A phospholipid complex to improve the oral bioavailability of flavonoids

Controlled dual release of phenol compounds from phospholipid complexes of short-chain lipophenols

Ethanol evaporation method was applied to synthesize phospholipid complexes from phosphatidylcholine (PC) and short-chain alkyl gallates (A-GAs, a typical representative of lipophenols) including butyl-, propyl- and ethyl gallates. 1H NMR, UV and FTIR showed that A-GAs were interacted with PC through weak physical interaction. Through the analysis of concentrations of A-GAs and gallic acid (GA) by an everted rat gut sac model coupled with HPLC-UV detection, phospholipid complexes were found to gradually release A-GAs. These liberated A-GAs were further hydrolyzed by intestinal lipases to release GA. Both of GA and A-GAs could cross intestinal membrane. Especially, the transmembrane A-GAs could also be hydrolyzed to produce GA. Undoubtedly, the dual release of phenol compounds from phospholipid complexes of short-chain lipophenols will be effective to extend the in vivo residence period of phenol compounds. More importantly, such behavior is easily adjusted by changing the acyl chain lengths of lipophenols in phospholipid complexes.

Enhanced absorption of prenylated cinnamic acid derivatives from Brazilian green propolis by turmeric in humans and rats

Prenylated cinnamic acid derivatives are the bioactive components of Brazilian green propolis (BGP). The effect of other botanical components on the pharmacokinetic profiles of these derivatives remains relatively unexplored. In the present study, we investigated the influence of several herbal extracts (turmeric, ginkgo leaf, coffee fruit, soybean, and gotu kola) on the plasma concentrations of cinnamic acid derivatives after BGP consumption. When the herbal extracts were co-administered with BGP in the clinical study, the area under the curve (AUC) values of artepillin C and drupanin, the major BGP components in plasma, were significantly increased by 1.7- and 1.5-fold, respectively, compared to those after BGP administration alone. Among the herbal extracts administered to rats, turmeric extract increased the AUC. Furthermore, a bidirectional transport assay suggested that artepillin C and drupanin are substrates of breast cancer resistance protein (BCRP), a drug elimination transporter. These results suggest that curcumin-containing turmeric extract may increase the plasma concentrations of artepillin C and drupanin via BCRP. Our findings enabled us to estimate the food-herb and herb-herb interactions in vivo in foods and herbal medicines containing cinnamic acid derivatives and prenylated compounds.

Bioactive Compounds Formulated in Phytosomes Administered as Complementary Therapy for Metabolic Disorders

Metabolic disorders (MDs), including dyslipidemia, non-alcoholic fatty liver disease, diabetes mellitus, obesity and cardiovascular diseases are a significant threat to human health, despite the many therapies developed for their treatment. Different classes of bioactive compounds, such as polyphenols, flavonoids, alkaloids, and triterpenes have shown therapeutic potential in ameliorating various disorders. Most of these compounds present low bioavailability when administered orally, being rapidly metabolized in the digestive tract and liver which makes their metabolites less effective. Moreover, some of the bioactive compounds cannot fully exert their beneficial properties due to the low solubility and complex chemical structure which impede the passive diffusion through the intestinal cell membranes. To overcome these limitations, an innovative delivery system of phytosomes was developed. This review aims to highlight the scientific evidence proving the enhanced therapeutic benefits of the bioactive compounds formulated in phytosomes compared to the free compounds. The existing knowledge concerning the phytosomes' preparation, their characterization and bioavailability as well as the commercially available phytosomes with therapeutic potential to alleviate MDs are concisely depicted. This review brings arguments to encourage the use of phytosome formulation to diminish risk factors inducing MDs, or to treat the already installed diseases as complementary therapy to allopathic medication.

Development and Evaluation of a Novel Hyaluronic Acid and Chitosan-modified Phytosome for Co-delivery of Oxymatrine and Glycyrrhizin for Combination Therapy

BACKGROUND

Multidrug resistance (MDR) of cancer cells is a major obstacle to efficient cancer chemotherapy. Combination therapy is expected to enhance the anticancer effect and reverse MDR. Numerous patents involve different kinds of nanoparticles for the co-delivery of multiple chemotherapeutics, but the FDA has approved none.

OBJECTIVE

In this study, oxymatrine (OMT) and glycyrrhizin (GL) were co-loaded into phytosomes as the core of nanocarriers, and the shell was cross-linked with chitosan (CS) and hyaluronic acid (HA) with the capability for the controlled, sequential release and the targeted drug uptake.

