Progress of Drug Nanocrystal Self-Stabilized Pickering Emulsions: Construction, Characteristics In Vitro, and Fate In Vivo.

A drug nanocrystal self-stabilized Pickering emulsion (DNSPE) is a novel Pickering emulsion with drug nanocrystals as the stabilizer. As a promising drug delivery system, DNSPEs have attracted increasing attention in recent years due to their high drug loading capacity and ability to reduce potential safety hazards posed by surfactants or specific solid particles. This paper comprehensively reviews the progress of research on DNSPEs, with an emphasis on the main factors influencing their construction, characteristics and measurement methods in vitro, and fate in vivo, and puts forward issues that need to be studied further. The review contributes to the advancement of DNSPE research and the promotion of their application in the field of drug delivery.

Current Status of Research on the Coal and Gas Outburst Control Technology of Hydration and Anhydrous.

China is one of the countries with the most frequent coal and gas outburst accidents in the world. In the early years of the founding of New China, coal and gas outburst accidents occurred frequently, causing serious casualties, equipment damage, and economic losses. In recent years, some scholars have tried to simulate the coal and gas outburst phenomenon using physical models to study the mechanisms of its occurrence. However, due to the complexity and nonreproducibility of coal and gas outburst disasters, the study of coal and gas outburst mechanisms is still in the hypothesis stage. In order to effectively reduce the risk of coal and gas outburst accidents, coal and gas outburst prevention and control technology have emerged and achieved remarkable results, and the probability of coal and gas outburst accidents has been greatly reduced. Among coal and gas protrusion outburst and control technologies, hydraulic and anhydrous prevention and control technologies are widely used. The purpose of this paper is to briefly explain the mainstream hypothesis of coal and gas outburst, analyze the action principle of hydration and anhydrous control technologies, discuss the current status of research on hydration and anhydrous control technologies, and put forward the problems of current technologies and future development trends.

Catalpol improves impaired neurovascular unit in ischemic stroke rats via enhancing VEGF-PI3K/AKT and VEGF-MEK1/2/ERK1/2 signaling.

Neurovascular unit (NVU) is organized multi-cellular and multi-component networks that are essential for brain health and brain homeostasis maintaining. Neurovascular unit dysfunction is the central pathogenesis process of ischemic stroke. Thus integrated protection of NVU holds great therapeutic potential for ischemic stroke. Catalpol, classified into the iridoid monosaccharide glycoside, is the main active ingredient of the radix from traditional Chinese medicine, Rehmannia glutinosa Libosch, that exhibits protective effects in several brain-related diseases. In the present study, we investigated whether catalpol exerted protective effects for NVU in ischemic stroke and the underlying mechanisms. MCAO rats were administered catalpol (2.5, 5.0, 10.0 mg·kg-1·d-1, i.v.) for 14 days. We showed that catalpol treatment dose-dependently reduced the infarction volume and significantly attenuated neurological deficits score in MCAO rats. Furthermore, catalpol treatment significantly ameliorated impaired NVU in ischemic region by protecting vessel-neuron-astrocyte structures and morphology, and promoting angiogenesis and neurogenesis to replenish lost vessels and neurons. Moreover, catalpol treatment significantly increased the expression of vascular endothelial growth factor (VEGF) through up-regulating PI3K/AKT signaling, followed by increasing FAK and Paxillin and activating PI3K/AKT and MEK1/2/ERK1/2 pathways. The protective mechanisms of catalpol were confirmed in an in vitro three-dimensional NVU model subjected to oxygen-glucose deprivation. In conclusion, catalpol protects NVU in ischemic region via activation of PI3K/AKT signaling and increased VEGF production; VEGF further enhances PI3K/AKT and MEK1/2/ERK1/2 signaling, which may trigger a partly feed-forward loop to protect NVU from ischemic stroke.

[Analysis of blood components of Yougui Yin in normal rats and rats with kidney deficiency caused by adenine based on UPLC-MS technology].

