Application of whey protein micro-bead coatings for enhanced strength and probiotic protection during fruit juice storage and gastric incubation

Context: Coated whey protein micro-beads may improve probiotic protection and provide delayed cell-release mechanisms.

Objective: Lactobacillus rhamnosus GG was encapsulated in whey protein micro-beads by droplet extrusion with coating via electrostatic deposition: primary-polysaccharide and secondary-whey protein.

Materials and methods: Storage studies were performed in cranberry and pomegranate juice (pH 2.4; 28 days; 4 and 25°C) followed by simulated ex vivo porcine gastric (pH 1.6) and intestinal (pH 6.6) digestion.

Results and discussion: After storage and simulated gastro-intestinal digestion, free cells, cells suspended in protein and cells encapsulated in alginate micro-beads, illustrated complete probiotic mortality, while coated micro-beads enhanced probiotic viability after juice storage (8.6?±?0.1 log₁₀CFUmL^?1). Beads also showed significant binding of hydrophobic molecules. Coated micro-beads illustrated high gastric survival (9.5?±?0.1 log₁₀CFUmL^?1) with 30?min delayed intestinal release relative to non-coated micro-beads.

Conclusions: Micro-bead coatings could be applied in delayed cell-release for targeted intestinal probiotic delivery.     

Effect of grapefruit juice and food on the pharmacokinetics of pirfenidone in healthy Chinese volunteers: a diet–drug interaction study

1.?Ingestion of grapefruit juice and food could be factors affecting the pharmacokinetics of pirfenidone, a promising drug for treatment of idiopathic pulmonary fibrosis.

2.?A randomized, open-label, three-period crossover study was carried out in 12 healthy Chinese male volunteers who were randomized to one of the three treatments: pirfenidone tablets (0.4?g) were orally administered to fasted or fed subjects, or with grapefruit juice. The washout period was 7 d.

3.?Significantly reduced maximum plasma concentration (C_max, 5.0 5?±?1.39 versus 10.9 0?±?2.94?mg·L^{? 1}), modestly affected area-under-the-plasma concentration–time curve (AUC) from time zero to 12?h post dosing (AUC_0–12?h, 21.8 9?±?6.47 versus 26.1 6?±?7.32?mg·h·L^{? 1}) and delayed time to reach C_max (T_max) were observed in fed group compared with fasted group. Similar effects on C_max (5.8 2?±?1.23 versus 10.9 0?±?2.94?mg·L^{? 1}) and AUC_0–12?h (modest but not statistically significant, 24.4 4?±?7.40 versus 26.1 6?±?7.32?mg·h·L^{? 1}) were observed for grapefruit juice compared to fasted subjects.

4.?Co-administration of pirfenidone with grapefruit juice resulted in modestly reduced overall oral absorption and significantly reduced peak concentrations compared to fasting, which was similar to effect of food ingestion. No adverse events were observed in the study, but relatively dramatic reduction of peak concentrations should raise concerns for clinical efficacy and safety.     

Physicochemical characteristics and gastrointestinal absorption behaviors of S-propargyl-cysteine,a potential new drug candidate for cardiovascular protection and antitumor treatment

Abstract

1. As a potential new drug candidate for cardiovascular protection and antitumor treatment, the physicochemical properties, gastrointestinal (GI) absorption behaviors and mechanisms of S-propargyl-cysteine (SPRC) were investigated in this study.

2. SPRC exhibited favorable solubility in aqueous media. The log P and log D values were low (≤1.93?±?0.08). The pK_a in the acidic and basic regions was 2.08?±?0.02 and 8.72?±?0.03, respectively. The isoelectric point was 5.40?±?0.02. SPRC was stable in the rat GI fluids, and showed no obvious adsorption and metabolism in the rat GI tract.

3. SPRC displayed poor gastric absorption and favorable intestinal absorption in the rat in situ GI perfusion model. Absorption rate constants (k_a), hourly absorption percentage (P) and apparent permeability coefficient (P_app) of SPRC in the small intestine were ≥0.77?±?0.06?h^?1, 59.25?±?4.02% and (7.99?±?0.88)?×?10^?5?cm/s, respectively. Absorption of SPRC exhibited a certain dependence on physiological pH and absorption region. Absorption of SPRC was not inhibited by l-methionine and 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid.