METHODS

Phospholipid complexes of OMT and GL (OGPs) were prepared by a solvent evaporation technique and could self-assemble in an aqueous solution to form phytosomes. CS and HA were sequentially coated on the surface of OGPs via electrostatic interactions to obtain CS coated OGPs (CS-OGPs) and HA modified CS-OGPs (HA-CS-OGPs), respectively. The particle size and zeta potential were measured to optimize the formulations. In vitro cytotoxicity and cellular uptake experiments on HepG2 cells were performed to evaluate the anticancer activity.

RESULTS

OGPs were obtained with nano-size around 100 nm, and CS and HA coating on phytosomes could change the particle size and surface potential. The drug loading of OMT and GL showed that the nanocarriers could maintain a fixed ratio of 1:1. The in vitro release experiments indicated the release of OMT and GL was pH-dependent and sequential: the release of OMT from CS-OGPs and HA-CS-OGPs was significantly increased at pH 5.0 compared to the release at pH 7.4, while GL exhibited sustained released from CS-OGPs and HA-CS-OGPs at pH 5.0. Furthermore, in vitro cytotoxicity and cellular uptake experiments on HepG2 cells demonstrated that the co-delivery system based on phytosomes had significant synergistic anti-tumor activities, and the effects were enhanced by CS and HA modification.

CONCLUSION

The delivery of OMT and GL via HA-CS-OGPs might be a promising treatment to reverse MDR in cancer therapy.

Piperine Liposome-Embedded in Hyaluronan Hydrogel as an Effective Platform for Prevention of Postoperative Peritoneal Adhesion

This study aimed to prepare piperine (PIP) loaded liposomes in hyaluronic acid (HA) hydrogel to provide a hybrid superstructure for postoperative adhesion prevention. Liposomes were prepared using thin-film hydration method. The optimised formulation was characterised by size, SEM, TEM, FTIR, encapsulation efficiency (EE)% (w/w), and release pattern. Liposome-in-hydrogel formulation was investigated by rheology, SEM, and release studies. The efficacy was evaluated in a rat peritoneal abrasion model. EE% (w/w) increased with increasing lipid concentration from 10 to 30; however, a higher percentage of Chol reduced EE% (w/w). The optimised liposome (EE: 68.10 ± 4.18% (w/w), average diameter: 513 ± 14.67 nm, PDI: 0.15 ± 0.04) was used for hydrogel embedding. No sign of adhesion in 5/8 rats and no collagen deposition confirmed the in vivo effectiveness of the optimised formulation. Overall, providing a sustained delivery of PIP, the developed liposome-in-hydrogel formulation can be a promising carrier to prevent postoperative adhesion.

Solvent Free Twin Screw Processed Silybin Nanophytophospholipid: In Silico, In Vitro and In Vivo Insights

Silybin (SIL) is a polyphenolic phytoconstituent that is commonly used to treat liver disorders. It is difficult to fabricate an orally delivered SIL product due to its low oral bioavailability (0.95%). Therefore, the current research focusses on the development of a novel composition of a phospholipid complex, termed as nanophytophospholipid, of SIL by employing a unique, solvent-free Twin Screw Process (TSP), with the goal of augmenting the solubility and bioavailability of SIL. The optimised SIL-nanophytophospholipid (H6-SNP) was subjected to physicochemical interactions by spectrometry, thermal, X-ray and electron microscopy. The mechanism of drug and phospholipid interaction was confirmed by molecular docking and dynamics studies. Saturation solubility, in vitro dissolution, ex vivo permeation and preclinical pharmacokinetic studies were also conducted. H6-SNP showed good complexation efficiency, with a high practical yield (80%). The low particle size (334.7 ± 3.0 nm) and positively charged zeta potential (30.21 ± 0.3 mV) indicated the immediate dispersive nature of H6-SNP into nanometric dimensions, with good physical stability. Further high solubility and high drug release from the H6-SNP was also observed. The superiority of the H6-SNP was demonstrated in the ex vivo and preclinical pharmacokinetic studies, displaying enhanced apparent permeability (2.45-fold) and enhanced bioavailability (1.28-fold). Overall, these findings indicate that not only can phospholipid complexes be formed using solvent-free TSP, but also that nanophytophospholipids can be formed by using a specific quantity of lipid, drug, surfactant, superdisintegrant and diluent. This amalgamation of technology and unique composition can improve the oral bioavailability of poorly soluble and permeable phytoconstituents or drugs.

