RÉSUMÉ
Entecavir, an effective anti-hepatitis B drug with low resistance rate, was designed as sustained-release micro spheres in our previous study. Here, we aimed to reveal the drug-release mechanism by observing the drug distribution and degradation behavior of poly (lactic-co-glycolic acid) and to investigate the pharmacodynamics of entecavir micro spheres. Raman spectroscopy was used to analyze the distribution of active pharmaceutical ingredients in the micro spheres. The results showed that there was little entecavir near the micro sphere surface. With increasing micro sphere depth, the drug distribution gradually increased and larger-size entecavir crystals were mainly distributed near the spherical center. The degradation behavior of poly (lactic-co-glycolic acid) was investigated using gel permeation chromatography. Changes in poly (lactic-co-glycolic acid) molecular weights during micro sphere degradation revealed that dissolution dominated the release process, which proved our previous research results. Pharmacodynamics studies on transgenic mice indicated that the anti-hepatitis B virus replication effect was maintained for 42 days after a single injection of entecavir micro spheres, similar to the effect of daily oral administration of entecavir tablets for 28 days. The entecavir micro spheres prepared in this study had a good anti-hepatitis B virus replication effect and it is expected to be used in anti hepatitis B virus treatment against hepatitis B virus.
Sujet(s)
Antiviraux , Guanine , Virus de l'hépatite B , Copolymère d'acide poly(lactique-co-glycolique) , Guanine/pharmacologie , Guanine/analogues et dérivés , Guanine/pharmacocinétique , Animaux , Antiviraux/pharmacologie , Antiviraux/pharmacocinétique , Copolymère d'acide poly(lactique-co-glycolique)/composition chimique , Virus de l'hépatite B/effets des médicaments et des substances chimiques , Libération de médicament , Souris transgéniques , Souris , Réplication virale/effets des médicaments et des substances chimiques , Microsphères , Préparations à action retardée , Hépatite B/traitement médicamenteux , Taille de particule , Acide polyglycolique/composition chimique , Analyse spectrale Raman , Acide lactiqueRÉSUMÉ
OBJECTIVE: To evaluate the pharmacokinetics of famciclovir and its metabolite penciclovir following a single dose administered orally and rectally in African elephants (Loxodonta africana). ANIMALS: 15 African elephants (6 males and 9 females) of various ages. METHODS: Famciclovir (15 mg/kg) was administered orally or per rectum once, with at least a three-week washout period between administrations. Blood was collected at 13 different timepoints per administration for 6 elephants, occurring between February and March 2020. An additional 9 elephants were sampled at variable timepoints per administration utilizing a sparse sampling design between July 2020 and January 2021. Plasma famciclovir and penciclovir levels were measured via HPLC and fluorescence detection. Pharmacokinetic analysis was completed in the summer of 2021 using noncompartmental analysis and nonlinear mixed-effects modeling. RESULTS: Famciclovir was not detected in any sample, suggesting complete metabolism. Key pharmacokinetic parameters for penciclovir following oral administration were time to maximum concentration (tmax; 2.12 hours), area under the concentration-versus-time curve (AUC; 33.93 µg·h/mL), maximum observed concentration (Cmax; 3.73 µg/mL), and absorption half-life (t1/2; 0.65 hours). Following rectal administration, the values were: tmax, 0.65 hours; AUC, 15.62 µg·h/mL; Cmax, 2.52 µg/mL; and absorption t1/2, 0.13 hours. CONCLUSIONS: Famciclovir was rapidly metabolized to penciclovir. Oral administration resulted in slower absorption but higher maximum plasma concentration and higher AUC compared to rectal administration. CLINICAL RELEVANCE: African elephants administered famciclovir via oral and rectal routes resulted in measurable serum penciclovir, and these findings may be utilized by clinicians treating viral infections in this species.
Sujet(s)
Aciclovir , Administration par voie rectale , Antiviraux , Éléphants , Famciclovir , Animaux , Famciclovir/pharmacocinétique , Famciclovir/administration et posologie , Éléphants/sang , Administration par voie orale , Mâle , Antiviraux/pharmacocinétique , Antiviraux/administration et posologie , Antiviraux/sang , Femelle , Aciclovir/pharmacocinétique , Aciclovir/administration et posologie , Aciclovir/sang , Aciclovir/analogues et dérivés , Guanine/analogues et dérivés , Guanine/pharmacocinétique , Guanine/administration et posologie , Aire sous la courbe , PériodeRÉSUMÉ
Per the well-known resistance of hepatitis B virus to nucleoside/nucleotide analogs, alternative treatment options with higher resistance barriers have been approved for use in both treatment-naïve and lamivudine-resistant hepatitis B virus infections. This phase I study was conducted in adults with normal and impaired renal function to evaluate the effect of renal impairment on the pharmacokinetics of besifovir, a prodrug of an acyclic nucleotide phosphonate, that is mainly cleared via renal excretion. An open-label, single-dose parallel-group clinical study was conducted in subjects with normal renal function and mild, moderate, and severe renal impairment. Subjects received a single oral dose of besifovir dipivoxil 150 mg, and serial blood and urine samples were collected for up to 72 hours after dosing to assess the pharmacokinetic characteristics of besifovir. The extent of plasma exposure of besifovir, detected as its major and active metabolites, LB80331 and LB80317, respectively, increased with worsening renal function. Compared to the subjects with normal renal function, the mean areas under the concentration-time curves of LB80331 increased by 1.5-, 2.5-, and 4.5-fold in subjects with mild, moderate, and severe impairment, respectively. LB80317 showed a 1.8-, 3.2-, and 6.2-fold increase in subjects with mild, moderate, and severe renal impairment compared to those with normal function. The ratios of LB80331 renal clearance and the average estimated glomerular filtration rate of each renal impairment group with respect to the normal group were similar. The increase in plasma exposure and decrease in renal clearance suggest the need to adjust dosage regimens in patients with moderate to severe renal impairment.
