Improvement of oral bioavailability of glycyrrhizin by sodium deoxycholate/phospholipid-mixed nanomicelles

Glycyrrhizin (GL), extracted from the Glycyrrhiza glabra L., is active triterpenoid saponin components. However, due to its impermeability across the gastrointestinal mucosa, oral bioavailability of the drug was relatively low. To improve its oral bioavailability, formulation of GL as sodium deoxycholate/phospholipid-mixed nanomicelles (SDC/PL-MMs) has been performed in this study. GL-SDC/PL-MMs were produced by a film dispersion method and then investigated using photon correlation spectroscopy (PCS), zeta potential measurement, as well as its physical stability after storage for 10, 20, 30, 60, 90 and 120 days. To verify the theoretical hypothesis, pharmacokinetics and pharmacodynamic studies based on carbon tetrachloride (CCl(4))-induced acute liver injury was investigated. Results showed that a narrow size distributed nanomicelles with a mean particle size of 82.99 ± 7.5 nm and a zeta potential of -32.23 ± 1.05 mV was obtained. In the pharmacokinetics, GL-SDC/PL-MMs show a significant superiority in AUC(0-t), C(max) and other pharmacokinetic parameters compared with the control group. In the pharmacodynamic studies, compared with the bifendate control group, GL-SDC/PL-MMs showed an equivalent effect in reducing alanine aminotransferase (ALT), aspartate aminotransferase (AST) and improving the pathological changes of liver tissue. These results revealed that SDC/PL-MMs could enhance GL absorption in gastrointestinal tract and pharmacodynamic effect in the treatment of acute liver injury caused by CCl(4), and SDC/PL-MMs might be a good choice for oral delivery of poor bioavailability drug like GL.     

Hepatoprotective effects of Juglans regia extract against CCl4-induced oxidative damage in rats

Abstract

Context: Different parts of the walnut [Juglans regia L. (Juglandaceae)] have been used in folk medicine for protection against liver injury, although its actual efficacy remains uncertain.

Objective: The present study investigated the protective effect of walnut leaf extract against carbon tetrachloride (CCl₄)-induced liver damage in rats.

Materials and methods: The rats were randomly divided into seven groups: control, CCl₄ (i.p., 0.5?mL/kg b.w., 50% CCl₄ in olive oil), walnut extract (at dose level of 0.2?g/kg b.w.) alone, walnut extract (at dose levels of 0.05, 0.1, 0.2 and 0.4?g/kg b.w.) with CCl₄, and treatment was carried out accordingly. On the 28th day, rats were sacrificed and blood was withdrawn by cardiac puncture. Liver damage was assessed by serum biochemical parameters (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and albumin), antioxidant enzymes (superoxide dismutase and catalase) and histopathological observation.

Results: Administration of walnut leaf extract (ranging from 0.2 to 0.4?g/kg b.w.) significantly lowered serum alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase levels in CCl₄-treated rats. Walnut leaf extract increased antioxidant enzymes, including superoxide dismutase and catalase. Histopathological examination of livers showed that walnut leaves extract reduced fatty degeneration, cytoplasmic vacuolization and necrosis in CCl₄-treated rats.

Discussion and conclusion: These results suggest that walnut extract has a protective effect over CCl₄-induced oxidative damage in rat liver. These results demonstrate that walnut extract acts as a good hepatoprotective and antioxidant agent in attenuating hepatocellular damage.     

Genoprotective and hepatoprotective effects of Guarana (Paullinia cupana Mart. var. sorbilis) on CCl4-induced liver damage in rats

Context: Several biological effects of Paullinia cupana (guarana) have been demonstrated, but little information is available on its effects on the liver. Objective: The current study was designed to evaluate the hepatoprotective and genoprotective effects of powder seeds from guarana on CCl₄-induced liver injury in rats. Materials and methods: Male Wistar rats were pretreated with guarana powder (100, 300 and 600?mg/kg) or silymarin 100?mg/kg daily for 14 days before treatment with a single dose of CCl₄ (50% CCl₄, 1?mL/kg, intraperitoneally). Results: The treatment with CCl₄ significantly increased the serum activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). In addition, CCl₄ increased the DNA damage index in hepatocytes. Guarana in all concentrations was effective in decreasing the ALT and AST activities when compared with the CCl₄-treated group. The treatment with guarana decreased DNA damage index when compared with the CCl₄-treated group. In addition, the DNA damage index showed a significant positive correlation with AST and ALT. Discussion and conclusion: These results indicate that the guarana has hepatoprotective activity and prevents the DNA strand breakage in the CCl₄-induced liver damage in rats.     