4. SPRC showed favorable oral absorption. It can be categorized as a BCS class I drug. The membrane pore transport appeared to be one of the predominant absorption modes for SPRC.     

Cis-resveratrol glucuronidation kinetics in human and recombinant UGT1A sources

1. It was hypothesized that cis-resveratrol glucuronidation contributes to a greater extent to in-vitro disposition of total resveratrol than previously assumed. To this end, the kinetic data for cis-resveratrol glucuronidation are reported.

2. Glucuronidation assays were conducted in human liver and intestinal microsomes and in uridine diphosphate-glucuronosyltransferases (UGTs) UGT1A1, UGT1A6, UGT1A9, and UGT1A10. Kinetic parameters were estimated for the major cis-resveratrol-3-O-glucuronide (cis-R3G). Substrate inhibition was observed with apparent V_max, K_m and K_i of 6.1?±?0.3/27.2?±?1.2 nmol min^?1 mg^?1, 415?±?48.1/989.9?±?92.8 and 789.6?±?76.3/1012?±?55.9?μM in human intestinal microsomes (HIMs) and UGT1A6, respectively (estimate?±?standard error (SE)). Biphasic kinetics were observed in human liver microsomes (HLMs), while sigmoidal kinetics were seen in UGT1A9 (V_max?=?11.92?±?0.2 nmol min^?1 mg^?1; K_m?=?360?μM; n?=?1.27?±?0.07). The 4′-O-glucuronide (cis-R4′G) exhibited atypical kinetics in HLM, HIM, UGT1A1, and UGT1A10. UGT1A9 catalysed cis-R4′G formation at high substrate concentrations (V_max?=?0.33?±?0.015 nmol min^?1 mg^?1; K_m?=?537.8?±?67.8?μM).

3. In conclusion, although the rates of formation of cis-R3G in HLM and UGT1A9 were higher than those for trans-R3G, the contribution to total resveratrol disposition could not be determined fully due to atypical kinetics observed.

     

Genkwanin nanosuspensions: a novel and potential antitumor drug in breast carcinoma therapy

Recently, genkwanin (GKA) has been shown to display in vitro antitumor activity against some cancer cells, but its poor solubility restricted the in vivo study and further investigation of its antitumor therapeutic efficacy. In this paper, genkwanin nanosuspensions (GKA-NSps) were successfully prepared using D-alpha tocopherol acid polyethylene glycol succinate (TPGS) as a stabilizer using the precipitation-homogenization method. The obtained GKA-NSps had an average particle size of 183.1?±?4.4?nm, a PDI value of 0.16?±?0.07, a zeta potential of ?16.2?±?0.1?mV, and a drug loading content of 49.36?±?0.14%. GKA-NSps showed spherical morphology and very good stability in normal saline, phosphate buffer saline (PBS, pH 7.4), 5% glucose, artificial gastric juice, artificial intestinal juice and plasma; thus, it is suitable for both oral and intravenous administration. The resultant GKA-NSps displayed sustained drug release behavior and stronger in vitro cytotoxicity against 4T1, MCF-7, MDA-MB-453, HeLa, HepG2, BT474, and A549 cells than free GKA. The in vivo study in MCF-7 tumor-bearing nude mice indicated that GKA-NSps (60?mg/kg, i.v.) achieved similar therapeutic efficacy as PTX injection (8?mg/kg, i.v.) (62.09% vs. 61.27%), while the minimal lethal dose was more than 320?mg/kg, indicating good safety. By using nanotechnology, our study suggested that some antitumor flavonoids of low potency, such as GKA, are promising as safe but effective anticancer drugs.     

