Preparation, characterisation, and pharmacodynamic study of myricetin pH-sensitive liposomes.

AIMS: Myricetin (MYR) was incorporated into pH-sensitive liposomes in order to improve its bioavailability and anti-hyperuricemic activity. METHODS: The MYR pH-sensitive liposomes (MYR liposomes) were prepared using thin film dispersion method, and assessed by particle size (PS), polydispersed index (PDI), zeta potential (ZP), encapsulation efficiency, drug loading, and in vitro release rate. Pharmacokinetics and anti-hyperuricemic activities were also evaluated. RESULTS: The PS, PDI, ZP, encapsulation efficiency, and drug loading of MYR liposomes were 184.34 ± 1.05 nm, 0.215 ± 0.005, -38.46 ± 0.30 mV, 83.42 ± 1.07%w/w, and 6.20 ± 0.31%w/w, respectively. The release rate of MYR liposomes was higher than free MYR, wherein the cumulative value responded to pH. Besides, the Cmax of MYR liposomes was 4.92 ± 0.20 µg/mL. The level of uric acid in the M-L-H group (200 mg/kg) was reduced by 54.74%w/v in comparison with the model group. CONCLUSION: MYR liposomes exhibited pH sensitivity and could potentially enhance the oral bioavailability and anti-hyperuricemic efficacy of MYR.

Isoliquiritigenin Containing PH Sensitive Micelles for Enhanced Anti-Colitis Activity.

Isoliquiritigenin (ISL) is known to have a variety of pharmacological activities, but its poor water solubility limits its application. In order to improve the bioavailability of ISL and its anti-colitis activity, this study aims to develop an effective drug delivery system loaded with ISL. In this study, ISL pH-sensitive micelles (ISL-M) were prepared by thin film hydration method. The micellar size (PS), polydispersity index (PDI), electrokinetic potential (ζ-potential), drug loading (DL), encapsulation rate (EE) and other physical parameters were characterized. The storage stability of ISL-M was tested, release in vitro and pharmacokinetic studies in rats were performed, and the anti-inflammatory effect of ISL-M on ulcerative colitis induced by dextran sulfate sodium (DSS) was evaluated. The results showed that PS, PDI, ZP, EE% and DL% of ISL-M were 151.15±1.04 nm, 0.092±0.014, -31.32±0.721 mV, 93.97±1.53 % and 8.42±0.34 %, respectively. Compared with unformulated ISL (F-ISL), the cumulative release rate of ISL-M in the three different media was significantly increased and showed a certain pH sensitivity. The area under drug curve (AUC0-t) and peak concentration (Cmax) of ISL-M group were 2.94 and 4.06 times higher than those of ISL group. In addition, ISL-M is expected to develop new methods for increasing the bioavailability and anti-inflammatory activity of ISL.

Preparation, characterization, pharmacokinetics and ulcerative colitis treatment of hyperoside-loaded mixed micelles.

At present, ulcerative colitis (UC) has become a global disease due to its high incidence. Hyperoside (HYP) is a naturally occurring flavonoid compound with many pharmacological effects. This study aimed to develop HYP-loaded mixed micelles (HYP-M) to improve oral bioavailability of HYP and to evaluate its therapeutic effect on UC. The prepared HYP-M exhibited stable physical and chemical properties, smaller particle size (PS) (21.48 ± 1.37 nm), good polydispersity index (PDI = 0.178 ± 0.013), negative Zeta potential (ZP) (- 20.00 ± 0.48 mV) and high entrapment rate (EE) (89.59 ± 2.03%). In vitro release and in vivo pharmacokinetic results showed that HYP-M significantly increased the releasing rate of HYP, wherein its oral bioavailability was 4.15 times higher than that of free HYP. In addition, HYP-M was more effective in the treatment of UC than free HYP. In conclusion, HYP-M could serve as a novel approach to improve bioavailability and increase anti-UC activity of HYP.

In-vitro and in-vivo evaluation and anti-colitis activity of esculetin-loaded nanostructured lipid carrier decorated with DSPE-MPEG2000.

