Disodium salt of glycyrrhizic acid – A novel supramolecular delivery system for anthelmintic drug praziquantel

Self-nanomicellizing solid dispersion: A promising platform for oral drug delivery

Amorphous solid dispersion (ASD) has been widely used to enhance the oral bioavailability of water-insoluble drugs for oral delivery because of its advantages of enhancing solubility and dissolution rate. However, the problems related to drug recrystallization after drug dissolution in media or body fluid have constrained its application. Recently, a self-nanomicellizing solid dispersion (SNMSD) has been developed by incorporating self-micellizing polymers as carriers to settle the problems, markedly improving the ability of supersaturation maintenance and enhancing the oral bioavailability of drug. Spontaneous formation and stability of the self-nanomicelle (SNM) have been proved to be the key to supersaturation maintenance of SNMSD system. This offers a novel research direction for maintaining supersaturation and enhancing the bioavailability of ASDs. To delve into the advantages of SNMSDs, we provide a concise review introducing the formation mechanism, characterization methods and stability of SNMs, emphasizing the advantages of SNMSDs for oral drug delivery facilitated by SNM formation, and discussing relevant research prospects.

Assessing the effectiveness of fenbendazole supramolecular complexes against schistosomiasis, monieziosis and parabronemosis in sheep

Helminth infections pose a significant economic threat to livestock production, causing productivity declines and, in severe cases, mortality. Conventional anthelmintics, exemplified by fenbendazole, face challenges related to low solubility and the necessity for high doses. This study explores the potential of supramolecular complexes, created through mechanochemical modifications, to address these limitations. The study focuses on two key anthelmintics, praziquantel (PZQ) and fenbendazole (FBZ), employing mechanochemical techniques to enhance their solubility and efficacy. Solid dispersions (SD) of PZQ with polymers and dioctyl sulfosuccine sodium (DSS) and fenbendazole with licorice extract (ES) and DSS were prepared. The helminthicidal activity of these complexes was assessed through helminthological dissections of sheep infected with Schistosoma turkestanicum, moniesiasis, and parabronemosis. In the assessment of supramolecular complex of FBZ (SMCF) at doses ranging from 1.0 to 3.0 mg/kg for the active substance (AS), optimal efficacy was observed with the fenbendazole formulation containing arabinogalactan and polyvinylpyrrolidone at a 3.0 mg/kg dosage. At this concentration, the formulation demonstrated a remarkable 100% efficacy in treating spontaneous monieziosis in sheep, caused by Moniezia expansa (Rudolphi, 1810) and M. benedenii (Moniez, 1879). Furthermore, the SMCF, administered at doses of 1.0, 2.0, and 3.0 mg/kg, exhibited efficacy rates of 42.8%, 85.7%, and 100%, respectively, against the causative agent of parabronemosis (Parabronema skrjabini Rassowska, 1924). Mechanochemical modifications, yielding supramolecular complexes of PZQ and FBZ, present a breakthrough in anthelmintic development. These complexes address solubility issues and significantly reduce required doses, offering a practical solution for combating helminth infections in livestock. The study underscores the potential of supramolecular formulations for revolutionizing helminthiasis management, thereby enhancing the overall health and productivity of livestock.

Curcumin and Its Supramolecular Complex with Disodium Glycyrrhizinate as Potential Drugs for the Liver Fluke Infection Caused by Opisthorchis felineus

