[Antibody drug conjugates (ADC) and bispecific antibodies in oncology - report of the 2022 Saint Louis day]

Antibody Drug Conjugates (ADC) and bispecific antibodies are booming and were the subject of the scientific event proposed by the French Society of Oncological Pharmacy, October 13, 2022. An ADC is composed of the antibody targeting a receptor expressed on the tumor cell, the spacer making it possible to attach the cytotoxic to the antibody and to control its distribution in the body, and the cytotoxic. Therapeutic antibodies, monoclonal and conjugated, have particular pharmacokinetics. Unlike monoclonal antibodies for which the standard dose is most often fixed, this is expressed in mg/m2 (or mg/kg) and capped at 2m2 (or 100kg) for conjugates. The linked cytotoxics are powerful cytotoxics: mitotic spindle poisons (emtansine, monomethyl auristatin E or vedotin), topoisomerase I inhibitors (deruxtecan, SN 38) or antibiotics (ozogamicin). In senology, trastuzumab deruxtecan (anti-HER2) and sacituzumab govitecan (anti-Trop 2) are now modifying treatment standards for patients with metastatic breast cancer, respectively HER2 3X or HER2 low and triple negative. In metastatic bladder cancer, enfortumab vedotin (anti-nectin 4) is positioned as the 2nd line of treatment. Bispecific antibodies, on the other hand, are able to target two epitopes, an antigen specific to a tumor cell and one to an immune cell, allowing a bridge between the killer immune cells and the tumor cells. For lymphoma proliferation, many bispecific antibodies are in development. The most advanced are glofitamab, epcoritamab and mosunetuzumab, which target the CD20 of B lymphocytes and the CD3 of T lymphocytes. Bispecific antibodies are also emerging in the treatment of myeloma with teclistamab and elranatamab (anti-CD3 and anti-BCMA) or talquetamab (anti-GPRC5D and anti-CD3). Conjugated antibodies, and more recently bispecific antibodies, are potential game changers in cancer treatment and researchs are needed to improve their efficacy and safety.

Improved oral bioavailability of febuxostat by liquid self-micro emulsifying drug delivery system in capsule shells

PURPOSE

Febuxostat is a non-purine xanthine oxidase inhibitor which belongs to the BCS class II. Main aim of this study is to enhance dissolution and bioavailability of a drug by formulating a liquid self-micro emulsifying drug delivery system (SMEDDS) in different capsule shells.

METHOD

Compatability of gelatin and cellulose capsule shells was checked with different oils, surfactants and co-surfactants. Solubility studies were then carried out in selected excipients. Capryol 90, labrasol, and PEG 400 were used in a liquid SMEDDS formulation based on phase diagram and the drug loading. Further SMEDDS was characterized for zeta potential, globule size and shape, thermal stability and in vitro release. Based on the in vitro release, pharmacokinetic study was carried out using SMEDDS in gelatin capsule shells.

RESULT

The diluted SMEDDS had globule size of 157.9±1.5d.nm, zeta potential of -16.2±0.4mV and they were thermodynamically stable. The formulation was found stable for 12 months in capsule shells. When tested in different media (0.1N HCl and pH 4.5 acetate buffer), the in vitro release of newly produced formulations differed substantially from that of commercially available tablets, while the release rate in alkaline medium (pH 6.8) was comparable and the highest. According to in vivo findings in rats, a threefold increase in plasma concentration, a fourfold increase in AUC0-t, and a reduction in oral clearance increased fuxostat's oral bioavailability.

CONCLUSION

This investigation revealed that the novel liquid SMEDDS formulation sealed in capsules has considerable potential as a vehicle for enhancing the bioavailability of febuxostat.

[An online tool to personalize the drug-doses for obese adults]

BACKGROUND

Between 1975 and 2014, the number of people suffering from obesity tripled, reaching 17% of the adult population in France and more than 35% in the United States. Obesity is defined by a Body Mass Index (BMI)>30kg/m2 and characterized by a significant accumulation of adipose tissue responsible for the increase in weight. This accumulation leads to physiological changes capable of modifying the pharmacokinetics of drugs, which can lead to the administration of inappropriate doses. For this reason, some significant dosage adjustments are necessary for obese patients. However, data on these adaptations are not easily accessible and sometimes complex to implement in practice.

