Hydroxysafflor yellows alleviate thrombosis and acetaminophen-induced toxicity in vivo by enhancing blood circulation and poison excretion.

BACKGROUND: Hydroxysafflor yellow A (HSYA) from the flower of Carthamus tinctorius (Safflower) has been reported to have various pharmacological effects. However, little is known about the bioactivities of other chemical constituents in Safflower and the relationship between enhancement of blood circulation and hepatoprotection by HSYA. PURPOSE: The present research was to evaluate the antithrombotic and hepatoprotective activities of HSYA and C, examine their mechanisms of actions, including influence on the excretion velocity of acetaminophen, and the relationship between the antithrombotic, hepatoprotective, and other bioactivities. METHODS: The hepatoprotective activities were examined by acetaminophen (APAP)-induced zebrafish toxicity and carbon tetrachloride (CCl4)-induced mouse liver injury. The concentrations of APAP in zebrafish and APAP that was excreted to the culture media were quantified by UHPLC-MS. The anti-thrombosis effect of HSYA and C were examined by the phenylhydrazine (PHZ)-induced zebrafish thrombosis. RESULTS: HSYA and HSYC showed robust protection on APAP-induced toxicity and PHZ-induced thrombosis. The hepatoprotective effects of HSYA and C were more potent than that of the positive control, acetylcysteine (61.7% and 58.0%, respectively, vs. 56.9% at 100 µM) and their antithrombosis effects were more robust than aspirin (95.1% and 86.2% vs. 52.7% at 100 µM). HSYA and C enhanced blood circulation, rescued APAP-treated zebrafish from morphological abnormalities, and mitigated APAP-induced toxicity in liver development in liver-specific RFP-expressing transgenic zebrafish. HSYC attenuated CCl4-induced mouse liver injury and regulated the levels of HIF-1α, iNOS, TNF-α, α-SMA, and NFκB in liver tissues. HSYA was also protective in a dual thrombotic and liver toxicity zebrafish model. By UHPLC-MS, HSYA accelerated the excretion of APAP. CONCLUSION: HSYA and C are the bioactive constituents of Safflower that are responsible for the herbal drug's traditional use in promoting blood circulation to remove blood stasis. Safflower and its chalcone constituents may protect from damage due to exogenous or disease-induced endogenous toxins by enhancing the excretion velocity of toxins.

Orostachys japonicus ameliorates acetaminophen-induced acute liver injury in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Orostachys japonicus A. Berger (O. japonicus), referred to as Wa-song in Korea is a traditional and herbal medicine. Even though it has been traditionally used to treat inflammation- and toxicity-related diseases, the effects of ethanol extract of O. japonicus (OJE) on acetaminophen (N-acetyl-p-aminophenol, APAP) overdose-induced hepatotoxicity have not been determined yet. AIM OF THE STUDY: The present study was aimed to investigate the effects of OJE against APAP-induced acute liver injury (ALI) and explore the underlying mechanisms. MATERIALS AND METHODS: Mice were treated orally with OJE (50, 100, or 200 mg/kg) for seven days before APAP (300 mg/kg) injection. After 12 h of APAP treatment, serum and liver tissues were collected. An in vitro system using primary hepatocytes was also applied in this study. RESULTS: Pretreatment with OJE, especially at a dose of 200 mg/kg, reduced APAP overdose-induced ALI in mice, as evidenced by decreased serum alanine/aspartate aminotransferase levels, histopathological damage, and inflammation. Consistently, OJE pretreatment reduced the gene transcription of cytochrome P450 (CYP) 3A11 and CYP1A2 in livers of mice injected with or without APAP, at least in part, via inactivation of nuclear receptor pregnane X receptor (PXR). Furthermore, the role of PXR in mediating the OJE regulation of CYPs was confirmed in primary hepatocytes, which showed that OJE pretreatment inhibited PXR activity and APAP hepatotoxicity enhanced by pregnenolone 16α-carbonitrile, a mouse agonist of PXR. Besides, the antioxidative activity provided by OJE, involving increases in hepatic glutathione (GSH) content and decreases in malondialdehyde levels, has been shown to exert hepatoprotective effects in normal and injured livers. Moreover, APAP-activated c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) in mice liver were indirectly inhibited by pretreatment with OJE. CONCLUSIONS: Taken together, our findings showed that OJE attenuated APAP-induced ALI by decreasing APAP-metabolizing enzymes via inactivation of PXR and the restoration of hepatic GSH content. Therefore, OJE could be a promising hepatoprotective agent.