OBJECTIVE: Encapsulation of esculetin into DSPE-MPEG2000 carrier was performed to improve its water solubility and oral bioavailability, as well as enhance its anti-inflammatory effect on a mouse model of ulcerative colitis that was induced with dextran sulphate sodium (DSS). METHODS: We determined the in-vitro and in-vivo high-performance liquid chromatographic (HPLC) analysis method of esculetin; Esculetin-loaded nanostructure lipid carrier (Esc-NLC) was prepared using a thin-film dispersion method, wherein a particle size analyser was used to measure the particle size (PS) and zeta potential (ZP) of the Esc-NLC, while a transmission electron microscope (TEM) was employed to observe its morphology. Also, HPLC was used to measure its drug loading (DL), encapsulation efficiency (EE) and the in-vitro release of the preparation, as well as investigate the pharmacokinetic parameters. In addition, its anti-colitis effect was evaluated via histopathological examination of HE-stained sections and detection of the concentrations of tumour necrosis factor-alpha (TNF-α), interleukin (IL)-1 beta (ß), and IL-6 in serum with ELISA kits. RESULTS: The PS of Esc-NLC was 102.29 ± 0.63 nm with relative standard deviation (RSD) of 1.08% (with poly-dispersity index-PDI of 0.197 ± 0.023), while the ZP was -15.67 ± 1.39 mV with RSD of 1.24%. Solubility of esculetin was improved coupled with prolonged release time. Its pharmacokinetic parameters were compared with that of free esculetin, wherein the maximum concentration of the drug in plasma was increased by 5.5 times. Of note, bioavailability of the drug was increased by 1.7 times, while the half-life was prolonged by 2.4 times. In the anti-colitis efficacy experiment, the mice in Esc and Esc-NLC groups exhibited significantly reduced levels of TNF-α, IL-1ß, and IL-6 in their sera comparable to the DSS group. Colon histopathological examination revealed that mice with ulcerative colitis in both Esc and Esc-NLC groups displayed improved inflammation, amid the Esc-NLC groups having the best prophylactic treatment effect. CONCLUSION: Esc-NLC could ameliorate DSS-induced ulcerative colitis by improving bioavailability, prolonging drug release time and regulating cytokine release. This observation confirmed the potential of Esc-NLC to reduce inflammation in ulcerative colitis, albeit the need for follow-up research to verify the application of this strategy to clinical treatment of ulcerative colitis.

Vitexin loaded mixed polymeric micelles: preparation, optimization, evaluation and anti-osteoporotic effect.

In this regard, we developed vitexin (Vi)-loaded D-ɑ-tocopherol polyethylene glycol succinate, polyvinylpyrrolidone K30 and sodium cholate mixed micelles (Vi-MMs) mainly for improving oral bioavailability and enhancing anti-osteoporotic effect of Vi. Thin layer dispersion method was employed to prepare Vi-MMs, and then the optimal prescription was optimized by the orthogonal design-response surface method, wherein encapsulation efficiency (EE) was used as optimizing index. The physical properties of Vi-MMs such as appearance morphology, particle size, and zeta potential were also characterized. We further analyzed thein-vitrorelease of Vi and Vi-MMs in three media and investigated the pharmacokinetics of Vi and Vi-MMs in rats. Anti-osteoporotic activity of Vi and Vi-MMs was assessed by establishing a zebrafish osteoporosis model with prednisone. Drug loading, EE, particle size and zeta potential of the optimized Vi-MMs were 8.58 ± 0.13%, 93.86 ± 1.79%, 20.41 ± 0.64 nm and -10 ± 0.56 mV, respectively. The optimized Vi-MMs were shaped spherically as exhibited by transmission electron microscopic technique, with evident core shell nano-structure, well dispersed. In all three media, the release rate of Vi-MMs was significantly higher than that of free Vi. The oral bioavailability of Vi-MMs was increased by 5.6-fold compared to free Vi. In addition, alleviation of prednisone induced osteoporosis in zebrafish by Vi-MMs further demonstrated good anti-osteoporotic effect. In summary, Vi-MMs exhibited enhanced bioavailability and anti-osteoporotic effect, which is expected to be potential nanocarrier for Vi applications in drug development.

Preparation, Physical Characterization, Pharmacokinetics and Anti-Hyperglycemic Activity of Esculetin-Loaded Mixed Micelles.

