Improving the solubility and bioavailability of dihydroartemisinin by solid dispersions and inclusion complexes

Hybrid Nanoparticle for Co-delivering Paclitaxel and Dihydroartemisinin to Exhibit Synergic Anticancer Therapeutics

AIM

Anticancer treatment is required to provide effective and safe patient medicines. This research aided in developing and applying nanoparticles (NPs) for cancer treatment.

BACKGROUND

The poor solubility of paclitaxel (PTX) restricts its therapeutic efficacy because of allergic side effects caused by formulation excipients. To overcome this, PTX was coupled with artemisinin derivatives and loaded into an NP drug delivery system to enhance its effects while addressing its low solubility.

OBJECTIVES

This study prepared and characterized a hybrid PLGA-lecithin NP containing dihydroartemisinin (DHA) and PTX for synergic anticancer therapy. A lyophilization study improved the stability of the NP drug formulations.

METHODS

Dual PTX- and DHA-loaded PLGA- and lecithin-based NPs were prepared using a single-step solvent evaporation method. The NP suspensions were lyophilized, and the types and ratios of cryoprotectants were investigated. The physicochemical properties of NPs and lyophilized cakes (Lyo-NPs) were characterized. The stability of the Lyo-NPs was investigated at 2-8°C and room conditions. The anticancer effects of the drug combination, NP suspension, and lyophilized powder were analyzed using an in vitro cytotoxicity assay and an in vivo model.

RESULTS

The optimal PTX-DHA loaded PLGA-lecithin-NP was formulated (200 nm, PDI: 0.248 ± 0.003, Zeta potential: -33.60 ± 3.39 mV). Mannitol was selected for lyophilization. Lyo-NPs improved the stability of the NPs (1 year), wherein the physicochemical properties of the NPs were maintained (RDI was close to 1.0). An in-vitro cytotoxicity assay of PTX combined with DHA showed a synergistic anticancer effect (CI <1.0). The suppressive effects of Lyo-NPs on tumor growth in vivo were dose-dependent. While the cocktail of free drugs showed high toxicity (7.5 mg PTX-15 mg DHA/kg) in-vivo, Lyo-NPs showed no statistical differences in hematological and biochemical parameters compared to the control.

CONCLUSION

Dual-drug-loaded hybrid PLGA-lecithin NP is a potential system to minimize severe side effects while enhancing antitumor efficacy, in which lyophilization is a key process to increase stability.

Structural, electronic and nonlinear optical properties, reactivity and solubility of the drug dihydroartemisinin functionalized on the carbon nanotube

Density functional theory (DFT) calculations of the antimalarial drug dihydroartemisinin (DHA) functionalized on the carbon nanotube (CNT) were carried out in gas phase and in solution to investigate the role of fCNTs as a nanovector for the targeted delivery of the DHA drug and to predict their chemical descriptors and electronic and nonlinear optical (NLO) properties. The results of the geometric optimization indicate that the functionalization does not change the molecular structure of DHA. Based on our findings of binding and solvation energies, two energetically stable configurations were identified in 1st (fCNT1-2) and 2nd (2fCNT1-2) functionalization. For these stable configurations, the energy gap value goes from 1.52 eV for the (5,5) single wall pristine CNT to 1.27 eV for the 1st functionalization and to 1.06 eV for the 2nd functionalization regardless of the considered media; which gives these nanostructures excellent semiconductor properties. Findings from global reactivity descriptors show that the reactivity of the functionalized CNT is strongly improved in solvent media and that the stability of DHA decreases while its reactivity increases during the functionalization. Thus, the fundamental gap (E_f) in gas phase decreases from 3.65 eV for the virgin CNT to 3.30 eV for fCNT2 and to 3.02 eV for 2fCNT2. On the contrary, in water E_f goes from 1.20 eV for the virgin CNT to 0.95 eV for fCNT2 and to 0.74 eV for 2fCNT2; demonstrating an improvement in the reactivity of our fCNTs as nanovectors for targeted delivery of DHA drug. Finally, our findings show that these nanostructures may also have good NLO properties and can be promising materials for NLO applications.