Sujet(s)
Antiviraux/pharmacocinétique , Guanine/analogues et dérivés , Phosphonates/pharmacocinétique , Insuffisance rénale/épidémiologie , Insuffisance rénale/métabolisme , Adulte , Antiviraux/sang , Antiviraux/usage thérapeutique , Antiviraux/urine , Aire sous la courbe , Femelle , Débit de filtration glomérulaire , Guanine/sang , Guanine/pharmacocinétique , Guanine/usage thérapeutique , Guanine/urine , Hépatite B/traitement médicamenteux , Hépatite B/épidémiologie , Humains , Rein/métabolisme , Tests de la fonction rénale , Mâle , Adulte d'âge moyen , Modèles biologiques , Phosphonates/sang , Phosphonates/usage thérapeutique , Phosphonates/urine , Acuité des besoins du patient , Jeune adulteRÉSUMÉ
Herpes labialis, caused by herpes simplex virus type 1, is usually characterized by painful skin or mucosal lesions. Penciclovir (PV) tablets are found to be effective against herpes labialis but suffer from poor oral bioavailability. This study aimed to combine the benefits of PV and lavender oil (LO), which exhibits anesthetic activity, in the form of a self-nanoemulsifying drug delivery system (SNEDDS) for the treatment of herpes labialis. Toward this purpose, LO (oil), Labrasol:Labrafil M1944 CS in the ratio of 6:4 (surfactant mixture), and Lauroglycol-FCC (co-surfactant, selected based on the solubility of PV) were evaluated as the independent factors using a distance quadratic mixture design. The formulation was optimized for the minimum globule size and maximum stability index and was determined to contain 14% LO, 40.5% Labrasol:Labrafil 1944 (6:4), and 45.5% Lauroglycol-FCC. The optimized PV-LO-SNEDDS was embedded in chitosan hydrogel and the resulting formulations coded by (O3) were prepared and evaluated. The rheological studies demonstrated a combined pseudoplastic and thixotropic behavior with the highest flux of PV permeation across sheep buccal mucosa. Compared to a marketed 1% PV cream, the O3 formulation exhibited a significantly higher and sustained PV release, nearly twice the PV permeability, and a relative bioavailability of 180%. Overall, results confirm that the O3 formulation can provide an efficient delivery system for PV to reach oral mucosa and subsequent prolonged PV release. Thus, the PV-LO-SNEDDS embedded oral gel is promising and can be further evaluated in clinical settings to establish its therapeutic use in herpes labialis.
Sujet(s)
Guanine/pharmacologie , Herpès labial/traitement médicamenteux , Nanoparticules/composition chimique , Huile essentielle/pharmacologie , Huiles végétales/pharmacologie , Administration par voie topique , Animaux , Chimie pharmaceutique , Chitosane/composition chimique , Préparations à action retardée , Systèmes de délivrance de médicaments , Libération de médicament , Stabilité de médicament , Émulsions/composition chimique , Glycérides/composition chimique , Guanine/administration et posologie , Guanine/pharmacocinétique , Hydrogels/composition chimique , Lavandula , Mâle , Huile essentielle/administration et posologie , Huile essentielle/effets indésirables , Taille de particule , Huiles végétales/administration et posologie , Huiles végétales/effets indésirables , Rats , Rat Wistar , Rhéologie , OvisRÉSUMÉ
Recently published work suggests that highly permeable low-molecular-weight (LMW) acidic drugs are transported by organic anion transporter 2 (OAT2). However, an asymmetric distribution of ionizable drugs in subcellular organelles where pH gradients are significant may occur in the presence of an inhibitor relative to its absence (e.g., lysosomal trapping). In the present study, OAT2-mediated transport of highly permeable LMW anions could not be demonstrated using OAT2 transfected cells, despite robust transport of the OAT2 substrate penciclovir. Moreover, a rifamycin SV (RifSV)-dependent reduction in the accumulation of highly permeable LMW anions previously observed in hepatocytes could be qualitatively reproduced using HepG2 cells and also in Madin-Darby canine kidney (MDCK) cells, which lack expression of OAT2. Neither HepG2 nor MDCK cells demonstrated meaningful penciclovir transport, nor was the cellular accumulation of the highly permeable LMW anions sensitive to competitive inhibition by the neutral OAT2 substrate penciclovir. Both cell lines, however, demonstrated sensitivity to the mitochondrial uncoupler p-trifluoromethoxy carbonyl cyanide phenyl hydrazone (FCCP) in a manner similar to RifSV. Furthermore, the transepithelial MDCK permeability of the highly permeable LMW anions was measured in the absence and presence of RifSV and FCCP at concentrations that reduced the cellular accumulation of anions. Neither inhibitor, nor the OAT2 inhibitor ketoprofen, reduced the transepithelial flux of the anions as would be anticipated for transported substrate inhibition. The findings presented here are aligned with cellular accumulation of highly permeable LMW anions being significantly determined by ion trapping sensitive to mitochondrial uncoupling, rather than the result of OAT2-mediated transport. SIGNIFICANCE STATEMENT: The manuscript illustrates that passive influx and ion trapping are more relevant to the cellular accumulation of highly permeable low-molecular-weight acidic drugs than is the previously proposed mechanism of OAT2-mediated transport. The outcome illustrated here highlights a rare, and perhaps previously not reported, observation of anionic drug trapping in a compartment sensitive to mitochondrial uncoupling (e.g., the mitochondrial matrix) that may be confused for transporter-mediated uptake.