Gastroprotective effects of amifostine in rats treated by T-2 toxin

Cytoprotector amifostine (AMI) was given in a dose of 50, 100 or 150?mg/kg ip in rats treated with several highly toxic doses of T-2 toxin. The best survival rate (24?h and 7?days after treatment) was obtained with AMI50 (50?mg/kg ip). After T-2 intoxication, a peak in the mean number of gastric lesions (petechiae and ulcerations) was reached on the third day (26.40?±?6.24). Administration of AMI50 reduced, almost completely, the total number of gastric lesions in rats acutely poisoned by 0.5 LD₅₀ T-2 (1.5?mg/kg sc), starting with day 1 after intoxication (5.60?±?3.42).     

The essential oils chemical compositions and antimicrobial,antioxidant activities and toxicity of three Hyptis species

Abstract

Context: Hyptis suaveolens (Linn.) Poit., Hyptis rhomboidea Mart. et Gal., and Hyptis brevipes Poit., are three species of Hyptis Jacq. (Lamiaceae). Hyptis suaveolens is used for the treatment of fever, headache, gastrointestinal bloating and rheumatism in the traditional folk medicine; Hyptis rhomboidea for hepatitis, ulcer and swollen poison; and Hyptis brevipes for asthma and malaria.

Objective: To characterize chemical compositions of the oils from three Hyptis species and evaluate their potential antimicrobial, radical scavenging activities and toxicities against brine shrimp.

Materials and methods: The oils were obtained by hydrodistillation, and their chemical compositions were investigated by gas chromatography-mass spectrometry (GC-MS). Minimum inhibitory concentrations (MICs) were determined using the tube double-dilution technique. The antioxidant activities were investigated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and toxicities by the brine shrimp bioassay.

Results: Forty-seven, 33 and 28 constituents of oils isolated, respectively, from H. suaveolens, H. rhomboidea and H. brevipes were identified. Among the essential oils, the strongest antioxidant activity was exhibited by H. brevipes with an SC₅₀ value of 2.019?±?0.25?μg?mL^?1. The H. brevipes oil exhibited the strongest antimicrobial activity (3.125–6.25?μg?mL^?1) on pathogens employed in the assay. They all showed significant toxicities with median lethal concentration (LC₅₀) values of 62.2?±?3.07?μg?mL^?1, 65.9?±?6.55?μg?mL^?1 and 60.8?±?9.04?μg?mL^?1, respectively.

Discussion and conclusions: The three Hyptis species oils possess strong antimicrobial activities and toxicities. Hyptis rhomboidea and H. brevipes showed considerable antioxidant activity compared to the positive control.     

Effects of exenatide versus sitagliptin on postprandial glucose,insulin and glucagon secretion,gastric emptying,and caloric intake: a randomized,cross-over study

ABSTRACT

Background: This study evaluated the effects of exenatide, a GLP-1 receptor agonist, and sitagliptin, a DPP-4 inhibitor, on 2-h postprandial glucose (PPG), insulin and glucagon secretion, gastric emptying, and caloric intake in T2D patients.

Methods: This double-blind, randomized cross-over, multi-center study was conducted in metformin-treated T2D patients: 54% female; BMI: 33?±?5?kg/m²; HbA_1c: 8.5?±?1.2%; 2-h PPG: 245?±?65?mg/dL. Patients received exenatide (5?µg BID for 1 week, then 10?µg BID for 1 week) or sitagliptin (100?mg QAM) for 2 weeks. After 2 weeks, patients crossed-over to the alternate therapy. Postprandial glycemic measures were assessed via standard meal test; caloric intake assessed by ad libitum dinner (subset of patients). Gastric emptying was assessed by acetaminophen absorption (Clinicaltrials.gov Registry Number: NCT00477581).