Development and optimisation of atorvastatin calcium loaded self-nanoemulsifying drug delivery system (SNEDDS) for enhancing oral bioavailability: in vitro and in vivo evaluation

The objective of this study was to develop and optimise self-nanoemulsifying drug delivery system (SNEDDS) of atorvastatin calcium (ATC) for improving dissolution rate and eventually oral bioavailability. Ternary phase diagrams were constructed on basis of solubility and emulsification studies. The composition of ATC–SNEDDS was optimised using the Box–Behnken optimisation design. Optimised ATC–SNEDDS was characterised for various physicochemical properties. Pharmacokinetic, pharmacodynamic and histological findings were performed in rats. Optimised ATC–SNEDDS resulted in droplets size of 5.66?nm, zeta potential of ?19.52?mV, t₉₀ of 5.43?min and completely released ATC within 30?min irrespective of pH of the medium. Area under the curve of optimised ATC–SNEDDS in rats was 2.34-folds higher than ATC suspension. Pharmacodynamic studies revealed significant reduction in serum lipids of rats with fatty liver. Photomicrographs showed improvement in hepatocytes structure. In this study, we confirmed that ATC–SNEDDS would be a promising approach for improving oral bioavailability of ATC.     

Hepatoprotective effects of sesamol loaded solid lipid nanoparticles in carbon tetrachloride induced sub‐chronic hepatotoxicity in rats

Sesamol is a phenolic component of sesame seed oil, which has been established as an antioxidant and also possesses potential for hepatoprotection. However, its protective role in carbon tetrachloride (CCl₄) induced sub‐chronic hepatotoxicity has not been studied. Limited oral bioavailability (BA) and rapid elimination (as conjugates) in rats is reported for sesamol. Considering its significant antioxidant potential and compromised BA, we packaged sesamol into solid lipid nanoparticles (S‐SLNs) to enhance its hepatoprotective bioactivity. S‐SLNs prepared by microemulsification method were nearly spherical in shape with an average particle size of 120.30 nm and their oral administration at 8 mg/kg body weight (BW) showed significantly (p < 0.001) better hepatoprotection than free sesamol (FS) and a well established hepatoprotective antioxidant silymarin [SILY (25 mg/kg BW); p < 0.05) in CCl₄ induced sub‐chronic liver injury in rats. Evaluations were done in terms of histological changes in the liver tissue, liver injury markers (serum alanine aminotransferase, serum aspartate aminotransferase, and serum lactate dehydrogenase); oxidative stress markers (lipid peroxidation, superoxide dismutase, and reduced glutathione) and proinflammatory response marker (tumor necrosis factor‐alpha). © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 520–532, 2016.     

Hepatoprotective and antioxidant activity of Melaleuca styphelioides on carbon tetrachloride-induced hepatotoxicity in mice

Context: Liver disease is a serious problem. Polyphenolic compounds have marked antioxidant effect and can prevent the liver damage caused by free radicals. In vitro studies have revealed the strong antioxidant activity of an ellagitannin-rich plant, namely, Melaleuca styphelioides Sm. (Myrtaceae).

Objective: In view of the limited therapeutic options available for the treatment of liver diseases, the hepatoprotective potential of the methanol extract of M. styphelioides leaves (MSE) was investigated against CCl₄-induced liver injury in mice.

Materials and methods: MSE was administered (500 and 1000?mg/kg/d p.o.) along with CCl₄ for 6 weeks. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were determined in the serum. Glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione transferase (GST), and malondialdehyde (MDA) were estimated in the liver homogenate. The bioactive components of MSE were identified by NMR, UV and HRESI-MS/MS data.