Opisthorchiosis is a parasitic liver disease found in mammals that is widespread throughout the world and causes systemic inflammation. Praziquantel remains the drug of choice for the treatment of opisthorchiosis, despite its many adverse effects. An anthelmintic effect is attributed to the main curcuminoid of Curcuma longa L. roots-curcumin (Cur)-along with many other therapeutic properties. To overcome the poor solubility of curcumin in water, a micellar complex of curcumin with the disodium salt of glycyrrhizic acid (Cur:Na₂GA, molar ratio 1:1) was prepared via solid-phase mechanical processing. In vitro experiments revealed a noticeable immobilizing effect of curcumin and of Cur:Na₂GA on mature and juvenile Opisthorchis felineus individuals. In vivo experiments showed that curcumin (50 mg/kg) had an anthelmintic effect after 30 days of administration to O. felineus-infected hamsters, but the effect was weaker than that of a single administration of praziquantel (400 mg/kg). Cur:Na₂GA (50 mg/kg, 30 days), which contains less free curcumin, did not exert this action. The complex, just as free curcumin or better, activated the expression of bile acid synthesis genes (Cyp7A1, Fxr, and Rxra), which was suppressed by O. felineus infection and by praziquantel. Curcumin reduced the rate of inflammatory infiltration, whereas Cur:Na₂GA reduced periductal fibrosis. Immunohistochemically, a decrease in liver inflammation markers was found, which is determined by calculating the numbers of tumor-necrosis-factor-positive cells during the curcumin treatment and of kynurenine-3-monooxygenase-positive cells during the Cur:Na₂GA treatment. A biochemical blood test revealed a normalizing effect of Cur:Na₂GA (comparable to that of curcumin) on lipid metabolism. We believe that the further development and investigation of therapeutics based on curcuminoids in relation Opisthorchis felineus and other trematode infections will be useful for clinical practice and veterinary medicine.

Unification of medicines and excipients: The roles of natural excipients for promoting drug delivery

INTRODUCTION

Drug delivery systems (DDSs) formed by natural active compounds be instrumental in developing new green excipients and novel DDS from natural active compounds (NACs). 'Unification of medicines and excipients'(UME), the special inherent nature of the natural active compounds, provides the inspiration and conduction to achieve this goal.

AREAS COVERED

This review summarizes the typical types of NACs from herbal medicine, such as saponins, flavonoids, polysaccharides, etc. that act as excipients and their main application in DDS. The comparison of the drug delivery systems formed by NACs and common materials and the primary formation mechanisms of these NACs are also introduced to provide a deepened understanding of their performance in DDS.

EXPERT OPINION

Many natural bioactive compounds, such as saponins, polysaccharides, etc. have been used in DDS. Diversity of structure and pharmacological effects of NACs turn out the unique advantages in improving the performance of DDSs like targeting ability, adhesion, encapsulation efficiency(EE), etc. and enhancing the bioavailability of loaded drugs.

Tunable Polymeric Mixed Micellar Nanoassemblies of Lutrol F127/Gelucire 44/14 for Oral Delivery of Praziquantel: A Promising Nanovector against Hymenolepis nana in Experimentally-Infected Rats

Hymenolepiasis represents a parasitic infection of common prevalence in pediatrics with intimidating impacts, particularly amongst immunocompromised patients. The present work aimed to snowball the curative outcomes of the current mainstay of hymenolepiasis chemotherapy, praziquantel (PRZ), through assembly of polymeric mixed micelles (PMMs). Such innovative nano-cargo could consolidate PRZ hydrosolubility, extend its circulation time and eventually upraise its bioavailability, thus accomplishing a nanoparadigm for hymenolepiasis tackling at lower dose levels. For consummating this goal, PRZ-PMMs were tailored via thin-film hydration technique integrating a binary system of Lutrol F127 and Gelucire 44/14. Box-Behnken design was planned for optimizing the nanoformulation variables employing Design-Expert^® software. Also, in Hymenolepis nana-infected rats, the pharmacodynamics of the optimal micellar formulation versus the analogous crude PRZ suspension were scrutinized on the 1st and 3rd days after administration of a single oral dose (12.5 or 25 mg/kg). Moreover, in vitro ovicidal activity of the monitored formulations was estimated utilizing Fuchsin vital stain. Furthermore, the in vivo pharmacokinetics were assessed in rats. The optimum PRZ-PMMs disclosed conciliation between thermodynamic and kinetic stability, high entrapment efficiency (86.29%), spherical nanosized morphology (15.18 nm), and controlled-release characteristics over 24 h (78.22%). ¹H NMR studies verified PRZ assimilation within the micellar core. Additionally, the in vivo results highlighted a significant boosted efficacy of PRZ-PMMs manifested by fecal eggs output and worm burden reduction, which was clearly evident at the lesser PRZ dose, besides a reversed effect for the intestinal histological disruptions. At 50 µg/mL, PRZ-PMMs increased the percent of non-viable eggs to 100% versus 47% for crude PRZ, whilst shell destruction and loss of embryo were only clear with the applied nano-cargo. Moreover, superior bioavailability by 3.43-fold with elongated residence time was measured for PRZ-PMMs compared to PRZ suspension. Practically, our results unravel the potential of PRZ-PMMs as an oral promising tolerable lower dose nanoplatform for more competent PRZ mass chemotherapy.