In vivo effect of Kaempferia parviflora extract on pharmacokinetics of acetaminophen.

Kaempferia parviflora is widely used as a food supplement and a herbal medicine for vitalization. Previous study has shown that K. parviflora had CYP2E1 inducer activity. It is likely to affect the metabolism of CYP2E1 substrates such as acetaminophen which is a common household pain relief medicine. This study investigated the possible pharmacokinetic interaction between K. parviflora and acetaminophen in rats. Acetaminophen (100 mg/kg, p.o) was administered to rats for nine consecutive days. On days 4-9, K. parviflora extract (250 mg/kg, p.o) was given to the acetaminophen-treated rats. After co-administration with K. parviflora, the concentrations of acetaminophen during day 5-8 markedly decreased compared with acetaminophen-only group. At day 9, the pharmacokinetic parameters of acetaminophen in the presence of K. parviflora extract also decreased, including area under the concentration-time curve (from 1.68 ± 0.16 to 0.34 ± 0.04 mg.min/mL), the maximum concentration (from 19.10 ± 1.90 to 4.48 ± 0.56 µg/mL), and half-life (from 21.29 ± 1.36 to 10.81 ± 1.24 min). In addition, clearance and the elimination rate constant of acetaminophen were significantly increased (from 0.003 ± 0.000 to 0.006 ± 0.001 L/min and 0.03 ± 0.00 to 0.07 ± 0.01 min-1, respectively) in the presence of K. parviflora extract. These findings provide the data for in vivo herb-drug interaction between K. parviflora extract and acetaminophen. Therefore, the concomitant use of K. parviflora as a food supplement and acetaminophen should occasion therapeutic and safety concerns.

A hepatoprotection study of Radix Bupleuri on acetaminophen-induced liver injury based on CYP450 inhibition.

We investigated the potential hepatoprotective effect of Radix Bupleuri (RB) by inducing acute liver injury (ALI) in an animal model using acetaminophen (APAP) after pretreatment with RB aqueous extract for three consecutive days. Compared to those of the APAP group, the biochemical and histological results of the RB pretreatment group showed lower serumaspartate transaminase (AST) and alanine transaminase (ALT) levels as well as less liver damage. Pharmacokinetic study of the toxicity related marker acetaminophen-cysteine (APC) revealed a lower exposure level in rats, suggesting that RB alleviated APAP-induced liver damage by preventing glutathione (GSH) depletion. The results of cocktail approach showed significant inhibition of CYP2E1 and CYP3A activity. Further investigation revealed the increasing of CYP2E1 and CYP3A protein was significantly inhibited in pretreatment group, while no obvious effect on gene expression was found. Therefore, this study clearly demonstrates that RB exhibited significant protective action against APAP-induced acute live injury via pretreatment, and which is partly through inhibiting the increase of activity and translation of cytochrome P450 enzymes, rather than gene transcription.

Mechanistic and Quantitative Understanding of Pharmacokinetics in Zebrafish Larvae through Nanoscale Blood Sampling and Metabolite Modeling of Paracetamol.

Zebrafish larvae are increasingly used for pharmacological research, but internal drug exposure is often not measured. Understanding pharmacokinetics is necessary for reliable translation of pharmacological results to higher vertebrates, including humans. Quantification of drug clearance and distribution requires measurements of blood concentrations. Additionally, measuring drug metabolites is of importance to understand clearance in this model organism mechanistically. We therefore mechanistically studied and quantified pharmacokinetics in zebrafish larvae, and compared this to higher vertebrates, using paracetamol (acetaminophen) as a paradigm compound. A method was developed to sample blood from zebrafish larvae 5 days post fertilization. Blood concentrations of paracetamol and its major metabolites, paracetamol-glucuronide and paracetamol-sulfate, were measured. Blood concentration data were combined with measured amounts in larval homogenates and excreted amounts and simultaneously analyzed through nonlinear mixed-effects modeling, quantifying absolute clearance and distribution volume. Blood sampling from zebrafish larvae was most successful from the posterior cardinal vein, with a median volume (interquartile range) of 1.12 nl (0.676-1.66 nl) per blood sample. Samples were pooled (n = 15-35) to reach measurable levels. Paracetamol blood concentrations at steady state were only 10% of the external paracetamol concentration. Paracetamol-sulfate was the major metabolite, and its formation was quantified using a time-dependent metabolic formation rate. Absolute clearance and distribution volume correlated well with reported values in higher vertebrates, including humans. Based on blood concentrations and advanced data analysis, the mechanistic and quantitative understanding of paracetamol pharmacokinetics in zebrafish larvae has been established. This will improve the translational value of this vertebrate model organism in drug discovery and development. SIGNIFICANCE STATEMENT: In early phases of drug development, new compounds are increasingly screened in zebrafish larvae, but the internal drug exposure is often not taken into consideration. We developed innovative experimental and computational methods, including a blood-sampling technique, to measure the paradigm drug paracetamol (acetaminophen) and its major metabolites and quantify pharmacokinetics (absorption, distribution, elimination) in zebrafish larvae of 5 days post fertilization with a total volume of only 300 nl. These parameter values were scaled to higher vertebrates, including humans.