Results: MSE treatment (500 and 1000?mg/kg/d) markedly inhibited the CCl₄-induced increase in the levels of AST (31 and 38%), ALT (29 and 32%), ALP (13 and 19%), and MDA (22 and 37%) at the tested doses, respectively. MSE treatment markedly increased the levels of GSH (29 and 57%) and antioxidant enzymes compared with the CCl₄-treated group. MSE was more effective than silymarin in restoring the liver architecture and reducing the fatty changes, central vein congestion, Kupffer cell hyperplasia, inflammatory infiltration, and necrosis induced by CCl₄. The LD₅₀ of MSE was more than 5000?mg/kg.

Conclusion: MSE confers potent antioxidant and hepatoprotective effects against CCl₄-induced toxicity.     

Pharmacokinetics of bicyclol in rats with acute hepatic failure

The aim of present study is to evaluate the pharmacokinetics of bicyclol in carbon tetrachloride (CCl₄)-intoxicated rats. The plasma concentration of bicyclol was detected in rats after a single oral or intravenous administration by high-performance liquid chromatography (HPLC) analysis. Rat intestinal and hepatic perfusion models were employed to clarify the respective effect of gut and liver on the pharmacokinetics of bicyclol in acute hepatic failure (AHF) rats. Rat in vitro microsomal incubation was also conducted. The bioavailability of bicyclol was increased 3.1-fold after CCl₄ intoxication in rats. The area under the curve (AUC)_(0–∞), C_max, and clearance (CL) of bicyclol after intravenous administration were 13.4 mg h l^?1, 18.8 mg l^?1, and 1.8 l h^?1 kg^?1 in control rats, and 130 mg h l^?1, 33.1 mg l^?1, and 0.15 l h^?1 kg^?1 in AHF rats, respectively. In the present study we investigated the pharmacokinetics of bicyclol in CCl₄-intoxicated rats and differentiated the respective role of intestine and liver by using in situ intestinal and hepatic perfusion in rats, and in vitro rat microsomes incubation. The studies are expected to provide a better understanding related to the alteration of pharmacokinetics of bicyclol in pathological situation.     

Methotrexate-Loaded Nanomixed Micelles: Formulation,Characterization, Bioavailability,Safety, and In Vitro Anticancer Study

Purpose

Methotrexate (MTX), a potent anticancer drug, shows low oral bioavailability due to its low aqueous solubility and permeability. Moreover, its multidrug resistance (MDR) in cancer and toxic effects restricts its clinical applications. The aim of the study was to prepare novel MTX-loaded Poloxamer 407 and Gelucire^®44/14 (GL44) mixed micelles (MTX-PGMM) to improve its oral bioavailability and cytotoxicity and to reduce its systemic toxicity.

Methods

MTX-PGMM was prepared by dialysis method, compared with blank or MTX-free blank mixed micelles (BMM) and aqueous dispersion of MTX (MTX-AD) with respect to morphology, size, zeta potential, entrapment efficiency, in vitro release, and in vitro cytotoxicity, bioavailability, and toxicity study in rats.

Results

The developed MTX-PGMM exhibited small particle size, good encapsulation efficiency, and good stability in media simulating the physiological conditions of the gastrointestinal tract. The MTX-PGMM micelles demonstrated sustained release, enhanced (6.5-fold) oral bioavailability, slow plasma elimination, and long circulation of MTX. Biocompatibility was also established as there were no signs of tissue toxicity. Moreover, MTX-PGMM produced higher in vitro cytotoxicity (GI₅₀ of 1.44?±?0.33 μg/mL) than free MTX (GI₅₀ 13.71?±?0.99 μg/mL) in human breast cancer MCF-7 cells.

Conclusion

Poloxamer 407 and Gelucire^®44/14 (GL44) mixed micelles are promising carriers for oral delivery of MTX and can be utilized for other Biopharmaceutical Classification System class IV anticancer drugs having poor oral bioavailability and multidrug resistance in cancer.

     

Pharmacokinetics of tafamidis,a transthyretin amyloidosis drug,in rats

1.?We characterized the pharmacokinetics of tafamidis, a novel drug to treat transthyretin-related amyloidosis, in rats after intravenous and oral administration at doses of 0.3–3?mg/kg. In vitro Caco-2 cell permeability and liver microsomal stability, as well as in vivo tissue distribution and plasma protein binding were also examined.