Development and Evaluation of a Novel Diammonium Glycyrrhizinate Phytosome for Nasal Vaccination

The objective of the present research was to formulate diammonium glycyrrhizinate (DG) into phytosomes (DG-P) to induce nasal immune responses and enhance absorption. Plackett- Burman design was used for process optimization, incorporating specific formulation and process variables to obtain the optimal parameters. Fourier transform infrared spectroscopy (FTIR), X-ray power diffraction (P-XRD), and transmission electron microscopy (TEM) were used for characterization. The adjuvant activity of the DG-P was evaluated by using bone marrow dendritic cells. In vitro nasal mucosal permeation and in situ nasal perfusion were also investigated to evaluate nasal absorption. The DG phytosomes were in the size range of 20~30 nm and zeta-potential range of −30~−40 mV. DG-P demonstrated 4.2-fold increased solubility in n-octanol. Coculturing bone marrow dendritic cells with DG-P led to enhanced dendritic cell maturation. Apparent permeability coefficient of the phytosomal formulation was almost four times higher than that of free DG determined by ex vivo permeation studies on excised porcine mucosa. In situ nasal perfusion studies in rats demonstrated that the nasal absorption of DG-P was significantly higher than that of free DG. Conclusively, the results confirmed that DG-P have potential for use as an adjuvant for nasal vaccine.

Preparation of an isorhamnetin phospholipid complex for improving solubility and anti-hyperuricemia activity

To improve the solubility and anti-hyperuricemia activity of the insoluble natural flavonoid isorhamnetin (ISO), an isorhamnetin phospholipid complex (ISO-PC) was prepared. ISO-PC was prepared through solvent evaporation and its prescription process was optimized. The formation of ISO-PC was verified via multiple characterization methods. Parameters such as drug loading, solubility, octanol-water partition coefficient, stability, and in vivo anti-hyperuricemia activity of ISO-PC were investigated. The complexation efficiency of ISO-PC was 95.1% ± 0.56%. The characterization results confirmed that ISO-PC was bound by intermolecular interactions between ISO and phospholipids. Compared to ISO, the solubility of ISO-PC in water and 1-octanol increased by 122 and 16.5 times, respectively. Additionally, the octanol-water partition coefficient decreased to 1.08. Pharmacodynamic studies have reported that ISO-PC has a more significant effect on reducing serum uric acid levels and renal protection. In conclusion, the findings of this study suggested that ISO-PC could be used as a promising formulation to improve the solubility and the anti-hyperuricemia activity of ISO.

Transdermal delivery of triptolide-phospholipid complex to treat rheumatoid arthritis

The aim of this study was to develop and evaluate a triptolide phospholipid complex (TPCX) for the treatment of rheumatoid arthritis (RA) by transdermal delivery. TPCX was prepared and characterized by differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR) analysis, transmission electron microscope (TEM), and scanning electron microscope (SEM). The solubility of TPCX was determined. Then, a TPCX cream was prepared to evaluate its percutaneous permeability and the antiarthritis effect. The transdermal permeability was determined using the Franz method, and a microdialysis system was used for skin pharmacokinetic study. A rat model of RA was prepared to evaluate the pharmacological effects. TPCX increased the solubility of triptolide in water, and the percutaneous permeability of TPCX cream was greatly enhanced compared with triptolide cream. The skin pharmacokinetic study indicated that TPCX cream has a longer biological half-life (t_1/2) and mean residence time (MRT), but it has a shorter T_max than that of triptolide cream in vivo. The area under the curve (AUC_0–t)/AUC_0–∞) and the peak concentration (C_max) of TPCX cream were obviously higher than those of triptolide cream. The TPCX-loaded cream alleviated paw swelling and slowed down the progression of arthritis by inhibiting the inflammatory response by down regulating the TNF-α, IL-1β, and IL-6 levels, thus exhibiting excellent antiarthritic effects. In summary, the prepared TPCX effectively increases the hydrophilicity of triptolide, which is good for its percutaneous absorption and enhances its effect on RA rats. TPCX can be a good candidate for the transdermal delivery to treat RA.

Erlotinib complexation with randomly methylated β-cyclodextrin improves drug solubility, intestinal permeability, and therapeutic efficacy in non-small cell lung cancer

The purpose of this study was to investigate the impact of anticancer drug erlotinib-randomly methylated-β-cyclodextrin complex (ERL-RAMEB CD) on drug solubility and dissolution rate. Phase solubility study showed erlotinib displayed maximum solubility in RAMEB CD solution and the stability constant (K_c) was calculated to be 370 ± 16 M^-1. The optimal formulation was obtained with ERL-RAMEB CD in a 1:1 molar ratio using the co-lyophilization technique. Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM) verified the inclusion of complex formation. In vitro dissolution study confirmed ERL-RAMEB CD as a favorable approach to increase drug dissolution with a 1.5-fold increase than free ERL at 1 h. An improved dissolution with ∼88.4% drug release at 1 h was observed, in comparison with Erlotinib with ∼58.7% release in 45 min. The in vitro cytotoxicity results indicated that the ERL-RAMEB CD inclusion complex reduced cell viability than free erlotinib. Caco-2 cell uptake that is indicative of drug intestinal permeability resulted in a 5-fold higher uptake of ERL-RAMEB CD inclusion complex than the ERL solution. Hence, ERL-RAMEB CD complexation displays a strong potential to increase dissolution and permeability of erlotinib leading eventually to enhanced oral bioavailability.