Sujet(s)
Transport biologique/physiologie , Guanine , Mitochondries du foie/physiologie , Membranes mitochondriales/physiologie , Transporteurs d'anions organiques sodium-indépendants/métabolisme , Animaux , Antiviraux/composition chimique , Antiviraux/pharmacocinétique , Lignée cellulaire , Chiens , Guanine/composition chimique , Guanine/pharmacocinétique , Humains , Concentration en ions d'hydrogène , PerméabilitéRÉSUMÉ
Background/Aims: Clinical equivalence of generic antiviral agents for chronic hepatitis B (CHB) has not been demonstrated, particularly in cases with previous antiviral resistance. Entecavir 1 mg is prescribed frequently as a mono- or combination therapy in antiviral-resistant CHB patients. This study evaluated the efficacy and safety of switching to generic entecavir 1 mg (Baracle®) in CHB patients taking brand-name entecavir 1 mg (Baraclude®) alone or in combination with other nucleotide analogs after the development of antiviral resistance. Methods: This study was a single-arm prospective study. The primary endpoint was undetectable HBV DNA (<20 IU/mL) at 12 months after switching treatment. The biochemical and serologic responses, virologic breakthrough, and antiviral resistance rates were also evaluated. Results: Forty CHB patients with undetectable HBV DNA through the brand-name entecavir 1 mg treatment as a mono- or combination therapy after developing antiviral resistance to nucleos(t)ide analogs were enrolled in this study. No significant difference in the HBV DNA non-detection rate was observed between the baseline and 12 months after switching therapy (p=0.324). Furthermore, non-inferiority of the generic entecavir 1 mg to the brand-name entecavir 1 mg with 10% margin in maintaining undetectable HBV DNA was demonstrated (95% CI -2.80 to 8.20%). Similarly, no difference in the biochemical response rate was observed after switching therapy. Serum hepatitis B e antigen loss was observed in 12.5%. No virologic breakthrough was reported. Conclusions: Generic entecavir 1 mg is a reasonable alternative to the brand-name entecavir 1 mg in antiviral-resistant CHB patients with viral suppression.
Sujet(s)
Antiviraux , ADN viral , Résistance virale aux médicaments , Guanine/analogues et dérivés , Virus de l'hépatite B , Hépatite B chronique , Adulte , Antiviraux/effets indésirables , Antiviraux/pharmacocinétique , Antiviraux/usage thérapeutique , ADN viral/sang , Substitution de médicament , Médicaments génériques/effets indésirables , Médicaments génériques/pharmacocinétique , Médicaments génériques/usage thérapeutique , Femelle , Guanine/effets indésirables , Guanine/pharmacocinétique , Guanine/usage thérapeutique , Virus de l'hépatite B/effets des médicaments et des substances chimiques , Virus de l'hépatite B/génétique , Virus de l'hépatite B/isolement et purification , Hépatite B chronique/sang , Hépatite B chronique/traitement médicamenteux , Hépatite B chronique/virologie , Humains , Mâle , Adulte d'âge moyen , Études prospectives , Équivalence thérapeutique , Résultat thérapeutiqueRÉSUMÉ
The estimation of the drug clearance by aldehyde oxidase (AO) has been complicated because of this enzyme's atypical kinetics and species and substrate specificity. Since human AO (hAO) and cynomolgus monkey AO (mAO) have a 95.1% sequence identity, cynomolgus monkeys may be the best species for estimating AO clearance in humans. Here, O6-benzylguanine (O6BG) and dantrolene were used under anaerobic conditions, as oxidative and reductive substrates of AO, respectively, to compare and contrast the kinetics of these two species through numerical modeling. Whereas dantrolene reduction followed the same linear kinetics in both species, the oxidation rate of O6BG was also linear in mAO and did not follow the already established biphasic kinetics of hAO. In an attempt to determine why hAO and mAO are kinetically distinct, we have altered the hAO V811 and F885 amino acids at the oxidation site adjacent to the molybdenum pterin cofactor to the corresponding alanine and leucine in mAO, respectively. Although some shift to a more monkey-like kinetics was observed for the V811A mutant, five more mutations around the AO cofactors still need to be investigated for this purpose. In comparing the oxidative and reductive rates of metabolism under anaerobic conditions, we have come to the conclusion that despite having similar rates of reduction (4-fold difference), the oxidation rate in mAO is more than 50-fold slower than hAO. This finding implies that the presence of nonlinearity in AO kinetics is dependent upon the degree of imbalance between the rates of oxidation and reduction in this enzyme. SIGNIFICANCE STATEMENT: Although they have as much as 95.1% sequence identity, human and cynomolgus monkey aldehyde oxidase are kinetically distinct. Therefore, monkeys may not be good estimators of drug clearance in humans.
