Women's health, hormonal balance, and personal autonomy

Hormone-based contraception disrupts hormonal balance, creating artificial states of anovulation and threatening women's health. We reviewed its main adverse effects and mechanisms on accelerated ovarian aging, mental health (emotional disruptions, depression, and suicide), sexuality (reduced libido), cardiovascular (brain stroke, myocardial infarction, hypertension, and thrombosis), and oncological (breast, cervical, and endometrial cancers). Other "collateral damage" includes negative effects on communication, scientific mistrust, poor physician-patient relationships, increased patient burden, economic drain on the healthcare system, and environmental pollution. Hormone-sensitive tumors present a dilemma owing to their potential dual effects: preventing some cancers vs. higher risk for others remains controversial, with denial or dismissal as non-relevant adverse effects, information avoidance, and modification of scientific criteria. This lack of clinical assessment poses challenges to women's health and their right to autonomy. Overcoming these challenges requires an anthropological integration of sexuality, as the focus on genital bodily union alone fails to encompass the intimate relational expression of individuals, complete sexual satisfaction, and the intertwined feelings of trust, safety, tenderness, and endorsement of women's femininity.

Role of caregivers on medication adherence management in polymedicated patients with Alzheimer's disease or other types of dementia

Background

Alzheimer's disease (AD) and other dementia patients may have severe difficulties to ensure medication adherence due to their generally advanced age, polymedicated and multi-pathological situations as well as certain degree of cognitive impairment. Thus, the role of patient caregivers becomes crucial to warrantee treatment compliance.

Purpose

To assess the factors associated to patients and caregivers on medication adherence of patients with AD and other types of dementia as well as the degree of caregiver satisfaction with respect to treatment.

Methods

An observational, descriptive, cross-sectional study among the caregivers of 100 patients with AD and other types of dementia of the "Cartagena and Region Association of Relatives of Patients with Alzheimer's Disease and other Neurodegenerative Diseases" was conducted to assess patient and caregiver factors that influence medication adherence evaluated with the Morisky-Green-Levine test.

Results

Overall, adherence to treatment was 71%, with similar proportions between male and female patients. Greater adherence was found in married or widowed patients (49.3%), first degree (85.9%) or female (81.7%) caregivers but lower in AD patients (75.9%). Multivariate analysis showed a statistically significant positive association between non-adherence and male sex of the caregiver (OR 3.512 [95%IC 1.124-10.973]), dementia (OR 3.065 [95%IC 1.019-9.219]), type of caregiver (non-first-degree relative) (OR 0.325 [95%IC 0.054-0.672]) and civil status of the patient (OR 2.011 [95%IC 1.155-3.501]) favorable for married or widowed patients. No or week association was found with gender, age, education level, number of drugs used or polymedicated status of the patient. Caregivers considered the use (90%) and administration (91%) of the treatment easy or very easy and rarely interfered with their daily life, especially for female caregivers (p = 0.016). Finally, 71% indicated that they were satisfied or very satisfied with the treatment received by the patient.

Conclusions

Caregivers influence therapeutic management with predictors for improved adherence including female gender and first-degree kinship, together with patient's marital status. Thus, training caregivers about the disease and the importance of medication adherence in AD patients may ensure optimal treatment.

Analysis in the ethical decision-making of dental, nurse and physiotherapist students, through case-based learning

INTRODUCTION

Training in ethical competencies is perceived with special interest among the objectives of health education. The dimensions of the person such as integrity, autonomy and dignity influence the choice of interventions, but the different specialties of the health sciences conceive these dimensions with different perspectives depending on the clinical setting. These divergences can be detected during the first years of undergraduate studies, and it is important to know the professional bias and its possible causes.

MATERIALS AND METHODS

A procedure was developed through case-based learning (CBL) to assess various characteristics of decision-making during the early stages of student training. A semi-quantitative method was designed based on the narrative responses of a case with ethical implications in the field of gender violence. The method was applied to 294 undergraduate students in nursing (95), physiotherapy (109) and dentistry (90) from the Faculty of Health Sciences of a Spanish university. A frequency analysis of the narrative responses of the students to the proposed case was carried out, using the chi-square test to determine any association between the variables studied: gender, specialty and ethical knowledge.

RESULTS

Four types of response categories were detected, as a result of combining the personal conversation, report to legal authority or require assistance of other teams. The most common option in dentists is conversation only, while physical therapists include the assistance of other teams. In nursing, a balance is observed between both possibilities. The results show that student responses differ significantly among specialties and also differ significantly according to test scores on ethical knowledge. However, no significant differences were found between the responses provided by men and women.

CONCLUSION

Most of the health sciences students highly valued their own capacity for dialogue and reflection to approach situations with complex ethical dimensions. We consider that case-based learning (CBL), in combination with narrative analysis is a valid means of evaluating the professional ethical competencies of students in health sciences careers applied to a common goal.

