxic effect on these cell lines. Spherical shape and nano-nature of PEG-D-SPM/pDNA complex at ratio 18 was observed using transmission electron microscopy. As PEG-D-SPM showed modest transfection efficiency in the leukemic cell lines, we conclude that further work is needed to improve the delivery efficiency of the PEG-D-SPM.

Extended release formulations for local anaesthetic agents.

Systemic toxicity through overdose of local anaesthetic agents is a real concern. By encapsulating local anaesthetics in biodegradable carriers to produce a system for prolonged release, their duration of action can be extended. This encapsulation should also improve the safety profile of the local anaesthetic as it is released at a slower rate. Work with naturally occurring local anaestheticss has also shown promise in the area of reducing systemic and neurotoxicity. Extended duration local anaesthetic formulations in current development or clinical use include liposomes, hydrophobic based polymer particles such as Poly(lactic-co-glycolic acid) microspheres, pasty injectable and solid polymers like Poly(sebacic-co-ricinoleic acid) P(SA:RA) and their combination with synthetic and natural local anaesthetic. Their duration of action, rationale and limitations are reviewed. Direct comparison of the different agents is limited by their chemical properties, the drug doses encapsulated and the details of in vivo models described.

Review of prolonged local anesthetic action.

IMPORTANCE OF THE FIELD: Pain following surgery is often treated by local anesthetic agents. Duration of the analgesia can be extended safely following administration of encapsulated large doses of local anesthetic agents. AREAS COVERED IN THIS REVIEW: This review considers formulations used for encapsulation of local anesthetic agents for prolonged anesthesia effect. All studies describing encapsulation of a commercial local anesthetic agent for providing prolonged analgesia were considered using the NCBI Medline site. of local anesthetic, prolonged anesthesia, polymers and liposomes were entered in order to retrieve appropriate articles and reviews from 1966 to 2010, with emphasis on the last 10 years. Reference pages were searched manually for other relevant articles. The topics covered include an overview of local anesthetic agents and a review of local anesthetic carrier agents, with emphasis on liposomes and polymer carriers. Articles were limited to the English language. WHAT THE READER WILL GAIN: The current research areas for prolongation of local anesthetic effect are evaluated, along with their limitations. Each topic has been summarized, and the review has attempted to cover all current laboratory and clinical studies in a simple manner that should also be useful for readers without a pharmacology background. The direction of research is promising and exciting, and this review should be a useful up-to-date reference. TAKE HOME MESSAGE: Many formulations including polymer and liposome carriers have facilitated prolonged local anesthetic action for several days, although few clinical studies have been performed. This field promises a safe way to deliver local anesthetics for effect far beyond that of commercially available agents, with potential cost and health benefits for patients suffering chronic or postoperative pain.

In-vitro and in-vivo characteristics of a modified-release double-pulse formulation for a water soluble drug.

OBJECTIVE: The aim of the present study was to evaluate the in-vitro dissolution and in-vivo pharmacokinetic profile of a novel two-phase modified-release formulation for diltiazem hydrochloride, as a water-soluble drug. MATERIALS AND METHODS: The delivery system consisted of two tablets inserted into a capsule. Both tablets comprised a coated drug core-matrix. The coating of the first tablet was intended to produce a first phase with a relatively fast release profile, while that of the second tablet included a unique controlling membrane designed to achieve a delayed controlled-release profile. Three different formulations were tested for their dissolution profiles both in water media and in buffer with a pH of 6.8. These formulations were also evaluated for their pharmacokinetic profile in healthy volunteers after single administration of a 240 mg dose. Serial venous blood samples were collected over 36 h post administration to measure diltiazem levels by HPLC. In addition the in-vivo /in-vitro correlation (IVIVC) was calculated for these formulations. RESULTS: The in-vitro characteristics of these formulations demonstrated a controlled release profile in both media but with different characteristics, as in Formulation 3 where faster dissolution profile obtained in water but slower one in pH 6.8 buffer. In-vivo the pharmacokinetic profile of these formulations showed that arabinogalactan containing formulations achieved plasma levels which allow a once daily administration. IVIVC calculation demonstrated that dissolution tested in buffer 6.8 media better correlates with the percent absorbed in-vivo and the best results were achieved with the formulation containing the highest amount of polysaccharide in the coating. CONCLUSION: It is concluded that the developed formulations achieved a controlled release profile both in-vitro and in-vivo which are suitable for once-daily administration.