Based on the serum medicinal method, this study aims to investigate the migrating components of Yougui Yin in the blood after intragastric administration, and to provide reference for the basic research of its pharmacodynamics. The kidney deficiency rat model was replicated by adenine method. Normal rats and model rats were administered orally for a single gavage of Yougui Yin. The components in blood were rapidly analyzed and identified by ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) and multiple reaction monitoring(MRM), and the migrating components in blood of Yougui Yin were explored by multivariate statistical analysis. The results showed that there were 42 characteristic peaks in the plasma of normal rats by UPLC-Q-TOF-MS technology and 13 chemical components were identified, including 6 alkaloids, 2 flavonoids, 2 triterpenoid saponins, 1 iridoid, 1 phenylpropanoid and 1 monoterpenoid. There were 22 characteristic peaks in the plasma of kidney-deficiency rats, and 12 chemical components were identified, including 2 iridoids, 6 alkaloids, 2 flavonoids, 1 monoterpenoid and 1 triterpenoid saponin. Verbascoside, isoacteoside, acteoside, pinoresinoldiglucoside, loganin and morroniside were identified by MRM both in the plasma of normal rats and kidney-deficiency rats. Compared with 85 monomer components in Yougui Yin, 17 common prototype components were found by UPLC-MS in the plasma of normal rats and kidney deficiency rats, including verbascoside, isoacteoside, acteoside, rehmapicrogenin derived from Rehmanniae Radix Praeparata, pinoresinol diglucoside and geniposidic acid from Eucommiea Cortex, loganin and morroniside derived from Corni Fructus, mesaconine, benzoylmesaconine, benzoylaconitine, benzoylhypacoitine, mesaconitine, aconitine derived from Aconiti Lateralis Radix Praeparata, liquiritin, isoliquiritin and glycyrrhizic acid derived from Glycyrrhizae Radix et Rhizoma. Thirty-one metabolites of medicinal ingredients not found in the plasma of adenine-induced kidney deficiency rats were also detected in the plasma of normal rats. Twelve metabolites of medicinal materials not found in the plasma of normal rats were detected in the plasma of kidney deficiency rats. The results of the study provide reference for explaining the material basis and mechanism of Yougui Yin in the treatment of kidney deficiency.

[Study on oral absorption mechanisms of puerarin in nanocrystals self-stabilized pickering emulsion].

Nanocrystals self-stabilized Pickering emulsion(NSSPE) is a new kind of emulsion where only nanocrystals of poorly soluble drugs are used as stabilizers. Our previous study showed that NSSPE with Ligusticum chuanxiong oil as the main oil phase can significantly promote oral absorption of puerarin. The present study aimed to explore its absorption mechanism in oral administration. The in vitro dissolution test was carried out to study the effect of NSSPE on release of puerarin. The effects and mechanism of NSSPE on uptake and transport of puerarin across Caco-2 cell were investigated. The results showed that the drug release rate of NSSPE was similar to that of nanocrystals, with their cumulative dissolution of puerarin not affected by pH of releasing mediums, both significantly higher than that of crude material. The uptake of puerarin in NSSPE was concentration-dependent and significantly higher than that of solution or surfactant stabilized emulsion. Genistein and indomethacin, inhibitors of lipid rafts/caveolin, could significantly reduce the uptake of puerarin in NSSPE. Compared with solution, NSSPE and surfactants stabilized emulsion obviously increased transport rate K_a and apparent permeability coefficient P_(app) of puerarin in AP → BL direction, but there was no significant difference in BL → AP direction. It could be inferred that there were both passive and active transport mechanisms, as well as lipid raft/caveolin mediated endocytosis for absorption of NSSPE. The promoted oral absorption of puerarin in NSSPE was mainly related to the existing nanocrystal form which could promote dissolution, puerarin as well as Ligusticum chuanxiong oil which could promote drug transmembrane transport and inhibit drug efflux. It is the unique structure and composition of the compound NSSPE that promoted the oral absorption of puerarin.

Intracellular uptake of nanocrystals: Probing with aggregation-induced emission of fluorescence and kinetic modeling.

Nanocrystal formulations have been explored to deliver poorly water-soluble drug molecules. Despite various studies of nanocrystal formulation and delivery, much more understanding needs to be gained into absorption mechanisms and kinetics of drug nanocrystals at various levels, ranging from cells to tissues and to the whole body. In this study, nanocrystals of tetrakis (4-hydroxyphenyl) ethylene (THPE) with an aggregation-induced emission (AIE) property was used as a model to explore intracellular absorption mechanism and dissolution kinetics of nanocrystals. Cellular uptake studies were conducted with KB cells and characterized by confocal microscopy, flow cytometry, and quantitative analyses. The results suggested that THPE nanocrystals could be taken up by KB cells directly, as well as in the form of dissolved molecules. The cellular uptake was found to be concentration- and time-dependent. In addition, the intracellular THPE also could be exocytosed from cells in forms of dissolved molecules and nanocrystals. Kinetic modeling was conducted to further understand the cellular mechanism of THPE nanocrystals based on first-order ordinary differential equations (ODEs). By fitting the kinetic model against experimental measurements, it was found that the initial nanocrystal concentration had a great influence on the dynamic process of dissolution, cellular uptake, and exocytosis of THPE nanocrystals. As the nanocrystal concentration increased in the culture media, dissolution of endocytosed nanocrystals became enhanced, subsequently driving the efflux of THPE molecules from cells.