2.?After intravenous injection, systemic clearance (CL), volumes of distribution at steady state (V_ss) and half-life (T_½) remained unaltered as a function of dose, with values in the ranges of 6.41–7.03?mL/h/kg, 270–354?mL/kg and 39.5–46.9?h, respectively. Following oral administration, absolute bioavailability was 99.7–104% and was independent of doses from 0.3 to 3?mg/kg. In the urine and faeces, 4.36% and 48.9% of tafamidis, respectively, were recovered.

3.?Tafamidis was distributed primarily in the liver and not in the brain, kidney, testis, heart, spleen, lung, gut, muscle, or adipose tissue. Further, tafamidis was very stable in rat liver microsomes, and its plasma protein binding was 99.9%.

4.?In conclusion, tafamidis showed dose-independent pharmacokinetics with intravenous and oral doses of 0.3–3?mg/kg. Tafamidis undergoes minimal first-pass metabolism, distributes mostly in the liver and plasma, and appears to be eliminated primarily via biliary excretion.     

Recombinant bovine pancreatic trypsin inhibitor protects the liver from carbon tetrachloride-induced chronic injury in rats

Abstract

Context: Bovine pancreatic trypsin inhibitor (BPTI) has been reported to relieve liver ischemia-reperfusion-induced injury in rats.

Objective: This study was designed to determine whether the recombinant BPTI (rBPTI) can prevent the chronic liver injury induced by CCl₄ in rats.

Materials and methods: Fifty male Wistar rats were divided into five groups. Rats were treated with 40% CCl₄ at a dose of 2?ml/kg body weight twice a week subcutaneously for 12 weeks. In the 8th week, they were administered intraperitoneally with rBPTI (80 MU/kg), BPTI (80 MU/kg) or hepatocyte growth-promoting factor (pHGF; 100?mg/kg) daily for the next 4 weeks.

Results: rBPTI significantly prevented the disruption of liver function of alanine aminotransferase (ALT; 172.7?±?18.16 versus 141.2?±?15.28, p?=?0.003), aspartate aminotransferase (AST; 225.10?±?36.54 versus 170.06?±?27.14, p?=?0.007) and hydroxyproline (Hyp; 1.14?±?0.27 versus 0.62?±?0.17, p?=?0.001). rBPTI significantly decreased the level of thiobarbituric acid reactive substances (TBARS; 1.15?±?0.16 versus 0.87?±?0.15, p?=?0.003) and increased the activities of superoxide dismutase (SOD; 6.07?±?0.95 versus 7.75?±?1.12, p?=?0.007). rBPTI reduced the production of cytokines of IL-1β and TGF-β. The hepatocyte necrosis, fibrosis, fatty degeneration and inflammatory cell infiltration were ameliorated by rBPTI administration.

Conclusion: This study demonstrated that rBPTI exerted a hepatoprotective effect on chronic liver fibrosis induced by CCl₄, which suggests that rBPTI may have the potential application for chronic liver injury induced by drugs metabolism and toxic substances.     

Duodenum-triggered delivery of pravastatin sodium: II. Design,appraisal and pharmacokinetic assessments of enteric surface-decorated nanocubosomal dispersions

Context: Pravastatin sodium (PVS) is a freely water-soluble HMG-CoA inhibitor that suffers from instability at gastric pH, extensive first pass metabolism, short elimination half-life (1–3?h) and low oral bioavailability (18%). Objective: To overpower these drawbacks and to maximize drug absorption at its main site of absorption at the duodenum, enteric surface-coated PVS-loaded nanocubosomal dispersions were presented. Materials and methods: Glyceryl monooleate (GMO)-based dispersions were developed by the fragmentation or the liquid precursor methods using Pluronic® F127 or Cremophor® EL as surfactants. As a challenging enteric-coating approach, the promising dispersions were surface-coated via lyophilization with Eudragit® L100-55; a duodenum-targeting polymer. The drug content, particle size, zeta potential, morphology and release studies of PVS-loaded dispersions were evaluated before and after surface-coating. Compared to an aqueous PVS solution, the pharmacokinetics of the best achieved system (E-F8) was evaluated (UPLC-MS/MS) in rats. Results: The enteric surface-coated nanocubosomal dispersions were more or less spherical in shape and showed high drug-loading, negative zeta potential values and fine-tuned biphasic drug-release patterns characterized by retarded (2?h) and sustained (10?h) phases in pH 1.2 and pH 6.8, respectively. E-F8 system showed significantly (p<?0.05) higher oral bioavailability, delayed T_max and prolonged MRT_0?∞ following oral administration in rats. Conclusions: The duodenum-triggering potential and the controlled-release characteristics of the best achieved system for smart PVS delivery were revealed.     

