Valganciclovir

Valganciclovir is a prodrug of ganciclovir which has been developed for the treatment of cytomegalovirus (CMV) retinitis in patients with AIDS. Oral valganciclovir is rapidly absorbed and hydrolysed to ganciclovir. The oral bioavailability of ganciclovir after oral valganciclovir administration is high. Oral valganciclovir 900 mg provides a daily exposure of ganciclovir comparable to that of intravenous ganciclovir 5 mg/kg. A single, randomised, nonblind study indicated that oral valganciclovir (900mg twice daily for 3 weeks then 900 mg once daily) and intravenous ganciclovir (5 mg/kg twice daily for 3 weeks then 5 mg/kg once daily) were equally effective in the treatment of newly diagnosed CMV retinitis in 160 patients with AIDS. Valganciclovir appears to have a similar tolerability profile to intravenous ganciclovir during induction therapy in patients with AIDS and newly diagnosed CMV retinitis. During maintenance therapy with valganciclovir, the most commonly reported adverse events included neutropenia, anaemia, thrombocytopenia, gastrointestinal (including diarrhoea, nausea, vomiting and abdominal pain), fever, headache, insomnia, peripheral neuropathy, paraesthesia and retinal detachment.     

Valganciclovir: new preparation. CMV retinitis: a simpler,oral treatment

For AIDS patients with cytomegalovirus (CMV) retinitis, the standard initial treatment has so far been ganciclovir or foscarnet, both of which are infused intravenously. The choice between these two antiviral agents is based on their differing side effects. Maintenance treatment is based on ganciclovir or foscarnet, but both these drugs must be given as daily intravenous infusions. Oral ganciclovir is less effective. Intraocular maintenance treatment in appropriate only for patients with localised infections and a low risk of relapse. Valganciclovir can be taken orally for both initial and maintenance treatment of CMV retinitis. Valganciclovir has good bioavailability and is rapidly metabolised into ganciclovir. A comparative randomised trial in 160 patients showed that oral valganciclovir is as effective as intravenous ganciclovir when used as an initial treatment. There are no comparative trials of oral valganciclovir as a maintenance treatment, but non comparative data and pharmacokinetic studies suggest that oral valganciclovir is about as effective as intravenous ganciclovir. The adverse effects of oral valganciclovir are similar to those of intravenous ganciclovir, except that the oral route avoids the risk of local complications at the infusion site. Valganciclovir causes more frequent diarrhoea and oral candidosis than intravenous ganciclovir. In practice, for patients with CMV retinitis who require systemic treatment, oral valganciclovir is easier to use and, in our opinion, should now replace IV ganciclovir for both initial and maintenance treatment. The convenience of oral valganciclovir should also limit the use of purely intraocular treatment of CMV retinitis.     

Pharmacokinetic profile of ganciclovir after its oral administration and from its prodrug, valganciclovir, in solid organ transplant recipients

BACKGROUND: Valganciclovir (Valcyte) has recently been approved for the prevention of cytomegalovirus (CMV) disease in high-risk (CMV donor positive [D+]/recipient negative [R-]) solid organ transplant (SOT) recipients. Large-scale studies describing the pharmacokinetics of valganciclovir in SOT recipients are lacking. A recent randomised, double-blind study of valganciclovir in 364 D+/R- (intent-to-treat population) SOT recipients provided valuable data on which a population pharmacokinetic analysis was performed. METHODS: The pharmacokinetics of ganciclovir from oral ganciclovir (Cymevene, 1000 mg three times daily) and from valganciclovir (900 mg once daily) were described with plasma levels from 240 patients (1181 datapoints describing 449 pharmacokinetic profiles) using nonlinear mixed-effects modelling (NONMEM) software. A two-compartment pharmacokinetic model with separate absorption/metabolism and absorption parameters for valganciclovir and ganciclovir, respectively, was developed. RESULTS: Exposure to ganciclovir from valganciclovir averaged 1.65-fold greater than that from oral ganciclovir (95% CI 1.58, 1.81); respective daily area under the plasma concentration-time curve values were 46.3 +/- 15.2 microg . h/mL and 28.0 +/- 10.9 microg . h/mL. The relative systemic exposure of ganciclovir was approximately 8-fold higher from valganciclovir than oral ganciclovir. Exposure to ganciclovir from valganciclovir was similar among liver, heart and kidney transplant recipients (46.0 +/- 16.1, 40.2 +/- 11.8 and 48.2 +/- 14.6 microg . h/ mL, respectively). Adherence to the prescribed dosing regimens, which were reduced for renal impairment, gave consistent exposure to ganciclovir. CONCLUSION: Oral valganciclovir produces exposures of ganciclovir exceeding those attained with oral ganciclovir, but in line with those reported after standard intravenous administration of ganciclovir. This indicates that oral valganciclovir is suitable in circumstances requiring prophylactic use of ganciclovir and allows for more convenient management of patients at risk of CMV disease.     

