Artificial Intestinal Fluid Research Articles

Minimally invasive detection of buprenorphine using a carbon-coated 3D-printed microneedle array.

Amachine learning-assisted 3D-printed conducting microneedle-based electrochemical sensing platformwas developed for wireless, efficient, economical, and selective determination of buprenorphine. The developed microneedle array-based sensing platform used 3D printing and air spray coating technologies for rapid and scalable manufacturing of a conducting microneedle surface. Upon optimization and understanding of the electrode stability, redox behavior, and electrochemical characteristics of as-prepared conducting microneedle array, the developed electrochemical platform was investigated for monitoring different levels of buprenorphine in the artificial intestinal fluid and found to be highly sensitive and selective towards buprenorphine for a wide detection range from 2 to 140μM, with a low limit of detection of 0.129μM. Furthermore, to make the sensing platform user accessible, the experimentally recorded sensing data was used to train a machine learning model and develop a web application for the numerical demonstration of buprenorphine levels at the point of site. Finally, the proof-of-concept study demonstrated that by advancing our prevailing 3D printing and additive manufacturing techniques, a low-cost, user-accessible, and compelling wearable electrochemical sensor could be manufactured for minimally invasive determination of buprenorphine in interstitial fluid.

Expression, Purification, and Anti-UV Irradiation Effect of RsSOD on HCE-T Human Corneal Epithelial Cells.

Superoxide dismutase (SOD) is a class of enzymes that catalyze the disproportionation of superoxide anion radicals into hydrogen peroxide and oxygen. It can remove excessive free radicals in organisms and acts as a potent antioxidant, cleaning free radicals generated by radiation and protecting cells from oxidative damage. In this study, we obtained a MnSOD gene from the radiation-resistant bacterium Radiobacillus sp. (RsSOD) and constructed its recombinant expression vector through gene synthesis. The recombinant RsSOD protein was efficiently expressed using IPTG induction, and purified via repeated freezing and thawing, heating, and DEAE anion-exchange chromatography. The purified RsSOD exhibited an enzyme activity of 2072.5 U/mg. Furthermore, RsSOD was demonstrated to have robust resistance to high temperatures, acid, alkali, and artificial intestinal fluid. Further studies were performed to investigate the radiation resistance of RsSOD against ultraviolet (UV) irradiation in human corneal epithelial (HCE-T) cells. The results indicated that a low concentration of RsSOD (6.25 U/mL) could promote HCE-T cell proliferation and protect these cells from damage caused by both long-term and short-term UV exposure, effectively reducing apoptosis induced by short-term UV irradiation. These findings suggest that the RsSOD protein possesses significant anti-UV irradiation property and is expected to be a candidate for treating ocular radiation-related diseases.

Synergistic effect of partially hydrolyzed guar gum on Clostridium butyricum in a synbiotic combination for enhanced butyrate production during in-vitro fermentation

Background: Clostridium butyricum is a butyrate-producing beneficial bacterium and is generally recognized as a significant indicator of appropriate gut microbial metabolism in human health. Objective: The synergistic effects of commercially available prebiotic partially hydrolyzed guar gum (PHGG) dietary fiber as a carbon source on a butyrate-producing bacterial strain were evaluated during in-vitro fermentation with Clostridium butyricum bacterial strain in a basal medium. Additionally, their prebiotic activities were compared to those of other dietary fibers. Methods: The examined functional dietary fiber substrates (PHGG, LMW-PHGG, indigestible dextrin, and inulin) demonstrated selective prebiotic effects on pH variation of a basal medium, leading to enhanced bacterial growth and butyrate production with Clostridium butyricum bacterial strains during in-vitro fermentation. Results: Prebiotic PHGG supplementation had the highest fermentability among dietary fibers, resulting in greater bacterial growth (OD660: 1.93 ± 0.01) of the Clostridium butyricum strain and enhanced butyrate generation (4.52 ± 2.09 mM) after cultivation in a basal medium. A significant difference in promoting bacterial growth (p < 0.05), pH reduction (p < 0.05), and butyrate production (p < 0.05) compared to indigestible dextrin and inulin was observed. Mannose demonstrated the strongest butyrogenic effect and improved fermentability on the Clostridium butyricum, among the studied prebiotic monosaccharides (galactose, glucose, and starch). The order of bacterial growth and butyrate synthesis was mannose > galactose > glucose > starch. The PHGG with a relatively lower molecular weight (LMW-PHGG) exhibited the improved bacterial growth of Clostridium butyricum and demonstrated the highest butyrate production after cultivation in a basal medium. A similar trend was observed when Clostridium butyricum was cultivated in-vitro using PHGG-supplemented artificial intestinal fluid containing MRS-agar medium. Conclusion: These findings suggest that the symbiotic combination of prebiotic PHGG and probiotic Clostridium butyricum could have major industrial applications as a therapeutic adjuvant for improved gastrointestinal health. Keywords: Partially hydrolyzed guar gum, synbiotic, prebiotic, probiotic, Clostridium butyricum, butyrate production