De Novo Nano-Erythrocyte Structurally Braced by Biomimetic Au(I)-peptide Skeleton for MDM2/MDMX Predation toward Augmented Pulmonary Adenocarcinoma Immunotherapy

In nature, cells rely on a structural framework called the "cytoskeleton" to maintain their shape and polarity. Based on this, herein a new class of cell-mimicking nanomedicine using bionic skeletons constituted by the oligomeric Au(I)-peptide complex is developed. The peptide function of degrading pathological MDM2 and MDMX is used to synthesize an oligomeric Au(I)-PMIV precursor capable of self-assembling into a clustered spherical bionic skeleton. Through coating by erythrocyte membrane, an erythrocyte-mimicking nano-cell (Nery-PMIV) is developed with depressed macrophage uptakes, increased colloidal stability, and prolonged blood circulation. Nery-PMIV potently restores p53 and p73 in vitro and in vivo by degrading MDM2/MDMX. More importantly, Nery-PMIV effectively augments antitumor immunity elicited by anti-PD1 therapy in a murine orthotopic allograft model for LUAD and a humanized patient-derived xenograft (PDX) mouse model for LUAD, while maintaining a favorable safety profile. Taken together, this work not only presents evidence showing that MDM2/MDMX degradation is a potentially viable therapeutic paradigm to synergize anti-PD1 immunotherapy toward LUAD carrying wild-type p53; it also suggests that cell-mimicking nanoparticles with applicable bionic skeletons hold tremendous promise in offering new therapies to revolutionize nanomedicine in the treatment of a myriad of human diseases.

Flavonoids from sea buckthorn: A review on phytochemistry, pharmacokinetics and role in metabolic diseases

Sea buckthorn (Hippophae rhamnoides L., SBT) is being used as a folk medicine for their diverse medicinal properties. Flavonoids are generally considered as the main bioactive and characteristic ingredients in SBT. This review was conducted using a comprehensive literature search on the chemical components, quality control, pharmacokinetics of flavonoids from SBT (FSBT). Particularly, we highlighted the therapeutic potential in metabolic diseases and clinical applications of FSBT. More than 95 flavonoids have been identified from SBT. Although the oral bioavailability of FSBT was relatively low, FSBT displays significant effect on the regulation of metabolism to ameliorate metabolic disorders and their complications. There is a heightened need to explore the bioactive compounds in SBT and mechanism(s) of action of FSBT in order to fully understand the pathways of their activities. PRACTICAL APPLICATIONS: For years, due to the increasing emergence of metabolic syndrome and diverse functions of FSBT in regulating metabolism, they can be efficiently utilized for human health and have an urgent need to become a hotspot for research. This review will broaden the understanding of FSBT, providing some directions for further development and expanding the therapeutic applications of FSBT.

The fate of flavonoids after oral administration: a comprehensive overview of its bioavailability

Despite advancements in synthetic chemistry, nature remains the primary source of drug discovery, and this never-ending task of finding novel and active drug molecules will continue. Flavonoids have been shown to possess highly significant therapeutic activities such as anti-inflammatory, anti-oxidant, anti-viral, anti-diabetic, anti-cancer, anti-aging, neuroprotective, and cardioprotective, etc., However, it has been found that orally administered flavonoids have a critical absorption disorder and, therefore, have low bioavailability and show fluctuating pharmacokinetic and pharmacodynamic responses. A detailed investigation is required to assess and analyze the variation in the bioavailability of flavonoids due to interactions with the intestinal barrier. This review will emphasize on the bioavailability and the pharmacological applications of flavonoids, key factors affecting their bioavailability, and strategies for enhancing bioavailability, which may lead to deeper understanding of the extent of flavonoids as a treatment and/or prevention for different diseases in clinics.

Natural compounds as inhibitors of SARS-CoV-2 endocytosis: A promising approach against COVID-19

BACKGROUND AND AIM

The recent COVID-19 pandemic caused by SARS-CoV-2 affected more than six million people and caused thousands of deaths. The lack of effective drugs or vaccines against SARS-CoV-2 further worsened the situation. This review is focused on the identification of molecules that may inhibit viral entry into host cells by endocytosis.