Sujet(s)
Aldehyde oxidase/métabolisme , Coenzymes/métabolisme , Métalloprotéines/métabolisme , Ptéridines/métabolisme , Aldehyde oxidase/génétique , Animaux , Dantrolène/pharmacocinétique , Évaluation préclinique de médicament/méthodes , Guanine/analogues et dérivés , Guanine/pharmacocinétique , Macaca fascicularis/génétique , Cofacteurs à molybdène , Mutagenèse dirigée , Oxydoréduction , Similitude de séquences d'acides aminés , Spécificité d'espèce , Spécificité du substrat/génétiqueSujet(s)
Antiviraux/administration et posologie , Guanine/analogues et dérivés , Hépatite B chronique/traitement médicamenteux , Hépatite D chronique/traitement médicamenteux , Cirrhose du foie/traitement médicamenteux , Antiviraux/sang , Antiviraux/pharmacocinétique , Co-infection/complications , Co-infection/traitement médicamenteux , Guanine/administration et posologie , Guanine/sang , Guanine/pharmacocinétique , Virus de l'hépatite B/effets des médicaments et des substances chimiques , Hépatite B chronique/complications , Hépatite D chronique/complications , Humains , Cirrhose du foie/complications , Cirrhose du foie/virologie , Mâle , Adulte d'âge moyen , Résultat thérapeutiqueRÉSUMÉ
O6 -benzylguanine (O6 BG) is an inhibitor of O6 -alkylguanine-DNA alkyltransferase (AGT). It binds to AGT by transferring its benzyl moiety to the cysteine residue at the active site of the enzyme. O6 BG synergizes the cytotoxic effects of alkylating agents by halting AGT-mediated DNA repair. O6 -benzyl-8-oxoguanine (8-oxo-O6 BG) is a metabolite of O6 BG, which is an equally potent inhibitor of AGT. In this work, we report the development and validation of an LC-MS/MS method for simultaneous determination of O6 BG and 8-oxo-O6 BG in human plasma. O6 BG and 8-oxo-O6 BG along with the analog internal standard, pCl-O6 BG, were extracted from alkalinized human plasma by liquid-liquid extraction using ethyl acetate, dried under nitrogen and reconstituted in the mobile phase. Reverse-phase chromatographic separation was achieved using isocratic elution with a mobile phase containing 80% acetonitrile and 0.05% formic acid in water at a flow rate of 0.600 ml/min. Quantification was performed using multiple-reaction-monitoring mode with positive ion-spray ionization. The linear calibration ranges of the method for O6 BG and 8-oxo-O6 BG were 1.25-250 ng/ml and 5.00-1.00 × 103 ng/ml, respectively, with acceptable assay accuracy, precision, recovery and matrix factor. This method was applied to the measurement of O6 BG and 8-oxo-O6 BG in patient plasma samples from a prior phase I clinical trial.
Sujet(s)
Chromatographie en phase liquide/méthodes , Guanine/analogues et dérivés , Spectrométrie de masse en tandem/méthodes , Guanine/sang , Guanine/composition chimique , Guanine/pharmacocinétique , Humains , Limite de détection , Modèles linéaires , Extraction liquide-liquide , Reproductibilité des résultatsRÉSUMÉ
To avoid severe exacerbations in the load of hepatitis B virus (HBV) as a consequence of discontinuous use of anti-HBV drugs, entecavir (ETV), the first-line anti-HBV drug, was primally formulated as extended-release poly (lactic-co-glycolic acid) microspheres in the present study. Because ETV is slightly soluble in water and in some other organic solvents used for microsphere preparation, methods for solid-microencapsulation were employed to fabricate the ETV microspheres. The optimized microspheres were evaluated for their morphology, particle size, drug loading, in vitro drug release, and in vivo pharmacokinetics in rats. The optimized formulation was found to have a mean particle size of 86⯵m and drug loading of 13%. Differential scanning calorimetry and powder X-ray diffraction indicated that ETV existed in crystal, amorphous, and molecular states in the microspheres. In vitro and in vivo release revealed that the dissolution of ETV dominated the release process. The morphology of the microspheres and changes in the morphology during in vitro release were assessed by scanning electron microscopy. The novel ETV-MS described in this study should have great potential for clinical use as an alternative treatment against HBV.