Despite its low water solubility, esculetin (EC) have been described to demonstrate various health benefits. Thus, we sought to develop esculetin-loaded mixed micelles (EC-M) delivery system to purposively improve biological availability and anti-hyperglycemia activity of EC. Thin-film hydration method was employed to fabricate EC-M, amid characterization with transmission electron microscopic analysis (TEM), coupled with physical properties such as particle size (PS), poly-dispersity index (PDI), zeta-potential (ZP) and stability testing. We analyzed in-vitro release and studied EC-M pharmacokinetics in rats. The hyperglycemic mice model was established with streptozotocin (STZ) to evaluate anti-hyperglycemic activity of EC-M. The PS, PDI and ZP of EC-M were 47.97 ± 0.41 nm, 0.189 ± 0.005 and -25.55 ± 0.28 mV, respectively. The release rate of EC-M increased comparable to free EC in the three media. The oral biological availability and half-life of EC-M increased respectively by 3.06 and 1.45 folds compared to free EC. Besides, we observed 46.21% decrease in blood glucose of mice in EC-M group comparable to the model control, wherein, the anti-hyperglycemic effect of EC-M was better compared to free EC. Conclusively, EC-M may ideally serve as a novel approach to enhance biological availability and increased anti-hyperglycemic activity of EC.

Preparation, in vitro and in vivo evaluation of pinocembrin-loaded TPGS modified liposomes with enhanced bioavailability and antihyperglycemic activity.

PURPOSE: To prepare polyethylene glycol succinate-vitamin E modified pinocembrin (PCB)-loaded liposomes (PCBT-liposomes) and evaluate PCBT-liposomal pharmacokinetics and antihyperglycemic activity. SIGNIFICANCE: The novel PCBT-liposomes demonstrated a promising application prospect as a nano drug carrier for future research. METHODS: Thin film dispersion was used to prepare PCBT-liposomes. We measured a series of characterization, followed by in vitro cumulative release, in vivo pharmacokinetic study, and antihyperglycemic activity evaluation. RESULTS: PCBT-liposomes displayed spherical and bilayered nanoparticles with mean particle size (roughly 92 nm), negative zeta potential (about -26.650 mV), high drug encapsulation efficiency (87.32 ± 1.34%) and good storage (at 4 or 25 °C) stability during 48 h after hydration. The cumulative release rate of PCBT-liposomes was markedly higher than free PCB in four different pH media. In vivo investigation showed that PCBT-liposomes could obviously improve oral bioavailability of PCB by 1.96 times, whereas the Cmax, MRT0-t, and T1/2 of PCBT-liposomes were roughly 1.700 ± 0.139 µg·mL-1, 12.695 ± 1.647 h, and 14.244 h, respectively. In terms of biochemical analysis, aspartate amino-transferase (AST), alanine amino-transferase (ALT), interleukin-1 (IL-1), and tumor necrosis factor-α (TNF-α) concentrations in serum of diabetic mice were respectively decreased 28.28%, 17.23%, 17.77%, and 8.08% after PCBT-liposomal treatment. CONCLUSION: These results show PCBT-liposomal preparation as an excellent nano-carrier which has the potential to improve water solubility, bioavailability, and antihyperglycemic activity of PCB, amid broadening the application of PCB in the clinical settings.

Preparation of Pinocembrin-Loaded F127/MPEG-PDLLA Polymer Micelles and Anti-Osteoporotic Activity.

Pinocembrin (PCB) is 5,7-dihydroxyl flavanone and has multiple pharmacological activities, namely, anti-inflammation, anti-osteoporotic, and so on. However, low water solubility and bioavailability have hindered its application. Herein, we aimed to increase its bioavailability through preparation of F127/MPEG-PDLLA polymer micelles (PCB-M). We characterized the micelles through appropriate attributes such as analysis of particle size (PS), polydispersity (PDI), transmission electron microscopic (TEM) image, stability test, and evaluation of in vitro release of drug. After physical characterization, the respective PS, PDI, and entrapment efficiency (EE) of PCB-M were estimated to be 27.63 ± 0.17 nm, 0.055 ± 0.02, and 90.53 ± 0.01%. Fluorescence probe method was employed to measure critical micelle concentration (CMC) of PCB-M, we observed CMC was low, thereby suggesting that PCB-M had good stability. In vitro release analysis indicated that the rate of cumulative PCB release from PCB-M was greater than 90% in each medium compared with free PCB, which was less than 40%, thus pointing to a significantly improved solubility of PCB. In vivo pharmacokinetic results showed that oral biological availability of PCB-M increased 5.3 folds comparable to free PCB. The effects of PCB on osteoblasts and ALP activities were investigated; subsequently, zebrafish osteoporotic model was established with prednisolone to study the anti-osteoporotic effects of PCB and PCB-M. The results showed that PCB improved osteoporosis with PCB-M being more effective than free PCB. Finally, PCB-M can be used as a promising method to improve the solubility of PCB, while the bioavailability and anti-osteoporotic effect of PCB could be improved, thus laying a foundation for clinical use in the future.