Assessment of uric acid-lowering activity, safety and stress tolerance of Lactiplantibacillus plantarum MC14 based on whole gene sequencing and phenotyping experiments

With lifestyle changes, hyperuricemia has become a global epidemic. Recent studies have indicated that some probiotic strains may help control serum uric acid. This study aimed to screen probiotic strains with uric acid-lowering potential and subsequently analyze the safety and stress tolerance of the strain in food applications, utilizing phenotyping experiments and genome sequencing. Initially, we isolated a strain of Lactiplantibacillus plantarum MC14 with the best in vitro uric acid-lowering activity. The inosine and guanosine degradation rates of MC14 were 5.00 and 4.11 mg/L·min, respectively, and the XOD inhibition rate was 81.56% ± 3.87%. Gene analysis revealed that the MC14 strain encodes three nucleoside hydrolases and six nucleoside and nucleobase transporter proteins. Subsequently, safety assessments of the MC14 strain in food applications revealed no nitroreductase, amino decarboxylase, or tryptophanase activities, absence of hemolysis, and no antibiotic resistance gene transfer risk. Finally, stress tolerance tests on MC14 indicated robust tolerance to gastrointestinal fluids and bile salts, with survival rates exceeding 98% after 3 h in artificial gastric fluids and approximately 100.49% ± 0.15% after 8 h in artificial intestinal fluids. Additionally, MC14 demonstrated effective antibacterial properties and antioxidant capacity, and its genome was annotated with numerous stress tolerance-related genes, including 18 acid-base stress, 4 bile salt tolerance, 11 heat stress, 3 cold stress, 6 osmotic stress, and 28 oxidative stress. Our findings highlighted MC14 as a promising candidate for probiotic and food applications.

Preparation and evaluation of microcapsules of sodium alginate based on microfluidic technology

Many active ingredients in food products are destroyed by gastric acids and enzymes as they pass through the stomach, thereby reducing the desired effect of the target ingredient. In addition, traditional microcapsule preparation methods usually break up the dispersion by mechanical stirring or oscillation, which generates droplets of uneven size and inconsistent inclusion content, and mechanical external forces may cause denaturation and inactivation of active substances. This study aimed to use microfluidics to generate Oil-in-water-in-oil (O/W/O) droplet structures with good monodispersity and highly tunable properties, and to further prepare microcapsules with high encapsulation rate and targeted intestinal release by taking advantage of the cross-linking properties of alginate that reacts with Ca2+ under acidic conditions. Finally, the particle size distribution, release effect, encapsulation effect and oxidative stability of the core-shell microcapsules were evaluated. In this study, two types of microcapsules, homogeneous and core-shell microcapsules, were prepared by selecting tea polyphenols and vitamin E as models for hydrophilic and lipophilic bioactive compounds, respectively. Thin shell microcapsules with a shell thickness of about 25 μm were prepared using PDMS chip conditioning. Large microcapsules with a particle size of 230 μm were generated by using capillary glass tube chips, which had an excellent antioxidant property with a retention rate of 88.66 ± 1.25% of VE after 20 days of storage at 4 °C, while all of the VE was oxidized in the bare environment. In addition, in simulated gastric fluid, the release of VE was only about 20%, while in artificial intestinal fluid, the release was close to 100%, so the microcapsules also had intestinal targeting properties.