Hepatoprotective effects of Ficus racemosa stem bark against carbon tetrachloride-induced hepatic damage in albino rats

In the present study, the hepatoprotective effects of petroleum ether (FRPE) and methanol (FRME) extract of Ficus racemosa Linn. (Moraceae) stem bark were studied using the model of hepatotoxicity induced by carbon tetrachloride (CCl₄) in rats. CCl₄ administration induced a significant decrease in serum total protein, albumin, urea and a significant increase (P?≤?0.01) in total bilirubin associated with a marked elevation in the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) as compared to control rats. Further, CCl₄ intoxication caused significant increase in the TBARS and decrease in glutathione (GSH) levels in serum, liver and kidney. Pretreatment with FRPE and FRME restored total protein and albumin to near normal levels. Both the extracts resulted in significant decreases in the activities of AST, ALT and ALP, compared to CCl₄-treated rats. However, a greater degree of reduction was observed in FRME pretreated group (FRPE 43%, 38%, and 33%; FRME 55%, 73%, and 38%). Total bilirubin content decreased from 2.1?mg/dL in CCl₄-treated rats to 0.8 and 0.3?mg/dL in FRPE and FRME pretreated rats, respectively. The extracts improved the antioxidant status considerably as reflected by low TBARS and high GSH values. FRME exhibited higher hepatoprotective activity than a standard liver tonic (Liv52), while the protective effect of FRPE was similar to that of Liv52. The protective effect of F. racemosa was confirmed by histopathological profiles of the liver. The results indicate that F. racemosa possesses potent hepatoprotective effects against CCl₄-induced hepatic damage in rats.     

Liver-targeting self-assembled hyaluronic acid-glycyrrhetinic acid micelles enhance hepato-protective effect of silybin after oral administration

Abstract

In order to enhance oral bioavailability and liver targeting delivery of silybin, two amphiphilic hyaluronic acid derivatives, hyaluronic acid-deoxycholic acid (HA-adh-DOCA) and hyaluronic acid-glycyrrhetinic acid (HA-adh-GA) conjugates, were designed and synthesized. Silybin was successfully loaded in HA-adh-DOCA and HA-adh-GA micelles with high drug-loading capacities (20.3%?±?0.5% and 20.6%?±?0.6%, respectively). The silybin-loaded micelles were spherical in shape with the average size around 130?nm. In vitro release study showed that two silybin-loaded micelles displayed similar steady continued-release pattern in simulated gastrointestinal fluids and PBS. Single-pass intestinal perfusion studies indicated that silybin-loaded micelles were absorbed in the whole intestine and transported via a passive diffusion mechanism. Compared with suspension formulation, silybin-loaded HA-adh-DOCA and HA-adh-GA micelles achieved significantly higher AUC and C_max level. Moreover, liver targeting drug delivery of micelles was confirmed by in vivo imaging analysis. In comparison between the two micellar formulations, HA-adh-GA micelles possessed higher targeting capacity than HA-adh-DOCA micelles, owing to the active hepatic targeting properties of glycyrrhetinic acid. In the treatment of acute liver injury induced by CCl₄, silybin-loaded HA-adh-GA micelles displayed better effects over suspension control and silybin-loaded HA-adh-DOCA micelles. Overall, pharmaceutical and pharmacological indicators suggested that the HA-adh-GA conjugates can be successfully utilized for liver targeting of orally administered therapeutics.     