Single-dose pharmacokinetics of valganciclovir in HIV- and CMV-seropositive subjects.

As a result of the low oral bioavailability of ganciclovir, a prodrug was developed to improve the bioavailability of ganciclovir. This study was designed to investigate the fasting, single-dose pharmacokinetics as well as the absolute and relative bioavailability of a valine ester prodrug of ganciclovir, valganciclovir, as compared to oral and intravenous ganciclovir in asymptomatic HIV+ and CMV+ subjects. In this open-label, randomized, three-period crossover study, 18 subjects received, in random order, single oral doses of valganciclovir 360 mg and ganciclovir 1000 mg and an intravenous infusion of ganciclovir 5 mg/kg over 1 hour. Valganciclovir was rapidly and extensively hydrolyzed to ganciclovir, resulting in significantly greater bioavailability compared to 1000 mg oral ganciclovir (60.9% vs. 5.6%, respectively). Higher peak serum concentrations were reached earlier following valganciclovir (ganciclovir [2.98 +/- 0.77 micrograms/mL at 1.0 +/- 0.3 h]) than following oral ganciclovir (0.47 +/- 0.17 microgram/mL and 2.2 +/- 1.0 h). Mean total ganciclovir AUCs following oral ganciclovir (1000 mg) and 360 mg valganciclovir (3.8 +/- 1.2 and 10.8 +/- 1.9 micrograms-h/mL) were less than that following a standard 5 mg/kg intravenous infusion of ganciclovir (25.1 +/- 3.8 micrograms-h/mL). In summary, valganciclovir is a prodrug with a favorable safety profile with enhanced bioavailability and significantly higher serum concentrations of ganciclovir than following oral administration of ganciclovir itself.     

Valganciclovir: a review of its use in the management of CMV infection and disease in immunocompromised patients

Valganciclovir (Valcyte) is an orally administered prodrug of the standard anti-cytomegalovirus (CMV) drug ganciclovir. Valganciclovir is as effective as intravenous ganciclovir for the treatment of AIDS-related CMV retinitis, and oral ganciclovir for the prophylaxis of CMV infection and disease in high-risk solid organ transplant recipients. The drug is generally well tolerated and has a similar tolerability profile to that of oral or intravenous ganciclovir, but is devoid of adverse events related to intravenous or indwelling catheter access associated with the use of intravenous ganciclovir, cidofovir and foscarnet. The simple and convenient once-daily valganciclovir regimen offers potential for improved patient compliance. It provides greater systemic ganciclovir exposure than oral ganciclovir, thus reducing the risk of viral resistance when used for prophylaxis in high-risk solid organ transplant recipients. Furthermore, the use of valganciclovir instead of intravenous ganciclovir may provide significant cost savings, based on data comparing oral versus intravenous regimens for the treatment of AIDS-related CMV retinitis. Overall, valganciclovir appears to have some advantages over ganciclovir. Therefore, when used as prophylaxis against CMV infection and disease in high-risk solid organ transplant recipients or as induction and maintenance therapy of CMV retinitis in patients with AIDS, oral valganciclovir is an attractive alternative to other available anti-CMV drugs.     