Solid self-emulsifying casein carrier for the improvement on the oral bioavailability of simvastatin

Simvastatin (SV) is a statin drug that can effectively control cholesterol and prevent cardiovascular diseases. However, SV is water-insoluble, and poor oral bioavailability (<5 %). Solid self-emulsifying carrier system is more stable than liquid emulsions, facilitating to improve the solubility and bioavailability of poorly soluble drugs. In the present study, a solid self-emulsifying carrier stabilized by casein (Cas-SSE) was successfully used to load SV to improve its solubility in water, by formulation selection and emulsification process optimization. Compared with oral tablets, the release of SV from Cas-SSE was significantly enhanced in artificial intestinal fluid. Furthermore, everted gut sac experiments indicated some water-soluble dispersing agents such as hydroxyethyl starch (HES), were not conducive to drug absorption. Pharmacokinetic studies suggested Cas-SSE without dispersing agent has much higher relative bioavailability (184.1 % of SV and 284.5 % of simvastatin acid) than SV tablet. The present work suggests Cas-SSE is a promising drug delivery platform with good biocompatibility for improving oral bioavailability of poorly water-soluble drugs.

NANOPARTICLE PREPARATION OF SIAM CITRUS PEEL EXTRACT (CITRUS NOBILIS L. VAR. MICROCARPA) USING SHORT-CHAIN CHITOSAN AND TRIPOLYPHOSPHATE AS CROSS LINKER AND CELLULAR UPTAKE STUDY ON MCF-7 CELL LINE BY IN VITRO

Objective: High consumption of oranges causes a lot of orange peel waste. Orange peel contains the compound naringenin, which has a cytotoxic effect on various cancer cells. This research aims to develop a preparation of Siamese orange peel extract nanoparticles with short-chain chitosan and tripolyphosphate carriers as an oral drug delivery system and determine its cytotoxic activity against the Michigan Cancer Foundation-7 (MCF-7) cell line. Methods: This research uses the micro tetrazolium (MTT) method to see the cytotoxic activity extract of methanol obtained from maceration extraction. The extract was then formulated into nanoparticles using chitosan and tripolyphosphate. Characterization and evaluation of nanoparticles were carried out, including particle size, zeta potential, entrapment efficiency, and stability in the stomach using 0.1 N HCl and in the intestine using Artificial Intestinal Fluid (AIF) in vitro. This research was also conducted to assess the ability of nanoparticles to enter MCF-7 cells (cellular uptake). Results: Nanoparticles were successfully developed from Siamese orange peel extract. The results of the day 0 nanoparticle characterization were spherical, with average particle size 284.3 nm, zeta potential 0.713 mV, entrapment efficiency 96.73%, and stability in 0.1 N HCl at the 0th hours, respectively. 1st, 2nd, and 3rd. 99.16%, 98.70%, 98.47%, 98.31%, stability on AIF at hours 0, 1, 2, 3 and 4 respectively 99.52%, 99.30%, 99.40%, 98.99%, 99.29%. Characterization of nanoparticles on day 25 showed that the average particle size was 196.2 nm, zeta potential 0.476 mV, entrapment efficiency 96.92%, stability in 0.1 N HCl at 0, 1, 2 and 3 h respectively 99.51%, 98.67%, 98.51%, 98.27%, stability in AIF at 0th, 1st, 2nd, 3rd, and 4th hours 99.24 respectively %, 98.76%, 98.46%, 97.93%, 97.58%. Cytotoxic activity of extract Siamese citrus peel against MCF-7 cells with IC50 of 290.58 µg/ml. The result shows that cellular uptake of Siamese citrus peel nanoparticles can penetrate MCF-7 cells. Conclusion: Stable nanoparticles were successfully developed from Siamese orange peel extract, and their stability was maintained throughout a 30-day storage period. This extract displayed cytotoxic effects and showcased the ability for cellular uptake in MCF-7 cell cultures in vitro.