AIM

To perform a new online tool allowing to calculate and propose an adjusted dose of a drug that should be administered to an obese patient.

METHOD

(i) carrying out an extensive bibliographic research according to the PRISMA methodology; and (ii) the development of a new website site proposing an adjusted dose for obese patients.

RESULTS

Firstly, 49 reviews concerning the dose adaptation have been evaluated and, secondly, 319 articles have been selected. Among them, 204 articles have been included in the database to justify the adjusted dose of 84 drugs and administration methods including antibiotics, antifungals, anticoagulants or even cancer drugs. This database is available online through a calculator on the website named Adapt'Obese. Thus, with the sex, height and weight of an obese patient, Adapt'Obese proposes a personalized and adjusted dose of the drug to administer.

PERSPECTIVES

Other drugs will be added soon, and functional improvements are planned, with the aim of adapting the dosages in obese patients, as for patients with renal insufficiency.

Oral anticancer agents as generators of relevant pharmacokinetic interactions

INTRODUCTION

The goal of this paper is to review the impact of marketed oral anticancer agents on the pharmacokinetics of co-administered medications in humans focusing on clinically relevant interactions.

METHODS

We identified the oral anticancer agents marketed in the United States and in Europe as December 31, 2021. Based on prescription information and literature, we selected the agents that were moderate/strong inducers or inhibitors of pharmacokinetic human molecular determinants of pharmacological interest (enzymes, drug transporters) highlighting on clinically meaningful interactions (i.e., at least a 2-fold variation in exposure of the comedication, excepting 1.5 for digoxin).

RESULTS

As December 31, 2021, 125 marketed oral anticancer agents were identified. Based on a≥2-fold exposure change (≥ 1.5 for digoxin), 24 oral anticancer agents commercialised in the European Union and the United States are susceptible to generate clinically meaningful pharmacokinetic interactions with comedications. All are recent agents and most of them (19/24) are indicated in the treatment of solid tumours. In all, 32 interactions with human molecular kinetic determinants were found for the 24 agents. Most of the pharmacokinetic interactions (26/32) are driven through cytochrome P450 (CYP) inhibition or induction, CYP3A4 being the major contributor (15).

CONCLUSION

24 anticancer agents (20% of the oral market) have the potential to significantly interact with co-administered drugs. These potential pharmacokinetic interactions are likely to occur in the ambulatory setting in a polymedicated and aged population, needing to reinforce the vigilance of community pharmacists and health care providers (particularly in thoracic oncology and genitourinary cancer) with these sometimes rarely prescribed agents.

Effects of students' peer teaching in a new pharmacokinetics teaching format

INTRODUCTION

The aim of this work was to evaluate the impact of a teaching method in pharmacokinetics (PK) in terms of satisfaction and performance in the final test of students.

MATERIAL AND METHODS

This method consisted of the development of a practical problem and a peer-tutored solution by small groups of three or four students. Students enrolled in the second year of pharmaceutical studies had to generate a PK practical problem, to propose a solution and to conduct a peer-tutored solution of the practical problem completed by another student group in a learning-connected classroom. Student's performance was assessed by individual semi-structured interviews and by comparing the scores obtained in the final test with those obtained in previous years.

RESULTS

More than 70% of the students were highly satisfied with the new format of the PK course, especially concerning the development and the design of a practical problem. More than 94% of the students considered that the content of the lecture-based teaching was at least adapted and in accordance with the objectives of the PK course. Students reported very constructive discussions and interactions with peers and the teacher. In addition, students significantly increased their score at the final PK test compared to previous years (53.27±19.10% in 2015-2017 vs. 71.30±13.47% in 2018-2019, P<.0001).

CONCLUSION

This new method including peer teaching was applied in PK and allowed to significantly increase the performance and the satisfaction of the students in PK.

[Impact of pregnancy on drug pharmacokinetics: What implication in clinical practice?]