N-trimethyl chitosan (TMC)-modified microemulsions for improved oral bioavailability of puerarin: preparation and evaluation

Abstract

The aim of this research was to increase the oral bioavailability of puerarin by N-trimethyl chitosan-modified microemulsions (TMC-MEs) loaded with puerarin. Different concentrations of TMC-modified microemulsions were prepared in our study, and then evaluated for particle size, zeta potential, morphological observation and changes of the microenvironment polarity of inner oil core. It was shown that the zeta potential of the microemulsion was increased with the increasing concentration of TMC, and the peak value was achieved when the concentration of TMC was 3.0?mg/mL. The enhancement of the ratio of I₁/I₃ (the ratio between the first band and the third band of the emission fluorescence spectrum of pyrene, I₁?=?373?nm, I₃?=?384?nm) indicated that polarity of the inner core of TMC-MEs was increased with the addition of the modifier. Pharmacokinetic studies demonstrated that after oral administration of puerarin N-trimethyl chitosan (TMC)-modified microemulsions (PUE-TMEs) and puerarin microemulsions (PUE-MEs) to rats at a dose of 100?mg/kg, relative bioavailability was enhanced about 6.8- and 1.2-fold, respectively, compared to puerarin suspension (PUE-SUS) as control. It indicated that the TMC-MEs could be used as an effective formulation for enhancing the oral bioavailability of puerarin.     

The effects of verapamil on the pharmacokinetics of curculigoside in rats

Context: Clarifying the potential mechanism of the poor oral bioavailability of curculigoside would be helpful for for investigating pharmacological effects and clinical applications.

Objective: To clarify the main mechanism for poor oral bioavailability.

Materials and methods: First, the pharmacokinetics of curculigoside (20?mg/kg) in rats with and without pretreatment with verapamil (10?mg/kg) was determined using a sensitive and reliable LC-MS method. Then the effects of verapamil on the transport and metabolic stability of curculigoside were investigated using Caco-2 cell transwell model and rat liver microsome incubation systems.

Results: The results showed that verapamil could significantly increase the peak plasma concentration (from 60.17?ng/mL to 93.66?ng/mL) and AUC_0?t (from 289.57 to 764.02?ng·h/mL) of curculigoside. The Caco-2 cell experiments indicated that the efflux ratio of curculigoside was 3.92 (P_appAB 6.43?±?0.57?×?10?^?7?cm/s; P_appBA 2.52?±?0.37?×?10?^?36?cm/s), P-gp might be involved in the transport of curculigoside, and verapamil could inhibit the efflux of curculigoside and increase the absorption of curculigoside significantly in the Caco-2 cell monolayer. Additionally, the rat liver microsome incubation experiments indicated that verapamil could significantly decrease the intrinsic clearance rate of curculigoside (from 38.8 to 23.6?μL/min/mg protein).

Discussion and conclusion: These results indicated that verapamil could significantly change the pharmacokinetic profiles of curculigoside in rats, the poor absorption due to P-gp mediated efflux in intestine and high intrinsic clearance rate in rat liver may be the main reason for the poor oral absolute bioavailability of curculigoside.     

Hepatoprotective effect of ethanol extract from Berchemia lineate against CCl4-induced acute hepatotoxicity in mice

Abstract

Context: The roots of Berchemia lineate (L.) DC. (Rhamnaceae) have been long used as a remedy for the treatment of some diseases in Guangxi Province, China.

Objective: The present study investigates the hepatoprotective effect of Berchemia lineate ethanol extract (BELE) on CCl₄-induced acute liver damage in mice.

Materials and methods: Effect of BELE administrated for 7 consecutive days was evaluated in mice by the serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin (TBIL), albulin (ALB), globulin (GLB), and total protein (TP) levels, as well as liver superoxide dismutase (SOD) activity and malondialdehyde (MDA) level. Moreover, histopathological examinations were also taken.