Sujet(s)
Antiviraux/administration et posologie , Vecteurs de médicaments/composition chimique , Guanine/analogues et dérivés , Copolymère d'acide poly(lactique-co-glycolique)/composition chimique , Animaux , Antiviraux/pharmacocinétique , Calorimétrie différentielle à balayage , Chimie pharmaceutique/méthodes , Modèles animaux de maladie humaine , Libération de médicament , Guanine/administration et posologie , Guanine/pharmacocinétique , Hépatite B chronique/traitement médicamenteux , Mâle , Microscopie électronique à balayage , Microsphères , Taille de particule , Rats , Rat Sprague-Dawley , Facteurs temps , Diffraction des rayons XRÉSUMÉ
Localized drug delivery systems (DDSs) provide therapeutic levels of drug agent while mitigating side effects of systemic delivery. These systems offer controlled release over extended periods of time making them attractive therapies. Monitoring drug dissolution is vital for developing safe and effective means of drug delivery. Currently, dissolution characterization methods are limited to bulk analysis and cannot provide dissolution kinetics at high spatial resolution. However, dissolution rates of drug particles can be heterogeneous with influences from many factors. Insights into finer spatiotemporal dynamics of single particle dissolution could potentially improve pharmacokinetic modeling of dissolution for future drug development. In this work, we demonstrate high-resolution chemical mapping of entecavir, a hepatitis B antiviral drug, embedded in a slow release poly(d,l-lactic acid) formulation with stimulated Raman scattering (SRS) microscopy. By tracking the volume change of individual micron-sized drug particles within the polymer matrix, we establish an analytical protocol for quantitatively profiling dissolution of single crystalline particles in implant formulations in an in situ manner.
Sujet(s)
Vecteurs de médicaments/composition chimique , Implant pharmaceutique/pharmacocinétique , Libération de médicament , Guanine/analogues et dérivés , Chimie pharmaceutique/méthodes , Implant pharmaceutique/administration et posologie , Guanine/administration et posologie , Guanine/pharmacocinétique , Microscopie/méthodes , Taille de particule , Polyesters/composition chimique , Analyse spectrale Raman/méthodesRÉSUMÉ
Hepatitis B, one of the most common contagious viral hepatitis with high infection rate, is challenging to treat. Although the treatment for hepatitis B has been improved over the years, many therapeutic drugs still have either severe adverse effects or insufficient effectiveness via systemic administration. In this study, we confirmed that glycyrrhetinic acid can enhance the accumulation of entecavir in HepaRG cell and liver. Then we constructed a novel albumin nanoparticle co-loading entecavir and glycyrrhetinic acid (ETV-GA-AN) to improve liver accumulation of entecavir and investigated its ability to deliver both drugs to liver. In vitro cellular uptake study and in vivo tissue distribution experiment showed that these negatively charged ETV-GA-AN (112 ± 2 nm in diameter) can increase the accumulation of entecavir in hepatic HepaRG cells and improve entecavir distribution in liver. We also revealed the mechanism that glycyrrhetinic acid enhances intracellular accumulation of entecavir by inhibiting the activity of specific efflux transporters. Our delivery system is the first liver-targeted albumin nanoparticle that utilizes the site-specific co-delivery strategy to delivery entecavir and glycyrrhetinic acid. As it combines high efficiency and low toxicity, it possess great potential for treating hepatitis B.
Sujet(s)
Albumines/composition chimique , Antiviraux/pharmacocinétique , Guanine/analogues et dérivés , Foie/métabolisme , Nanoparticules/composition chimique , Animaux , Antiviraux/usage thérapeutique , Technique de Western , Chromatographie en phase liquide , Énoxolone/administration et posologie , Énoxolone/pharmacocinétique , Énoxolone/usage thérapeutique , Guanine/administration et posologie , Guanine/pharmacocinétique , Guanine/usage thérapeutique , Cellules HepG2 , Hépatite B , Humains , Foie/effets des médicaments et des substances chimiques , Foie/anatomopathologie , Tumeurs du foie/traitement médicamenteux , Tumeurs du foie/métabolisme , Mâle , Rats , Rat Wistar , RT-PCR , Spectrométrie de masse en tandemRÉSUMÉ
The objectives of this study were to formulate microcrystals of entecavir-3-palmiate (EV-P), a palmitic acid ester of entecavir (EV), and evaluate the influence of particle size on its pharmacokinetic behavior following subcutaneous (SC) injection. Systemic toxicity and local tolerability of the hepatitis B anti-viral suspension were further evaluated in normal rats. EV-P microcrystals possessing median diameters of 2.1, 6.3, and 12.7⯵m were fabricated using anti-solvent crystallization technique with polysorbate 20 and polyethylene glycol 4000 as steric stabilizer. Dissolution rate of EV-P microcrystals was controlled by adjusting the particle size, under sink condition. Pharmacokinetic profiles of 2.1⯵m-sized and 6.3⯵m-sized EV-P microcrystals were quite comparable (1.44â¯mg/kg as EV), over 46â¯days in rats. The absorption rate and extent of EV after SC injection of 12.7⯵m-sized microcrystals were significantly retarded, due to its slower dissolution rate in aqueous media. No single-dose systemic toxicity was observed after SC injection of high dose of EV-P microcrystal suspension (30-300â¯mg/kg as EV). The microcrystals were tolerable in the injected site, showing mild inflammatory responses at a dose of 30â¯mg/kg. Therefore, the novel microcrystal system with median particle size of below 6.3⯵m is expected to be a unique long-acting system of the anti-viral agent, improving patient's compliance with chronic disease.