Sulfate radical-based advanced oxidation process effects on tire wear particles aging and ecotoxicity

Tire wear particles (TWPs) are widely distributed in natural water and pose as major pollutants in aquatic environments. In this study, heat-activated persulfate (HPT) and ultraviolet-activated persulfate treatments (UPT) were employed to investigate the influence of sulfate radical (SO4−•)-based advanced oxidation process (SAOPs) on TWP physicochemical properties and to clarify their ecotoxic effects in laboratory-level studies. Results showed that the specific surface areas of TWPs increased after UPT but decreased after HPT. In terms of chemical properties, the increase of oxygen-containing functional groups on the surfaces of TWPs was more evident in UPT than that in HPT. The atrazine (ATZ) adsorption capacity of TWPs after HPT and UPT was increased compared with the untreated TWPs. Atrazine adsorbed by TWPs was easily resolved and released in artificial intestinal fluid (1.89–2.08 mg/g) and artificial gastric fluid (1.60–2.04 mg/g) conditions. Acute toxicity experiments of Photobacterium phosphoreum and SEM-EDS detection results suggested that various heavy metals (e.g., Zn2+, Cu2+) in the TWPs would be released into the water system in SAOPs. ATZ released from TWPs that adsorbed ATZ herbicide, rather than TWPs themselves, had a negative effect on aquatic plant growth (e.g., C. vulgaris). The leaching solution of oxidized TWPs (after HPT and UPT) showed a more significant inhibition effect on the zebrafish survival compared with that of untreated TWPs, which was possibly caused by the generation of oxidation byproducts such as N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone.

Absorption of oenothein B nanoparticles constructed using casein phosphopeptide and chitosan

The Oenothein B (OEB) rich in eucalyptus is a kind of extremely development of prospects of antioxidant activity, but low oral bioavailability limits its application. The novel polyelectrolyte nanoparticle was designed for OEB delivery through the self-assembly of casein phosphopeptides (CPP) and natural active polysaccharides-chitosan (CS). The OEB nanoparticle with small particle size and high embedding rate were constructed to solve the problem of low oral bioavailability of OEB, and its stability as well as in vivo absorption were investigated. The storage stability analysis, digital inverted fluorescence microscopy and emission field scanning electron microscopy showed that the particle size and total amount of OEB nanoparticles did not vary significantly after 96 h of continuous storage at room temperature, and the particle size distribution was uniform, and the particles kept their integrity pH 1.2. The maximum release rate of OEB nanoparticles was only 0.72% in artificial gastric fluid and 21.77% in artificial intestinal fluid. It greatly reduces the risk of its decomposition and plays a better protective role. The results of in vivo absorption showed that OEB nanoparticle gavage mice did not detect OEB in blood and its metabolites except for OEB in gastric juice, indicating that OEB changes in vivo after release. Therefore, although OEB nanoparticles can effectively protect their decomposition in gastrointestinal fluid, it is best to achieve sustained release at the target location in order to improve the absorption and utilization effect.

The isolation, identification, whole-genome sequencing of Clostridium butyricum LV1 and its effects on growth performance, immune response, and disease-resistance of Litopenaeus vannamei

In this study, a strain of Clostridium butyricum was isolated from the intestine of Litopenaeus vannamei with the method of anaerobic microbial isolation and culture. Next, the probiotic properties of LV1 were evaluated with susceptibility tests, tolerance tests, and whole genome sequencing in vivo and in vitro, followed by the analysis of the effect of LV1 on the growth performance, immune response, and disease resistance of Litopenaeus vannamei. According to the results, the 16 S rDNA sequence of LV1 was 100% homolofgous to the reference sequence of Clostridium butyricum. Moreover, LV1 was resistant to several antibiotics including amikacin, streptomycin, and gentamicin and highly tolerated artificial gastric and artificial intestinal fluids. The whole genome of LV1 was 4625,068 bp in size and included 4336 coding genes. Among these genes, GO, KEGG, and COG databases exhibited the highest number of genes annotated to metabolic pathway classes and 105 genes annotated as glycoside hydrolases. Meanwhile, 176 virulence genes were predicted. The use of diets supplemented with 1.2 × 109 CFU/kg of LV1 live cells significantly increased the weight gain and specific growth rates of Litopenaeus vannamei and the activity of serum superoxide dismutase, glutathione peroxidase, acid phosphatase, and alkaline phosphatase (P < 0.05). Meanwhile, the use of these diets markedly improved the relative expression of intestinal immunity- and growth-related genes. In conclusion, LV1 has excellent probiotic properties. Specifically, the addition of 1.2 × 109 CFU/kg of LV1 live cells to the diet improved the growth performance, immune response, and disease-resistance of Litopenaeus vannamei.