Results: After 2 weeks of therapy, 2-h PPG was lower with exenatide versus sitagliptin: 133?±?6?mg/dL versus 208?±?6?mg/dL, p?<?0.0001 (evaluable, N?=?61). Switching from exenatide to sitagliptin increased 2-h PPG by +73?±?11?mg/dL, while switching from sitagliptin to exenatide further reduced 2-h PPG by ?76?±?10?mg/dL. Postprandial glucose parameters (AUC, C_ave, C_max) were lower with exenatide than sitagliptin (p?<?0.0001). Reduction in fasting glucose was similar with exenatide and sitagliptin (?15?±?4?mg/dL vs. ?19?±?4?mg/dL, p?=?0.3234). Compared to sitagliptin, exenatide improved the insulinogenic index of insulin secretion (ratio exenatide to sitagliptin: 1.50?±?0.26, p?=?0.0239), reduced postprandial glucagon (AUC ratio exenatide to sitagliptin: 0.88?±?0.03, p?=?0.0011), reduced postprandial triglycerides (AUC ratio exenatide to sitagliptin: 0.90?±?0.04, p?=?0.0118), and slowed gastric emptying (acetaminophen AUC ratio exenatide to sitagliptin: 0.56?±?0.05, p?<?0.0001). Exenatide reduced total caloric intake compared to sitagliptin (?134?±?97?kcal vs. +130?±?97?kcal, p?=?0.0227, N?=?25). Common adverse events with both treatments were mild to moderate in intensity and gastrointestinal in nature.

Conclusions: Although this study was limited by a 2-week duration of exposure, these data demonstrate that, exenatide had: (i) a greater effect than sitagliptin to lower postprandial glucose and (ii) a more potent effect to increase insulin secretion and reduce postprandial glucagon secretion in T2D patients. In contrast to sitagliptin, exenatide slowed gastric emptying and reduced caloric intake. These key findings differentiate the therapeutic actions of the two incretin-based approaches, and may have meaningful clinical implications.     

Pulmonary Protective and Vasodilator Effects of a StandardizedPanax GinsengPreparation Following Artificial Gastric Digestion

We have previously demonstrated that purified ginsenosides produce pulmonary vasodilation and prevent effects of free radical injury on the lung. We examined the effect of artificially digested standardized ginseng preparation G115 in perfused rabbit lungs. G115 was incubated in artificial gastric juice (0.03 M NaCl+0.08 M HCl) 37°C for 1 h, and artificial intestinal juice (0.05 M KH₂PO₄+0.02 M NaOH) 37°C for 5 h, neutralized with NaOH and lyophilized. Pulmonary vasoconstriction was induced with U46619, and cumulative additions of G115 in undigested, gastric digested and gastric and intestinal digested forms were made to the perfusate. In separate experiments, oxygen free radical injury by electrolysis was produced in the presence of G115 in the perfusate and ACh-induced vasodilation assessed before and after injury. Undigested, gastric digested and combined gastric and intestinal digested G115 significantly dilated lungs (44%, undigested; 26%, gastric digested; 45%, gastric and intestinal digested). In addition, both undigested (−27±5% vs. −24±5%) as well as gastric and intestinal digested G115 (−23±3% vs. −16±2%) preserved ACh-induced vasodilation following injury. Artificially digested G115 is a pulmonary vasodilator which protects against free radical injury, suggesting that oral G115 has the same effects.     

PLGA nanoparticles for the oral delivery of nuciferine: preparation,physicochemical characterization and in vitro/in vivo studies

This article reports a promising approach to enhance the oral delivery of nuciferine (NUC), improve its aqueous solubility and bioavailability, and allow its controlled release as well as inhibiting lipid accumulation. NUC-loaded poly lactic-co-glycolic acid nanoparticles (NUC-PLGA-NPs) were prepared according to a solid/oil/water (s/o/w) emulsion technique due to the water-insolubility of NUC. PLGA exhibited excellent loading capacity for NUC with adjustable dosing ratios. The drug loading and encapsulation efficiency of optimized formulation were 8.89?±?0.71 and 88.54?±?7.08%, respectively. NUC-PLGA-NPs exhibited a spherical morphology with average size of 150.83?±?5.72?nm and negative charge of ?22.73?±?1.63?mV, which are suitable for oral administration. A sustained NUC released from NUC-PLGA-NPs with an initial exponential release owing to the surface associated drug followed by a slower release of NUC, which was entrapped in the core. In addition, ～77?±?6.67% was released in simulating intestinal juice, while only about 45.95?±?5.2% in simulating gastric juice. NUC-PLGA-NPs are more efficient against oleic acid (OA)-induced hepatic steatosis in HepG₂ cells when compared to naked NUC (n-NUC, *p < 0.05). The oral bioavailability of NUC-PLGA-NPs group was significantly higher (**p < 0.01) and a significantly decreased serum levels of total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C), as well as a higher concentration of high-density lipoprotein cholesterol (HDL-C) was observed, compared with that of n-NUC treated group. These findings suggest that NUC-PLGA-NPs hold great promise for sustained and controlled drug delivery with improved bioavailability to alleviating lipogenesis.     