Biocompatibility of a polymeric implant for the treatment of osteomyelitis.

We evaluated the biocompatibility of an injectable gelling polymeric device for the controlled release of gentamicin sulfate in the treatment of invasive bacterial infections in bone of male Wister rats. The biodegradable delivery carrier, poly(sebacic-co-ricinoleic-ester-anhydride), designated as p(SA:RA), was injected, with and without gentamicin, into the tibial canal. Rats were killed 3 weeks later. The tibiae were processed histologically, leaving the injectable polymer in situ. The local tissue reaction to the polymer with or without antibiotic consisted mainly of mild reactive fibroplasia/fibrosis and mild to moderate increased reactive bone formation. At this stage, no evidence for any active inflammatory response to the polymer was seen. Thus, the injection of p(SA:RA) was well tolerated and did not induce any signs of a progressive inflammatory reaction.

Electrocoating of stainless steel coronary stents for extended release of paclitaxel.

Nonbiodegradable polymer coating based on N-(2-carboxyethyl)pyrrole (PPA) and butyl ester of PPA (BuOPy) were successfully electrodeposited on a stainless steel stent surface using cyclic voltammetry. Chemical composition of the coating was examined by X-ray photoelectron spectroscopy. Polymer stability was examined by immersing the coated stent into 1:1 solution of fetal calf serum:seline solution up to 1 year and implantation subcutaneously in mouse for 1 week. Morphology changes were then recorded by scanning electron microscopy. Paclitaxel loading was carried out by immersion into drug solution and its release was detected by HPLC. The results show that thin (single micrometers), uniform coating with various morphology and hydrophobicity can be created by electrochemical deposition. The polymer did not show significant histopathological or morphological changes in vitro and in vivo. The surface properties allow loading appropriate amounts of paclitaxel and release it slowly up to a month.

Cyclosporine safety and bioavailability with two second-generation softgel capsules using serum concentrations/TDM and modeling in transplant patients--a retrospective, parallel, comparative evaluation study.

OBJECTIVE: Deximune soft-gelatin capsules (Dexcel Ltd., Hadera, Israel), the test preparation and Sandimmun Neoral (Novartis Inc., Basel, Switzerland), the reference preparation, are two cyclosporine (CyA) formulations widely used after stem cells and solid organ transplantation. A post-marketing, retrospective, parallel, comparative, multicenter survey study in transplant patients receiving these two formulations after transplantation was carried out in order to compare the toxicity profile and bioavailability. MATERIALS AND METHODS: The study was conducted in the five main leading transplantation centers in Israel and included 174 patients. A total of 1-3 CyA serum levels at different periods after transplantation were measured in each subject and the bioavailability, efficacy and toxicity profile were assessed. The blood concentrations were compared using a statistical model after adjustment for type of transplantation, dose and time after transplantation as confounding factors. RESULTS: No distinct differences were observed between the two CyA formulations. Using model-derived least squares means (LSM) of the CyA blood levels and adjusting for relevant confounding factors, no significant difference could be found between the blood levels of the test and reference formulations. Most of the side effects were mild and transient with both formulations, whereas 23% of the patients reported serious adverse events (mainly hypertension, 15%). 20% of the patients developed infectious complications during the therapy. CONCLUSIONS: Deximune administration is safe. The toxicity profile of the product, incidence and type of side effects and bioavailability are similar to those of Sandimmun Neoral.

Comparative in vivo bioequivalence and in vitro dissolution of two cyclosporin A soft gelatin capsule formulations.