Effect of glycyrrhizic acid on phospholipid membranes in media with different pH

Glycyrrhizic acid (GA) is the active ingredient in licorice root, which exhibits a wide range of biological activities, including anti-inflammatory and antiviral activities. In particular, the virus-inhibiting effect of GA on SARS-associated coronavirus was demonstrated. In addition, GA was found to be capable of increasing bioaccessibility of other drugs when used together. All these effects can be based on the ability of GA to incorporate into cell membranes and change their physical and functional properties. One of the possible mechanisms of the antiviral action of GA against COVID-19 is also considered to be the prevention of fusion of the virus envelope with the plasma membrane of the host cell. The interaction of GA with model lipid membranes was studied by the NMR method. Different factors influencing the incorporation of the GA molecule into the lipid bilayer (phospholipid structure, pH of the medium) were examined.

Photostabilization of ketoprofen by inclusion in glycyrrhizin micelles and gel nanoparticles

Ketoprofen (KP) is known to be the most photosensitive among the nonsteroidal anti-inflammatory drugs and may induce phototoxic and photoallergic reactions. Phototoxic side effects of KP are associated with the...

Mechanism of the enhancing effect of glycyrrhizin on nifedipine penetration through a lipid membrane

The saponin glycyrrhizin from liquorice root shows the ability to enhance the therapeutic activity of other drugs when used as a drug delivery system. Due to its amphiphilic properties, glycyrrhizin can form self-associates (dimers, micelles) and supramolecular complexes with a wide range of hydrophobic drugs, which leads to an increase in their solubility, stability and bioavailability. That is why the mechanism of the biological activity of glycyrrhizin is of considerable interest and has been the subject of intensive physical and chemical research in the last decade. Two mechanisms have been proposed to explain the effect of glycyrrhizin on drug bioavailability, namely, the increase in drug solubility in water and enhancement of the membrane permeability. Interest in the membrane-modifying ability of glycyrrhizic acid (GA) is also growing at present due to its recently discovered antiviral activity against SARS-CoV-2 Bailly and Vergoten (2020) [1]. In the present study, the passive permeability of the DOPC lipid membrane for the calcium channel blocker nifedipine was elucidated by parallel artificial membrane permeability assay (PAMPA) and full atomistic molecular dynamics (MD) simulation with free energy calculations. PAMPA experiments show a remarkable increase in the amount of nifedipine (NF) permeated with glycyrrhizin compared to free NF. In previous studies, we have shown using MD techniques that glycyrrhizin molecules can integrate into the lipid bilayer. In this study, MD simulation demonstrates a significant decrease in the energy barrier of NF penetration through the lipid bilayer in the presence of glycyrrhizin both in the pure DOPC membrane and in the membrane with cholesterol. This effect can be explained by the formation of hydrogen bonds between NF and GA in the middle of the bilayer.