Results: Compared with the model group, administration of 400?mg/kg BELE for 7?d in mice significantly decreased the serum ALT (56.25?U/L), AST (297.67?U/L), ALP (188.20?U/L), and TBIL (17.90?mol/L), along with the elevation of TP (64.67?g/L). In addition, BELE (100, 200, and 400?mg/kg, i.g.) treated mice recorded a dose-dependent increment of SOD (291.17, 310.32, and 325.67?U/mg prot) and reduction of MDA (7.27, 6.77, and 5.33?nmol/mg prot) levels. Histopathological examinations also confirmed that BELE can ameliorate CCl₄-induced liver injuries, characterized by extensive hepatocellular degeneration/necrosis, inflammatory cell infiltration, congestion, and sinusoidal dilatation.

Discussion and conclusion: The results indicated that BELE possessed remarkable protective effect against acute hepatotoxicity and oxidative injuries induced by CCl₄, and that the hepatoprotective effects of BELE may be due to both the inhibition of lipid peroxidation and the increase of antioxidant activity.     

姜黄素纳米乳的制备和药动学及药效学研究

目的 探究姜黄素纳米乳在大鼠体内的药动学特性和对大鼠高脂血症的药效作用。方法 建立大鼠血浆中姜黄素的高效液相色谱-质谱联用（HPLC-MS）含量测定方法,考察纳米乳的体内药动学过程。建立SD大鼠高脂血症动物模型,初步考察姜黄素纳米乳对高脂饮食诱导的大鼠高脂血症的药效作用。结果 体内药动学研究结果表明,以姜黄素原料药为参比制剂,姜黄素纳米乳的相对生物利用度为313.47%;以市售片剂为参比制剂,姜黄素纳米乳的相对生物利用度为279.52%。纳米乳组的Cmax为原料药组的201.48%,为片剂组的193.02%,且比原料药组及片剂组具有更高的MRT值（为原料药组的183.52%,是片剂组的154.21%）。药效学研究结果表明姜黄素纳米乳口服给药系统能显著降低模型大鼠的血清总胆固醇（TC）、低密度脂蛋白（LDLc）,缓解高脂饮食给模型大鼠造成的肝脏脂质沉积及肝损伤。结论 姜黄素纳米乳口服给药系统能够有效改善姜黄素的生物利用度,具有良好的降血脂作用,并能够控制高脂血症大鼠体重增长和改善由脂质代谢紊乱造成的肝脏系数变化。     

Preparation and pharmacokinetics evaluation of oral self-emulsifying system for poorly water-soluble drug Lornoxicam

Abstract

The present work was performed aiming to develop a new solid self-emulsifying system (SMEDDS) for poorly water-soluble drug Lornoxicam and evaluate the bioavailability in Wister rats by oral gavage. Liquid SMEDDS of Lornoxicam was formulated with Labrafil M 1944 CS as oil phase, Kolliphor HS 15 as a surfactant and Transcutol HP as a cosurfactant after screening various vehicles. The microemulsion system selected from the phase diagram and optimized by central composite design (CCD) response surface method was transformed into solid-SMEDDS (S-SMEDDS) by lyophilization using sucrose as cryoprotectant. The formulations were further characterized by the particle size, poly dispersity index (PDI), self-emulsifying time, zeta potential, transmission electron microscope (TEM), differential scanning calorimeter (DSC), in vitro drug release and in vivo pharmacokinetics. Results of DSC studies confirmed that the drug was incorporated in the S-SMEDDS. The in vitro drug release from Lornoxicam SMEDDS was found to be greatly higher in comparison with that from the commercial tablets. It was indicated that SMEDDS might be effective in reducing the effect of pH variability of Lornoxicam and improving the release performance of Lornoxicam. HPLC system was applied to study the concentration of Lornoxicam in the plasma of the Wister rats after oral administration of Lornoxicam SMEDDS and Lornoxicam commercial tablets. The pharmacokinetics parameters of the rats were C_max 1065.91?±?224.90 and 1855.22?±?748.25?ngmL^?1, T_max were 2.5?±?0.4?h and 1.8?±?0.5?h, and AUC_0～t were 5316.35?±?323.62 and 7758.07?±?241.57?ngmL^?1?h, respectively. Calculated by AUC_0～∞, the relative bioavailability of Lornoxicam S-SMEDDS was 151.69?±?15.32%. It suggested that this S-SMEDDS could be used as a successful oral solid dosage form to improve the solubility and bioavailability of poorly water-soluble drug Lornoxicam as well.     