Physiological changes that occur during pregnancy in the maternal body can lead to alterations in the response to drugs in the mother. Pregnancy modifies the volume of distribution of drugs, their binding to plasma proteins, the activity of their metabolizing enzymes, and their elimination. However, to date, due to the dynamic and complex processes involved, adjustments to the dosage regimen during pregnancy remain impossible to standardize. Knowledge of these modifications will help to better understand the possible loss of drug efficacy during pregnancy, as well as anticipating the clinical and plasma monitoring of drugs with a low therapeutic margin.

[Drug-drug interactions of tyrosine kinase inhibitors in treatment of non-small-cell lung carcinoma]

The development of tyrosine kinase inhibitors has revolutionized the treatment strategy in patients with non-small cell lung cancer with activating EGFR mutations, ALK or ROS-1 gene rearrangements. The Food and Drug Administration and European Medicines Agency have approved several inhibitors for the treatment of non-small cell lung cancer : five tyrosine kinase inhibitors targeting EGFR (erlotinib, gefitinib, afatinib, osimertinib and dacomitinib) and six tyrosine kinase inhibitors targeting ALK (crizotinib, céritinib, alectinib, brigatinib, lorlatinib and entrectinib). Interestingly, these tyrosine kinase inhibitor treatments are administered orally. While this route of administration improves the treatment flexibility and provides a comfortable and preferable option for patients, it also increases the risk of drug-drug interactions. The latter may result in changes in pharmacokinetics or pharmacodynamics of the tyrosine kinase inhibitors or their concomitant treatments, with subsequent risks of increasing their toxicity and/or reducing their effectiveness. This review provides an overview of drug-drug interactions with tyrosine kinase inhibitors targeting EGFR and ALK, as well as practical recommendations to guide oncologists and clinical pharmacists in the process of managing drug-drug interactions during the treatment of non-small cell lung cancer with tyrosine kinase inhibitors.

[Pharmacokinetic modifications and pharmacokinetic/pharmacodynamic optimization of beta-lactams in ICU]

Pharmacokinetic modifications in critically ill patients and those induced by ICU therapeutics raise a lot of issues about antibiotic dose adaptation. Beta-lactams are anti-infectious widely used in ICU. Frequent beta-lactam underdoses induce a risk of therapeutic failure potentially lethal and of emergence of bacterial resistance. Overdoses expose to a neurotoxic and nephrotoxic risk. Therefore, an understanding of pharmacokinetics modifications appears to be essential. A global pharmacokinetic/pharmacodynamic approach is required, including use of prolonged or continued beta-lactam infusions to optimise probability of pharmacokinetic/pharmacodynamic target attainment. Beta-lactam therapeutic drug monitoring should also be considered. Experts agree to target a free plasma betalactam concentration above four times the MIC of the causative bacteria for 100 % of the dosing interval. Bayesian methods could permit individualized doses adaptations.

[Pharmacokinetic changes related to acute infection. Examples from the SARS-CoV-2 pandemic]

The knowledge of factors of pharmacokinetic variability is important in order to personalize pharmacological treatment, particularly for drugs with a narrow therapeutic range for which pharmacological therapeutic monitoring is recommended. Inflammation is a protective response against acute infections and injuries that contributes to intra- and inter-individual variability in drug exposure by modulating the activity of enzymes involved in drug metabolism, and by altering the binding of drugs to plasma proteins. The understanding of the impact of inflammation on drug metabolism and the related clinical consequences allow to better take into consideration the effect of inflammation on the variability of drug exposure. We first summarized the molecular mechanisms by which inflammation contributes to the inhibition of drug metabolism enzymes. We then presented an updated overview of the consequences of the outcome of acute infectious event on pharmacokinetic exposure of drugs with a narrow therapeutic range and that are substrates of cytochrome P450, and the related clinical consequences. Finally, in the context of the COVID-19 pandemic, we reported examples of drug overexposures in COVID- 19 infected patients.

[Off label uses of tigecycline]

INTRODUCTION

Tigecycline is a relatively new antibiotic that have very limited valid indications. When no other alternative is available, this drug is widely used off label with promising results. The objective of this study is to summarize the different off label uses of tigecycline so that we can decide when and how to prescribe it in the absence of guidelines.

MATERIAL AND METHODS

This study a revue of the literature collecting all the articles concerning the off label uses of tigecycline.