Quercetin reduced the formation of N-acetyl-p-benzoquinoneimine, a toxic metabolite of paracetamol in rats and isolated rat hepatocytes.

N-acetyl-p-benzoquinoneimine (NAPQI) is toxic metabolite of paracetamol formed primarily by cytochrome P4502E1 (CYP2E1) metabolic pathway when administered at therapeutic doses or overdose. The influence of quercetin (flavonoid) on the bioactivation of paracetamol to NAPQI was investigated using rat liver microsomes and rats in vivo. Paracetamol (80 mg/kg) was administered orally without or with silymarin (100 mg/kg), a known inhibitor of CYP2E1, CYP3A4 and quercetin (10 and 20 mg/kg) to rats for 15 consecutive days. Area under the plasma concentration-time curve (AUC0-∞ ) and the peakplasma concentration (Cmax ) of paracetamol were dose-dependently increased with quercetin (10 and 20 mg/kg) compared to paracetamol control group (p < 0.001). On the other hand, the AUC0-∞ and Cmax of NAPQI were decreased significantly with quercetin. The same results were observed with silymarin also. The elevated liver and kidney functional enzymes/compounds were significantly reduced by quercetin and silymarin compared to paracetamol control group. The formation of NAPQI was reduced in the incubation samples in presence of quercetin in experiment using isolated rat hepatocytes. The presentstudy results revealed that quercetin might be inhibited the CYP2E1-mediated metabolism of paracetamol; thereby decreased the formation of NAPQI and protected the liver and kidney.

Mathematical modelling of a liver hollow fibre bioreactor.

A mathematical model has been developed to assist with the development of a hollow fibre bioreactor (HFB) for hepatotoxicity testing of xenobiotics; specifically, to inform the HFB operating set-up, interpret data from HFB outputs and aid in optimizing HFB design to mimic certain hepatic physiological conditions. Additionally, the mathematical model has been used to identify the key HFB and compound parameters that will affect xenobiotic clearance. The analysis of this model has produced novel results that allow the operating set-up to be calculated, and predictions of compound clearance to be generated. The mathematical model predicts the inlet oxygen concentration and volumetric flow rate that gives a physiological oxygen gradient in the HFB to mimic a liver sinusoid. It has also been used to predict the concentration gradients and clearance of a test drug and paradigm hepatotoxin, paracetamol (APAP). The effect of altering the HFB dimensions and fibre properties on APAP clearance under the condition of a physiological oxygen gradient is analysed. These theoretical predictions can be used to design the most appropriate experimental set up and data analysis to quantitatively compare the functionality of cell types that are cultured within the HFB to those in other systems.

Using the 150 rule to prevent hepatotoxicity from acetaminophen.

Acetaminophen-induced hepatotoxicity is the most common cause of acute liver failure in adults and a major cause of acute liver failure in children. Prompt treatment with N-acetylcysteine can mitigate hepatotoxicity and progression to liver failure. This article describes a 16-year-old girl who ingested a large dose of extra-strength acetaminophen, and how the 150 rule was used in her management.

Acetaminophen, ibuprofen, and tramadol analgesic interactions after adenotonsillectomy.