OBJECTIVE: A study was conducted to establish the bioequivalence between a newly developed cyclosporin A (CsA) oral formulation, Deximune soft-gelatin capsules (Dexcel Ltd.) and Sandimmune Neoral (Novartis Inc.). MATERIALS AND METHODS: The clinical investigation was designed as a randomized, open-labeled, two-period, two-treatment crossover study, in 24 healthy fasted male volunteers. The subjects were administered a single 200 mg CsA dose of either formulation. Serial venous blood samples were obtained over 24 hours after each administration to measure CsA in whole blood by a specific TDx-immunoassay. In addition, the comparative drug release rate was assessed using a dissolution apparatus test according to the USP-24 method. RESULTS: For both treatments, a mean maximum blood concentration (Cmax) of approximately 1,200 ng/ml was obtained at about 1.6 hours (tmax) after administration and the geometric mean of the area under the blood concentration-time curve (AUC) both for test and reference was approximately 4,900 ng x h/ml. Bioequivalence was conclusively demonstrated for both rate (Cmax and tmax) and extent (AUC) of CsA absorption, between the two treatments. Moreover, the CsA blood concentration measurement at 2 hours after administration (C2), demonstrated equivalent results between the two products. The point estimates and their 90% confidence intervals were within the respective equivalence ranges for the pharmacokinetic parameters and were included in the range for drugs with a narrow therapeutic index. The comparative dissolution test for both formulations showed an in vitro release rate of more than 90% within 15 minutes. CONCLUSIONS: Based on the results, the two oral CsA formulations compared are bioequivalent and can be interchanged without need for dosage adjustment.

Characterization and in vivo performance of dextran-spermine polyplexes and DOTAP/cholesterol lipoplexes administered locally and systemically.

In this study, we compared two systems which can be applied for transfection in vitro and in vivo: polyplexes based on the polymer dextran-spermine (D-SPM) and lipoplexes based on 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)/cholesterol. The carriers differ in (1) solubility in aqueous media, (2) source of the positive charges (quaternary amines for DOTAP and primary plus secondary amines for D-SPM), (3) electrostatics, i.e., for lipid and polymer, respectively: zeta-potential (81.0 and 48.1 mV), surface potential (180 and 92 mV), and surface pH (10.47 and 8.97), and (4) charge distribution (ordered versus non-ordered). The stability of the complex upon interaction with serum proteins was studied by means of fluorescence resonance energy transfer (FRET) between rhodamine-labeled cationic carriers and fluorescein-labeled DNA. Addition of serum increases the lipid-DNA average distance and decreases the polymer-DNA distance. However, FRET efficiency indicates that serum proteins do not induce a major DNA dissociation for either polyplexes or lipoplexes. Comparing the biodistribution of rhodamine-labeled complexes and the transgene expression after intravenous (i.v.), intramuscular (i.m.), and intranasal (i.n.) administration, we found that local administration of lipoplexes resulted in the lipoplexes remaining at the site of injection, whereas the polyplexes showed systemic distribution, accompanied by transgene expression in lungs and liver. It is suggested that the high water-solubility of the polymer combined with its lower positive charge (compared to DOTAP), which makes its association with the cells at the site of injection weaker, enables the polymer to reach and transfect distant organs through the blood stream. Using chemically modified D-SPM, we demonstrated the importance of high density of positive charges and a sufficient level of secondary amines for achieving efficient transgene expression in vivo.

Exploiting EPR in polymer drug conjugate delivery for tumor targeting.