Hyperoside-loaded TPGs/mPEG-PDLLA self-assembled polymeric micelles: preparation, characterization and in vitro/in vivo evaluation.

Hyperoside (Hyp) self-assembled polymeric micelles (Hyp-PMs) were purposely developed to enhance aqueous solubility, in vivo availability and anti-oxidative effect of Hyp. In preparing Hyp-PMs, we employed the thin film dispersion method with the micelles consisting of TPGs and mPEG2000-PDLLA3000. The particle size, polydispersity index and zeta potential of Hyp-PMs were 67.42 ± 1.44 nm, 0.229 ± 0.015 and -18.67 ± 0.576 mV, respectively, coupled with high encapsulation efficiency （EE）of 90.63 ± 1.45% and drug loading (DL) of 6.97 ± 1.56%. Furthermore, the value of critical micelle concentration (CMC) was quite low, which indicated good stability and improved self-assembly ability of Hyp-PMs. Also, trend of in vitro Hyp release from Hyp-PMs demonstrated enhanced solubility of Hyp. Similarly, in comparison with free Hyp, oral bioavailability of Hyp-PMs was improved (about 8 folds) whilst half-life of Hyp-PMs was extended (about 3 folds). In vitro anti-oxidative effect showed obvious strong scavenging DPPH capability of Hyp-PMs, which may be attributed to its smaller size and better solubility. Altogether, Hyp-PMs may serve as a possible strategy to potentially enhance aqueous solubility, bioavailability and anti-oxidative effect of Hyp, which may play a key role in Hyp application in the pharmaceutical industries.

Pinocembrin polymeric micellar drug delivery system: preparation, characterisation and anti-hyperuricemic activity evaluation.

Aim: Hydrophobic pinocembrin (PCB) was incorporated into a new nano-drug delivery system to enhance solubility, bioavailability and anti-hyperuricemic activity of the drug.Methods: We fabricated PCB loaded polymeric micelles (PCB-FPM) by thin film dispersion method and appropriately determined their physical characteristics. The oral relative bioavailability and anti-hyperuricemic activity of PCB-FPM and free PCB were observed.Results: The optimum particle size of the micelles was 19.90 ± 0.93 nm. PCB-FPM exhibited great stability within 18 days, coupled with lower cytotoxicity and higher biocompatibility. Moreover, the percent cumulative release of PCB-FPM was much higher than free PCB in the dissolution media. The oral bioavailability of PCB-FPM was increased by 2.61 times compared with free PCB. Uric acid (UA) level of rats was reduced in PCB-FPM group (200 mg/kg) by 78.82% comparable to the model control.Conclusion: PCB-FPM may become an ideal strategy to increase oral in-vivo availability and anti-hyperuricemic activity of PCB.

Liquiritin-Hydroxypropyl-Beta-Cyclodextrin Inclusion Complex: Preparation, Characterization, Bioavailability and Antitumor Activity Evaluation.

The pharmacological activities of liquiritin (LT) are greatly limited by its insolubility and low oral absorption. The purpose of this study was to prepare LT-hydroxypropyl-beta-cyclodextrin inclusion complex (LT-HP-ß-CD) to increase water solubility, oral bioavailability and antitumor effect of LT. Herein, saturated aqueous solution method was applied to prepare the LT-HP-ß-CD prior to characterization via scanning electron microscope (SEM), infrared radiation (IR) spectroscopy, X-ray diffraction analysis (XRD), and differential scanning calorimetry (DSC). Also, in vitro release and in vivo pharmacokinetics were evaluated. Moreover, the anti-tumor activity of the formulation was investigated in the A549 lung cancer cells. The results of SEM, IR, XRD and DSC showed that LT-HP-ß-CD was successfully formulated. In vitro release and oral bioavailability of LT-HP-ß-CD compared with the free LT was significantly higher. Successfully, antitumor effect of LT was remarkably enhanced by the preparation of LT-HP-ß-CD. Altogether, the LT-HP-ß-CD represents a potential carrier for enhancing the water solubility and oral bioavailability of LT coupled with antitumor activity enhancement.

Enhancement of oral bioavailability and anti-hyperuricemic activity of aloe emodin via novel Soluplus®-glycyrrhizic acid mixed micelle system.