Sujet(s)
Antiviraux/administration et posologie , Systèmes de délivrance de médicaments , Guanine/analogues et dérivés , Acides palmitiques/composition chimique , Animaux , Antiviraux/composition chimique , Antiviraux/pharmacocinétique , Chimie pharmaceutique/méthodes , Cristallisation , Préparations à action retardée , Guanine/administration et posologie , Guanine/composition chimique , Guanine/pharmacocinétique , Injections sous-cutanées , Mâle , Taille de particule , Polyéthylène glycols/composition chimique , Polysorbates/composition chimique , Rats , Rat Sprague-Dawley , SuspensionsRÉSUMÉ
Entecavir (EV), an anti-viral agent for hepatitis B infection, should be administered under fasted state, as intestinal absorption of this hydrophilic compound is markedly decreased under post-prandial conditions. Herein, in order to improve therapeutic adherence, a parenteral sustained delivery system was constructed, by synthesizing water-insoluble ester prodrugs of the nucleotide analogous with fatty acids. EV-3-palmitate (named EV-P), exhibited the lowest solubility in phosphate buffered saline (pH 7.4, 1.1⯵g/ml), with extended release profile compared with EV, EV-3-myristate, and EV-3-stearate, was selected as a candidate to formulate drug suspension. The crystalline suspension was fabricated using anti-solvent crystallization technique, with a mean particle size of 7.7⯵m. After subcutaneous (SC) injection in beagle dogs (0.43â¯mg/kg as EV), the plasma concentrations of EV were markedly protracted with lowered maximum plasma concentration (Cmax, 4.7â¯ng/ml), extended time required to reach Cmax (Tmax, 9.0â¯days), and lengthened elimination half-life (T1/2, 129.3â¯h) compared with those after oral administration (0.0154â¯mg/kg, Cmax, 15.4â¯ng/ml; Tmax, 0.01â¯days; T1/2, 4.1â¯h). The systemic exposure of the lipidic prodrug was below 0.1% compared with that of EV following SC injection, denoting that EV-P was rapidly converted into the parent compound in blood. Therefore, SC delivery of EV-P microsuspension can be an alternative to oral EV therapy, offering prolonged pharmacokinetic profile after single injection.
Sujet(s)
Antiviraux/administration et posologie , Acides gras/administration et posologie , Guanine/analogues et dérivés , Promédicaments/administration et posologie , Animaux , Antiviraux/pharmacocinétique , Préparations à action retardée/administration et posologie , Préparations à action retardée/pharmacocinétique , Chiens , Libération de médicament , Esters , Acides gras/pharmacocinétique , Guanine/administration et posologie , Guanine/pharmacocinétique , Injections sous-cutanées , Mâle , Promédicaments/pharmacocinétique , SuspensionsRÉSUMÉ
Multidrug resistance protein 4 (MRP4) is capable of transporting acyclic nucleotide phosphonates, but little is known about its role in lamivudine (LAM) and entecavir (ETV) transport. In the present study, the involvement of MRP4 in the transport of LAM and ETV was investigated through in vitro experiments. The cytotoxicity of three antiviral drugs and their activities against HBV as characterized in HepG2.4D14 [wildtype hepatitis B virus (HBV)] and HepG2.A64 (ETVresistant HBV) cells. LAM, ETV and tenofovir (TFV) demonstrated a 50% effective concentration against HBV of 4.14±0.03, 0.13±0.02 and 3.24±0.01 µM in HepG2.4D14 cells and of 5.94±0.20, 6.28±0.07 and 11.43±0.09 µM in HepG2.A64 cells, respectively. After administering 3-([(3-(2-[7-chloro-2-quinolinyl]ethyl)phenyl]-[(3-dimethylamino-3-oxoporphyl)-thio)-methyl]-thio) propanoic acid (MK571), the intracellular concentrations of all three drugs were much lower than the extracellular drug concentrations in these two cell types, whereas the intracellular drug concentrations in wildtype cells were higher than those in ETVresistant cells. Furthermore, the intracellular levels of LAM, ETV and TFV were enhanced and the extracellular concentrations were reduced by addition of MK571. Thus, MRP4 is mainly responsible for the efflux of LAM and ETV in hepatocyte cultures. These results may contribute to enhancing antiviral efficacy.