Gliclazide in Binary and Ternary Systems Improves Physicochemical Properties, Bioactivity, and Antioxidant Activity

The poor solubility of the antidiabetic drug gliclazide (Glc) is due to its hydrophobic nature. This research is aimed at improving Glc's solubility and drug release profile, as well as at investigating additional benefits such as bioactivity and antioxidant activity, by forming binary complexes with HPβCD at different w/w ratios (1 : 1, 1 : 2.5, 1 : 4, and 1 : 9) and ternary complexes with HPβCD and Tryp at 1 : 1 : 1, 1 : 1 : 0.27, 1 : 2.5 : 0.27, 1 : 3.6 : 3.6, 1 : 4 : 1, and 1 : 9 : 1, respectively. Complexes were prepared by the physical mixing (PM) and solvent evaporation (SE) methods. The prepared inclusion complexes were meticulously characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra. To verify our findings, the inclusion complexes were evaluated by equilibrium solubility, in vitro drug release profile, kinetic models, and antidiabetic and antioxidant activities in animal models. Our results demonstrated that the solubility and drug release profile were found to be enhanced through binary as well as ternary complexes. Notably, ternary complexes with a ratio of 1 : 9 : 1 showed the highest solubility and drug release profile compared to all other preparations. Data on antioxidant activity indicated that the ternary complex had the higher total antioxidant status (TAS), superoxide dismutase (SOD), and catalase (CAT) activity than the binary complex and Glc alone, in contrast to the diabetic group. In vivo antidiabetic activity data revealed a high percentage reduction in the blood glucose level by ternary complexes (49-52%) compared to the binary complexes (45-46%; p ≤ 0.05). HPβCD and Tryp provide a new platform for overcoming the challenges associated with poorly soluble Glc by providing greater complexing and solubilizing capabilities and imparting ancillary benefits to improve the drug's antidiabetic and antioxidant activities.

Dihydroartemisinin-Loaded Magnetic Nanoparticles for Enhanced Chemodynamic Therapy

Recently, chemodynamic therapy (CDT) has represented a new approach for cancer treatment with low toxicity and side effects. Nonetheless, it has been a challenge to improve the therapeutic effect through increasing the amount of reactive oxygen species (ROS). Herein, we increased the amount of ROS agents in the Fenton-like reaction by loading dihydroartemisinin (DHA) which was an artemisinin (ART) derivative containing peroxide groups, into magnetic nanoparticles (MNP), thereby improving the therapeutic effect of CDT. Blank MNP were almost non-cytotoxic, whereas three MNP loading ART-based drugs, MNP-ART, MNP-DHA, and MNP-artesunate (MNP-AS), all showed significant killing effect on breast cancer cells (MCF-7 cells), in which MNP-DHA were the most potent. What's more, the MNP-DHA showed high toxicity to drug-resistant breast cancer cells (MCF-7/ADR cells), demonstrating its ability to overcome multidrug resistance (MDR). The study revealed that MNP could produce ferrous ions under the acidic condition of tumor microenvironment, which catalyzed DHA to produce large amounts of ROS, leading to cell death. Further experiments also showed that the MNP-DHA had significant inhibitory effect on another two aggressive breast cancer cell lines (MDA-MB-231 and MDA-MB-453 cells), which indicated that the great potential of MNP-DHA for the treatment of intractable breast cancers.

Complexation of phytochemicals with cyclodextrin derivatives - An insight

Natural compounds have been attracting huge attention because of their broad therapeutic properties with specificity in their action in human health care as functional foods, pharmaceuticals and nutraceuticals. However poor bioavailability and reduced bioactivity attributed to poor solubility and instability is the major drawback hindering the incorporation of these therapeutically potential molecules in novel drug delivery systems. Based on the findings of reported research investigations; complexation of poorly water soluble phytochemicals with cyclodextrins has emerged to be a promising approach to improve their aqueous solubility, stability, rate of dissolution and bioavailability. The present article summarizes the encapsulation of natural compounds ranging from various flavonoids, phenolic derivatives, coumestans to triterpenes, with cyclodextrin and their derivatives. Also the article highlights the method of complexation, complexation ability, drug solubility, stability, bioavailability and safety aspects of reported natural compounds. Additionally we present the glimpses of patents published in recent 10-15 years to highlight the significance of inclusion of phytochemicals in cyclodextrins. In patents narrated, improvement in stability and solubility of curcumin by complexation with alkyl ether derivative of gamma-cyclodextrin is claimed. Another patent mentioned, complexation of artemisinins with β-cyclodextrin, improved the stability and integrity of peroxide part of artemisinins for long period. On the other hand the complex of dihydromyricetin with γ-CD has shown improved solubility, stability and bioavailability. Thus it can be concluded that phytochemicals have multiple biological activities with broader safety index and improvement of their solubility will be truly beneficial to aid their effective delivery in healthcare.