Valganciclovir: A new oral alternative for cytomegalovirus retinitis in human immunodeficiency virus-seropositive individuals

Oral valganciclovir recently was approved by the Food and Drug Administration for treatment of cytomegalovirus (CMV) retinitis. We performed MEDLINE (June 1998-May 2002) and AIDSLINE (June 1998-December 2000) searches of available information on valganciclovir, and the drug's prescribing information was used to identify relevant articles. Additional studies, case reports, reviews, and abstracts were identified from references in the reviewed literature. Most of the information was obtained from abstracts or product labeling, since few trials have been published in the medical literature. Valganciclovir is a prodrug of ganciclovir and has been shown to have significantly higher oral absorption than ganciclovir capsules. One short-term study found valganciclovir to be as effective as intravenous ganciclovir in treating CMV retinitis. Recommended dosages for patients with normal renal function are valganciclovir 900 mg twice/day for induction and 900 mg once/day for maintenance. Side effects are similar to those of intravenous ganciclovir and require periodic monitoring of complete blood count and renal function. Given the need for lifelong therapy for CMV retinitis in some human immunodeficiency virus-positive patients, valganciclovir is a welcome alternative to long-term administration of intravenous antivirals.     

口服抗病毒新药——缬更昔洛韦

缬更昔洛韦 (valganciclovir)是抗病毒药更昔洛韦的前体药物 ,用于治疗AIDS病人发生的巨细胞病毒 (CMV)视网膜炎。缬更昔洛韦口服后迅速吸收 ,并水解为更昔洛韦 ,其口服给药的生物利用度较高 (60 % )。试验表明 ,口服缬更昔洛韦 (90 0mg)与静脉注射更昔洛韦 (5mg·kg-1) ,bid,3wk后改为 qd ,治疗 1 60例AIDS病人发生的CMV视网膜炎有相同疗效 ,且耐受性相似。缬更昔洛韦维持治疗中最常见的不良反应为中性粒细胞减少症、贫血、胃肠道反应 (腹泻、恶心、呕吐 )、发热、头痛和失眠等     

Valganciclovir: oral prevention and treatment of cytomegalovirus in the immunocompromised host

Herpes virus infections, particularly those caused by cytomegalovirus (CMV), lead to significant and, sometimes severe, clinical problems for the immunocompromised host. As effective agents have become available, several treatment and prevention strategies have evolved over the past decade, first in intra-venous form and more recently, as oral preparations. Valganciclovir, the valine ester of ganciclovir, is an orally administered, potent, antiviral agent active against all herpes viruses. When taken orally, valganciclovir has much-improved bioavailability compared with oral ganciclovir and achieves ganciclovir exposures similar to intravenous ganciclovir. Clinical trials evaluating the safety and efficacy of valganciclovir for the treatment of new AIDS-associated CMV retinitis showed equivalency to intravenous ganciclovir and prevented progression of quiescent disease. In solid organ recipients, once-daily valganciclovir has been proven equivalent to oral ganciclovir for the prevention of CMV infection. The high bioavailability and convenient dosing formulation make valganciclovir an attractive option for these indications.     

Valganciclovir: oral prevention and treatment of cytomegalovirus in the immunocompromised host

Herpes virus infections, particularly those caused by cytomegalovirus (CMV), lead to significant and, sometimes severe, clinical problems for the immunocompromised host. As effective agents have become available, several treatment and prevention strategies have evolved over the past decade, first in intra-venous form and more recently, as oral preparations. Valganciclovir, the valine ester of ganciclovir, is an orally administered, potent, antiviral agent active against all herpes viruses. When taken orally, valganciclovir has much-improved bioavailability compared with oral ganciclovir and achieves ganciclovir exposures similar to intravenous ganciclovir. Clinical trials evaluating the safety and efficacy of valganciclovir for the treatment of new AIDS-associated CMV retinitis showed equivalency to intravenous ganciclovir and prevented progression of quiescent disease. In solid organ recipients, once-daily valganciclovir has been proven equivalent to oral ganciclovir for the prevention of CMV infection. The high bioavailability and convenient dosing formulation make valganciclovir an attractive option for these indications.     

Incremental cost-effectiveness analysis of intravenous ganciclovir versus oral ganciclovir in the maintenance treatment of newly diagnosed cytomegalovirus retinitis in patients with AIDS.