RESULTS

Tigecycline was widely prescribed, off label, to treat infections with controversial results. Randomised clinical trials were conducted to evaluate its use to treat pneumonia. The results for this indication have a respectable level of evidence. For the other indications, the data collected was insufficient to support tigecycline prescription. In fact, different protocols were used which makes it hard to evaluate the efficacy and to conclude to the best treatment regimen. A tendency to prescribe high doses of the molecule was noted in different studies. When prescribed off label, tigecycline prescriptions were associated with a higher mortality and incidence of side effects.

CONCLUSION

The tigecycline remains a valid option for the treatment of infections dues to multi-resistant bacteria especially when other alternatives are scarce or in cases of renal failure.

[Summary of the recommendations of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT) on the therapeutic drug monitoring of tacrolimus]

Recently, the International Association of Therapeutic Drug Monitoring (IATDMCT), that is the learning society for biological pharmacology and toxicology, issued recommendations on the therapeutic drug monitoring (TDM) of tacrolimus. This is the second consensus after the one issued in 2009. In this document, the role of tacrolimus TDM for the four principal transplanted organs is discussed. The analytical aspects, pharmacogenetics, TDM alternative approaches and the positioning of biomarkers are also presented. Stronger recommendations are about trough concentration targets in kidney and liver transplantation and for other indication of tacrolimus use. For the first time, an area under the curve of tacrolimus concentrations target is recommended for recipients management. Eventually, another set of recommendations are proposed for pharmacodynamic biomarkers used in patients' follow-up.

Validated RP-HPLC method for quantification of doxazosin in human plasma: Application in a bioequivalence study

OBJECTIVES

The aim of the present study was to validate a simple, sensitive, HPLC method of analysis of doxazosin in human plasma with fluorescence detection.

METHODS

The validated method employed one-step direct protein precipitation with acetonitrile. Chromatographic separation was attained using a reverse-phase 250mm×4.6mm 5μ Hypersil® BDS C 18 column and the mobile phase consisted of 10mm sodium dihydrogen phosphate dihydrate (pH=3.0) and acetonitrile at a ratio of (65:35 v/v). The method was evaluated in terms of linearity, precision, accuracy, selectivity and stability as per standard guidelines. The total run time was about 4.5min which make this method suitable for high throughput analyses. This method was applied to the bioequivalence study of two doxazosin tablets in healthy human volunteers.

RESULTS

Good linear response was achieved over the range of 5.0-200ng/mL. The observed within- and between-day assay precision ranged from 0.64% to 14.73%; accuracy varied between 94.11% and 105%. The 90% confidence intervals for the ratio Cmax, and AUC 0-∞ of the test product over those of reference were within the acceptable range (0.8-1.25) for bioequivalence.

CONCLUSION

The developed method was simple and could be applied to therapeutic drug monitoring of doxazosin.

Antibiotics and chronic kidney disease: Dose adjustment update for infectious disease clinical practice

Antibiotic prescription in chronic kidney disease patients poses a twofold problem. The appropriate use of antibacterial agents is essential to ensure efficacy and to prevent the emergence of resistance, and dosages should be adapted to the renal function to prevent adverse effects. SiteGPR is a French website for health professionals to help with prescriptions to chronic kidney disease patients. A working group of infectious disease specialists and nephrology pharmacists reviewed the indications, dosing regimens, administration modalities, and dose adjustments of antibiotics marketed in France for patients with renal failure. Data available on the SiteGPR website and detailed in the present article aims to provide an evidence-based update of infectious disease recommendations to health professionals managing patients with chronic kidney disease.

[Assessment for antihypertensive drug intake: How, where and when?]

AIM

Hypertension is a public health problem managed according to therapeutic strategies published in France by the Hauteautoritéde santé (HAS - French Health Authorities). For patients with resistant hypertension, related or not to a non-adherence, prescribers need to be sure the exposure is high enough to achieve the tensional target. Quantitative analysis of antihypertensive drugs in different biological matrices (blood/urine) is one possible solution. However, this involves determining the concentrations observed at standard doses and knowing how to interpret the measured concentrations. It is also necessary to identify medical laboratories that can assay antihypertensive drugs. This was the aim of our work.