Glycyrrhiza acid micelles loaded with licochalcone A for topical delivery: Co-penetration and anti-melanogenic effect

The co-penetration of micellar vehicles and the encapsulated drugs into the skin layers, as well as the mechanisms underlying the penetration enhancement have not been clearly elucidated. We developed licochalcone A (LA)-loaded glycyrrhiza acid (GA) (GA+LA) micelles for topical delivery of LA into the epidermis. The in vitro co-penetration, penetration pathways, mechanism of interaction between skin and the micelles, and the in vitro and in vivo whitening effect of GA+LA micelles were evaluated. Co-penetration and penetration pathways were visualized on the abdominal skin of rats model with confocal laser scanning microscopy (CLSM) using a nile blue A-labeled GA (GA-NB). We found that GA significantly increased the transport of LA into the skin predominantly via the hair follicles and GA mainly accumulated in the SC and epidermis, while LA was localized in the epidermis and dermis. Moreover, 73.4% of the LA deposited into the epidermis within 12 h and approximately 9.32% of the LA permeated across the SC in the form of entire micelles within 24 h. GA-NB+LA micelles disaggregated and accumulated in the specific skin layers, and the LA released from the carrier penetrated into deeper layers. Moreover, the GA+LA micelles promoted drug penetration via intracellular or intercellular routes by loosening the skin surface and enhancing fluidization through lipid distortion and keratin denaturation. Furthermore, GA+LA micelles exhibited synergistic whitening effect on B16 cells and UVB-exposed C57BL/6 mice. Collectively, GA micelles can enhance penetration of LA to the epidermis mainly via the hair follicles following topical application, and reduce skin pigmentation.

Effects of Three-time Administration of a Supramolecular Complex of Praziquantel with Disodium Glycyrrhizinate on Trematode Opisthorchis felineus in Hamsters

BACKGROUND

Praziquantel (PZQ) is the most commonly used anthelmintic drug for treating trematodiases. It was shown here that PZQ in complex with disodium glycyrrhizinate (PZQ-Na₂GA, in the 1:10 ratio) has higher bioavailability than PZQ alone. Our aim was to determine the effects of three-time administration of PZQ-Na₂GA in an experimental opisthorchiasis felinea model.

METHODS

The PZQ-Na₂GA complex (1:10) at a 400 mg/kg dose (meaning 36.4 mg/kg PZQ) was administered to Opisthorchis felineus-infected hamsters three times under a "9:00 am-6:00 pm-9:00 am" regimen (PZQ-Na₂GA × 3). Effects of treatment were assessed as a reduction of helminth load in the hamsters and as changes in physiological, hematological, and blood biochemical parameters. The helminths extracted from the liver of the hamsters that received PZQ-Na₂GA thrice were assayed for sensitivity to PZQ in vitro.

RESULTS

PZQ-Na₂GA × 3 reduced the number of O. felineus helminths in the liver by 87%, which is 30% better than a previously reported effect of one-time administration of the complex. Meanwhile, relative weights of the liver and thymus diminished, and some hematological parameters improved. The helminths extracted from the hamsters 1 month after the PZQ-Na₂GA × 3 treatment showed elevated sensitivity to PZQ, as determined in vitro.

CONCLUSION

Compared with previously published data on the effectiveness of various drugs in experimental opisthorchiasis felinea, PZQ-Na₂GA × 3 exerts the most potent anthelmintic effect. In addition, PZQ-Na₂GA × 3 improves physiological status of O. felineus-infected hamsters and sensitizes the surviving parasites to subsequent PZQ treatment.

Saponin surfactants used in drug delivery systems: A new application for natural medicine components

Saponins are a group of compounds widely distributed in the plant kingdom. Due to their amphiphilic characteristic structure, saponins have high surface activity and self-assembly property and can be used as natural biosurfactants. Therefore, saponin has become a potential drug delivery system (DDS) carrier and has attracted the attention of many researchers. Increasing studies have found that when drugs combining with saponins, their solubility or bioavailability are improved. This phenomenon may be due to a synergistic mechanism and provides a potentially novel concept for DDS: saponins may be also used for carrier materials. This review emphasized the molecular characteristics and mechanism of saponins as carriers and the research on the morphology of saponin carriers. Besides, the article also introduced the role and application of saponins in DDS. Although there are still some limitations with the application of saponins such as cost, applicability, and hemolysis, the development of technology and in-depth molecular mechanism research will provide saponins with greater application prospects as DDS carriers.