OBJECTIVE: To evaluate the cost effectiveness of a new product, oral ganciclovir, in comparison to a current therapy, intravenous (i.v.) ganciclovir, in the maintenance treatment of newly diagnosed cytomegalovirus (CMV) retinitis in patients with AIDS. DESIGN: This was a retrospective economic study of a prospective non-blinded randomised clinical trial. The model included i.v. ganciclovir induction, i.v. or oral ganciclovir maintenance and i.v. ganciclovir reinduction for patients whose CMV retinitis progressed. Safety and efficacy data were derived from the trial. A panel of Canadian infectious disease physicians and family physicians estimated the following in relation to i.v. ganciclovir treatment for CMV retinitis and related adverse events: healthcare resource utilisation, clinical practice patterns, patient out-of-pocket expenses and time loss from work. The incremental cost-effectiveness analysis is reported from a societal and a Ministry of Health perspective. SETTING: The trial was conducted in Canada (2 centres) and the US (13 centres) between March 1991 and November 1992. The model assumed that patients received either inpatient or outpatient care, or both. The model provided an analysis in a Canadian setting. PATIENTS AND PARTICIPANTS: Participants were patients with AIDS and newly diagnosed CMV retinitis. INTERVENTIONS: All patients received induction therapy with i.v. ganciclovir 5 mg/kg, twice daily for 14 days then once daily for 7 days. Patients whose CMV retinitis stabilised were randomised to maintenance therapy with either i.v. ganciclovir (5 mg/kg/day; n = 57) or oral ganciclovir (3000 mg/day; n = 60) and were followed for up to 140 days after the start of maintenance therapy. MAIN OUTCOME MEASURES AND RESULTS: The trial demonstrated that the mean time to progression of CMV retinitis was 57 days for oral ganciclovir compared with 62 days for i.v. ganciclovir maintenance therapy, as measured by masked fundus photography, and 96 days with i.v. ganciclovir compared with 68 days with oral ganciclovir according to the funduscopy results. There were more adverse events in the i.v. ganciclovir group compared with the oral ganciclovir group. The cost-effectiveness results provide the dollar amount expended in order to continue to provide additional benefit using i.v. ganciclovir compared with oral ganciclovir. The incremental cost-effectiveness (C/E) ratio was 482 Canadian dollars ($Can: 1993 to 1995 values) per progression-free day gained with i.v. ganciclovir. Sensitivity analysis using funduscopy, rather than fundus photography, to document progression of CMV retinitis resulted in a C/E ratio of $Can42. CONCLUSIONS: This analysis found that i.v. ganciclovir provided additional days free of progression of CMV retinitis when compared with oral ganciclovir, but the costs were higher.     

Absolute bioavailability and dose proportionality of oral ganciclovir after ascending multiple doses in human immunodeficiency virus (HIV)-positive patients

This study was designed to determine the bioavailability and dose linearity and proportionality of ganciclovir after multiple oral administrations of 3,000 mg to 6,000 mg per day. In an open-label, randomized, four-treatment crossover design, 24 patients seropositive for human immunodeficiency virus (HIV) and cytomegalovirus (CMV) received in random order multiple oral doses of ganciclovir 1,000 mg every 3 hours (six times a day), 1,000 mg four times a day, and 1,000 mg three times a day and a single 5-mg/kg intravenous infusion (over 1 hour) of ganciclovir. Blood samples for pharmacokinetic determinations were obtained on day 3 of each oral regimen and on the day of the intravenous infusion over a 24-hour time interval. Mean steady-state average serum concentrations of ganciclovir were 0.54, 0.79, and 0.99 microgram/mL, respectively, with the 3, 4, and 6 g/day oral regimens. The steady-state area under the concentration-time curve (AUC0-24) for the 6,000 mg/day oral regimen approached that of the single-dose intravenous regimen. There was a proportional increase in AUC0-24 between the 3 and 4 g/day dosage regimens, but not between the 4 and 6 g/day regimens. This suggests nonlinear absorption of ganciclovir at higher dosages, although the departure from proportionality was less than 11%.     