A Novel Solid Nanocrystals Self-Stabilized Pickering Emulsion Prepared by Spray-Drying with Hydroxypropyl-ß-cyclodextrin as Carriers.

A drug nanocrystals self-stabilized Pickering emulsion (NSSPE) with a unique composition and microstructure has been proven to significantly increase the bioavailability of poorly soluble drugs. This study aimed to develop a new solid NSSPE of puerarin preserving the original microstructure of NSSPE by spray-drying. A series of water-soluble solid carriers were compared and then Box-Behnken design was used to optimize the parameters of spray-drying. The drug release and stability of the optimized solid NSSPE in vitro were also investigated. The results showed that hydroxypropyl-ß-cyclodextrin (HP-ß-CD), rather than solid carriers commonly used in solidification of traditional Pickering emulsions, was suitable for the solid NSSPE to retain the original appearance and size of emulsion droplets after reconstitution. The amount of HP-ß-CD had more influences on the solid NSSPE than the feed rate and the inlet air temperature. Fluorescence microscopy, confocal laser scanning microscopy and scanning electron microscopy showed that the reconstituted emulsion of the solid NSSPE prepared with HP-ß-CD had the same core-shell structure with a core of oil and a shell of puerarin nanocrystals as the liquid NSSPE. The particle size of puerarin nanocrystal sand interfacial adsorption rate also did not change significantly. The cumulative amount of released puerarin from the solid NSSPE had no significant difference compared with the liquid NSSPE, which were both significantly higher than that of puerarin crude material. The solid NSSPE was stable for 3 months under the accelerated condition of 75% relative humidity and 40 °C. Thus, it is possible todevelop the solid NSSPE preserving the unique microstructure and the superior properties in vitro of the liquid NSSPE for poorly soluble drugs.

Effects of Hydrophilic Carriers on Structural Transitions and In Vitro Properties of Solid Self-Microemulsifying Drug Delivery Systems.

Self-microemulsifying drug delivery systems (SMEDDS) offer potential for improving the oral bioavailability of poorly water-soluble drugs. However, their susceptibilities during long term storage and in vivo precipitation issues limit their successful commercial application. To overcome these limitations, SMEDDS can be solidified with solid carriers, thus producing solid self-microemulsifying drug delivery systems (S-SMEDDS). In this study, effects of various hydrophilic carriers on structural transitions and in vitro properties of S-SMEDDS were investigated in order to set up in vitro methods for screening out appropriate carriers for S-SMEDDS. Liquid SMEDDS was prepared and characterized using nimodipine as a model drug. The effects of various hydrophilic carriers on internal microstructure and solubilization of SMEDDS were investigated by conductivity measurement and in vitro dispersion test. The results showed that hydrophilic carriers including dextran 40, maltodextrin and PVP K30 seemed to delay the percolation transition of SMEDDS, allowing it to maintain a microstructure that was more conducive to drug dissolution, thus significantly increasing the solubilization of nimodipine in the self-microemulsifying system and decreasing drug precipitation when dispersed in simulated gastric fluid. S-SMEDDS of nimodipine were prepared by using spray drying with hydrophilic carriers. The effects of various hydrophilic carriers on in vitro properties of S-SMEDDS were investigated by using SEM, DSC, PXRD and in vitro dissolution. The results showed that properties of hydrophilic carriers, especially relative molecular mass of carriers, had obvious influences on surface morphologies of S-SMEDDS, reconstitution of microemulsion and physical state of nimodipine in S-SMEDDS. Considering that in vitro properties of S-SMEDDS are closely related to their pharmacokinetic properties in vivo, the simple and economical in vitro evaluation methods established in this paper can be used to screen solid carriers of S-SMEDDS well.