Anthelmintics for drug repurposing: Opportunities and challenges

Drug repositioning is defined as a process to identify a new application for drugs. This approach is critical as it takes advantage of well-known pharmacokinetics, pharmacodynamics, and toxicity profiles of the drugs; thus, the chance of their future failure decreases, and the cost of their development and the required time for their approval are reduced. Anthelmintics, which are antiparasitic drugs, have recently demonstrated promising anticancer effects in vitro and in vivo. This literature review focuses on the potential of anthelmintics for repositioning in the treatment of cancers. It also discusses their pharmacokinetics and pharmacodynamics as antiparasitic drugs, proposed anticancer mechanisms, present development conditions, challenges in cancer therapy, and strategies to overcome these challenges.

Nanotechnological Improvement of Veterinary Anthelmintics

Helminths infections are among the most important problems in animal health and husbandry. Moreover, zoonotic helminths endanger rural communities, particularly in developing countries. Helminthiasis are not only important in relation to the harmful effects of parasites; additional issues like anthelmintic resistance spread became more important over time. As new anthelmintic development takes many years and millions of dollars of investment, some strategies are currently focused on the modification of already available drugs, in order to improve their efficacy and overcome their limitations. In this field, nanotechnology has brought a novel approach, showing advantages like the regulation of the drug's delivery and kinetics, reaching of specific targets, and possibilities to avoid the systemic spread and side effects. Taking this into account, the present review aims to introduce some of the current knowledge in anthelmintic improvement based on nanotechnology, and how researchers could benefit from this technology in order to overcome the drugs limitations. Finally, some insights into potential field applications are discussed, based on the most important concerns of current anthelmintic therapy.

Solubility, Permeability, Anti-Inflammatory Action and In Vivo Pharmacokinetic Properties of Several Mechanochemically Obtained Pharmaceutical Solid Dispersions of Nimesulide

Nimesulide (NIM, N-(4-nitro-2-phenoxyphenyl)methanesulfonamide) is a relatively new nonsteroidal anti-inflammatory analgesic drug. It is practically insoluble in water (<0.02 mg/mL). This very poor aqueous solubility of the drug may lead to low bioavailability. The objective of the present study was to investigate the possibility of improving the solubility and the bioavailability of NIM via complexation with polysaccharide arabinogalactan (AG), disodium salt of glycyrrhizic acid (Na₂GA), hydroxypropyl-β-cyclodextrin (HP-β-CD) and MgCO₃. Solid dispersions (SD) have been prepared using a mechanochemical technique. The physical properties of nimesulide SD in solid state were characterized by differential scanning calorimetry and X-ray diffraction studies. The characteristics of the water solutions which form from the obtained solid dispersions were analyzed by reverse phase and gel permeation HPLC. It was shown that solubility increases for all complexes under investigation. These phenomena are obliged by complexation with auxiliary substances, which was shown by ¹H-NMR relaxation methods. The parallel artificial membrane permeability assay (PAMPA) was used for predicting passive intestinal absorption. Results showed that mechanochemically obtained complexes with polysaccharide AG, Na₂GA, and HP-β-CD enhanced permeation of NIM across an artificial membrane compared to that of the pure NIM. The complexes were examined for anti-inflammatory activity on a model of histamine edema. The substances were administered per os to CD-1 mice. As a result, it was found that all investigated complexes dose-dependently reduce the degree of inflammation. The best results were obtained for the complexes of NIM with Na₂GA and HP-β-CD. In noted case the inflammation can be diminished up to 2-fold at equal doses of NIM.