METHODS

We performed the literature search for these natural compounds in the articles indexed in PubMed.

RESULTS

Natural products against viral infections have been gaining importance in recent years. Specific natural compounds like phytosterols, polyphenols, flavonoids, citrus, galangal, curcuma and hydroxytyrosol are being analyzed to understand whether they could inhibit SARS-CoV-2.

CONCLUSIONS

We reviewed natural compounds with potential antiviral activity against SARS-CoV-2 that could be used as a treatment for COVID-19.

Fabrication of Nanosuspensions to Improve the Oral Bioavailability of Total Flavones from Hippophae rhamnoides L. and their Comparison with an Inclusion Complex

The aim of this work was to increase the solubility and oral bioavailability of isorhamnetin, kaempferol, and quercetin in the total flavones of Hippophae rhamnoides L. (TFH) by preparing their nanosuspensions (NSs) and an inclusion complex. Based on the particle size and zeta potential, P407, Soluplus, SDS, PEG-6000, and HP-β-CD were selected as stabilizers. TFH NSs and a TFH/HP-β-CD inclusion complex were prepared, and their morphology, crystallinity, molecular interactions, and cytotoxicity were investigated. Furthermore, the saturation solubility, dissolution, and pharmacokinetics of the three flavonoids in the TFH, TFH NSs, and TFH/HP-β-CD inclusion complex were compared. The five obtained TFH NSs were physically stable, and their particle sizes were all below 200 nm. The solubility and dissolution of the three active components were obviously enhanced by the formation of the TFH NSs and TFH/HP-β-CD inclusion complex. Correspondingly, the oral bioavailability of isorhamnetin, kaempferol, and quercetin increased up to 4.11-, 3.85-, and 6.73-fold, respectively, in the TFH NSs and 2.89-, 3.71-, and 9.51-fold, respectively, in the TFH/HP-β-CD inclusion complexes compared to those in the raw TFH. In brief, both NSs and inclusion complexes can improve the oral bioavailability of the three flavonoids in TFH. Taking the drug loading and the stable ratio of the multiple components into consideration, the NSs is a more promising strategy than the inclusion complex for increasing the oral bioavailability of multiple water-insoluble components in herbal extracts. Graphical abstract.

Naringenin-Loaded Dipalmitoylphosphatidylcholine Phytosome Dry Powders for Inhaled Treatment of Acute Lung Injury

Background: Acute lung injury is a severe respiratory disorder characterized by overwhelming lung inflammation. Dipalmitoylphosphatidylcholine (DPPC) is the major lipid component of pulmonary surfactant, which here acts as a carrier delivery system for drugs, while also preserving surface tension in the lung. The clinical development of naringenin (NG) is limited by its low solubility and bioavailability. Methods: Novel NG-loaded DPPC phytosomes for dry powder inhalation (NPDPIs) were prepared by solvent evaporation and a freeze-drying method. The particle size, electric potential, in vitro release, and lung deposition were characterized. A rat model of acute lung injury was established and used for pharmacodynamic evaluations. Results: A mixture of NG/DPPC 1:2 (w/w) formed stable phytosomes with the addition of appropriate ethanol. The phytosomes had high complexation efficiency (92.1% ± 1.87%) with NG, a small mean size (150.8 ± 6.9 nm), and a high zeta potential (20.97 ± 0.55 mV). NPDPIs composed of mannitol/DPPC/NG (4:2:1, w/w/w) presented a satisfactory appearance, good fluidity, quick reconstitution to naringenin phytosomes (NGPs), and small (167.2 nm) reconstituted NGPs. The aerodynamic diameter (12.48 μm) and fine particle fraction (23.90%) were suitable for pulmonary delivery by inhalation. The in vivo NPDPIs demonstrated efficacy in a rat model of acute lung injury. NPDPIs significantly inhibited the phosphorylation of P38 in the mitogen-activated protein kinase pathway and suppressed oxidative stress. Surprisingly, the DPPC vehicle exhibited potential effects against acute lung injury by protecting respiratory function. Conclusions: NPDPIs were developed for sustained drug release, promoting pulmonary bioavailability of drug and protecting against acid-induced acute lung injury in rats by pulmonary delivery. NPDPIs are a promising dry powder inhaler for clinical application in acute lung injury.