Pharmacological characterization of the muscarinic receptor subtypes responsible for the contractile response in the rat urinary bladder

1 Contractile responses of smooth muscle from the Wistar rat urinary bladder were studied with the use of muscarinic agonists and antagonists. 2 McN-A-343 induced only weak contractile responses of the bladder muscle. In contrast, oxotremorine showed higher potency than either acetylcholine or bethanechol in inducing a contractile response (the respective pD₂ values were 6.38 ± 0.25, 4.82 ± 0.24 and 4.42 ± 0.14). 3 The M₂ antagonists, methoctramine (10^?9m to 10^?5m ) and gallamine (10^?9m to 10^?5m ), did not reduce acetylcholine-induced (10^?5m ) contractions of the bladder muscle strip. On the other hand, 4-diphenyl-acetoxy-N-methyl piperidine methiodide (4-DAMP, 10^?10m to 10^?7m ), an M₃ receptor blocker, effectively antagonized the acetylcholine-induced contractions in a concentration-dependent manner. 4-DAMP had a similar pA₂ value to those of the non-selective antagonists, atropine and scopolamine (pA₂ values were 8.26 ± 0.05, 8.36 ± 0.05 and 8.41 ± 0.11, respectively). Pirenzepine, an M₁ blocker, antagonized the contractions at higher concentrations (10^?8m to 10^?5m , pA₂= 6.23 ± 0.04). 4 It is concluded that (1) the dominant muscarinic receptor subtype responsible for smooth muscle contraction in the rat urinary bladder is M₃; and (2) the muscarinic agonist oxotremorine was more potent than acetylcholine and bethanechol in inducing a contractile response.     

Effects of triptolide on pharmacokinetics of fenofibrate in rats and its potential mechanism

1. Triptolide and fenofibrate are often used together for the treatment of nephrotic syndrome in Chinese clinics.

2. This study investigates the effects of triptolide on the pharmacokinetics of fenofibrate in rats and it potential mechanism.

3. The pharmacokinetics of fenofibrate (20?mg/kg) with or without triptolide pretreatment (2?mg/kg/day for seven days) were investigated. Additionally, the inhibitory effects of triptolide on the metabolic stability of fenofibrate were investigated using rat liver microsome incubation systems.

4. The results indicated that the C_max (35.34?±?7.52 vs. 30.43?±?6.45?μg/mL), t_1/2 (6.17?±?1.15 vs. 4.90?±?0.82?h) and AUC_(0–t) (468.12?±?35.84 vs. 416.35?±?32.68?mg?h?L^?1) of fenofibric acid decreased significantly (p?<?.05). The T_max of fenofibric acid increased significantly (p?<?.05) from 5.12?±?0.36 to 6.07?±?0.68?h. Additionally, the metabolic stability of fenofibrate was prolonged from 35.8?±?6.2 to 48.6?±?7.5?min (p?<?.05) with the pretreatment of triptolide.

5. In conclusion, these results indicated that triptolide could affect the pharmacokinetics of fenofibric acid, possibly by inhibiting the metabolism of fenofibrate in rat liver when they were co-administered.

     

Mechanism of action of relaxant effect of Agastache mexicana ssp.mexicana essential oil in guinea-pig trachea smooth muscle

Context: Agastache mexicana ssp. mexicana (Kunth) Lint &; Epling (Lamiaceae), popularly known as ‘toronjil morado’, is used in Mexican traditional medicine for the treatment of several diseases such as hypertension, anxiety and respiratory disorders.