pH-Sensitive Glycyrrhizin Based Vesicles for Nifedipine Delivery

Glycyrrhizic acid, or glycyrrhizin (GA), a major active component of licorice root, has been widely used in traditional Chinese and Japanese medicine since ancient times. However, only in the last decades has a novel and unusual property of the GA been discovered to form water-soluble, supramolecular complexes with a variety of lipophilic drugs. These complexes show significant advantages over other known delivery systems, in particular, due to strong pH sensitivity, the properties of GA self-associates. In the present study, a supramolecular complex formation of the hypotensive and antiarrhythmic drug nifedipine with GA has been studied at different pH values, corresponding to the different degrees of GA dissociation, including a fully dissociated state of GA. Both NMR experiments and molecular dynamics simulations demonstrate the existence of the nifedipine complex with GA at all dissociation states of GA. However, optical absorption experiments show the decrease of complex stability and solubility at pH > 6 when the GA molecule is fully deprotonated. It means the higher release rate of the drug in a neutral and basic environment compared with acid media. These results could form the basis of follow-up studies of GA self-associates as pH-controlled drug delivery systems.

Study of supramolecular complex of nifedipine with arabinogalactan on Wistar and ISIAH rats

Aim: Physicochemical and pharmacological study of the supramolecular inclusion complexes of the hypotensive drug nifedipine (NF) with the larch polysaccharide arabinogalactan (AG). Materials & methods: The NF:AG complexes were obtained and their physicochemical properties were studied. Their hypotensive action and pharmacokinetic profiles were evaluated in rats with normal and elevated arterial blood pressure. Results: In both rat lines the NF:AG complex decreased the arterial blood pressure at a lower dose than free NF (1.75 mg/kg of NF in complex compared with 3.5 mg/kg of free NF) and has a better pharmacokinetic profile than free NF. Conclusion: The use of the NF:AG complex is an effective way to sufficiently enhance and hasten NF's hypotensive action.

Water-Soluble Substances of Arglabin

The article discusses the results of a study of the water solubility of natural sesquiterpene lactone arglabin, in particular, its ability to complex formation with complexing agents polyvinylpyrrolidone, the disodium salt of glycyrrhizic acid, magnesium carbonate. Mechanocomposites with polyvinylpyrrolidone and disodium salt of glycyrrhizic acid, which have increased water solubility, were obtained by the method of mechanochemical treatment of arglabin native. At the same time, the best result of dissolution in water is achieved by a two-hour treatment with polyvinylpyrrolidone and with disodium salt of glycyrrhizic acid. The water solubility of complex compounds of arglabin with polyvinylpyrrolidone increases by 4.61 times, and with disodium salt of glycyrrhizic acid by 4.42 times.

Praziquantel-Clays as Accelerated Release Systems to Enhance the Low Solubility of the Drug

Praziquantel is an antiparasitic drug indicated for the treatment of the schistosomiasis disease. This drug has very low aqueous solubility, requiring high oral doses for its administration which gives rise to side effects, therapeutic noncompliance and the appearance of resistant forms of the parasite. Clay minerals, like sepiolite and montmorillonite, are innocuous, non-toxic, biocompatible and low-cost excipients. Additionally, clays have high adsorbent properties that allow them to encapsulate drugs in nanometric spaces present in the channels in the case of the sepiolite or between the layers in the case of the montmorillonite. The interactions between the drug and clay minerals are studied experimentally with the strategy for preparing interactions products in organic solvents (ethanol, acetonitrile and dichloromethane) so that the interaction will be more effective and will be enhanced the aqueous solubility of praziquantel. The results showed that in the interaction products, the drug interacted with both clay minerals, which produced the loss of the crystallinity of the drug demonstrated by different techniques. This led to a significant increase in the dissolution rate of the praziquantel in all the interaction products in the simulated gastrointestinal tract media, except for the praziquantel–montmorillonite product prepared in dichloromethane that presented a controlled release in acid medium. Moreover, in vitro cytotoxicity and cell cycle studies were performed in the interaction products prepared with ethanol. The interaction product with sepiolite was biocompatible with the HTC116 line cells, and it did not produce alterations in the cell cycle. However, interaction products with montmorillonite did not produce cell death, but they showed affectation and damage of cells in the cell cycle study at the highest concentration tested (20–100 µM). Therefore, the different organic solvents used are adequate for the improvement of the biopharmaceutical profile of praziquantel. Drug–clay interaction products, specifically with sepiolite, showed very promising results in which new accelerated oral release systems of the praziquantel were obtained.