A matrix dispersion based on phospholipid complex system: preparation, lymphatic transport, and pharmacokinetics

Raloxifene hydrochloride (RH) suffers from low oral bioavailability due to its low water-solubility and first-pass metabolism. Therefore, a novel phospholipid complex of RH (RHPC) and a matrix dispersion based on phospholipid complex (RHPC-MD) were successfully prepared and optimized. Several methods were used to validate the formation of RHPC and RHPC-MD, such as differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, particle size, and zeta potential, meanwhile, their octanol-water partition coefficient, solubility, and dissolution in vitro were also evaluated. To investigate the absorption mechanism of RHPC in vivo, the RHPC was administered to the chylomicron flow blockage rat model. Interestingly, as we expected, a significant reduction in RHPC absorption (67%) (**p< .01) in presence of cycloheximide (CXI) inhibitor was observed, thus confirming the RHPC could be absorbed by lymphatic transport in vivo. Pharmacokinetic studies revealed that the relative oral bioavailability of RHPC as well as RHPC-MD was 223% and 329%, respectively, when comparing with the commercial RH tablets. These outcomes suggested that the current study provided an attractive formulation to enhance the oral bioavailability of RH and stimulated to further research the absorption mechanism of RHPC in vivo.

Development of catechin-phospholipid complex to enhance the bioavailability and modulatory potential against cadmium-induced oxidative stress in rats liver

The natural flavonoid (catechin) has been shown to possess a multitude of pharmacological activities. However, oral administrated catechin (CT) failed to fulfil its therapeutic potential due to poor absorption and low bioavailability. Thus, is a pressing need to develop a new approach from to increase its intestinal absorption and improved bioavailability. In this work, we intended the increase the bioavailability of CT by preparing catechin-phospholipid complex (CT-PH) and evaluate the protective effect of CT-PH complex against cadmium caused liver injuries in rats. Oral bioavailability of CT and CT-PH complex was evaluated in rats and the plasma CT was estimated by HPLC analysis. The greater absorption of CT-PH complex rats indicated that improved bioavailability. Liver function markers, lipid peroxidation, protein oxidation, antioxidant status and histopathological changes were determined in normal and treated rats. Moreover, biochemical analysis and histopathological examinations indicated that CT-PH provided better protection to rat liver than free CT.

Preparation of ursolic acid-phospholipid complex by solvent-assisted grinding method to improve dissolution and oral bioavailability

To improve the aqueous solubility and the oral bioavailability of a poorly water-soluble biologically active pentacyclic triterpenoid, ursolic acid (UA), ursolic acid-phospholipid complex (UA-PC) was prepared using solvent-assisted grinding method which is green and simple. The phospholipid complex was characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), scanning electron microscope (SEM), and transmission electron microscope (TEM), which confirmed the formation of the phospholipid complex. Specifically, compared with free UA, the formulation demonstrated over 276-fold higher aqueous solubility of UA and exhibited faster dissolution rate and higher cumulative dissolution percentages. Finally, the oral bioavailability of the prepared UA-PC was evaluated using Sprague-Dawley (SD) rats. Compared with free UA, the UA-PC exhibited considerable enhancement in the bioavailability with an increase in Cmax (183.80 vs 68.26 μg/l) and AUC 0-24 h (878.0 vs 212.1 μg·h/l), which was consistent with the in vitro results. This enhancement was attributed to the improvement of solubility and dissolution in vitro. Therefore, the method of solvent-assisted grinding appears to be an efficient approach for the preparation of UA-PC, and the prepared UA-PC showed a promising potential to overcome the limitation of poor oral bioavailability associated with low water solubility.

A Solid Dispersion of Quercetin Shows Enhanced Nrf2 Activation and Protective Effects against Oxidative Injury in a Mouse Model of Dry Age-Related Macular Degeneration

Age-related macular degeneration (AMD) represents a major reason for blindness in the elderly population. Oxidative stress is a predominant factor in the pathology of AMD. We previously evaluated the effects of phospholipid complex of quercetin (Q-PC) on oxidative injury in ARPE-19 cells, but the underlying mechanisms are not fully understood. Herein, the solid dispersion of quercetin-PC (Q-SD) was prepared with solubility being 235.54 μg/mL in water and 2.3×10⁴ μg/mL in chloroform, which were significantly higher than that of quercetin (QT) and Q-PC. Q-SD also exhibited a considerably higher dissolution rate than QT and Q-PC. Additionally, Q-SD had Cmax of 4.143 μg/mL and AUC of 12.015 μg·h/mL in rats, suggesting better bioavailability than QT and Q-PC. Then, a mouse model of dry AMD (Nrf2 wild-type (WT) and Nrf2 knockout (KO)) was established for evaluating the effects of Q-SD in vivo. Q-SD more potently reduced retinal pigment epithelium sediments and Bruch's membrane thickness than QT and Q-PC at 200 mg/kg in Nrf2 WT mice and did not work in Nrf2 KO mice at the same dosage. Additionally, Q-SD significantly decreased ROS and MDA contents and restored SOD, GSH-PX, and CAT activities of serum and retinal tissues in Nrf2 WT mice, but not in Nrf2 KO mice. Furthermore, Q-SD more potently increased Nrf2 mRNA expression and stimulated its nuclear translocation in retinal tissues of Nrf2 WT mice. Q-SD significantly increased the expression of Nrf2 target genes HO-1, HQO-1, and GCL of retinal tissues in Nrf2 WT mice, not in Nrf2 KO mice. Altogether, Q-SD had improved physicochemical and pharmacokinetic properties compared to QT and Q-PC and exhibited more potent protective effects on retina oxidative injury in vivo. These effects were associated with activation of Nrf2 signaling and upregulation of antioxidant enzymes.