Objective: This study investigates the relaxant action mechanism of A. mexicana ssp. mexicana essential oil (AMEO) in guinea-pig isolated trachea model.

Materials and method: AMEO was analyzed by GC/MS. The relaxant effect of AMEO (5–50?μg/mL) was tested in guinea-pig trachea pre-contracted with carbachol (3?×?10?^??⁶?M) or histamine (3?×?10?^??⁵?M) in the presence or absence of glibenclamide (10?^??⁵?M), propranolol (3?×?10?^??⁶?M) or 2′,5′-dideoxyadenosine (10?^??⁵?M). The antagonist effect of AMEO (10–300?μg/mL) against contractions elicited by carbachol (10?^??¹⁵–10?^??³?M), histamine (10?^??¹⁵–10?^??³?M) or calcium (10–300?μg/mL) was evaluated.

Results: Essential oil composition was estragole, d-limonene and linalyl anthranilate. AMEO relaxed the carbachol (EC_50?=_?18.25?±?1.03?μg/mL) and histamine (EC_50?=_?13.3?±?1.02?μg/mL)-induced contractions. The relaxant effect of AMEO was not modified by the presence of propranolol, glibenclamide or 2′,5′-dideoxyadenosine, suggesting that effect of AMEO is not related to β₂-adrenergic receptors, ATP-sensitive potassium channels or adenylate cyclase activation. AMEO was more potent to antagonize histamine (pA₂′?=??1.507?±?0.122) than carbachol (pA₂′?=??2.180?±?0.357). Also, AMEO antagonized the calcium chloride-induced contractions.

Conclusion: The results suggest that relaxant effect of AMEO might be due to blockade of calcium influx in guinea-pig trachea smooth muscle. It is possible that estragole and d-limonene could contribute majority in the relaxant effect of AMEO.     

Inhibition of P-glycoprotein in Caco-2 cells: Effects of herbal remedies frequently used by cancer patients

1. The herbal products Natto K2, Agaricus, mistletoe, noni juice, green tea and garlic were investigated for in vitro inhibitory potential on P-glycoprotein (P-gp)-mediated transport of digoxin (30 nM) in differentiated and polarized Caco-2 cells. 2.?Satisfactory cell functionality was demonstrated through measurements of assay linearity, transepithelial electric resistance (TEER), cytotoxicity, mannitol permeability, and inclusion of the positive inhibition control verapamil. 3.?The most potent inhibitors of the net digoxin flux (IC₅₀) were mistletoe?>?Natto K2?>?Agaricus?>?green tea (0.022, 0.62, 3.81, >4.5 mg ml^?1, respectively). Mistletoe also showed the lowest IC₂₅ value, close to that obtained by verapamil (1.0 and 0.5 µg ml^?1, respectively). The IC₅₀/IC₂₅ ratio was found to be a good parameter for the determination of inhibition profiles. Garlic and noni juice were classified as non-inhibitors. 4.?This study shows that mistletoe, Natto K2, Agaricus and green tea inhibit P-gp in vitro. Special attention should be paid to mistletoe due to very low IC₅₀ and IC₂₅ values and to Natto K2 due to a low IC₅₀ value and a low IC₅₀/IC₂₅ ratio.     

In vitro metabolism of the epoxide substructure of cryptophycins by cytosolic glutathione S-transferase: Species differences and stereoselectivity

The enzyme kinetics of the glutathione (GSH) conjugation of cryptophycin 52 (C52, R-stereoisomer) and cryptophycin 53 (C53,?S-stereoisomer) by cytosolic glutathione S-transferases (cGSTs) from human, rat, mouse, dog and monkey liver were studied. V_max, K_m, and CL_int values for glutathione conjugation of C52 (R-stereoisomer) were 0.10?±?0.01?nmol?min^?1?mg^?1, 3.24?±?0.23?µM, and (3.15?±?0.09)?×?10^?2?ml?min^?1?mg^?1, respectively, in human cytosol. Due to limited solubility relative to the K_m, only CL_int values were determined in rat ((7.76?±?0.10)?×?10^?2?ml?min^?1?mg^?1) and mouse ((7.61?±?0.50)?×?10^?2?ml?min^?1?mg^?1) cytosol. Enzyme kinetic parameters could not be determined for C53 (S-stereoisomer). Microsomal GSH conjugation in human, rat, and mouse was attributed to cytosolic contamination. No GSH conjugation was seen in any biological matrix from dog or monkey. There was little GSH conjugation of C53 by cytosol or microsomes from any species. The metabolism of C52 and C53 by epoxide hydrolase was also investigated. No diol product was observed in any biological matrix from any species. Thus, cGSTs are primarily responsible for C52 metabolism.     