BACKGROUND: The impact of tramadol in children given acetaminophen-ibuprofen combination therapy is uncertain in acute pediatric pain management. A model describing the interaction between these three drugs would be useful to understand the role of supplemental analgesic therapy. METHODS: Children undergoing tonsillectomy were given oral paracetamol and ibuprofen perioperatively. Blood was taken for paracetamol and ibuprofen drug assay on up to six occasions over 6 h after the initial dose. Tramadol was administered by caregivers for unacceptable postoperative pain. Pain was measured using the Parent's Postoperative Pain Measurement rating two hourly on the first postoperative day. A first-order absorption, one-compartment linear model with first-order elimination was used to describe acetaminophen and ibuprofen disposition. Analgesia was described using an EMAX model extended for three drugs, assuming additive effects. Curve fitting was performed using nonlinear mixed effects models. RESULTS: Pharmacodynamic parameter estimates, expressed using fractional Hill equation, were maximum effect (EMAX ) 0.65 (95%CI 0.54, 0.74), the concentration of acetaminophen associated with 50% of the maximal drug effect (C50,ACET ) 7.06 (95%CI 7.03, 7.72) mg/L, and the ibuprofen C50 (C50,IBU ) 3.95 (95%CI 2.57, 7.53) mg/L. The Hill coefficient was 1.48 (95%CI 0.92, 2.62) and an interaction term was fixed at zero (additivity). The half-time (t1/2 keo) for equilibration between the plasma and effect site was 0.34 hour (95%CI 0.23, 1.98) for acetaminophen and 1.04 hour (95%CI 0.75, 1.77) for ibuprofen. Tramadol had a C50,TRAM of 0.07 (95%CI 0.048, 1.07) mg/L with a t1/2 keo,TRAM 1.78 hour (95%CI 1.06, 1.96). CONCLUSION: Ibuprofen has an EC50 for analgesia in children similar to that of adults (3.95 mg/L; 95%CI 2.57-7.53, vs 5-10 mg/L adults). The maximum effect from combination therapy (ie, 65% reduction in pain score) achieves satisfactory analgesia with commonly used doses but increased dose adds little additional benefit. The addition of tramadol to this analgesic mixture prolongs analgesia duration.

Enzyme-inducing effects of berberine on cytochrome P450 1A2 in vitro and in vivo.

AIMS: Berberine (BER) is an important anti-bacterial drug from Chinese herbal medicine and a novel drug candidate for preclinical development in recent years. Here we provide evidence that the effects of berberine on cytochrome P450 (CYP) 1A2 in vitro and in vivo. MAIN METHODS: Real-time polymerase chain reaction and western blotting analysis were employed to evaluate the CYP1A2 mRNA levels and protein expression. The enzyme activity was assessed by the metabolic rate of phenacetin to acetaminophen by LC-MS/MS method. KEY FINDINGS: The results indicated that the CYP1A2 mRNA expression and enzyme activity in HepG2 cells after treated with BER (4.5µg/ml) exhibited a significant induction (16.11-fold and 5.0-fold, respectively), which was consistent with those on rat liver microsomes (4.5-fold and 1.98-fold, respectively) by BER induction (10mg/kg/day, i.p.) ex vivo. Beside, BER induced CYP1A2 activity with increases in AUC0-t and Cmax of acetaminophen and the Ke and t1/2 of phenacetin after oral administration of phenacetin (p<0.05) in vivo. SIGNIFICANCE: This study firstly reported the induction effect of BER on rats CYP1A2 by intraperitoneal route. But, BER didn't show significant induction effect on CYP1A2 by high-dose orally administrating to rats for 6 consecutive days due to the extremely low bioavailability. The potential drug-drug interactions were supposed to happen when the liver exposed to high dose of BER in vivo by changing administration route.

Pharmacokinetic Modeling of Paracetamol Uptake and Clearance in Zebrafish Larvae: Expanding the Allometric Scale in Vertebrates with Five Orders of Magnitude.

Zebrafish larvae (Danio rerio) are increasingly used to translate findings regarding drug efficacy and safety from in vitro-based assays to vertebrate species, including humans. However, the limited understanding of drug exposure in this species hampers its implementation in translational research. Using paracetamol as a paradigm compound, we present a novel method to characterize pharmacokinetic processes in zebrafish larvae, by combining sensitive bioanalytical methods and nonlinear mixed effects modeling. The developed method allowed quantification of paracetamol and its two major metabolites, paracetamol-sulfate and paracetamol-glucuronide in pooled samples of five lysed zebrafish larvae of 3 days post-fertilization. Paracetamol drug uptake was quantified to be 0.289 pmole/min and paracetamol clearance was quantified to be 1.7% of the total value of the larvae. With an average volume determined to be 0.290 µL, this yields an absolute clearance of 2.96 × 107 L/h, which scales reasonably well with clearance rates in higher vertebrates. The developed methodology will improve the success rate of drug screens in zebrafish larvae and the translation potential of findings, by allowing the establishment of accurate exposure profiles and thereby also the establishment of concentration-effect relationships.