Development of Delayed-Release Matrix Tablets Comprising Solid Dispersion of Mefenamic Acid

Mefenamic acid (MA), a member of nonselective nonsteroidal anti-inflammatory drugs (NSAIDs), has been widely use to relief pain and inflammation. Its medical uses are limited by poor aqueous solubility resulting in low bioavailability and gastric irritation. The aim of this study was to develop a mefenamic acid delayed-release matrix tablet formulation using solid dispersion (SD). Delayed-release drug delivery systems were designed to retard drug release in upper gastrointestinal tract avoiding gastrointestinal (GI) adverse reactions. SDs of MA were successfully prepared by solvent evaporation method employing methanol as a solvent. SDs incorporated surfactant and super disintegrant gave much higher rates of dissolution than SDs with combined carriers (PEG and surfactant), SD containing PEG and pure drug, respectively. The optimal SD containing MA:PEG4000:poloxamer188:crospovidone in the ratio 1:8:1:3 exhibited higher amount of drug release up to 8-fold compared with pure MA. FTIR and DSC were performed to identify the physicochemical interaction between drug and polymers. The resulting data justified that no change in the chemical structure of MA and the crystalline MA transformed into the amorphous state after preparation. The formulation F4 delayed-release tablet comprising SD of MA dissolved less than 4 % in artificial gastric fluid in the initial 2 h and released more than 95 % at 3 h in the artificial intestinal fluid. Accordingly, formulation F4 containing polyethylene oxide as a time-controlled matrix-forming polymer was a promising delayed-release solid dispersion system of MA. HIGHLIGHTS The present study demonstrated a mefenamic acid delayed-release matrix tablet formulation using solid dispersion (SD) The optimal SD of mefenamic acid exhibited higher amount of drug release (8-fold) compared with that of the pure drug The tablet formulation F4 containing polyethylene oxide is capable of releasing mefenamic acid in a typical delayed-release profile GRAPHICAL ABSTRACT

Utility of a Systematic Approach to Selecting Candidate Prodrugs: A Case Study Using Candesartan Ester Analogues

Development of prodrugs is a useful strategy to overcome some disadvantages of candidate drugs. Recently, we established a systematic approach to selecting appropriate prodrugs, and validated the utility of this approach using oseltamivir analogues. In this study, the utility of the approach was further examined using candesartan cilexetil and 20 kinds of its analogues having various types of side chain as model compounds. Log D values of analogues (2.5 to 4.7) were higher than that of candesartan (1.0), their active metabolite, and the results were reasonable for the purpose of improving permeability of candesartan. The analogues tended to be more soluble in artificial intestinal fluids than in artificial gastric fluid, owing to their acidic physicochemical characteristics. Their membrane permeabilities were not correlated with log D values, which can be attributed to the metabolism in Caco-2 cells used in this system. In human hepatocytes and enterocytes, 11 out of the 20 analogues were immediately hydrolyzed to candesartan, and species differences were observed in the hydrolysis efficiency. This study confirmed the utility of the systematic approach for selection of appropriate prodrugs that could be proceeded to in vivo pharmacokinetics study, with selection of suitable experimental animals.

Antiviral effects of Pediococcus acidilactici isolated from Tibetan mushroom and comparative genomic analysis.