Preparation and preliminary pharmacokinetics study of GNA-loaded zein nanoparticles

OBJECTIVES

Gambogenic acid (GNA), one of the main active ingredients isolated from Garcinia cambogia, has shown diverse antitumour activities. However, short biological half-life and low oral bioavailability severely limit its clinical application. Here, we developed GNA-loaded zein nanoparticles (GNA-ZN-NPs) based on phospholipid complex and zein nanoparticles to prolong the circulation time and enhance oral bioavailability of GNA.

METHODS

The physicochemical properties of GNA-ZN-NP were characterized in details. The in vitro release profile, in vivo pharmacokinetic experiments and tissue distribution of GNA-ZN-NPs were also evaluated.

KEY FINDINGS

The particle size, PDI and encapsulation efficiency of GNA-ZN-NPs were 102.90 nm, 0.027 and 76.35 ± 0.64%, respectively. The results of SEM, FTIR, DSC and XRD demonstrated that GNA-ZN-NPs were prepared successfully. The in vitro dissolution of GNA-ZN-NPs exhibited controlled release compared with raw GNA solution. The pharmacokinetic study showed that the AUC of GNA-ZN-NPs was significantly increased, and the t_1/2 and MRT values of GNA-ZN-NPs were 3.21-fold and 2.19-fold higher than that of GNA solution. Tissue distribution results illustrated that GNA-ZN-NPs showed hepatic-targeting properties.

CONCLUSION

GNA-ZN-NPs significantly enhanced the oral bioavailability and prolonged half-life of GNA, providing a promising oral drug delivery system to improve in vivo pharmacokinetic behaviour of GNA.

Pharmacokinetic properties of phytochemicals in Hypericum perforatum influence efficacy of regulating oxidative stress

BACKGROUND

Hypericum perforatum is used in ethnopharmacology and has recently become popular in conventional medicine for treatment of mild to moderate depression. The abundance of potentially functional phytochemicals and their broader utilizations in traditional medicine suggests that ingestion of H. perforatum may impart additional secondary health benefits.

HYPOTHESIS/PURPOSE

Considering that many phytochemicals are known to display antioxidant activity, it was hypothesized that H. perforatum ingestion may inhibit oxidative stress and inflammation (OSI) which occurs in transient cycles following exercise and consumption of meals. The aim of this study was to explore the pharmacokinetics of H. perforatum phytochemicals after ingestion to predict the absorption timing of putative medicinal phytochemicals.

STUDY DESIGN/METHODS

In silico analyses of previously published plant extract phytochemical profiles were performed, wherein the Phytochemical Absorption Prediction (PCAP) model was used to predict the pharmacokinetics of phytochemicals. The predicted times for phytochemicals to reach maximum plasma concentration (T_max), and associated antioxidant activities, were compared to prior clinical in vivo studies to assess the accuracy and applicability of predictions.

RESULTS

The PCAP model identified that phytochemicals with antioxidant activity concurrently accumulate in plasma with T_max in the range of 1.6-2.3 h after ingestion. Comparison with previously published results identified that attenuation of OSI following H. perforatum ingestion aligns with the predicted T_max of antioxidant phytochemicals.

CONCLUSION

Based on these results it is therefore recommended that H. perforatum administration occurs 2 h before meals to provide optimal secondary health benefits associated with inhibition of postprandial stress. Additionally, these results highlight the use of in silico analyses to inform ingestion time and optimize the health benefits from ingestion of plant-based foods and medicines.

Novel self-nanomicellizing solid dispersion based on rebaudioside A: a potential nanoplatform for oral delivery of curcumin

Purpose

Rebaudioside A (RA) has nanocarrier characteristics that allow it to self-assemble into micelles in aqueous solutions. The purpose of this study was to determine if a self-nanomicellizing solid dispersion based on RA could be utilized as an oral nano-drug delivery system.