The objective of this study was to fabricate a novel drug delivery system using Soluplus® (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer) and glycyrrhizic acid to improve solubility, bioavailability, and anti-hyperuricemic activity of aloe emodin (AE). The AE-loaded mixed micelles (AE-M) were prepared by thin-film hydration method. The optimal AE-M contained small-sized (30.13 ± 1.34 nm) particles with high encapsulation efficiency (m/m, %) of 90.3 ± 1.08%. The release rate of AE increased in the micellar formulation than that of free AE in the four media (DDW, pH 7.0; phosphate buffer solution, pH 7.4; phosphate buffer solution, pH 6.8; and hydrochloric acid aqueous solution, pH 1.2). In comparison to free AE, the pharmacokinetic study of AE-M showed that its relative oral bioavailability increased by 3.09 times, indicating that mixed micelles may promote gastrointestinal absorption. More importantly, AE-M effectively reduced uric acid level by inhibiting xanthine oxidase (XOD) activity in model rats. The degree of ankle swelling, serum levels of interleukin (IL)-1, and IL-6-related inflammatory factors levels all decreased in the gouty arthritis model established via monosodium urate (MSU) crystals. Taken together, the AE-M demonstrated the potential to improve the bioavailability, anti-hyperuricemic activity, and anti-inflammation of AE.

Enhanced oral bioavailability and anti-hyperuricemic activity of liquiritin via a self-nanoemulsifying drug delivery system.

BACKGROUND: This study focused on the development of a self-nanoemulsifying drug delivery system (SNEDDS) to improve, potentially, the solubility and oral bioavailability of liquiritin (LQ). METHODS: The solubility of LQ in different types of excipient, namely oils (OLs), emulsifiers (EMs), and co-emulsifiers (CO-EMs), was evaluated, and a pseudo-ternary phase diagram (PTPD) and the formulation optimization were established. The prepared self-nanoemulsifying drug delivery system of liquiritin (LQ-SNEDDS) was assessed using droplet size (DS), zeta potential (ZP), polydispersity index (PDI), droplet morphology, drug release in vitro, and oral bioavailability. RESULTS: After the dilution of the LQ-SNEDDS, a transparent nanoemulsion was obtained with an acceptable DS (24.70 ± 0.73 nm), ZP (-18.69 ± 1.44 mV), and PDI (0.122 ± 0.006). The LQ-SNEDDS that was developed had a better release rate in vitro than the free LQ suspension. Pharmacokinetic evaluation showed that the relative oral bioavailability of LQ-SNEDDS was increased by 5.53 times, and LQ-SNEDDS exhibited a delayed half life and longer retention time in comparison with those of free LQ. Similarly, LQ-SNEDDS had a better urate lowering effect and provided better organ protection than free LQ at the same dose (P < 0.05). CONCLUSIONS: The incorporation of LQ into SNEDDS could serve as a promising approach to improve the solubility, oral bioavailability, and anti-hyperuricemic effect of LQ. © 2021 Society of Chemical Industry.

Preparation, characterization, pharmacokinetics, and antirenal injury activity studies of Licochalcone A-loaded liposomes.

A liposome of Licochalcone A (LCA-Liposomes) was purposively prepared to ameliorate the low in vivo availability and efficacy of LCA. Physical characterization of LCA-Liposomes was carried out mainly by determining particle size, morphology, zeta potential (Z-potential), and efficiency of LCA encapsulation (EE) via appropriate techniques. Also, the rate of LCA release in vitro and distribution in vivo (plasma and tissues) was evaluated. Evaluation of the antirenal activity of LCA-liposomes was carried out by establishing chronic renal failure (CRF) model in mice through intragastric administration of adenine (200 mg/kg) and subsequent determination of biochemical parameters and examination of tissue sections. Respectively, the mean size of liposomal particles, Z-potential and EE of LCA-Liposomes were 71.78 ± 0.99 nm, -38.49 ± 0.06 mV, and 97.67 ± 1.72%. Pharmacokinetic and tissue distribution studies showed that LCA-Liposomes could improve the availability of LCA in the blood and tissues, whereas during pharmacodynamics studies, the liposome effectively improved the therapeutic effect of LCA on CRF mice by potentially protecting the renal tissues while exhibiting antioxidant activity. In conclusion, LCA-Liposomes could effectively improve the bioavailability of LCA and provide platform for the development of LCA-related functional products. PRACTICAL APPLICATIONS: As a traditional Chinese medicine, licorice is widely used in food and pharmaceutical industries. LCA is a small molecule flavonoid extracted from the root of licorice. In this study, LCA was loaded on liposome carriers, which significantly improved the water solubility and oral bioavailability, and proved that LCA-Liposomes have certain therapeutic effects on chronic renal failure, thereby providing a basis for the development of LCA into drugs or functional food in the future.