Development of an Oral Compound Pickering Emulsion Composed of Nanocrystals of Poorly Soluble Ingredient and Volatile Oils from Traditional Chinese Medicine.

In this study, an oral drug nanocrystals self-stabilized Pickering emulsion (NSSPE), which used nanocrystals of a poorly soluble ingredient from Puerariae Radix called puerarin as solid particle stabilizers and Ligusticum chuanxiong essential oil since the main oil phase had been developed to improve the oral bioavailability of puerarin. The appearance of emulsions, size and zeta potential of droplets, and content of puerarin in emulsified layer during a storage of six months at 4, 25, and 40 °C were investigated. The centrifugation stability at 4000× g was also studied. The micro-structure of emulsion droplets was characterized by a scanning electron micrograph (SEM), confocal laser scanning microscopy (CLSM), a fluorescence microscope (FM), and differential scanning calorimetry (DSC). The in vivo oral bioavailability of puerarin NSSPE was investigated in rats. Results showed that appearances of puerarin NSSPE kept stable after centrifugation at 4000× g for 15 min or storage for six months at 4, 25, and 40 °C. SEM, CLSM, FM, and DSC showed that the puerarin NSSPE had a stable core-shell structure of emulsion droplets formed by the adsorption of puerarin nanocrystals on the surface of oil droplets of mixed oil of Ligusticum chuanxiong essential oil and Labrafil M 1944 CS (9:1, v/v). The relative bioavailability of puerarin NSSPE to puerarin coarse powder suspension, nanocrystal suspension, and surfactant emulsion were 262.43%, 155.92%, and 223.65%, respectively. All these results indicated that puerarin nanocrystals could stabilize Pickering emulsion of Ligusticum chuanxiong essential oil without any other stabilizers and Pickering emulsion could improve the oral bioavailability of puerarin, which suggests that the drug nanocrystal self-stabilized Pickering emulsion as a promising oral drug delivery system for Traditional Chinese Medicine containing poorly soluble ingredients and volatile oils.

[Intestinal absorption of puerarin nanocrystalline self-stabilizing pickering emulsion in rats].

To study the intestinal absorption characteristics of drug's nanocrystalline self-stabilizing Pickering emulsion (NSSPE) in situ in rats. Rat single-pass intestinal perfusion model was established, and high performance liquid chromatography (HPLC) was used to detect the concentration of puerarin in rat intestinal perfusion solution, assay the absorption rate constant (Ka) and the intestinal apparent permeability coefficient (Papp) of NSSPE in duodenum, jejunum, ileum, and colon, which were compared with those of raw material, nanocrystal and normal emulsion, respectively. For NSSPE, the Ka and Papp values were in the following order: duodenum>jejunum>ileum (P<0.05)>colon (P<0.01). However, there was no obvious difference between jejunum and ileum. As compared with raw material, nanocrystal and normal emulsion, the Ka and Papp values of NSSPE in duodenum were significantly higher than those of other three preparations (P<0.05); and the Ka and Papp values of NSSPE in jejunum and colon were significantly higher than those of raw material, nanocrystal and normal emulsion (P<0.01); and the Ka and Papp of NSSPE in ileum were also higher than those of raw material and normal emulsion (P<0.05), but had no obvious difference with nanocrystal. The results showed that NSSPE could significantly improve the absorption of puerarin in the intestine of rats.

Hemostasis and uterine contraction promoting effect of the extract from drugs in the Zi-Yin-Tiao-Jing granule, a traditional Chinese compound preparation.