Increased Bioavailability of β-Alanine by a Novel Controlled-Release Powder Blend Compared to a Slow-Release Tablet

BACKGROUND

β-Alanine is a sport supplement with increasing popularity due to its consistent ability to improve physical performance, with the downside of requiring several weeks of supplementation as imposed to the maximum daily and single dose tolerated without side effects (i.e., paresthesia). To date, the only alternative to overcome this problem has been use of a sustained-release tablet, while powders are the most commonly used format to deliver several grams of amino acids in a single dose. In this study we assessed the bioavailability, pharmacokinetics and paresthesia effect of β-alanine after administration in a novel controlled-released powder blend (test) versus a sustained-release tablet (reference).

METHODS

Twelve subjects (25.6 ± 3.2 y, 50% female) participated in a randomized, single-blind, crossover study. Each participant was administered orally the test (β-alanine 8 g, l-histidine 300 mg, carnosine 100 mg) or the reference product (10 tablets to reach β-alanine 8 g, Zinc 20 mg) with a 1-week washout period. β-Alanine plasma concentrations (0-8 h) were determined by LC-MS/MS and model-independent pharmacokinetic analysis was carried out. Paresthesia intensity was evaluated using a Visual Analog Score (VAS) and the categorical Intensity Sensory Score (ISS).

RESULTS

The CMAX and AUC0→∞ increased 1.6- and 2.1-fold (both p < 0.001) in the test product, respectively, which yielded 2.1-fold higher bioavailability; Ka decreased in the test (0.0199 ± 0.0107 min-1) versus the reference (0.0299 ± 0.0121 min-1) product (p = 0.0834) as well as V/F and Cl/F (both p < 0.001); MRT0→last increased in the test (143 ± 19 min) versus reference (128 ± 16 min) formulation (p = 0.0449); t1/2 remained similar (test: 63.5 ± 8.7 min, reference: 68.9 ± 9.8 min). Paresthesia EMAX increased 1.7-fold using the VAS (p = 0.086) and the ISS (p = 0.009). AUEC increased 1.9-fold with the VAS (p = 0.107) and the ISS (p = 0.019) reflecting scale intrinsic differences. Pharmacokinetic-pharmacodynamic analysis showed a clockwise hysteresis loop without prediction ability between CMAX, AUC0→∞ and EMAX or AUEC. No side effects were reported (except paresthesia).

CONCLUSIONS

The novel controlled-release powder blend shows 100% higher bioavailability of β-alanine, opening a new paradigm that shifts from chronic to short or mid-term supplementation strategies to increase carnosine stores in sports nutrition.

Microwave-assisted Preparation of Cross-linked Gelatin-Paracetamol Matrices: Optimization Using the D-optimal Design

Objectives

This study was conducted to assess the effect of microwave heating on the preparation of paracetamol cross-linked gelatin matrices by using the design of experiment (DoE) approach and explore the influence of the duration of microwave irradiation, the concentrations of crosslinker, and the amount of sodium bicarbonate (salt) on paracetamol release. These parameters were also compared with those of the matrices prepared via conventional heating.

Materials and Methods

Twenty gel matrices were prepared with different durations of microwave irradiation, amounts of maize, and concentrations of sodium bicarbonate as suggested by Design Expert (DX^®). The percentage drug release, the coefficient of variance (CV) in release, and the mean dissolution time (MDT) were the properties explored in the designed experimentation.

Results

Target responses were dependent on microwave irradiation time, cross-linker amount, and salt concentration. Classical and microwave heating did not demonstrate statistically significant difference in modifying the percentage of drug released from the matrices. However, the CVs of microwave-assisted formulations were lower than those of the gel matrices prepared via classical heating. Thus, microwave heating produced lesser variations in drug release. The optimized gel matrices demonstrated that the observed percentage of drug release, CV, and MDT were within the prediction interval generated by DX^®. The release mechanism of the matrix formulations followed the Peppas-Korsmeyer anomalous transport model.

Conclusion

The DoE-supported microwave-assisted approach could be applied to optimize the critical factors of drug release with less variation.

Moral dilemmas involving anthropological and ethical dimensions in healthcare curriculum

BACKGROUND

Currently a variety of novel scenarios have appeared within nursing practice such as confidentiality of a patient victim of abuse, justice in insolvent patients, poorly informed consent delivery, non-satisfactory medicine outputs, or the possibility to reject a recommended treatment. These scenarios presuppose skills that are not usually acquired during the degree. Thus, the implementation of teaching approaches that promote the acquisition of these skills in the nursing curriculum is increasingly relevant.

OBJECTIVE

The article analyzes an academic model which integrates in the curriculum a series of specific theoretical concepts together with practical skills to acquire the basic ethic assessment competency.

RESEARCH DESIGN

The project includes designing two subjects, General Anthropology and Ethics-Bioethics, with an applied approach in the nursing curriculum. The sequential structure of the curriculum in both subjects is constituted by three learning domains (theoretical, practical, and communicative) with different educational strategies.

ETHICAL CONSIDERATIONS

No significant ethical considerations as this is a discussion paper.

FINDINGS

The model was structured from the anthropology's concepts and decision-making process, applied to real situations. The structure of the three domains theoretical-practical-communicative is present in each session.