Sujet(s)
Antiviraux/pharmacocinétique , Guanine/analogues et dérivés , Hépatocytes/métabolisme , Lamivudine/pharmacocinétique , Protéines associées à la multirésistance aux médicaments/métabolisme , Antiviraux/pharmacologie , Transport biologique , Guanine/pharmacocinétique , Guanine/pharmacologie , Cellules HepG2 , Hépatite B/traitement médicamenteux , Virus de l'hépatite B/effets des médicaments et des substances chimiques , Hépatocytes/virologie , Humains , Lamivudine/pharmacologieRÉSUMÉ
A simple and fast ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated to determine entecavir in human plasma with the stable isotopically labeled internal standard entecavir-13C215N. Samples (100 µL each) were pretreated by protein precipitation with methanol, and then separated on an ACQUITY UPLC BEH C18 analytical column (2.1 × 50 mm, 1.7 µm) with a simple isocratic elution. The detection was operated by a positive ionization electrospray mass spectrometry in multiple reaction monitoring mode. The method had a short chromatographic run time of 2 minutes, and obtained sharp peaks of entecavir and the internal standard. Good linearity was found within 0.1 - 20 ng/mL. The intra- and inter-day precision and accuracy met the acceptance criteria, and no matrix effect was observed. This method was successfully applied in a bioequivalence study of two kinds of entecavir tablets in healthy Chinese volunteers. And the results showed that no significant differences were found between the test and reference preparations in pharmacokinetic parameters (p > 0.05) by ANOVA. The 90% confidence intervals for the geometric mean ratios (test/reference) of Cmax, AUC0-tlast, and AUC0-∞ fell within the bioequivalence acceptance criteria (80 - 125%). No significant difference was found in tmax between the two preparations. The two one-sided t-tests showed that these two products were bioequivalent.â©.
Sujet(s)
Chromatographie en phase liquide à haute performance/méthodes , Guanine/analogues et dérivés , Spectrométrie de masse en tandem/méthodes , Guanine/sang , Guanine/pharmacocinétique , Humains , Équivalence thérapeutiqueRÉSUMÉ
1. Failure to predict human pharmacokinetics of aldehyde oxidase (AO) substrates using traditional allometry has been attributed to species differences in AO metabolism. 2. To identify appropriate species for predicting human in vivo clearance by single-species scaling (SSS) or multispecies allometry (MA), we scaled in vitro intrinsic clearance (CLint) of five AO substrates obtained from hepatic S9 of mouse, rat, guinea pig, monkey and minipig to human in vitro CLint. 3. When predicting human in vitro CLint, average absolute fold-error was ≤2.0 by SSS with monkey, minipig and guinea pig (rat/mouse >3.0) and was <3.0 by most MA species combinations (including rat/mouse combinations). 4. Interspecies variables, including fraction metabolized by AO (Fm,AO) and hepatic extraction ratios (E) were estimated in vitro. SSS prediction fold-errors correlated with the animal:human ratio of E (r2 = 0.6488), but not Fm,AO (r2 = 0.0051). 5. Using plasma clearance (CLp) from the literature, SSS with monkey was superior to rat or mouse at predicting human CLp of BIBX1382 and zoniporide, consistent with in vitro SSS assessments. 6. Evaluation of in vitro allometry, Fm,AO and E may prove useful to guide selection of suitable species for traditional allometry and prediction of human pharmacokinetics of AO substrates.
Sujet(s)
Aldehyde oxidase/métabolisme , Foie/effets des médicaments et des substances chimiques , Foie/métabolisme , Pharmacocinétique , Acétamides/pharmacocinétique , Animaux , Femelle , Guanidines/pharmacocinétique , Guanine/analogues et dérivés , Guanine/métabolisme , Guanine/pharmacocinétique , Cochons d'Inde , Humains , Macaca fascicularis , Macaca mulatta , Mâle , Souris , Pyrazoles/pharmacocinétique , Pyridazines/pharmacocinétique , Pyrimidines/pharmacocinétique , Rat Sprague-Dawley , Spécificité d'espèce , Suidae , Porc miniature , Triazoles/pharmacocinétiqueRÉSUMÉ
INTRODUCTION: Besifovir (LB80380) is a relatively new oral acyclic nucleotide phosphonate. We reviewed the pharmacokinetic characteristics of LB80380 and discussed its role in the treatment of chronic hepatitis B infection. Areas covered: LB80380 is a prodrug of LB80331 and LB80317. It is rapidly absorbed when taken orally. Escalating doses of besifovir produce linear increase of the plasma concentration. Doses above 60mg are effective for inhibiting HBV in human. Using 60mg as an example, the maximal concentration of LB80331 in plasma is 397 ng/mL. The time required to reach maximal concentration in plasma and elimination half-life are 2.0 and 3.0 h, respectively. Besifovir and its metabolites are mainly excreted via the kidneys. Its antiviral efficacy is non-inferior to ETV 0.5mg daily. It is generally safe in terms of renal and bone toxicity. The most common adverse event is carnitine depletion which affects almost all patients on besifovir requiring carnitine supplementation. Expert opinion: Besifovir demonstrated predictable pharmacokinetic characteristics in human subjects. Few clinical studies on besifovir have been conducted. More data are expected particularly for special populations. The adverse events upon long term exposure should be monitored. Large scale head-to-head trials comparing besifovir with existing NA, especially tenofovir alafenamide, should be conducted.