ETHNOPHARMACOLOGICAL RELEVANCE: Zi-Yin-Tiao-Jing granule (ZG) is a traditional Chinese medicine compound preparation for perimenopausal dysfunctional uterine bleeding. It is made from 9 Chinese crude drugs based on a modified traditional Chinese prescription recorded in Fu Qingzhu Nvke as Guben Zhibeng Tang. AIM OF THE STUDY: This study aimed to investigate the hemostasis and uterine contraction promoting effect of quality controlled ZG extract on animals as a preclinical study. MATERIALS AND METHODS: ZG extract was quality controlled by determining the contents of asperosaponin Ⅵ and tetrahydroxystilbene glucoside (TSG) with high-performance liquid chromatography (HPLC) and the contents of total tannins, total saponins and total flavonoids with ultraviolet spectrophotometry (UV). Bleeding time, clotting time, prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen (FIB) content were assayed to test the hemostasis effect of ZG extract on sixty healthy female Kunming mice. In addition, ten healthy female Sprague-Dawley rats were used to test the effect of ZG extract on uterine contractions in vitro with the BL-420 Biological Function Experiment System. RESULTS: The ZG extract contained 0.81mgg-1 asperosaponin Ⅵ, 0.15mgg-1 TSG, 1.98mgg-1 total tannins, 1.83mgg-1 total saponins, and 4.09mgg-1 total flavonoids. Compared with placebo, the ZG extract shortened the bleeding time at a dosage of 1.2gkg-1 and 2.4gkg-1, and shortened the clotting time at 0.6gkg-1, 1.2gkg-1 and 2.4gkg-1 in mice (P < 0.01). It also decurtated the APTT at a dosage of 0.6gkg-1 (P < 0.05) and raised the content of FIB in the plasma at a dosage of 2.4gkg-1 (P < 0.05). However, the PT showed no changes after the administration of ZG extract (P > 0.05). In addition, ZG extract at the doses of 1.8mgmL-1, 3.6mgmL-1, and 5.4mgmL-1 increased the amplitude and motoricity of uterine contractions of rats (P < 0.05 or P < 0.01) but maintained the frequency as unchanged. CONCLUSIONS: The ZG extract was quality controllable by assaying for asperosaponin Ⅵ, TSG, total tannins, total saponins and total flavonoids. It could promote the hemostasis of mice in vivo, as well as the uterine contractions of rats in vitro. Therefore, it may be a promising preparation for clinical treatment of perimenopausal dysfunctional uterine bleeding.

[Effects of drug-oil properties on fabrication of drug nanocrystalline self-stabilizied Pickering emulsions].

To investigate the effects of drug and oil properties on the formation and stability of drug nanocrystalline self-stabilizied Pickering emulsions (NSSPE). Three insoluble Chinese medicine components (puerarin, tanshinone ⅡA and ferulic acid) were selected as model drugs, and Capmul C8, Fabrafil M 1944 CS, isopropyl myristate, Pzechwan Lovage Rhizome oil, and olive oil were used as oil phase. NSSPEs were developed by high pressure homogenization method and were evaluated for their appearance, centrifugal stability, droplet size and drug content changes in emulsion layer after storing at room temperature for 14 d. Then the properties of the oil (surface tension and viscosity) and properties of the drugs (surface energy, oil-water partition coefficient, size and Zeta potential of nanocrystalline and drug-water-oil contact angle) on the formation and stability of NSSPE were analyzed. The emulsification property and stability of five samples prepared with ferulic acid nanocrystals and different oils were significantly lower than those of puerarin and tanshinone ⅡA; the particle size of ferulic acid nanocrystals was 3.90 µm, extremely higher than 305 nm of puerarin and 406 nm of tanshinone ⅡA (P<0.05); the zeta potential of ferulic acid nanocrystals was -0.018 0 mV, significantly lower than －29.1 mV of puerarin and -42.6 mV of tanshinone ⅡA (P<0.05). Three samples prepared with isopropyl myristate and different drugs were not emulsions and the viscosity of isopropyl myristate was 4.67 mPa•s, significantly lower than that of the other oils (P<0.01). Puerarin-NSSPEs prepared with Pzechwan Lovage Rhizome oil showed best emulsification property and stability; the contact angle of puerarin in Pzechwan Lovage Rhizome oil-water was 69.7°, close to 90°, significantly higher than other contact angles. NSSPEs made by tanshinone ⅡA-Capmul C8-water, tanshinone ⅡA-Labrafil M 1944 CS-water showed highest stability, with a contact angle of 99.2° and 112° respectively, more close to 90° than other oils. The results indicated that viscosity, size and Zeta potential of nanocrystalline and three-phase contact angle had great influence on the formation and stability of NSSPE; surface tension of oil, surface energy of drug and oil-water partition coefficient may not be related to the construction of NSSPE.

[Stability optimization of puerarin nanocrystalline self-stabilizied Pickering emulsion by response surface methodology].