Rotavirus is one of the main pathogens that cause diarrhoea in young animals, and countless animals have died of rotavirus infection worldwide. Three strains of lactic acid bacteria isolated from Tibetan mushrooms were used to study the inhibition of rotavirus in vitro and in vivo. One part was to identify and study the biochemical and probiotic characteristics of three isolated lactic acid bacteria, and the other part was to evaluate the inhibitory effect on rotavirus via in vivo and in vitro experiments. The whole genome of the lactic acid bacteria with the best antiviral effect was sequenced, and the differences between them and the standard strains were analyzed by comparative genomic analysis, so as to provide a theoretical basis for exploring the antiviral effect of lactic acid bacteria.The three strains were identified as Pediococcus acidilactici, Lactobacillus casei and Lactobacillus paracasei. Pediococcus acidilactici showed good acid tolerance, bile salt tolerance, survival in artificial intestinal fluid, survival in gastric fluid and bacteriostasis. In in vitro experiments, pig intestinal epithelial cells cocultured with Pediococcus acidilactici exhibited reduced viral infection. In the in vivo experiment, the duodenum of mice fed Pediococcus acidilactici had extremely low numbers of virus particles. The total genome size was 2,026,809 bp, the total number of genes was 1988, and the total length of genes was 1,767,273 bp. The proportion of glycoside hydrolases and glycoside transferases in CAZy was 50.6 and 29.6%, respectively. The Metabolism function in KEEG had the highest number of Global and overview maps. Among the comparative genomes, Pediococcus acidilactici had the highest homology with GCF 000146325.1, and had a good collinearity with GCF 013127755.1, without numerous gene rearrangement events such as insertion, deletion, inversion and translocation. In conclusion, Pediococcus acidilactici was a good candidate strain for antiviral probiotics.

Characterization of a novel marine microbial uricase from Priestia flexa and evaluation of the effects of CMCS conjugation on its enzymatic properties

A novel uricase producing marine bacterium Priestia flexa alkaAU was isolated and identified. The 16S rDNA and the uricase coding gene were sequenced, analyzed and submitted to GenBank. The uricase from Priestia flexa alkaAU (PFU) was purified, determined to be 58.87 kDa, and conjugated with carboxymethyl chitosan (CMCS) by ionic gelation. CMCS conjugation had no effect on the optimum pH of PFU but decreased the optimum temperature by 10 °C. CMCS conjugation increased the specific activity of PFU by 53% at the human body temperature (37 °C) and small intestine’s pH (pH 6.8). Uricase thermostabilizing ability of CMCS was significant in the range of 37–80 °C but not at lower temperatures. For improvement of the pH stability of PFU, CMCS was more effective at pHs 3–5 than pHs 6–11. CMCS increased the half-life of PFU against artificial intestinal fluid by 1.5 folds, which demonstrated the potential capability of CMCS–PFU for oral administration.

The effect of surfactant on the solubility of kencur rhizome ethanol extract in self-nanoemulsifying drug delivery system

Kencur ( Kaempferia galanga L.) rhizome ethanol extract contains a lipophilic compound of ethyl p-methoxycinnamate. Self-nanoemulsifying drug delivery system (SNEDDS) formulation can increase the solubility of the extract in water. The purpose of this study was to determine the effect of surfactant combination on the kencur rhizome extract in the SNEDDS system. The SNEDDS formulations were carried out by selecting the surfactant ratio of Tween 80:Span 80 and Tween 80:Chremophor RH 40, followed by selecting the ratio of surfactant mixtures to polyethylene glycol 400 as co-surfactant, and to virgin coconut oil as the oil phase. The clarity, transmittance, emulsification time, particle size, and polydispersity index were evaluated. The stability test was carried out in aquadest, artificial gastric fluid, and artificial intestinal fluid for 4 hours at 37°C. The results showed that the combination of Tween 80: Chremophor RH 40 produced better SNEDDS than Tween 80:Span 80. The combination of surfactant-cosurfactant of Tween 80:Chremophor RH 40:PEG 400 at ratio 3:1 and 1:1 could produce homogenous dispersed SNEDDS showing droplet size of 23,0 and 21,8 nm; transmittance of 95.63% and 93.83%, and SNEDDS preconcentrate emulsified less than 35 seconds. The single surfactant Tween 80:PEG 400 at the ratio 3:1 produce better dispersed SNEDDS than the combined surfactant with droplet size 16.3 nm, transmittance 97.85%, and SNEDDS preconcentrate emulsified less than 45 seconds. The SNEDDS system could produce a smaller droplet size than the extract in aquadest.