Sujet(s)
Antiviraux/administration et posologie , Guanine/analogues et dérivés , Hépatite B chronique/traitement médicamenteux , Phosphonates/administration et posologie , Administration par voie orale , Animaux , Antiviraux/effets indésirables , Antiviraux/pharmacocinétique , Relation dose-effet des médicaments , Guanine/administration et posologie , Guanine/effets indésirables , Guanine/pharmacocinétique , Période , Humains , Phosphonates/effets indésirables , Phosphonates/pharmacocinétique , PromédicamentsRÉSUMÉ
Entecavir (ETV) is a superior nucleoside analogue used to treat hepatitis B virus (HBV) infection. Although its advantages over other agents include low viral resistance and the elicitation of a sharp decrease in HBV DNA, adverse effects such as hepatic steatosis, hepatic damage and lactic acidosis have also been reported. Glycyrrhizin has long been used as hepato-protective medicine. The clinical combination of ETV plus glycyrrhizin in China displays better therapeutic effects and lower rates of liver damage. However, there is little evidence explaining the probable synergistic mechanism that exists between these two drugs from a pharmacokinetics view. Here, alterations in the plasma pharmacokinetics, tissue distribution, subcellular distribution, and in vitro and in vivo antiviral activity of ETV after combination with glycyrrhizic acid (GL) were analysed to determine the synergistic mechanisms of these two drugs. Specific efflux transporter membrane vesicles were also used to elucidate their interactions. The primary active GL metabolite, glycyrrhetic acid (GA), did not affect the plasma pharmacokinetics of ETV but promoted its accumulation in hepatocytes, increasing its distribution in the cytoplasm and nucleus and augmenting the antiviral efficiency of ETV. These synergistic actions were primarily due to the inhibitory effect of GA on MRP4 and BCRP, which transport ETV out of hepatocytes. In conclusion, GA interacted with ETV at cellular and subcellular levels in the liver through MRP4 and BCRP inhibition, which enhanced the antiviral activity of ETV. Our results partially explain the synergistic mechanism of ETV and GL from a pharmacokinetics view, providing more data to support the use of these compounds together in clinical HBV treatment.
Sujet(s)
Antiviraux/usage thérapeutique , Énoxolone/pharmacologie , Acide glycyrrhizique/pharmacologie , Guanine/analogues et dérivés , Hépatite B/traitement médicamenteux , Animaux , Antiviraux/sang , Antiviraux/pharmacocinétique , Cellules cultivées , ADN viral/sang , Interactions médicamenteuses , Acide glycyrrhizique/sang , Acide glycyrrhizique/pharmacocinétique , Guanine/sang , Guanine/pharmacocinétique , Guanine/usage thérapeutique , Cellules HepG2 , Hépatite B/sang , Virus de l'hépatite B/génétique , Hépatocytes/métabolisme , Humains , Foie/métabolisme , Mâle , Protéines de transport membranaire/génétique , Souris transgéniques , Rat Sprague-DawleyRÉSUMÉ
α-Carboxy nucleoside phosphonates (α-CNPs) are modified nucleotides that represent a novel class of nucleotide-competing reverse transcriptase (RT) inhibitors (NcRTIs). They were designed to act directly against HIV-1 RT without the need for prior activation (phosphorylation). In this respect, they differ from the nucleoside or nucleotide RTIs [N(t)RTIs] that require conversion to their triphosphate forms before being inhibitory to HIV-1 RT. The guanine derivative (G-α-CNP) has now been synthesized and investigated for the first time. The (L)-(+)-enantiomer of G-α-CNP directly and competitively inhibits HIV-1 RT by interacting with the substrate active site of the enzyme. The (D)-(-)-enantiomer proved inactive against HIV-1 RT. In contrast, the (+)- and (-)-enantiomers of G-α-CNP inhibited herpes (i.e. HSV-1, HCMV) DNA polymerases in a non- or uncompetitive manner, strongly indicating interaction of the (L)-(+)- and the (D)-(-)-G-α-CNPs at a location different from the polymerase substrate active site of the herpes enzymes. Such entirely different inhibition profile of viral polymerases is unprecedented for a single antiviral drug molecule. Moreover, within the class of α-CNPs, subtle differences in their sensitivity to mutant HIV-1 RT enzymes were observed depending on the nature of the nucleobase in the α-CNP molecules. The unique properties of the α-CNPs make this class of compounds, including G-α-CNP, direct acting inhibitors of multiple viral DNA polymerases.