A new Pickering emulsion, puerarin nanocrystalline self-stabilized Pickering emulsion (Pu-NSSPE) was developed. Box-Behnken design was used for optimizing the preparation formulation of Pu-NSSPE to improve its stability, and the effects of concentration of puerarin, volume ratio of water to oil, and pH value of water phase on the stratification index of emulsion, droplet size and drug concentration in emulsion were investigated. Results showed that the optimized Pu-NSSPE could be prepared with the concentration of puerarin of 0.5%, the volume ratio of water to oil of 9∶1 and the pH of water of 9. The size of emulsion droplet of optimized Pu-NSSPE was (12.70±1.17) µm and the drug content was (4.49±0.21) g•L⁻¹. The above indexes had no significant changes within the storage of 6 months at room temperature, indicating good stability. Microstructure characterizations by scanning electron micrograph, confocal laser scanning microscope and fluorescence microscope showed that the optimized Pu-NSSPE had a stable core-shell structure of emulsion droplet formed by the adsorption of puerarin nanocrystallines at the surface of oil droplets, which may be the microstructure reason for the long stability of Pu-NSSPE.

[Effect factors and mechanisms of borneol's bidirectional regulation on blood-brain barrier permeability].

In recent twenty years, there are a lot of studies about the effect of borneol on permeability of blood-brain barrier(BBB); however, it isDODOrt of regular conclusions of effect factors and in-depth analysis of functional mechanisms. The current researching data were collected and analyzed in this paper for illuminating the effect factors and mechanisms of borneol on permeability of BBB.The following conclusions were obtained: five factors about borneol influencing the permeability of BBB. First, opticity activity of borneol had no significant effect on action effects. Second, dose of borneol in the range of 50.00-200.00 mg•kg⁻¹, did not affect the effect direction, but only affect its action intensity either with use alone or combination use. Third, the borneol can increase the permeability of physiological BBB, and decrease the permeability of pathological BBB. Fourth, regardless of using singly or using compatibility with musk, borneol can decrease the permeability of BBB in different brain disease models. Fifth, when used with astragalus, catalpol or puerarin, borneol can increase the permeability of BBB and promote the drugs through BBB in pathological conditions. The target spots and mechanisms of borneol's bidirectional regulation on the permeability of BBB are related to the structure and function of cerebral endothelial cells, the exocytosis effects of P-gp and low pinocytosis internal transport effects. On one hand，borneol can down-regulate P-gp by inhibiting NF-κB to reduce the exocytosis effects of P-gp and promote the blood brain barrier pinocytosis to increase the permeability of BBB; On the other hand，borneol can reduce the degradation of basement membrane of blood vessel and tight junctions by inhibiting the expression of IL-1ß, MMP-9 to decrease the permeability of BBB；moreover，borneol has bidirectional regulation effects on blood-brain barrier permeability by influencing the signaling pathways of Ca2+-eNOS-NO, VEGF-eNOS-NO. However, the detailed mechanisms that borneol regulates and controls the permeability of BBB are so complicated, so they shall be further proved and clarified.

Enhancing both oral bioavailability and brain penetration of puerarin using borneol in combination with preparation technologies.

Now there are few good oral preparations of puerarin used in cerebrovascular diseases because of its poor oral absorption caused by the low water solubility and the poor penetration into brain. In this study, three oral formulations of puerarin, nanocrystals suspension (NCS), inclusion compounds solution (ICS) and self-microemulsifying drug delivery system (SMEDDS) were prepared with borneol as an oral brain-targeting enhancer. A rat syngeneic in vitro model of the brain-blood barrier (BBB) was established to investigate effects of borneol on the permeability of puerarin across the BBB. The pharmacokinetics of puerarin in mice after oral administration was investigated by a high performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS) method. The in vitro BBB model study showed the permeability of puerarin was increased significantly (p < 0.05) and the value of transepithelial electrical resistance at 2 h was decreased significantly (p < 0.01) when the concentration of borneol was over 12.5 µg/mL compared with the control group. The pharmacokinetics results indicated borneol with doses of over 50 mg/kg could obviously increase both intestinal absorption and brain penetration of puerarin. With co-administration of borneol (100 mg/kg), the AUC of puerarin both in plasma (AUCplasma) and in brain (AUCbrain) for SMEDDS were significantly higher than those for NCS (p < 0.01) and ICS (p < 0.05). These results suggested borneol in combination with SMEDDS could improve both the oral absorption and the brain penetration of puerarin in mice, which was promising for the development of an oral formulation of puerarin used in cerebrovascular diseases.

A new drug nanocrystal self-stabilized Pickering emulsion for oral delivery of silybin.