Hepatotoxicity and nephrotoxicity in rats induced by carbon tetrachloride and the protective effects of Teucrium polium and vitamin C

This work investigated the protective effects of Teucrium polium (T. polium) and vitamin C (Vit C) against carbon tetrachloride (CCl₄) induced hepatotoxicity and nephrotoxicity in rats. T. polium reduced the Fer reduced antioxidant power (FRAP) (IC₅₀?=?0.89?mg/ml) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) (IC₅₀?=?0.049 µg/ml) than Vit C, FRAP (IC₅₀?=?0.71?mg/ml) and DPPH (IC₅₀?=?0.029 µg/ml). Male albino Wistar rats were divided into six groups: Group I was used as controls, Group II received CCl₄ in olive oil (0.5?ml/kg) by gavage, Group III received CCl₄ in olive oil (0.5?ml/kg) by gavage after 3 d of receiving T. polium (5?g/l), orally, Group IV received T. polium (5?g/l) alone, by gavage, for 7 d, Group V received CCl₄ in olive oil (0.5?ml/kg) by gavage after 3 d of receiving Vit C (250?mg/kg) by gavage and Group VI received Vit C (250?mg/kg) alone by gavage. CCl₄ showed an increase of serum hepatic and renal markers aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, and creatinine. Moreover, we noted an increase of lipid peroxidations and a decrease in antioxidants enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) of CCl₄ rats compared to controls. The pretreatment with (200?mg/kg) of T. polium and with Vit C (250?mg/kg) by gavage, for 7 d, displayed their ability to protect against oxidative damage and biochemical changes induced by CCl₄. Our results were in accordance with histopathological observations.     

Effects of quercetin on the bioavailability of doxorubicin in rats: Role of CYP3A4 and P-gp inhibition by quercetin

Quercetin, a flavonoid, is an inhibitor of P-glycoprotein-mediated efflux transport, and its oxidative metabolism is catalyzed by CYP enzymes. Thus, it is expected that the pharmacokinetics of both intravenous and oral doxorubicin can be changed by quercetin. The purpose of this study was to investigate the effect of oral quercetin on the bioavailability and pharmacokinetics of orally and intravenously administered doxorubicin in rats. The effects of quercetin on the P-glycoprotein (P-gp) and CYP3A4 activities were also evaluated. Quercetin inhibited CYP3A4 enzyme activity in a concentration-dependent manner with a 50% inhibition concentration (IC₅₀) of 1.97 μM. In addition, quercetin significantly enhanced the intracellular accumulation of rhodamine-123 in MCF-7/ADR cells overexpressing P-gp. The pharmacokinetic parameters of doxorubicin were determined in rats after oral (50 mg/kg) or intravenous (10 mg/kg) administration of doxorubicin to rats in the presence and absence of quercetin (0.6, 3 or 15 mg/kg). Compared to control, quercetin significantly (p < 0.05 for 0.6 mg/kg, p < 0.01 for 3 and 15 mg/kg) increased the area under the plasma concentration-time curve (AUC_0−∞, 31.2-136.0% greater) of oral doxorubicin. Quercetin also significantly increased the peak plasma concentration (C_max) of doxorubicin, while there was no significant change in T_max and T_1/2 of doxorubicin. Consequently, the absolute bioavailability of doxorubicin was increased by quercetin compared to control, and the relative bioavailability of oral doxorubicin was increased by 1.32 to 2.36 fold. In contrast, the pharmacokinetics of intravenous doxorubicin were not affected by quercetin. These results suggest that the quercetin-induced increase in bioavailability of oral doxorubicin can be attributed to enhanced doxorubicin absorption in the gastrointestinal tract via quercetin-induced inhibition of P-gp and reduced first-pass metabolism of doxorubicin due to quercetin-induced inhibition of CYP3A in the small intestine and/or in the liver rather than reduced renal and/or hepatic elimination of doxorubicin. Therefore, it appears that the development of oral doxorubicin preparations is possible, which will be more convenient than the intravenous dosage forms. Therefore, concurrent use of quercetin provides a therapeutic benefit — it increases the bioavailability of doxorubicin administered orally.