Materials and methods

Curcumin (Cur) served as a model hydrophobic drug, and a Cur-loaded self-nanomicellizing solid dispersion based on RA (RA-Cur) was formulated. The properties of RA-Cur in the solid state and in aqueous solution were characterized. The antioxidant activity and mechanism of RA-Cur endocytosis were also investigated. The pharmacokinetics, biodistribution in the intestinal tract, and anti-inflammation properties were also evaluated in vivo.

Results

RA-Cur could be easily fabricated, and it self-assembled into ultrasmall micelles (particle size ~4 nm) in a homogeneous distribution state (polydispersity index <0.2) when dissolved in water. Cur was readily encapsulated into RA micelles and this improved its water solubility (to 14.34±1.66 mg/mL), as well as its in vitro release and membrane permeability. The antioxidant activities of Cur in RA-Cur were also significantly improved. Biodistribution in the intestinal tract confirmed a significant enhancement of Cur absorption in the duodenum, jejunum, and ileum by encapsulation in RA-Cur, and the absorption of RA-Cur was governed by mixed transcytosis mechanisms. Pharmacokinetic tests of RA-Cur in rats revealed a dramatic 19.06-fold enhancement of oral bioavailability when compared to free Cur. More importantly, oral administration of RA-Cur could efficiently ameliorate ulcerative colitis in a mouse model induced by dextran sodium sulfate.

Conclusion

Self-nanomicellizing solid dispersions based on RA have great potential as novel oral nano-drug delivery systems for hydrophobic drugs such as Cur.

Improved oral bioavailability and therapeutic efficacy of erlotinib through molecular complexation with phospholipid

The current study was aimed to prepare a molecular complex of erlotinib (ERL) with phospholipid (PC) for enhancement of solubility and thus bioavailability, therapeutic efficacy and reducing the toxicity of erlotinib. Phospholipid complex of drug was prepared by solvent evaporation method and characterized by differential scanning calorimetry (DSC), Fourier transform infra-red spectroscopy (FT-IR), proton and phosphorus nuclear magnetic resonance spectroscopy (1H NMR and 31P NMR), powder X-ray diffraction (P-XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which all explained the interactions of two components, validating the complexation phenomenon. In silico study also supported the phase change and molecular interactions for the establishment of ERL-PC. Spherical shaped nanostructures with 183.37±28.61nm size, -19.52±6.94mV potential and 28.59±2.66% loading efficiency were formed following dispersion of ERL-PC in aqueous media. In vitro release study revealed the higher release of ERL-PC due to amorphization and solubilization of drug. Caco-2 cell uptake resulted in ∼2 fold higher uptake of ERL-PC than free drug. In vitro cell culture studies were performed using human pancreatic adenocarcinoma cell lines, which demonstrated the higher cytotoxicity and apoptosis in case of ERL-PC. In vivo pharmacokinetics also supported the in vitro observations and showed ∼1.7 fold higher bioavailability with ERL-PC than ERL. Finally, in vivo efficacy and toxicity studies explained the superiority of ERL-PC over the free drug. Based on the results, phospholipid complex appears to be a promising tool to enhance bioavailability, efficacy, cytotoxicity and safety of erlotinib.

Flavonoids: promising natural compounds against viral infections

Flavonoids are widely distributed as secondary metabolites produced by plants and play important roles in plant physiology, having a variety of potential biological benefits such as antioxidant, anti-inflammatory, anticancer, antibacterial, antifungal and antiviral activity. Different flavonoids have been investigated for their potential antiviral activities and several of them exhibited significant antiviral properties in in vitro and even in vivo studies. This review summarizes the evidence for antiviral activity of different flavonoids, highlighting, where investigated, the cellular and molecular mechanisms of action on viruses. We also present future perspectives on therapeutic applications of flavonoids against viral infections.

Discovery and Current Status of Evaluation System of Bioavailability and Related Pharmaceutical Technologies for Traditional Chinese Medicines--Flos Lonicerae Japonicae--Fructus Forsythiae Herb Couples as an Example

Traditional Chinese medicines (TCMs) have attracted extensive interest throughout the world due to their long history of health protection and disease control, and the internalization of TCM preparations or patented drugs has been considered a wind vane in the process of TCM modernization. However, multi-target effects, caused by multiple components in TCMs, hinder not only the construction of the quality evaluation system (bioavailability), but also the application of pharmaceutical technologies, which results in the poor efficacy in clinical practice. This review describes the methods in the literature as well as in our thoughts about how to identify the marker components, establish the evaluation system of bioavailability, and improve the bioavailability in TCM preparations. We expect that the current study will be positive and informative.