METHODS

The main antihypertensive drugs recommended by the HAS have been listed. For each of them, we looked for published steady-state plasma/serum concentrations and quantities excreted in the urine at usual dosages. In addition, the elimination half-life and linear pharmacokinetic profile were specified for each antihypertensive agent measured in plasma/serum. Pharmacology-Toxicology laboratories in France likely to carry out assays were identified. The time taken to report the result and the cost of the analysis were also specified.

RESULTS

All of the afore-mentioned information has been collected and presented in a table. This can then be used to compare the plasma/serum concentration or the quantity measured in a patient's urine with the values reported in the literature. In cases where the blood sampling times differ between those of the patient and the published data, the patient's measured value is compared to the estimated value based on the published concentrations and pharmacokinetics.

CONCLUSION

Interpretation of the plasma/serum/urinary value measured or estimated for an antihypertensive drug is a particularly interesting approach to determine if drug exposure is enough and a possible non-adherence. However, this activity is mostly carried out in hospital centres.

[5-fluorouracil therapeutic drug monitoring: Update and recommendations of the STP-PT group of the SFPT and the GPCO-Unicancer]

Despite being 60-years old now, 5-FU remains the backbone of numerous regimen to treat a variety of solid tumors such as breast, head-and-neck and digestive cancers either in neo-adjuvant, adjuvant or metastatic settings. Standard 5-FU usually claims 15-40% of severe toxicities and up to 1% of toxic-death. Numerous studies show a stiff relationship between 5-FU exposure and toxicity or efficacy. In addition, 5-FU pharmacokinetics is highly variable between patients. Indeed, 80% of the 5-FU dose is catabolized in the liver by dihydropyrimidine dehydrogenase (DPD) into inactive compounds. It is now well established that DPD deficiency could lead to severe toxicities and, thus, require dose reduction in deficient patients. However, despite dosage adaptation based on DPD status, some patients may still experience under- or over-exposure, leading to inefficacy or major toxicity. The "Suivi thérapeutique pharmacologique et personnalisation des traitements" (STP-PT) group of the "Société française de pharmacologie et de thérapeutique" (SFPT) and the "Groupe de pharmacologie clinique oncologique" (GPCO)-Unicancer, based on the latest and most up-to-date literature data, recommend the implementation of 5-FU Therapeutic Drug Monitoring in order to ensure an adequate 5-FU exposure.

[Pharmacokinetic risk factors of beta-blockers overdose in the elderly: Case report and pharmacology approach]

Beta-blockers are widely prescribed in elderly patients and may induce severe adverse drug reactions. We report a case of bisoprolol-induced bradycardia in an elderly patient with impaired renal function and use of cytochrome P450 inhibitors. A literature review has been performed in order to analyze pharmacokinetic risk factors of beta-blockers overdosing in geriatrics. Various mechanisms can result in decreased elimination of beta-blockers. These mechanisms vary according to the beta-blocker agent and may be combined in some individuals, especially elderly patients. This can lead to unexpected overexposure. Knowledge about drug interactions and pharmacokinetic elimination pathways is important for preventing overexposure and adverse drug reactions when using beta-blockers.

[Systemic safety following intravitreal injections of anti-VEGF]

The goal of this manuscript is to assess data suggesting that intravitreal injection of anti-vascular endothelial growth factors (anti-VEGFs) could result in systemic adverse events (AEs). The class-specific systemic AEs should be similar to those encountered in cancer trials. The most frequent AE observed in oncology, hypertension and proteinuria, should thus be the most common expected in ophthalmology, but their severity should be lower because of the much lower doses of anti-VEGFs administered intravitreally. Such AEs have not been frequently reported in ophthalmology trials. In addition, pharmacokinetic and pharmacodynamic data describing systemic diffusion of anti-VEGFs should be interpreted with caution because of significant inconsistencies reported. Thus, safety data reported in ophthalmology trials and pharmacokinetic/pharmacodynamic data provide robust evidence that systemic events after intravitreal injection are very unlikely. Additional studies are needed to explore this issue further, as much remains to be understood about local and systemic side effects of anti-VEGFs.