Studies on a new potential dopaminergic agent: in vitro BBB permeability,in vivo behavioural effects and molecular docking evaluation

2-Amino-N-[2-(3,4-dihydroxy-phenyl)-ethyl]-3-phenyl-propionamide (DA-PHEN) has been previously synthesized to obtain a potential prodrug capable of release dopamine (DA) into CNS. However, DA-PHEN could act per se as a dopaminergic drug. In this study, the permeability transport (P_e), obtained by parallel artificial permeability assay (PAMPA), indicated a low passive transcellular transport (P_e?=?0.32?±?0.01?×?10^?6?cm/s). Using the Caco-2 cell system, the P_{app AP-BL} in absorptive direction (3.36?±?0.02?×?10^?5?cm/s) was significantly higher than the P_{app BL-AP} in secretive direction (1.75?±?0.07?×?10^?5?cm/s), suggesting a polarized transport. The efflux ratio (P_{app AP-BL}/P_{app BL-AP}?=?0.52?±?0.02) indicated a low affinity of DA-PHEN to efflux carriers. The forced swim test highlighted a reduction of immobility time in both pre-test and test sessions (p?<?0.0001), with an exacerbation in the number of headshakes and divings in the pretest (p?<?0.0001). Morris water maze strengthened the hypothesis that DA-PHEN induces adaptive responses to environmental challenges which are involved on cognitive functions (DA-PHEN versus CTR: escape latency; p?<?0.001; distance swum p?<?0.001, time spent on target quadrant p?<?0.001), without any change in locomotor activity for the administered dose. The molecular docking revealed the interaction of DA-PHEN with the identified D1 site mapping human brain receptor.     

Influence of the MDR1 haplotype and CYP3A5 genotypes on cyclosporine blood level in Chinese renal transplant recipients

1. The purpose of the study was to elucidate the influence of multidrug resistance gene (MDR1) haplotype and CYP3A5 genotype on cyclosporine (CsA) blood level in Chinese renal transplant recipients.

2. CsA trough level (C₀) and peak level (C₂) of 115 patients 1 week and 1 month after renal transplantation were determined. MDR1 C1236T, G2677T/A, C3435T and CYP3A5*3 genotypes were determined by polymerase chain reaction (PCR) assays based on amplification refractory mutation.

3. Dose-adjusted C₀ (C₀/D), C₂ (C₂/D) were 50.5?±?22.5, 267.8?±?110.1 ng·kg·(ml·mg)^?1 after 1 week of therapy, and 79.3?±?29.4, 406.0?±?135.3 ng·kg·(ml·mg)^?1 after 1 month of therapy. Frequencies of MDR1 haplotype TTT, CGC, and TGC were 27.0%, 25.2% and 20.0%, respectively. After 1 month of therapy, C₂/D of TTT/TTT patients were 30% (p = 0.057) and 53% (p = 0.003) higher than CGC/TTT and CGC/CGC patients. C₀/D of CYP3A5 *1/*1, *1/*3 and *3/*3 patients after 1 month of therapy were 51.8?±?25.0, 71.5?±?27.6, and 86.7?±?28.6 ng·kg·(ml·mg)^?1 (p < 0.05).

4. MDR1 haplotypes and CYP3A5*3 genotypes can be related to C₂ and C₀ of CsA, respectively.

     

Pharmacokinetics of the prodrug thiamphenicol glycinate and its active parent compound thiamphenicol in beagle dogs following intravenous administration

1. This study investigated the pharmacokinetics of thiamphenicol glycinate (TG) and thiamphenicol (TAP) in beagles (n?=?6) after intravenous administration of 50?mg/kg TG hydrochloride. Plasma concentrations of TG and TAP were measured by a HPLC-UV method.