SMEDDS for improved oral bioavailability and anti-hyperuricemic activity of licochalcone A.

The aim of this study was to develop licochalcone A-loaded self-microemulsifying drug delivery system (LCA-SMEDDS) to improve bioavailability and anti-hyperuricemic activity of hydrophobic natural compound licochalcone A (LCA). The prepared LCA-SMEDDS was characterised by transmission electron microscopy analysis, particle size, polymer dispersity index (PDI), zeta potential, stability tests and in vitro release analysis. LCA-SMEDDS and free LCA were orally administered to Sprague-Dawley rats to investigate respective bioavailability. The hyperuricaemia rat model was established to evaluate anti-hyperuricemic activity. The particle size, PDI, and zeta potential of LCA-SMEDDS were 25.68 ± 0.79 nm, 0.074 ± 0.024, -14.37 ± 2.17 mV. The oral bioavailability of LCA-SMEDDS was increased 2.36-fold compared with the free LCA. The uric acid level of LCA-SMEDDS group (200 mg/kg) was decreased 60.08% compared with model control group. The developed LCA-SMEDDS could be an outstanding candidate for improving oral bioavailability and anti-hyperuricemic activity of LCA.

Mixed micelles for enhanced oral bioavailability and hypolipidemic effect of liquiritin: preparation, in vitro and in vivo evaluation.

OBJECTIVES: Liquiritin, as one of the main flavonoids in Glycyrrhiza, exhibits extensive pharmacological effects, such as the anti-oxidant, anti-inflammatory, anti-tumor and so on. Herein, the aqueous solubility and oral bioavailability of liquiritin was purposely enhanced via the preparation of the mixed micelles. METHODS: The liquiritin-loaded micelles (LLM) were fabricated via thin-film dispersion method. The optimal LLM formulation was evaluated through physical properties including particle size (PS), encapsulation efficiency (EE) and drug loading (DL). In vitro accumulate release as well as in vivo pharmacokinetics were also evaluated. Moreover, the hypolipidemic activity of LLM was observed in the hyperlipidemia mice model. RESULTS: The LLM exhibited a homogenous spherical shape with small mean PS, good stability and high encapsulation efficiency. The accumulate release rates in vitro of the LLM were obviously higher than free liquiritin. The oral bioavailability of the formulation was heightened by 3.98 times in comparison with the free liquiritin. More importantly, LLM increased the hypolipidemic and effect of alleviating lipid metabolism disorder in hepatocytes of liquiritin in hyperlipidemia mice model. CONCLUSIONS: Collectively, the improved solubility of liquiritin in water coupled with its enhanced oral bioavailability and concomitant hypolipidemic activity could be attributed to the incorporation of the drug into the mixed micelles.

Enhancement of oral bioavailability and hypoglycemic activity of liquiritin-loaded precursor liposome.

The purpose of this study was to develop a precursor liposome nano-delivery system for liquiritin (LT) to improve its solubility, oral bioavailability, and efficacy. The characterizations of the particle diameter, zeta potential, polydispersity index (PDI), droplet morphology, drug release in vitro, and oral bioavailability of the prepared LT precursor liposomes (LTMs) were carried out. In addition, streptozotocin intraperitoneal injection successfully induced diabetic mouse model, while the LT hypoglycemic effect, oral glucose tolerance, biochemical parameters and pathological sections were studied. The prepared LTMs were diluted to obtain a clear and transparent solution with a diameter of 91.84 ± 1.85 nm, zeta potential of -38.59 ± 2.65 mV and PDI of 0.215 ± 0.016. The in vitro release of the LTMs was superior to that of the free LT suspension, which may be related to the increased solubility of LT, as well as the small diameter and increased surface area. The obtained pharmacokinetic parameters indicated that the relative oral bioavailability of LTMs was increased by 8.8 times compared with the free LT suspension. Pharmacodynamic studies showed that LTMs effectively improved LT's hypoglycemic effect and diabetes-related organ repair, simultaneously confirmed its antioxidant activity. These results implied that the LTMs was an effective method to improve the solubility, oral bioavailability, and hypoglycemic activity of LT.