[Icodextrin: What arguments for and against its use as an osmotic agent in peritoneal dialysis]

Icodextrin is a glucose polymer derived from starch that is used as an osmotic agent in peritoneal dialysis. Its high molecular weight limits blood absorption and is useful for long dwell since there is few osmotic gradient dispersal. Its benefits are numerous: ltrafiltration optimization and better salt and water control especially in anuric patients with a high peritoneal permeability and also in case of infectious peritonitis, glucose sparing with less metabolic complications and a better preservation of peritoneal membrane, better biocompatibility. However it should not be forgotten that icodextrin has also side effects that must be known: allergies, cases of aseptic peritonitis, overintense water and salt depletion, lymphatic absorption of icodextrin and its metabolites (including maltose) with a risk of false capillary glucose rate estimation and a moderate increase in plasma osmolality. That is why it is not recommended now to use more than one daily icodextrin dwell. Nevertheless, several dialysis units use icodextrin in more than one daily dwell, especially in patients with an important ultrafiltration loss or in those in whom glucose sparing is essential. It seems to profit them with no more side effects. A large multicenter trial is in progress to test the efficacy and safety of icodextrin dwell twice a day in elder incident patients in peritoneal dialysis (DIDo). Moreover, icodextrin is also used combined with glucose in a long dwell (bimodal ultrafiltration) with encouraging results in terms of ultrafiltration and glucose sparing.

Success of tardive electroconvulsive therapy sessions after loxapine-induced malignant syndrome in the context of very poor metabolisation

We report the success of tardive electroconvulsive therapy in a case of loxapine malignant syndrome with catatonia. Loxapine and its metabolites were measured in biological samples by liquid chromatography coupled to tandem mass spectrometry. Genes were studied by sequencing and quantitative polymerase chain reaction (PCR). Plasmatic drug concentrations showed a supratherapeutic concentration of loxapine with a very low 8-hydroxyloxapine/loxapine ratio (range from 0.32 to 0.66, normal value>2 for 100mg) and a very long elimination half-life of loxapine (half-life>140h, normal value from 1 to 4hours). We tried to explain this kinetics by exploring the main pharmacogenes implicated in the metabolism of loxapine. No genetic abnormality for CYP1A2 was observed. The study of associated treatments showed the potential contribution of valproate. Pharmacokinetics and pharmacogenetics investigations revealed a blockade of the CYP1A2 metabolic pathway without genetic abnormalities, probably due to valproate co-medication. Toxicological monitoring of loxapine and its metabolites helped to explain the persistence of symptoms and to adapt the therapeutic management.

[Modeling for clinical trial in psychiatry: rationale, benefits and limitations]

Drug development of new compounds implies to define the dosage as well as the conditions of their use (indication, treatment duration, drug interactions, warnings …). This information requires the identification of the time course response. The decisions made during the clinical phases are now based on mathematical models. These models are continuously described and improved during all phases of the drug development using data collected in healthy volunteers and patients. Their objectives are to describe the most precisely, the link between the compound characteristics (pharmacology), the patient demographics and the effects. Further, the natural history of the disease, the placebo effect and the probability of dropping out will be integrated into the model to optimize the evaluation of the compound. These technical improvements are not only statistical, in the sense that they allow a better understanding of the advantages and pitfalls of the new drug. This article presents these methods used in psychiatry and which will become the new standard of drug evaluation.

Effect of CYP2D6 polymorphisms on the pharmacokinetics of propafenone and its two main metabolites

AIM OF THE STUDY

Propafenone (PPF) is an antiarrhythmic drug, metabolized mainly by CYP2D6 to 5-hydroxypropafenone (5OH-PPF) and by CYP3A4 to norpropafenone (NOR-PPF). CYP2D6 shows a high degree of genetic polymorphism which is associated with diminished antiarrhythmic efficacy or cardiac seizures/cardiotoxicity. This study aimed to investigate the effect of the CYP2D6 polymorphism on the pharmacokinetics of PPF and its two main metabolites. The usefulness of PPF/5OH-PPF ratio for CYP2D6 phenotyping in healthy adults was also evaluated.

METHODS

Twelve healthy volunteers, 3 poor metabolizers (PM), 2 intermediate metabolizers (IM) and seven extensive metabolizers (EM) received an oral dose of PPF. Concentrations of PPF and its metabolites were analyzed in serum samples over 27h.