2. Two-compartment model was selected to describe the pharmacokinetic characteristics of TG and TAP in vivo. Main parameters were as follows: AUC_0–∞ of TAP and TG were 16,328?±?1682 µg·min/mL and 3943?±?546 µg·min/mL, respectively. The total plasma clearance (CL) of TG and TAP were 12.7?±?2.0?mL/min/kg and 2.5?±?0.3?mL/min/kg, respectively. Mean residence time (MRT) of TG and TAP were 27.5?±?3.5 and 207.2?±?20.2?min, respectively. The transformative rate constant (k_1M) from TG to TAP was 0.0477?±?0.0028?min^?1. The elimination rate constant (k_M10) from TAP was 0.0238?±?0.0044?min^?1. Coefficients of variation (CV) between observed values and predicted ones were 5.9% and 18.2%, respectively. The volume of distribution of the central compartment for TG (V_C) and TAP (V_CM) were 0.264?±?0.022?L/kg and 0.127?±?0.023?L/kg, respectively.

3. Pharmacokinetic parameters suggested that TG was presumably cleaved quickly by tissue esterase to release TAP for effectiveness in beagles after administration.

     

Cyclodextrin-based nanosponges: effective nanocarrier for Tamoxifen delivery

The purpose of the present study was to develop Tamoxifen loaded β-cyclodextrin nanosponges for oral drug delivery. The three types of Tamoxifen loaded β-cyclodextrin nanosponges were synthesized by varying the molar ratios of β-cyclodextrin to carbonyldiimidazole as a crosslinker viz. 1:2, 1:4 and 1:8. The Tamoxifen nanosponge complex (TNC) with particle size of 400–600?nm was obtained by freeze drying method. Differential scanning calorimetry, Fourier transformed infra-red spectroscopy and X-ray powder diffraction studies confirmed the complexation of Tamoxifen with cyclodextrin nanosponge. AUC and C_max of TNC formulation (1236.4?±?16.12 µg·mL^?1 h, 421.156?±?0.91 µg/mL) after gastric intubation were 1.44 fold and 1.38 fold higher than plain drug (856.079?±?15.18 µg·mL^?1 h, 298.532?±?1.15 µg/mL). Cytotoxic studies on MCF-7 cells showed that TNC formulation was more cytotoxic than plain Tamoxifen after 24 and 48?h of incubation.     

Sulfation of resveratrol in human liver: Evidence of a major role for the sulfotransferases SULT1A1 and SULT1E1

Sulfation of resveratrol, a polyphenolic compound present in grapes and wine with anticancer and cardioprotective activities, was studied in human liver cytosol. In the presence of 3′-phosphoadenosine-5′-phosphosulfate, three metabolites (M1–3) whose structures were identified by mass spectrometry and NMR as trans-resveratrol-3-O-sulfate, trans-resveratrol-4′-O-sulfate, and trans-resveratrol-3-O-4′-O-disulfate, respectively. The kinetics of M1 formation in human liver cytosol exhibited an pattern of substrate inhibition with a K_i of 21.3?±?8.73?µM and a V_max/K_m of 1.63?±?0.41?µL?min^?1mg^?1 protein. Formation of M2 and M3 showed sigmoidal kinetics with about 56-fold higher V_max/K_m values for M3 than for M2 (2.23?±?0.14 and 0.04?±?0.01?µL?min^?1?mg^?1). Incubation in the presence of human recombinant sulfotransferases (SULTs) demonstrated that M1 is almost exclusively catalysed by SULT1A1 and only to a minor extent by SULT 1A2, 1A3 and 1E1, whereas M2 is selectively formed by SULT1A2. M3 is mainly catalysed by SULT1A2 and 1A3. In conclusion, the results elucidate the enzymatic pathways of resveratrol in human liver, which must be considered in humans following oral uptake of dietary resveratrol.