Effectiveness of Repeated Administration of Praziquantel with Disodium Glycyrrhizinate and Two Enantiomers of Praziquantel on Opisthorchis felineus (Rivolta, 1884)

BACKGROUND

Nowadays, it is still important to develop effective anti-opisthorchiasis agents. In this work, we tested a complex of praziquantel (PZQ) with a plant origin compound-disodium glycyrrhizinate-in the ratio 1:10 PZQ:Na₂GA, containing 11-fold less of the active ingredient. Our aim was to study various ways to treat trematode Opisthorchis felineus with this complex in vitro. Additionally, an in vitro comparison of the anthelmintic action was made among racemic-PZQ, (R)-PZQ, and (S)-PZQ on juvenile and adult maritae of O. felineus.

METHODS

Worms extracted from the hamsters were subjected to various regimens of administration of the complex: once a day for 3 days or three times within 1 day. Moreover, mature maritae and juvenile worms of O. felineus were subjected to the comparison the anthelmintic effectiveness of racemic-PZQ, (R)-PZQ, and (S)-PZQ.

RESULTS

The O. felineus maritae that received PZQ:Na₂GA (1:10) thrice within 1 day were most strongly affected by the drug. Their motility substantially decreased already on the second day after the last dose, and the percentage of live worms by the end of the experimental period was the lowest. These results indicate a cumulative anthelmintic effect of this substance under the regimen "three times within 1 day." For the first time, we report that among the three substances (racemic-PZQ and two enantiomers), (R)-PZQ has the highest anthelmintic activity, toward both juvenile and sexually mature maritae of O. felineus.

CONCLUSION

These findings suggest that the development of a supramolecular complex of (R)-PZQ with disodium glycyrrhizinate and administration of this complex three times within 1 day are promising approaches.

Supramolecular Carotenoid Complexes of Enhanced Solubility and Stability-The Way of Bioavailability Improvement

Carotenoids are natural dyes and antioxidants widely used in food processing and in therapeutic formulations. However, their practical application is restricted by their high sensitivity to external factors such as heat, light, oxygen, metal ions and processing conditions, as well as by extremely low water solubility. Various approaches have been developed to overcome these problems. In particular, it was demonstrated that application of supramolecular complexes of “host-guest” type with water-soluble nanoparticles allows minimizing the abovementioned disadvantages. From this point of view, nanoencapsulation of carotenoids is an effective strategy to improve their stability during storage and food processing. Also, nanoencapsulation enhances bioavailability of carotenoids via modulating their release kinetics from the delivery system, influencing the solubility and absorption. In the present paper, we present the state of the art of carotenoid nanoencapsulation and summarize the data obtained during last five years on preparation, analysis and reactivity of carotenoids encapsulated into various nanoparticles. The possible mechanisms of carotenoids bioavailability enhancement by multifunctional delivery systems are also discussed.

Glycyrrhizin-Assisted Transport of Praziquantel Anthelmintic Drug through the Lipid Membrane: An Experiment and MD Simulation

Praziquantel (PZQ) is one of the most widespread anthelmintic drugs. However, the frequent insufficient application of PZQ after oral administration is associated with its low solubility, penetration rate, and bioavailability. In the present study, the permeation of PZQ through a 1,2-dioleoyl- sn-glycero-3-phosphocholine (DOPC) membrane was investigated to probe glycyrrhizin-assisted transport. Glycyrrhizin (or glycyrrhizic acid, GA), a natural saponin, shows the ability to enhance the therapeutic activity of various drugs when it is used as a drug delivery system. However, the molecular mechanism of this effect is still under debate. In the present study, the transport rate was measured experimentally by a parallel artificial membrane permeation assay (PAMPA) and molecular dynamics (MD) simulation with DOPC lipid bilayers. The formation of the noncovalent supramolecular complex of PZQ with disodium salt of GA (Na2GA) in an aqueous solution was proved by the NMR relaxation technique. PAMPA experiments show a strong increase in the amount of the penetrating praziquantel molecules in comparison with a saturated aqueous solution of pure drug used as a control. MD simulation of PZQ penetration through the bilayer demonstrates an increase in permeability into the membrane in the presence of a glycyrrhizin molecule. A decrease in the free energy barrier in the middle of the lipid bilayer was obtained, associated with the hydrogen bond between PZQ and GA. Also, GA reduces the local bilayer surface resistance to penetration of PZQ by rearranging the surface lipid headgroups. This study clarifies the mechanism of increasing the drug's bioavailability in the presence of glycyrrhizin.