A new silybin nanocrystal self-stabilized Pickering emulsion (SN-SSPE) has been developed using a high pressure homogenization method to improve the oral bioavailability of silybin. Influences of homogenization pressure and drug content on the formation of SN-SSPE were studied. The morphology, structure and size of Pickering emulsion droplets were characterized using a scanning electron micrograph, confocal laser scanning microscopy and atomic force microscopy. The stability, in vitro release and in vivo oral bioavailability of SN-SSPE were investigated. Results indicated that the particle size of silybin nanocrystals (SN-NC) decreased when homogenization pressure increased until 100MPa. When the content of silybin reached 300mg or above, a stable Pickering emulsion of silybin could be formed by sufficient SN-NC covering surfaces of oil droplets completely and thus self-stabilizing the Pickering emulsion. The emulsion droplet of SN-SSPE with the size of 27.3±3.1µm showed a core-shell structure consisting of a core of oil and a shell of SN-NC. SN-SSPE has shown high stability over 40days. The in vitro release rate of SN-SSPE was faster than silybin coarse powder and similar to silybin nanocrystalline suspension (SN-NCS). The peak concentration of silybin of SN-SSPE following intragastric administration in rats was increased by 2.5-fold and 3.6-fold compared with SN-NCS and silybin coarse powder, respectively. The AUC of SN-SSPE was increased by 1.6-fold and 4.0-fold compared with SN-NCS and silybin coarse powder, respectively. All these results showed that the Pickering emulsion of silybin could be stabilized by nanocrystals of silybin itself and increased the oral bioavailability of silybin. The drug nanocrystalline self-stabilized Pickering emulsion was a promising oral drug delivery system for poorly soluble drugs.

[Preparation and evaluation of silybin nanocrystallines self-stabilizing Pickering emulsion].

A new silybin nanocrystallines self-stabilizing Pickering emulsion(SN-SSPE) was developed using the high pressure homogenization method to improve the oral bioavailability of silybin. The influences of homogenization pressure from 50 to 120 MPa and drug content from 100 mg to 1000 mg on the formation of SN-SSPE were studied. The morphology, structure and size of emulsion droplet in SN-SSPE were characterized using scanning electron micrograph and confocal laser scanning microscope.SN-SSPE was evaluated, including stability, in vitro release and in vivo oral bioavailability. The particle size of silybin nanocrystallines (SN-NC) was decreased as the pressure increased until 100 MPa. When the drug content reached 300 mg or above, stable SN-SSPE was formed from sufficient SN-NC covering surfaces of oil droplets completely. The emulsion droplet of SN-SSPE with the size of 27.3 ± 3.1 µm showed a core-shell structure consisting of oil droplet as core and SN-NC as shell.SN-SSPE showed a high stability over 40 days. In vitro release rate of SN-SSPE was faster than silybin coarse powder and similar to silybin nanocrystallines suspension(SN-NCS).After intragastric administration in rats, the peak concentration of SN-SSPE was increased by 2.5-fold and 2.3-fold compared with SN-NCS and silybin coarse powder, respectively. The AUC of SN-SSPE was increased by 1.4-fold and 3.8-fold compared with SN-NCS and silybin coarse powder, respectively. All these results showed that nanocrystallines of the poorly soluble drug could stabilize Pickering emulsions, which provides a promising application to the improvement of the oral bioavailability of poorly soluble drugs.

[In vitro inhibitory effects of Jiawei Foshou San capsule on activity of cytochrome P450 enzymes in rat and human liver microsomes].

This study was designed to investigate the inhibitory effects of Jiawei Foshou San (JWFSS) capsule in vitro on five major human liver microsomes CYP1A2, CYP2C9, CYP2D6, CYP2E1, CYP3A4, as well as on rat liver microsomes CYP1A2, CYP2C9, CYP2D2, CYP2E1, CYP3A1/2. The test groups included a negative control group, an inhibitor positive control group, an ferulic acid (FA) group, a ligustrazine (LZ) group, a tetrahydropalmatine (THP) group, and an JWFSS capsule group. After incubating the liver microsomes with a cocktail of probe drugs, the metabolites were quantitated with LC-MS/MS, and IC(50) values were calculated to assess the inhibitory effect of JWFSS capsule and its components on five rat/human CYP450 enzymes. All of the IC(50) values for the FA and the LZ for the five CYPs could not be determined. The IC(50) of the THP for rat CYP3A1/2 and for human CYP2D6 was 7.46 and 9.24 µmol·L(-1), respectively. The IC(50) of the JWFSS capsule for rat CYP2D2, CYP2E1 and CYP3A1/2 was 241.3, 369.8 and 293.0 mg·L(-1), for human CYP2D6, CYP2E1 and CYP3A4 was 123.9, 189.9 and 171.3 mg·L(-1) respectively. The results indicated there were little probability that FA and LZ inhibited the activity of rat and human liver five CYPs; THP was identified as moderate-intensity inhibitor of rat liver CYP3A1/2 and human liver CYP2D6; JWFSS capsule might have a inhibitory effect on the activity of rat and human liver CYP2D, CYP2E1 and CYP3A in vitro, showing that there was a strengthened efficacy and a prolonged effective time for drugs metabolized by CYP2D, CYP2E1, CYP3A and combined with JWFSS capsule.