Preparation of pelargonic acid vesicles and sustained drug release

This study has selected the medium-chain saturated fatty acid pelargonic acid as the raw material for the first time, and added the surface catalyst Tween 80 to the aqueous solution to form pelargonic acid–Tween 80 composite vesicles by a surface tension method. The compound vesicle was used to encapsulate five heterocyclic drugs (cefazolin sodium, chlorpromazine hydrochloride, gemcitabine hydrochloride, metronidazole, and isoniazid), all of which have disadvantages when used directly, and the effects of the vesicles on the five kinds of drugs were evaluated in terms of encapsulation rate and the in vitro sustained release in a simulated artificial intestinal fluid environment. The results revealed that the pelargonic acid–Tween 80 composite vesicles exhibit an encapsulation efficiency above 45%, and that the encapsulated drugs achieve a cumulative release effect of 6–10 h in a simulated artificial intestinal fluid environment, and the cumulative release rate is above 35%. This study proves that pelargonic acid–Tween 80 composite vesicles can be used as a carrier for encapsulated drugs, and this can extend the time of action of the drugs. This research illustrates the potential for application of pelargonic acid in the field of medicine.

Content Determination and Release Characteristics of Six Components in the Different Phases of "Glycyrrhizaglabra-Nux vomica" Decoction by UPLC-MS/MS.

The decoction turns into a complex multiphase system following exposure to high temperature and a complex chemical environment. However, the differences in the concentration of key active ingredients in different phase states and the release of drugs in sedimentary phase have yet to be elucidated. A simple ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the simultaneous quantitative determination of brucine, strychnine, liquiritin, isoliquiritin, isoliquiritigenin and glycyrrhizic acid concentrations and it was applied to compare the content of different phases and measure the release characteristics of the sedimentary phase in “Glycyrrhiza glabra-Nux vomica” decoction (NGD). The results show that the method’s selectivity, precision (intraday and interday ≤ 2%), matrix effect (101–108%), recovery and stability results were acceptable according to the guidelines. The method is sensitive and reliable. The content determination results show that the most toxic strychnine in the sedimentary phase accounted for 75.70% of the total components. The different components exhibited differential release in different media, and its components were released in the artificial intestinal fluid up to 81.02% in 12 h. Several components conformed to the primary kinetic model and the Ritger–Peppas model, and the most toxic compound exhibited slow release, thus conforming to the Ritger–Peppas model. This study provides a standard of reference for studies investigating reduction in toxicity of the combination of Glycyrrhiza glabra (Glycyrrhiza glabra L.) and Nux vomica (Strychnos nux-vomica L.).

Changes in the antioxidant properties of Ocimum africanum leaves aqueous extract from the southeastern region of Nigeria after in vitro gastrointestinal digestion

ABSTRACT The potential for antioxidant compounds to be released from the original food matrix is greatly determined by bioaccessibility. Digestive enzymes have a substantial impact on the antioxidant properties of dietary items after ingestion. The present study aimed to determine the antioxidant properties of Ocimum africanum leaves aqueous extract (OALAE) before and after in vitro digestion. In vitro gastro-pancreatic digestion of extracted samples (steamed, air dried and fried) was done using artificial gastric fluid, and 4 mL of artificial intestinal fluid. Antioxidant analyses were carried out on the OALAE samples (group 1: steamed, group 2: fried, group 3: air dried and group 4: garlic acid standard), before digestion (undigested), post-intestinal digestion with enzymes and post-intestinal digestion without enzymes. The trends of antioxidant properties of the OALAE (in-vitro) were as follows: air dried > steamed > fried. A significant (p < 0.05) decrease in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric reducing antioxidant power (FRAP), total antioxidant capacity (TAC), reduced glutathione (GSH), vitamin E, vitamin C, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and non-heme iron content of OALAE in post-intestinal digestion with enzyme and post-intestinal digestion without enzyme was found compared to the undigested extract in group 1, 2, 3, and 4. Significant decrease was observed in antioxidant activity (illustrated using DPPH, ABTS, FRAP, and TAC) of post-intestinal digestion with enzyme compared to post-intestinal without enzymes in group 1, 2, 3 and 4. The results suggested that antioxidant properties of O. africanum leaves are unstable and may show limited activity after stimulated gastrointestinal digestion.