Preparation, characterization, pharmacokinetics and anti-hyperuricemia activity studies of myricitrin-loaded proliposomes.

Myricitrin has many pharmacological effects, such as anti-inflammation, liver protection and anti-oxidation. However, its clinical application is limited by poor solubility and low oral bioavailability. The preparation of myricitrin-loaded proliposomes (MPs) was achieved via the combination of thin-film dispersion technique and freeze-drying method. The in vitro release of MPs compared with free myricitrin was measured in different dissolution media while the pharmacokinetic study was also conducted in rats. Moreover, the uric acid-lowering activity of MPs was investigated in the hyperuricemic rat model. The prepared myricitrin appeared to be spherical. Notably, compared with the free myricitrin, the cumulative release in vitro and in vivo oral bioavailability of MPs were markedly increased. Besides, the MPs could significantly lower the serum uric acid level as well as ameliorate liver and kidney damage in hyperuricemic rats compared with the model group. Therefore, the present work supports the fact that MPs improved the oral bioavailability of myricitrin for the prospect of clinical application.

Self-Micro-Emulsifying Controlled Release of Eugenol Pellets: Preparation, In vitro/In vivo Investigation in Beagle Dogs.

This report aimed to formulate self-micro-emulsifying (SMEDDS) controlled-release pellets delivery system to improve aqueous solubility and in vivo availability of eugenol, a main constituent of clove oil with multiple pharmacological activities. The optimal formulation of eugenol-SMEDDS was eugenol: ethyl oleate: cremophor EL: 1, 2-propylene glycol at the ratio of 5:5:12:8. The SMEDDS were observed under transmission electron microscopy (TEM), and the size distribution was measured with dynamic laser light scatting (DLS). The particle size, index of dispersity (PDI), and zeta potential (Z-potential) were 68.8 ± 0.1 nm, 0.285 ± 0.031, and - 11.62 ± 0.63 mV, respectively. Eugenol-SMEDDS exhibited substantial increased in vitro dissolution compared with the free eugenol. The eugenol-SMEDDS sustained-release pellets (eugenol-SMEDDS-SR pellets) comprising of eugenol-SMEDDS, hydroxypropyl methylcellulose (HPMC), microcrystalline cellulose (MCC), and ethyl cellulose (EC) coats were obtained via extrusion spheronization technique. Consequently, the obtained pellets observed under scanning electron microscopy (SEM) showed spherical shape with smooth surface, desirable drug loading capacity (7.18 ± 0.17%), greater stability, and controlled release. Meanwhile, the oral test showed that bioavailability of eugenol in pellets was highly improved 23.6-fold to the free eugenol. Overall, these results suggested that the improvement of the oral bioavailability of eugenol-SMEDDS-SR could be due to the successful incorporation of the drug into SMEDDS.

Enhancement of Oral Bioavailability and Anti-hyperuricemic Activity of Isoliquiritigenin via Self-Microemulsifying Drug Delivery System.

The aim of this study was to develop a self-microemulsifying drug delivery system (SMEDDS) for enhancement of the oral bioavailability of isoliquiritigenin (ISL) as well as evaluate its in vivo anti-hyperuricemic effect in rats. The ISL-loaded self-microemulsifying drug delivery system (ISL-SMEDDS) was comprised of ethyl oleate (EO, oil phase), Tween 80 (surfactant), and PEG 400 (co-surfactant). The ISL-SMEDDS exhibited an acceptable narrow size distribution (44.78 ± 0.35 nm), negative zeta potential (- 10.67 ± 0.86 mV), and high encapsulation efficiency (98.17 ± 0.24%). The in vitro release study indicated that the release rates of the formulation were obviously higher in different release media (HCl, pH 1.2; PBS, pH 6.8; double-distilled water, pH 7.0) compared with the ISL solution. The oral bioavailability of the ISL-SMEDDS was enhanced by 4.71 times in comparison with the free ISL solution. More importantly, ISL-SMEDDS significantly reduced uric acid level by inhibiting xanthine oxidase (XOD) activity in the model rats. Collectively, the prepared ISL-SMEDDS proved to be potential carriers for enhancing the solubility and oral bioavailability of ISL, as well as ameliorating its anti-hyperuricemic effect.