Treatment of tumor tissue without affecting normal cells has always been formidable task for drug delivery scientists and this task is effectively executed by polymer drug conjugate (PDC) delivery. The novelty of this concept lies in the utilization of a physical mechanism called enhanced permeability and retention (EPR) for targeting tumors. EPR is a physiological phenomenon that is customary for fast growing tumor and solves the problem of targeting the miscreant tissue. PDCs offer added advantages of reduced deleterious effects of anticancer drugs and augmentation of its formulation capability (e.g. Solubility). There are now at least eleven PDCs that have entered phase I/II/III clinical trial as anticancer drugs. PDCs once entered into the tumor tissue, taking advantage of EPR, are endocytosed into the cell either by simple or receptor mediated endocytosis. Various polymeric carriers have been used with hydrolyzable linker arm for conjugation with bioactive moiety. The hydrolyzable linkages of PDC are broken down by acid hydrolyses of lysosomes and releases the drug. High concentrations of the chemotherapeutic agent are maintained near the nucleus, the target site. Passive targeting by PDCs is due to the physiological event of EPR, which is becoming one of the major thrust areas for targeting solid tumors.

Copolymers of pharmaceutical grade lactic acid and sebacic acid: drug release behavior and biocompatibility.

Pharmaceutical grade D,L-lactic acid, which is rather an economic source in comparison to lactide monomer, was utilized for synthesis of a series of copolymers with sebacic acid. Polymers were characterized by GPC, FTIR, NMR and DSC techniques, and formulated into blank and methotrexate (MTX) loaded microspheres by emulsion-solvent evaporation method. In vitro degradation of blank microspheres was studied by FTIR, GPC and SEM analysis. MTX loaded microspheres showed the encapsulation efficiency of 44-64% and were in the size range of 40-60 microm. These were used to study the release profile of the encapsulated drug. The release was found to be affected by the pH and buffer concentration of the release medium which was in turn revealed by solubility studies of MTX. The overall study demonstrates significance of drug as well as polymer properties on release. Biocompatibility of polymer was evaluated by injecting microspheres subcutaneously into Sprague-Dawley (SD) rat and no local histopathological abnormalities were found.

Structure and biological activity of heparinoid.

Heparin is a biogenic anionic charged sulfated polysaccharide that has a range of desired activities including inhibition of tumor metastasis and inhibition of restenosis. However, its clinical use is limited to treating blood-clotting disorders. Anionic macromolecules called heparinoids have been investigated with the objective of developing heparin-like molecules with reduced anti-coagulant activity and selective anti-metastasis and anti-restenosis activity. This mini-review summarizes the synthesis and biological activity of the main synthetic heparinoids reported in the past three decades.

Role of polyanhydrides as localized drug carriers.

Many drugs that are administered in an unmodified form by conventional systemic routes fail to reach target organs in an effective concentration, or are not effective over a length of time due to a facile metabolism. Various types of targeting delivery systems and devices have been tried over a long period of time to overcome these problems. Targeted delivery or localized drug delivery offers an advantage of reduced body burden and systemic toxicity of the drugs, especially useful for highly toxic drugs like anticancer agents. Local drug delivery via polymer is a simple approach and hypothesized to avoid the above stated problems. Polyanhydrides are a unique class of polymer for drug delivery because some of them demonstrate a near zero order drug release and relatively rapid biodegradation in vivo. Further, the release rate of polyanhydride fabricated device can be altered over a thousand fold by simple changes in the polymer backbone. Hence, these are one of the best-suited polymers for drug delivery, with biodegradability and biocompatibility. The review focuses on the advantages of polyanhydride carriers in localized drug delivery along with their degradability behavior, toxicological profile and role in various disease conditions.

Polymers for DNA delivery.

Nucleic acid delivery has many applications in basic science, biotechnology, agriculture, and medicine. One of the main applications is DNA or RNA delivery for gene therapy purposes. Gene therapy, an approach for treatment or prevention of diseases associated with defective gene expression, involves the insertion of a therapeutic gene into cells, followed by expression and production of the required proteins. This approach enables replacement of damaged genes or expression inhibition of undesired genes. Following two decades of research, there are two major methods for delivery of genes. The first method, considered the dominant approach, utilizes viral vectors and is generally an efficient tool of transfection. Attempts, however, to resolve drawbacks related with viral vectors (e.g., high risk of mutagenicity, immunogenicity, low production yield, limited gene size, etc.), led to the development of an alternative method, which makes use of non-viral vectors. This review describes non-viral gene delivery vectors, termed "self-assembled" systems, and are based on cationic molecules, which form spontaneous complexes with negatively charged nucleic acids. It introduces the most important cationic polymers used for gene delivery. A transition from in vitro to in vivo gene delivery is also presented, with an emphasis on the obstacles to achieve successful transfection in vivo.