Study on the Absorption of Arsenic Species in Realgar Based on the Form and Valence.

At present, several experiments have been carried out to study the changes in total arsenic content of realgar and its prescription, but few researches on its form and valence. We evaluated the change in arsenic species concentration in realgar from the perspective of absorption by using an in vitro dissolution study, an in vivo unidirectional intestinal perfusion study, transmembrane transport in Caco-2 cells, and a pharmacokinetic study in rats. In the gastrointestinal tract, arsenic species are mainly present inorganic forms of AsIII and AsV. The cumulative dissolution rates of soluble arsenic in 4 h artificial gastric fluid and 8 h artificial intestinal fluid were 21.99% and 59.20%, respectively. The Papp values of soluble arsenic in realgar in the duodenum, jejunum, and ileum of rats were 5.4 × 10−3, 6.1 × 10−3 and 5.8 × 10−3 cm/min, respectively. In the process of small intestine perfusion, the AsIII of realgar was partially converted into AsV in the duodenum and jejunum. As the transport time increased, the transmembrane transport rate and Papp value of soluble arsenic in realgar were increased in Caco-2 cells, and it also suggested that arsenic species may be passively transported across the Caco-2 cell monolayer. The Cmax and AUC (0-24) of AsIII, AsV, and DMA in plasma of realgar were 41.26 ng L−1/343.977 ng h mL−1, 21.626 ng L−1/47.310 ng h mL−1, and 2.372 ng L−1/30.429 ng h mL−1, respectively. Tmax and MRT (0-∞) of AsIII, AsV, and DMA were 2.571 h/9.649 h, 0.393 h/2.790 h, and 3.143 h/23.145 h, respectively. It is hoped to provide a basis for clarifying the arsenic species in realgar.

Inhibitory effect of 20(S)-protopanaxadiol on cytochrome P450: Potential of its pharmacokinetic interactions in vivo

20(S)-Protopanaxadiol [20(S)-PPD] is a fully deglycosylated ginsenoside metabolite produced by the gut microbiota in the gastrointestinal tract. Although diverse pharmacological effects have been reported, information on the pharmacokinetic interactions of 20(S)-PPD with cytochrome P450s (CYPs) remains limited. Therefore, the inhibitory potential of 20(S)-PPD on CYP enzymes, which mainly contribute to drug pharmacokinetics, was investigated in this study. The inhibitory effect of 20(S)-PPD was strong for CYP3A4 and moderate for CYP2B6 in human liver microsomes. 20(S)-PPD inhibited Cyp3a and Cyp2b in mouse liver microsomes with a potency similar to that in humans. The solubility of 20(S)-PPD in the artificial intestinal fluid was close to IC50 values of Cyp3a and Cyp2b in the mouse intestine. Systemic exposure to buspirone (Cyp3a specific substrate) and bupropion (Cyp2b specific substrate) increased significantly, whereas the area under the plasma concentration–time curve (AUC) ratio of metabolite to parent drug decreased significantly when co-administered with 20(S)-PPD in mice. The pharmacokinetics of felodipine, a widely used anti-hypertensive agent metabolized mainly by Cyp3a, was also altered following 20(S)-PPD treatment in mice. In conclusion, 20(S)-PPD likely affects the in vivo metabolism of CYP3A4 or CYP2B6 substrates, suggesting a need for careful attention when concomitantly administering 20(S)-PPD with other medications. This study will broaden our understanding of ginseng and products containing precursor ginsenosides of 20(S)-PPD for safer and more efficient use in humans.