RESULTS

The PPF/5OH-PPF ratio distinguished EMs from PMs, but not from IMs. In PMs, the mean transit time (MTT) values were almost the same for PPF and NOR-PPF and much higher than those of EMs and IMs. 5OH-PPF was not detected in EMs. Mean MTT values of 5OH-PPF and NOR-PPF in IMs were 5.27- and 1.52-fold higher than those of EMs.

CONCLUSION

A single time point serum PPF-MR approach is a useful tool to identify PMs. CYP2D6 polymorphism significantly affects the pharmacokinetics of PPF and its two metabolites.

Comparative plasma disposition kinetics of albendazole and its new benzimidazol prodrug in dog

The comparative pharmacokinetic behavior of albendazole (ABZ) and its new benzimidazol prodrug [1-tert-butyloxycarbonyl-5-propylthio-1-H-benzimidazol-2ylcarbamate of methyl] (ABZBoc), following their oral administration (10mg/kg) to healthy dogs was explored. Blood samples were obtained serially over a 24h period after treatment, then the plasma was analyzed by high-performance liquid chromatography (HPLC) to search the albendazole metabolites (ABZSO and ABZSO2). However, the albendazole parent drug was not detectable at any time after both treatments (ABZ and ABZBoc). By albendazole metabolites (ABZSO and ABZSO2) were the analytes recovered in the plasma after oral administration of ABZ and ABZBoc. Furthermore, some amounts of ABZBoc were also available in the plasma samples treated with this new produg. The plasma profile of each analyte followed a similar pattern after both treatments, the active metabolite (ABZSO) was the major analyte recovered in plasma (between 1 and 24h post-treatment). The pharmacokinetic parameters of both groups were calculated (Cmax, Tmax, t1/2, AUC0-›∞), and analyzed using the Student's t-test, P<0.05. Thus,the pharmacokinetic analysis indicated four statistically significant changes in the pharmacokinetic parameters defined above of the albendazole metabolites (ABZSO, ABZSO2) between the group treated with albendazole (group A) and that treated with ABZBoc prodrug (group B). Hence, the levels of the various pharmacokinetics parameters were low in the group treated with prodrug, as well they did not reach equivalent concentrations to that of albendazole. These differences between albendazole and its new prodrug may be explained by the fact that ABZBoc prodrug was not effectively reduced in the intestine of dogs.

[Drug dosage adjustment in patients with renal impairment and evaluation of renal function: focus on the cardiologic patients]

Chronic kidney disease is a progressive disease which has become a real public health issue. In patients with renal disease, drugs pharmacokinetics may be altered. The handling of drugs requires a special attention in these patients. Indeed, there is a risk of accumulation and drug overdose if dosage is not adjusted to the stage of renal insufficiency. Thus, to achieve a dosage adjustment knowing how to evaluate renal function is absolutely necessary. Different formulae are available including the Cockcroft and Gault formula aMDRD and CKD-EPI. In patients with cardiac issues, it appears that the CKD-EPI formula is that of choice in terms of clinical risk stratification. However, some summaries of product characteristics (SmPC) of drugs used in cardiology, such as Dabigatran(®), mention the need to use the Cockcroft-Gault, less accurate than aMDRD and CKD-EPI, in order to adjust the dose in patients with impaired renal function. Standardization of recommendations is necessary to limit disparities in dosage and drug exposure according to the formula. SmPCs however, are not the only source of information to obtain data on the use of drugs in the renal insufficient population. Some other information sources exist, reliable, updated and easily accessible.

[Pharmacology of misoprostol (pharmacokinetic data, adverse effects and teratogenic effects)]

Misoprostol is a synthetic analogue of prostaglandin E1. It is used in gynaecology because of its properties of myometrium smooth muscle cells contraction and its effects on the cervix. Misoprostol oral bioavailability is low and several authors have assessed whether the administration by other routes increased its pharmacodynamic effects. This paper summarizes the pharmacokinetic studies after other routes of administration: vaginal, sublingual, buccal or rectal. It also provides an update on its adverse effects and teratogenic effects.