[Borneol promotes oral absorption and penetration into brain of puerarin and catalpol].

To investigate the effect of borneol on the oral absorption and penetration into brain of puerarin and catalpol from cell level and animal level, and screen the concentration of borneol that is suitable for Zige compound oral preparation. Blood-brain barrier(BBB) model was established by co-culture of primary brain microvessel endothelial cells(BMEC) and astrocytes(As) in rats, and it was used to investigate the effect of borneol(concentration from 6.25 to 100 mg•L⁻¹) on the transport of puerarin and catalpol. The pharmacokinetics of puerarin and catalpol in plasma and brain of rats were compared after intragastric administration of borneol solution (0, 25, 50 and 100 mg•kg⁻¹) immediately followed by puerarin(200 mg•kg⁻¹) and catalpol(45 mg•kg⁻¹) nanocrystal suspension. Barrier function was basically formed after co-culturing of brain microvascular endothelial cells and astrocytes for 7 d. The permeability of puerarin and catalpol across blood-brain barrier was increased significantly(P<0.05) and transendothelial electrical resistance(TEER) values at 2 h were decreased significantly(P<0.01) when the concentration of borneol was between 12.5 to 100 mg•L⁻¹ as compared with the control group. Borneol at the dose of 50 mg•kg⁻¹ and 100 mg•kg⁻¹ could significantly increase the oral absorption of puerarin(P<0.05), but there was no obvious effect for catalpol. AUCbrain/AUCblood for puerarin was highest with borneol at dose of 100 mg•kg⁻¹ (P<0.05), while AUCbrain/AUCblood for catalpol was highest with borneol at dose of 50 mg•kg⁻¹ (P<0.05). AUCbrain was highest at 100 mg•kg⁻¹ for puerarin(P<0.05); while for catapol, it was highest at 50 mg•kg⁻¹, but it was not significantly different from 100 mg•kg⁻¹. In conclusion, borneol could increase the amount of puerarin and catalpol in brain after oral administration and the optimized dose shall be 100 mg•kg⁻¹.

[Effects of different preparation technologies on concentrations of puerarin and catalpol in plasma and brain of rats after oral administration].

To compare the effects of different preparation technologies on the concentrations of puerarin and catalpol in plasma and brain of rats after oral administration, in order to lay an experimental basis for developing new oral Zige preparations. The nanocrystal, self-microemulsions (tween-80 and Cremophor RH-40 as emulsifiers) and inclusion complex of HP-ß-CD containing puerarin and catalpol were prepared. The concentrations of puerarin and catalpol in plasma and brain of rats after oral administration were determined by HPLC-MS/MS method. The pharmacokinetic parameters and brain target index were compared. The results showed that preparation technologies had different influences on the concentrations of puerarin and catalpol in plasma and brain. The self-microemulsion (tween-80) could significantly increase the oral absorption of puerarin than other technologies(P<0.05), and inclusion complex could remarkably increase the oral absorption of catalpol than nanocrystal(P<0.01). For puerarin, the brain targeting index of inclusion complex was the highest (P<0.05); but for catalpol, the brain targeting index of inclusion complex and self-microemulsions were both higher than nanocrystal (P<0.05). The self-microemulsion(tween-80) had the highest AUCbrain of puerarin than other groups (P<0.01); the inclusion complex had the highest AUCbrain for catalpol, but there was no significant difference compared with self-microemulsions. In conclusion, the self-microemulsion (tween-80) technology could increase the amount of puerarin and catalpol in brain, and was expected to be used in new oral Zige preparations.