HIV/AIDS感染型的巨细胞病毒视网膜炎药物治疗研究

巨细胞病毒(Cytomegalovirus,CMV)视网膜炎是AIDS患者中最普遍的视觉损伤,严重危害着人们的健康,所有年龄段的人群都可能感染CMV病毒,尤其是新生儿、器官移植者和免疫功能缺损者如HIV/AIDS患者等。感染CMV初期,一般呈无症状或隐性感染,一旦免疫功能缺损时将导致发生严重疾病如视网膜脱落、失明等。目前CMV视网膜炎的治疗药物有更昔洛韦,膦甲酸,西多福韦,缬更昔洛韦,更昔洛韦埋植剂,其中更昔洛韦埋植剂、口服缬更昔洛韦已经广泛用于治疗CMV视网膜炎。     

Oral valganciclovir: a new option for treatment of cytomegalovirus infection and disease in immunocompromised hosts

Immunocompromised hosts are at increased risk of cytomegalovirus (CMV) infection and serious CMV disease. CMV infection is an important cause of morbidity among patients infected with HIV and after solid organ transplantation (SOT) and may cause life-threatening disease in allogeneic stem cell transplant (SCT) recipients. The introduction into clinical use of potent antiviral compounds and of rapid detection assays for CMV during the past two decades has allowed development of strategies for the prevention and treatment of disease caused by CMV in these groups of immunocompromised patients. At present, the antiviral drugs ganciclovir, foscarnet and cidofovir are commonly used in the treatment of CMV infection and disease. However, these agents have a poor oral bioavailability and, for systemic use, require iv. administration for most indications. Valganciclovir is an oral prodrug of ganciclovir, with a 10-fold greater bioavailability than oral ganciclovir. Studies of the pharmacokinetics of valganciclovir among HIV-infected CMV-seropositive patients and liver transplant recipients suggest that this oral compound has the potential to replace both oral and iv. ganciclovir in many situations if it is shown to be as efficacious and safe as those ganciclovir formulations in immunodeficient patients. In the first part of this review, currently established approaches to the management of CMV infection and disease in SCT and SOT recipients and HIV-infected patients are discussed to highlight possible indications for future valganciclovir use; in the second part, data from human studies of valganciclovir are presented.     

AIDS-related cytomegalovirus retinitis

Until recently, chronic daily intravenous infusions of ganciclovir or foscarnet were the only available treatment regimens for cytomegalovirus (CMV) retinitis, a sight-threatening complication that has historically affected approximately one-third of all AIDS patients in industrialized countries. In recent years, results of many randomized clinical trials of new treatments for AIDS-related CMV retinitis have been disseminated. These trials have involved four novel treatment modalities (i.e., an oral formulation of ganciclovir, a ganciclovir intraocular device, a combined intravenous ganciclovir/foscarnet regimen and a new agent, cidofovir) that offer better efficacy and/or less inconvenience than standard daily intravenous therapy with either ganciclovir or foscarnet. This review summarizes the main points clinicians should know about the available treatments for CMV disease.     

Cidofovir: a review of its use in cytomegalovirus retinitis in patients with AIDS.