Pharmacokinetic Herb-Drug Interaction between Essential Oil of Aniseed (Pimpinella anisum L., Apiaceae) and Acetaminophen and Caffeine: A Potential Risk for Clinical Practice.

Aniseed (Pimpinella anisum L., Apiaceae) and its essential oil (EO) have been widely used. Because there are some data about the impact of aniseed EO on drug effects, this survey aimed to assess the potential of pharmacokinetic herb-drug interaction between aniseed EO and acetaminophen and caffeine in mice. The chemical analysis (gas chromatography-mass spectrometry) of aniseed EO has confirmed trans-anethole (87.96%) as the main component. The pharmacokinetic studies of intraperitoneally (i.p.) and orally applied acetaminophen (200 mg/kg) and caffeine (20 mg/kg) were performed in mice after 5 days of oral treatment with human equivalent dose of aniseed EO (0.3 mg/kg/day). The analysis of pharmacokinetic data showed that in the group treated by aniseed EO, the significant decrease in the peak plasma concentration of acetaminophen after oral application (p = 0.024) was revealed when compared with control group and the reduction of systemic exposure to the drug after oral application (74 ± 32% vs. 85 ± 35% in the control) was noted. The bioavailability of orally applied caffeine was also significantly decreased (p = 0.022) after the EO treatment in comparison with the control (57 ± 24% vs. 101 ± 29%). Therefore, the compromised therapeutic efficacy of acetaminophen and caffeine during the usage of aniseed EO preparations should be considered.

Effect of orally administered cisapride, bethanechol, and erythromycin on the apparent efficiency of colostral IgG absorption in neonatal Holstein-Friesian calves.

OBJECTIVE: To evaluate the effect of orally administered cisapride, bethanechol, and erythromycin on the absorption of colostral IgG in dairy calves. ANIMALS: Twenty-four healthy neonatal Holstein-Friesian calves. PROCEDURES: Calves were randomly assigned to one of the following treatments: 0.9% NaCl solution (2 mL, p.o.; negative control); erythromycin lactobionate (20 mg/kg BW, p.o.; anticipated to be a positive control); cisapride (0.5 mg/kg BW, p.o.); bethanechol chloride (0.5 mg/kg BW, p.o.). Calves were fed 3 L of pooled bovine colostrum containing acetaminophen (50 mg/kg) by suckling and oroesophageal intubation 30 minutes after each treatment was administered. Jugular venous blood samples were obtained periodically after the start of feeding and plasma total IgG, protein, acetaminophen, and glucose concentrations determined. Abomasal emptying rate was assessed by the time to maximal plasma acetaminophen concentration. RESULTS: Oral administration of cisapride facilitated the absorption of colostral IgG and protein. The effect of cisapride on abomasal emptying rate could not be evaluated because cisapride appeared to interfere with acetaminophen metabolism. Based on the total IgG and total protein concentration-time relationships, the beneficial effects of cisapride appeared to occur early after oral administration and were transient. CONCLUSIONS AND CLINICAL IMPORTANCE: Additional studies appear indicated to characterize the effect of cisapride dose on the magnitude and duration of its effect on facilitating the absorption of colostral IgG and protein. Identification of a nonantimicrobial method for increasing abomasal emptying rate, such as cisapride, will potentially provide a practical and effective method for facilitating transfer of passive immunity in colostrum-fed dairy calves.

Glucosamine enhances paracetamol bioavailability by reducing its metabolism.

Paracetamol has an extensive first-pass metabolism that highly affects its bioavailability (BA); thus, dose may be repeated several times a day in order to have longer efficacy. However, hepatotoxicity may arise because of paracetamol metabolism. Therefore, this project aimed to increase paracetamol BA in rats by glucosamine (GlcN). At GlcN-paracetamol racemic mixture ratio of 4:1 and paracetamol dose of 10 mg/kg, paracetamol area under the curve (AUC) and maximum concentration (Cmax ) were significantly increased by 99% and 66%, respectively (p < 0.05). Furthermore, paracetamol AUC and Cmax levels were increased by 165% and 88% in rats prefed with GlcN for 2 days (p < 0.001). Moreover, GlcN significantly reduced phase Ι and phase I/ΙΙ metabolic reactions in liver homogenate by 48% and 54%, respectively. Furthermore, GlcN molecule was found to possess a good in silico binding mode into the CYP2E1 active site-forming bidentate hydrogen bonding with the Thr303 side chain. Finally, serum ALT and AST levels of rats-administered high doses of paracetamol were significantly reduced when rats were prefed with GlcN (p < 0.01). In conclusion, GlcN can increase the relative BA of paracetamol through reducing its metabolism. This phenomenon is associated with reduction in hepatocytes injury following ingestion of high doses of paracetamol.