Effects of supramolecular complexation of praziquantel with disodium glycyrrhizinate on the liver fluke Opisthorchis felineus: An in vitro and in vivo study

Millions of people worldwide have a chronic infection with the liver fluke Opisthorchis felineus, which causes opisthorchiasis in humans and animals. The only known effective drug for this disease is praziquantel (PrzQ); however, its efficacy is below 100%, and it has some adverse effects. In this study, a water-soluble complex of PrzQ with a disodium salt of glycyrrhizic acid (disodium glycyrrhizinate; Na₂GA) in a 1:10 ratio (PrzQ:GA) allowed the PrzQ dose to be decreased 11-fold for effective killing of O. felineus. An in vitro experiment showed a sufficient anthelmintic efficiency of PrzQ:GA against both adult and juvenile O. felineus individuals. A Syrian golden hamster model of opisthorchiasis revealed a considerable anthelmintic effect at all tested PrzQ:GA doses (50, 100, 200, 400, and 1100 mg/kg) with the best performance at 400 and 1100 mg/kg. Further comparison of the effects of PrzQ (400 mg/kg) and PrzQ:GA (400 mg/kg) regarding the state of the host indicated significant advantages of the latter. Histological examination showed that PrzQ:GA was better at decreasing the O. felineus-induced inflammatory infiltration (as compared with PrzQ alone) as well as interfered with the development of epithelial dysplasia and metaplasia in large bile ducts and cholangiofibrosis. Both PrzQ and PrzQ:GA decreased the number of myeloid (CFU-GM) and erythroid (BFU-E + CFU-E) colonies induced by O. felineus infection. The drugs had no negative effect on the animal behavior in an open field test 2-4 h after administration. Thus, PrzQ:GA proved to be a good anthelmintic agent having no evident adverse effects on the host, thereby suggesting that further preclinical and clinical trials would be warranted.

Glycyrrhizic acid as a multifunctional drug carrier - From physicochemical properties to biomedical applications: A modern insight on the ancient drug

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Glycyrrhizic acid (GA), saponin of licorice shows wide range of biological activity.

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Mechanism of GA activity on the cell and molecular level is rarely discussed.

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GA activity could be caused by the cell membrane modification.

Glycyrrhizic acid is the main active component of Licorice root which has been known in traditional Chinese and Japanese medicine since ancient times. In these cultures glycyrrhizic acid (GA) is one of the most frequently used drugs. However, only in 21-st century a novel unusual property of the GA to enhance the activity of other drugs has been discovered. The review describes briefly the experimental evidences of wide spectrum of own biological activities of glycyrrhizic acid as well as discusses the possible mechanisms of the ability of GA to enhance the activity of other drugs. We have shown that due to its amphiphilic nature GA is able to form self-associates in aqueous and non-aqueous media, as well as water soluble complexes with a wide range of lipophilic drugs. The main purpose of our review is to focus reader's attention on physicochemical studies of the molecular mechanisms of GA activity as a drug delivery system (DDS). In our opinion, the most intriguing feature of glycyrrhizic acid which might be the key factor in its therapeutic activity is the ability of GA to incorporate into the lipid bilayer and to increase the membrane fluidity and permeability. The ability of biomolecules and their aggregates to change the properties of cell membranes is of great significance, from both fundamental and practical points of view.