Inclusion of terpenes in cyclodextrins: Preparation, characterization and pharmacological approaches

Terpenes constitute the largest class of natural products and are important resources for the pharmaceutical, food and cosmetics industries. However, due to their low water solubility and poor bioavailability there has been a search for compounds that could improve their physicochemical properties. Cyclodextrins (natural and derived) have been proposed for this role and have been complexed with different types of terpenes. This complexation has been demonstrated by using analytical techniques for characterizing complexes such as DSC, NMR, XRD, FTIR, and TGA. The formation of inclusion complexes has been able to improve drug characteristics such as bioavailability, solubility and stability; and to enhance biological activity and efficacy. This review shows strong experimental evidence that cyclodextrins improve the pharmacological properties of terpenes, and therefore need to be recognized as being possible targets for clinical use.

Development, characterization and antimalarial efficacy of dihydroartemisinin loaded solid lipid nanoparticles

Effective use of dihydroartemisinin (DHA) is limited by poor water-solubility, poor pharmacokinetic profile and unsatisfactory clinical outcome especially in monotherapy. To reduce such limitations, we reformulated DHA into solid lipid nanoparticles (SLNs) as a nanomedicine drug delivery system. DHA-SLNs were characterized for physical parameters and evaluated for in vitro and in vivo antimalarial efficacy. DHA-SLNs showed desirable particle characteristics including particle size (240.7 nm), particle surface charge (+17.0 mV), drug loadings (13.9 wt %), encapsulation efficacy (62.3%), polydispersity index (0.16) and a spherical appearance. Storage stability up to 90 days and sustained release of drug over 20 h was achieved. Enhanced in vitro (IC50 0.25 ng/ml) and in vivo (97.24% chemosuppression at 2mg/kg/day) antimalarial activity was observed. Enhancement in efficacy was 24% when compared to free DHA. These encouraging results show potential of using the described formulation for DHA drug delivery for clinical application.

FROM THE CLINICAL EDITOR

Malaria still poses a significant problem worldwide. One of the current drugs, artemisinin has been shown to be effective, but has poor water-solubility. The authors here described their formulation of making dihydroartemisinin (DHA) into solid lipid nanoparticles, with subsequent enhancement in efficacy. These results would have massive potential in the clinical setting.

Exploring versatile applications of cyclodextrins: an overview

CONTEXT

Ever since the discovery of cyclodextrins, a family of cyclic oligosaccharides based on α (1 → 4) linkage among glucopyranose subunits, these versatile supramolecular hosts have received tremendous attention for scientific explorations. Due to their property of forming host-guest type inclusion complex, cyclodextrins and their synthetic derivatives exhibit wide range of utilities in different areas viz. pharmaceuticals, drug delivery systems, cosmetics, food and nutrition, textile and chemical industry etc.

OBJECTIVE

The purpose of this review is to highlight properties, advantages, recent studies and versatile benefits of cyclodextrins and to re-strengthen their prospective applications in novel directions for future research.

METHODS

This article summarizes a variety of applications of cyclodextrins in various industrial products, technologies, analytical and chemical processes and recent industrial advancements by extensively literature search on various scientific databases, Google and websites of various associated pharmaceutical industries and patenting authorities across the world.

RESULTS AND CONCLUSION

Due to possibility of multidimensional changes in physical and chemical properties of molecules upon inclusion complexation in cyclodextrins, these compounds are of great commercial interest and may offer solution to many of the scientific problems of the current world.

Synthesis and evaluation of hybrid drugs for a potential HIV/AIDS-malaria combination therapy

Malaria and HIV are among the most important global health problems of our time and together are responsible for approximately 3 million deaths annually. These two diseases overlap in many regions of the world including sub-Saharan Africa, Southeast Asia and South America, leading to a higher risk of co-infection. In this study, we generated and characterized hybrid molecules to target Plasmodium falciparum and HIV simultaneously for a potential HIV/malaria combination therapy. Hybrid molecules were synthesized by the covalent fusion of azidothymidine (AZT) with dihydroartemisinin (DHA), a tetraoxane or a 4-aminoquinoline derivative; and the small library was tested for antiviral and antimalarial activity. Our data suggests that compound 7 is the most potent molecule in vitro, with antiplasmodial activity comparable to that of DHA (IC(50)=26 nM, SI>3000), a moderate activity against HIV (IC(50)=2.9 μM; SI>35) and not toxic to HeLa cells at concentrations used in the assay (CC(50)>100 μM). Pharmacokinetics studies further revealed that compound 7 is metabolically unstable and is cleaved via O-dealkylation. These studies account for the lack of in vivo efficacy of compound 7 against the CQ-sensitive Plasmodium berghei N strain in mice, when administered orally at 20mg/kg.