[The ultrastructural organization of the liver of rats with experimental hepatitis after drinking mineral water containing humic acids].

We undertook the ultrastructural analysis of liver parenchyma taken from male rats with experimental hepatitis induced by the administration of paracetamol at a dose of 1000 mg per 1 kg body weight either following a course of drinking mineral water containing humic acids at a concentration of 20 mg/sq. decimeter) or 14 days after the termination of the drug action (the after-effect phase). It was shown that the consumption of mineral water during 21 days resulted in the modification of the ultrastructural organization of hepatocytes apparent as the increased amount of cisterns in the granulosa endoplasmic system, glycogen rosettes, and mitochondrial polymorphism. These changes give evidence of the restoration of the energy, glycogen and protein synthesizing functions disturbed by paracetamol administration. The after-effect phase was characterized by the further strengthening of reparative processes and the functional activity of hepatic cells.

Interaction between different extracts of Hypericum perforatum L. from Serbia and pentobarbital, diazepam and paracetamol.

Herb-drug interactions are an important safety concern and this study was conducted regarding the interaction between the natural top-selling antidepressant remedy Hypericum perforatum (Hypericaceae) and conventional drugs. This study examined the influence of acute pretreatment with different extracts of Hypericum perforatum from Serbia on pentobarbital-induced sleeping time, impairment of motor coordination caused by diazepam and paracetamol pharmacokinetics in mice. Ethanolic extract, aqueous extract, infusion, tablet and capsule of Hypericum perforatum were used in this experiment. The profile of Hypericum perforatum extracts as well as paracetamol plasma concentration was determined using RP-HPLC analysis. By quantitative HPLC analysis of active principles, it has been proven that Hypericum perforatum ethanolic extract has the largest content of naphtodianthrones: hypericin (57.77 µg/mL) and pseudohypericin (155.38 µg/mL). Pretreatment with ethanolic extract of Hypericum perforatum potentiated the hypnotic effect of pentobarbital and impairment of motor coordination caused by diazepam to the greatest extent and also increased paracetamol plasma concentration in comparison to the control group. These results were in correlation with naphtodianthrone concentrations. The obtained results have shown a considerable influence of Hypericum perforatum on pentobarbital and diazepam pharmacodynamics and paracetamol pharmacokinetics.

Does adding milk to tea delay gastric emptying?

BACKGROUND: Many preoperative fasting guidelines suggest that hot tea or coffee with milk added should be considered similar to solid food, allowing an interval of 6 h before commencing anaesthesia. There is little evidence to support these instructions, with recent guidelines undecided on the issue. This study aimed to establish whether there was a clinically significant delay in gastric emptying associated with adding a modest amount of milk to tea. METHODS: This randomized controlled crossover study was conducted in 10 healthy volunteers. The paracetamol absorption technique and real-time ultrasound measurement of the cross-sectional area of the gastric antrum were used to assess gastric emptying after ingestion of 300 ml of black tea or 300 ml of tea with milk (250 ml black tea plus 50 ml of full fat milk). RESULTS: The mean difference in the time to reach the peak paracetamol concentration (tmax) was -8 min [95% confidence interval (CI) -23.1 to 7] in favour of tea with milk. Ultrasound assessment indicated that the geometric mean of the half-time to gastric emptying (T1/2) after tea without milk was 22.7 (95% CI 12.7-40.9) min and after tea with milk 23.6 (95% CI 13.5-41.0) min (ratio 1.04) (95% CI 0.47-2.29). CONCLUSIONS: This study demonstrated no difference in gastric emptying times when a modest amount of milk was added to tea. These findings suggest that it may be acceptable to allow patients to add a small quantity of milk to their tea or coffee and follow the same fasting restrictions applied to clear fluids.

Abrogation by Trifolium alexandrinum root extract on hepatotoxicity induced by acetaminophen in rats.