Novel dextran-spermine conjugates as transfecting agents: comparing water-soluble and micellar polymers.

Recently, a novel cationic polymer, dextran-spermine (D-SPM) was developed for gene delivery. An efficient transfection was obtained using this polycation for a variety of genes and cell lines in serum-free or serum-poor medium. However, transfection using the water-soluble D-SPM-based polyplexes decreased with increasing serum concentration in cell culture in a concentration-dependent manner, reaching 95% inhibition at 50% serum in the cell growth medium. In order to overcome this obstacle, oleyl derivatives of D-SPM (which form micelles in aqueous phase) were synthesized at 1, 10, and 20 mol% of oleyl moiety to polymer epsilon-NH2 to form N-oleyl-D-SPM (ODS). Polyplexes based on ODS transfected well in medium containing 50% serum. Comparison with polyplexes based on well-established polymers (branched and linear polyethyleneimine) and with DOTAP/Cholesterol lipoplexes showed that regarding beta-galactosidase transgene expression level and cytotoxicity in tissue culture, the D-SPM and ODS compare well with the above polyplexes and lipoplexes. Intracellular trafficking using FITC-labeled ODS and Rhodamine-labeled pGeneGrip plasmid cloned with hBMP2 monitored by confocal microscopy revealed that during the transfection process the fluorescent-labeled polymer concentrates in the Golgi apparatus and around the nucleus, while the cell cytoplasm was free of fluorescent particles, suggesting that the polyplexes move in the cell toward the nucleus by vesicular transport through the cytoplasm and not by a random diffusion. We found that the plasmids penetrate the cell nucleus without the polymer. Preliminary results in zebra fish and mice demonstrate the potential of ODS to serve as an efficient nonviral vector for in vivo transfection.

[A new gel for topical use in treating severe periodontal disease--clinical observations].

Within the framework of the efforts to find non-invasive treatment methods for severe periodontitis, a topical gel was developed by an Israeli research group. The aim of the current study is to present clinical observations and X-ray measurements of alveolar bone changes following an 8 week, self-care periodontal treatment in two groups of patients with severe periodontitis. All 31 patients who participated in the study showed an improvement of the periodontal condition as expressed in all the indexes examined. The observation findings testify to the fact that through self-care using a topical gel, significant results were achieved: decrease in probing depth, decrease in bleeding, significant improvement in teeth mobility and in level of the alveolar bone height and its density. These clinical findings raise interesting research questions and hint at the potential for regeneration of supportive periodontal tissues in cases of severe periodontitis, currently achieved only through surgical means. In order to obtain more accurate data regarding the treatment potential of this gel, it is important to conduct additional controlled clinical trials on different populations and also to try and determine how it works.

Conjugation of amino-containing drugs to polysaccharides by tosylation: amphotericin B-arabinogalactan conjugates.

The coupling of amphotericin-B (AmB), a water-insoluble antifungal and antileishmanial agent, to arabinogalactan (AG) via tosylate or mesylate derivatives was investigated as a method for the conjugation of amino-containing drugs to polysaccharides. In the first step, AG was reacted with tosyl- or mesyl-chloride at different ratios to obtain tosylate or mesylate AG derivatives. AmB was conjugated to AG derivatives in either aqueous or organic media via an amine bond. AG-AmB conjugates were soluble in water and exhibited improved stability in aqueous solutions as compared to the unbound drug. The conjugates showed comparable inhibitory concentration values against the pathogenic yeast Candida albicans, and against Leishmania major parasites. They were about 60 times less hemolytic against sheep erythrocytes than the free drug, and less toxic when injected i.v. to BALB/c mice.