Cidofovir is an antiviral nucleotide analogue with significant activity against cytomegalovirus (CMV) and other herpesviruses. The drug is indicated for the treatment of CMV retinitis, a sight-threatening condition, in patients with AIDS. Cidofovir has a long intracellular half-life which allows for a prolonged interval (2 weeks) between maintenance doses. In contrast, other intravenous treatment options for patients with CMV retinitis (i.e. ganciclovir and foscarnet) must be administered on a daily basis. The efficacy of intravenous cidofovir has been demonstrated in patients with AIDS and previously untreated CMV retinitis in multicentre randomised trials, and in a dose-finding study of cidofovir in patients with AIDS and previously treated relapsing CMV retinitis. Clinical trials have been relatively small (n < or = 100 patients) and no studies have been conducted directly comparing intravenous cidofovir with the more established intravenous agents, ganciclovir or foscarnet. Indirect comparisons of clinical trial data suggest that intravenous cidofovir may have similar efficacy to intravenous ganciclovir or foscarnet in delaying progression of CMV retinitis. However, such comparisons must be made with caution because of potential differences in patient populations, data analysis techniques and interobserver variability in the masked assessment of retinal photographs. Nevertheless, intravenous cidofovir offers a less intrusive administration regimen than intravenous ganciclovir or foscarnet because of its prolonged dosage interval. Since therapy is life-long, patients receiving daily intravenous ganciclovir or foscarnet (but not cidofovir) usually require an indwelling central venous catheter and are therefore at increased risk of serious infection. The relatively long dosage interval for cidofovir may also have favourable implications in terms of overall treatment costs and patient quality of life, although specific data are very limited. Potentially irreversible nephrotoxicity is the major treatment-limiting adverse event associated with intravenous cidofovir in patients with AIDS-related CMV retinitis. Anterior uveitis/iritis has been reported frequently with intravenous cidofovir in postmarketing reports and a small number of patients have developed hypotony. Other treatment options for CMV retinitis are also associated with serious adverse events, and selection of pharmacotherapy will depend on a number of factors including retinitis lesion characteristics, patient quality-of-life issues and efficacy and tolerability profiles of available therapies. CONCLUSION: Although the extent of its use may be limited by its adverse event profile, cidofovir offers a useful addition to the limited number of drugs available for the treatment of CMV retinitis in patients with AIDS.     

German health economic cost evaluation on oral ganciclovir in treating cytomegalovirus retinitis

The purpose of this study was to discuss the cost of oral ganciclovir in comparison with its intravenous formulation in treating CMV retinitis. A cost-cost evaluation was carried out to compare the costs of oral and intravenous treatment with ganciclovir. Costs were calculated by employing the usual prices charged to sickness funds (German social health insurers). The costs of induction and maintenance therapy depend on the period of time the therapy takes, the site of administration (e.g. hospital, physician's office, patient's home) and the charges for the services. Different treatment scenarios were created in order to calculate the costs of the treatment alternatives and in a sensitivity analysis the robustness of the results was tested. Different probabilities for adverse effects were used. The study results showed that total costs of treating CMV retinitis with oral ganciclovir were substantially lower than the costs of intravenous treatment.     

Influence of food on the oral bioavailability of deramciclane from film-coated tablet in healthy male volunteers.

The effect of a high-fat meal on the oral bioavailability of deramciclane 30 mg tablet was evaluated in 18 healthy male volunteers in a randomised, single dose, two-way crossover study. The drug was administered following an overnight fast or a standardised high-fat breakfast. The plasma concentrations of deramciclane and N-desmethylderamciclane were determined by using a validated HPLC-MS -MS/MS method. An effect of food on the bioavailability was indicated if the 90% confidence interval (CI) for the ratio of geometric means of fed and fasted treatments was not contained in the equivalence limit of 0.8-1.25 for AUC and C(max). The ratios of the mean C(max) and AUC(0-infinity) values of deramciclane were 1.24 (90% CI 1.12-1.38) and 1.31 (90% CI 1.21-1.41) in fed versus fasted subjects, which overlapped but exceeded the equivalence limit. In contrast to the parent compound, the 90% CI of the mean ratios for AUC(0-infinity) and C(max) of N-desmethylderamciclane were within the predefined range. The 24 and 31% increase in C(max) and AUC(0-infinity) of deramciclane, respectively, under fed condition is modest and probably has no clinical significance since it is relatively small compared to the inter-individual variability of these parameters.     

Pharmacokinetics of BOF-4272, a xanthine oxidase inhibitor, after single intravenous or oral administration to male mice and rats.