OBJECTIVE: Acetaminophen (APAP) is a substance that harms human health by stimulating free radical production. This study investigated the ability of Trifolium alexandrinum root (TAR) extract to reduce the hepatotoxicity induced by APAP in rats. METHODS: Animals were classified into four groups and treated for 6 weeks. Group 1: normal control-treated (saline); Group 2: TAR extract-treated (100 mg/kg); Group 3: APAP-treated; Group 4: APAP plus TAR extract. RESULTS: APAP significantly elevated AST (aspartate amino transferase), ALT (amino alanine transferase), ALP (alkaline phosphatase), GGTP (gamma glutamyl transpeptidase), bilirubin, and malondialdehyde with a significant decrease in glutathione, superoxide dismutase, glutathione peroxidase, catalase, and glutathione S-transferase compared with the control group. Administration of TAR extract combined with APAP improved the liver damage induced by APAP. Histopathological evidence, together with observed DNA fragmentation, supported the detrimental effect of APAP and the ameliorating effect of TAR extract on liver toxicity. CONCLUSION: TAR extract has beneficial properties and can reduce the liver damage and toxicity induced by APAP. DISCUSSION: Free radical mediated processes have been implicated in the pathogenesis of many diseases. The protective effect of TAR root extract on APAP-induced hepatotoxicity in rats appears to be related to inhibition of lipid peroxidation and enhancement of antioxidant enzyme levels, in addition to a free radical scavenging action.

Effect of a herbal extract containing curcumin and piperine on midazolam, flurbiprofen and paracetamol (acetaminophen) pharmacokinetics in healthy volunteers.

AIMS: Turmeric extract derived curcuminoids (curcumin, demethoxycurcumin and bisdemethoxycurcumin) are currently being evaluated for the treatment of cancer and Alzheimer's dementia. Previous in vitro studies indicate that curcuminoids and piperine (a black pepper derivative that enhances curcuminoid bioavailability) could inhibit human CYP3A, CYP2C9, UGT and SULT dependent drug metabolism. The aim of this study was to determine whether a commercially available curcuminoid/piperine extract alters the pharmacokinetic disposition of probe drugs for these enzymes in human volunteers. METHODS: A randomized placebo-controlled six way crossover study was conducted in eight healthy volunteers. A standardized curcuminoid/piperine preparation (4 g curcuminoids plus 24 mg piperine) or matched placebo was given orally four times over 2 days before oral administration of midazolam (CYP3A probe), flurbiprofen (CYP2C9 probe) or paracetamol (acetaminophen) (dual UGT and SULT probe). Plasma and urine concentrations of drugs, metabolites and herbals were measured by HPLC. Subject sedation and electroencephalograph effects were also measured following midazolam dosing. RESULTS: Compared with placebo, the curcuminoid/piperine treatment produced no meaningful changes in plasma C(max), AUC, clearance, elimination half-life or metabolite levels of midazolam, flurbiprofen or paracetamol (α = 0.05, paired t-tests). There was also no effect of curcuminoid/piperine treatment on the pharmacodynamics of midazolam. Although curcuminoid and piperine concentrations were readily measured in plasma following glucuronidase/sulfatase treatment, unconjugated concentrations were consistently below the assay thresholds (0.05-0.08 µM and 0.6 µM, respectively). CONCLUSION: The results indicate that short term use of this piperine-enhanced curcuminoid preparation is unlikely to result in a clinically significant interaction involving CYP3A, CYP2C9 or the paracetamol conjugation enzymes.

The influence of the degree of esterification on the release characteristics of in situ gelling pectin formulations for oral sustained delivery of paracetamol.

The aim of this study was to examine the effect of a change of the degree of esterification of pectin on the in situ gelation and release characteristics of 1.5% (w/v) pectin solutions over a wide pH range. Formulations of pectin with degrees of esterification of 9% (DE9) and 31% (DE31) containing complexed calcium ions formed gels in vitro at pH 1.2 as a consequence of cross-linking of the pectin chains by free calcium ions released from the complex. In vitro release of paracetamol from these gels was diffusion controlled. A sustained release of paracetamol was observed following oral administration of pectin DE9 and DE31 formulations to gastric acidity-controlled rats at pH 2.5 but only with DE9 formulations at pH 5.5. Examination of the stomach contents confirmed effective in situ gelation of pectin DE9 formulations at a gastric pH of 6 but there was no evidence of the gelation of pectin DE31 formulations at this pH.