BOF-4272, (+/-)-8-(3-methoxy-4-phenylsulphinylphenyl) pyrazolo [1,5-a]-1,3,5-triazine-4 (1H)-one), is a new drug intended for the treatment of hyperuricaemia. This report describes the detailed pharmacokinetics of BOF-4272 in mice and rats after intravenous or oral administration. Plasma concentrations of BOF-4272 at 2-8h after intravenous administration were significantly higher in mice than in rats. Plasma concentrations of BOF-4272 after oral administration were significantly higher in fed mice than in fasted mice, but were similar in fasted and fed rats. The elimination half-life of the distribution phase (t1/2(alpha)) was similar in mice (0.158 h) and rats (0.210 h). The elimination half-life of the terminal elimination phase (t1/2(beta)) in mice was 1.936 h, while that in rats was 0.742 h. The volume of the central compartment (V1) was almost the same in mice (415 mL kg(-1)) and rats (440 mL kg(-1)). However, the volume of the peripheral compartment (V2) in mice was 1068 mL kg(-1), while that in rats was 92 mL kg(-1). The steady-state volume of distribution (Vss) was 2.8 times larger in mice than in rats. The area under the plasma concentration-time curve (AUC) in mice was 5332 ng h mL(-1), while that in rats was 3806 ng h mL(-1). The AUC0-24 h after oral administration was 2.5 times greater in fed mice than in fasted mice, and was 1.4 times greater in fasted rats than in fed rats. The correlation coefficients of Cmax and AUC0-24 h in both mice and rats after oral administration were greater than 0.997 in the dose range 1 - 125 mg kg(-1), indicating that the linear range of absorption or elimination (or both) of BOF-4272 is very wide. The results of the present study demonstrate that the mouse is a suitable animal species for evaluating the clinical pharmacokinetics of BOF-4272.     

Bioavailability of Enrofloxacin after Oral Administration to Fed and Fasted Pigs

Abstract: The disposition of enrofloxacin was measured after intravenous and oral administration to pigs. Eight clinically healthy pigs weighing 25 to 40 kg received a dose of 5 mg/kg intravenously and 10 mg/kg orally in both a fasted and a fed condition in a three-way cross-over design. Enrofloxacin was present in plasma for up to 72 hr after both intravenous and oral administration to fasted as well as fed pigs. The steady state volume of distribution was determined to 3.9±0.5 1/kg body weight which indicates that enrofloxacin was widely distributed in the body. The bioavailability was determined to 83±13% in fed and to 101±32% in fasted pigs. Based on the bioavailability and the resulting plasma concentrations it is concluded that a therapeutically active concentration for the most common porcine microbial pathogens are maintained for at least 24 hr after oral administration of 10 mg/kg body weight to fasted as well as to fed pigs. Ciprofloxacin which is an active metabolite of enrofloxacin was observed in plasma samples from all treated pigs, but the concentration never exceeded 0.1 μg/ml. During the first 24 hr after the administration of enrofloxacin the concentration of the metabolite made up less than 10% of the corresponding concentration of the parent compound.     

Atypical dose-route-dependent food effects of eplerenone in the dog: presence of food effects following intravenous dosing and lack of food effects of following oral dosing

This study was conducted to investigate why a food effect was observed following an intravenous dose of eplerenone (EP) in the dog, but not following oral dosing. Three female dogs were implanted with a chronic portal vein access port and received radiolabeled EP doses orally (15 mg/kg in solution) and intravenously (7.5 mg/kg via cephalic and portal veins) under fasted and fed conditions. Mean AUC values for EP after infusion through the cephalic vein were 23.0 +/- 2.7 and 18.2 +/- 1.1 h.microg/mL under fasted and fed conditions, respectively. Corresponding values after infusion through the portal vein were 20.7 +/- 3.2 and 12.9 +/- 1.3 h.microg/mL, respectively. After oral administration, EP was absorbed 82.0 +/- 6.9 and 98.0 +/- 8.3% under fasted and fed conditions; corresponding mean AUC values were 32.0 +/- 2.0 and 30.8 +/- 3.6 h.microg/mL, respectively. The AUC value for SC-70303 acid (the open lactone form of EP) was lower under fed conditions after cephalic vein infusion, but was greater under fed conditions after portal vein infusion or oral solution administration. The hepatic first-pass effect of EP was 12.6 +/- 6.3% under fasted conditions and 27.1 +/- 6.0% under fed conditions. Pharmacokinetic analysis of EP concentrations after portal vein infusion and oral administration showed that under fed conditions the rate constants for bile excretion and for liver metabolism and urinary excretion were increased while the rate constant for elimination and/or metabolism in the gastrointestinal tract was reduced. In conclusion, the apparent lack of food effect after oral administration was observed because enhanced clearance was compensated by increased absorption.