DISCUSSION

It is observed that theoretical domain fosters the capacity for critical analysis and subsequent ability to judge diverse situations. The practical domain reflected two significant difficulties: students' resistance to internalizing moral problems and the tendency to superficial criticism. The communicative domain has frequently shown that the conflicting points are in the principles to be applied.

CONCLUSION

We conclude that this design achieves its objectives and may provide future nursing professionals with ethical competences especially useful in healthcare practice. The three domains of the presented scheme are associated with the same process used in decision making at individual levels, where the exercise of clinical prudence acquires particular relevance.

Moral enhancement, at the peak of pharmacology and at the limit of ethics

The debate over the improvement of moral capacity or moral enhancement through pharmacology has gained momentum in the last decade as a result of advances in neuroscience. These advances have led to the discovery and allowed the alteration of patterns of human behavior, and have permitted direct interventions on the neuronal structure of behavior. In recent years, this analysis has deepened regarding the anthropological foundations of morality and the reasons that would justify the acceptance or rejection of such technology. We present a review of proposals for pharmacological interventions directed directly towards moral enhancement. In addition, we identify the ethical dilemmas that such interventions may generate, as well as the moral assessment of the authors of these studies. There is a moderate consensus on the risks of any intervention on the intimate structure of the human condition, its autonomy and identity, but there are large differences in explaining the reasons for this concern and especially in justifying such interventions. These findings show that it is necessary to investigate the moral assessment of authors and the ethical dimension within the field of pharmacology in order to identify future trends.

Ethical Challenges of Germline Genetic Enhancement

The new reproductive technologies have opened the door to different processes of germline genetic enhancement by which the characteristics of an individual according to the interests of the agents involved could be selected during its gestation. Although the initiative is apparently oriented towards developing individuals that would excel in society, critical voices raise the concerns about that this approach would generate and need for a reflection on the ethical, social and legal implications of these techniques and their implementation in society. We reviewed the literature about these issues throughout their historical records to date, focusing on the moral arguments and non-clinical aspects that affect the legal and social environment. We have observed various trends of thought with divergent positions (proactive, preventive, and regulatory) as well as a large number of articles that try to reconcile the different approaches. This review illustrates a series of concepts from the ethics and philosophy fields which are frequently used in studies that evaluate the ethical implications of germline genetic enhancement, such as dignity, benefit, autonomy, and identity. In addition, amongst the many unresolved controversies surrounding genetic enhancement, we identify procreative beneficence, genetic disassociation, gender selection, the value of disability, embryo chimerization, and the psychosocial inequality of potentially enhanced individuals as crucial. We also develop possible scenarios for future debate. We consider especially important the definition and specification of three aspects which are essential for the deployment of new reproductive technologies: the moral status of the embryo undergoing enhancement, the legal status of the enhanced individual, and the responsibility of the agents executing the enhancement. Finally, we propose the precautionary principle as a means to navigate ethical uncertainties.

Sex-Divergent Clinical Outcomes and Precision Medicine: An Important New Role for Institutional Review Boards and Research Ethics Committees

The efforts toward individualized medicine have constantly increased in an attempt to improve treatment options. These efforts have led to the development of small molecules which target specific molecular pathways involved in cancer progression. We have reviewed preclinical studies of sunitinib that incorporate sex as a covariate to explore possible sex-based differences in pharmacokinetics and drug–drug interactions (DDI) to attempt a relationship with published clinical outputs. We observed that covariate sex is lacking in most clinical outcome reports and suggest a series of ethic-based proposals to improve research activities and identify relevant different sex outcomes. We propose a deeper integration of preclinical, clinical, and translational research addressing statistical and clinical significance jointly; to embed specific sex-divergent endpoints to evaluate possible gender differences objectively during all stages of research; to pay greater attention to sex-divergent outcomes in polypharmacy scenarios, DDI and bioequivalence studies; the clear reporting of preclinical and clinical findings regarding sex-divergent outcomes; as well as to encourage the active role of scientists and the pharmaceutical industry to foster a new scientific culture through their research programs, practice, and participation in editorial boards and Institutional Ethics Review Boards (IRBs) and Research Ethics Committees (RECs). We establish the IRB/REC as the centerpiece for the implementation of these proposals. We suggest the expansion of its competence to follow up clinical trials to ensure that sex differences are addressed and recognized; to engage in data monitoring committees to improve clinical research cooperation and ethically address those potential clinical outcome differences between male and female patients to analyze their social and clinical implications in research and healthcare policies.

Sunitinib Possible Sex-Divergent Therapeutic Outcomes

Sunitinib is a tyrosine kinase inhibitor used for the treatment of renal cell carcinoma and metastatic brain tumors. Preclinical pharmacokinetic studies have shown higher sunitinib hepatic and brain exposure in female mice and higher sunitinib kidney concentrations in male mice. We explored whether sex-divergent tissue pharmacokinetics may anticipate sex-divergent therapeutic and toxicology responses in male and female patients. The review of the available scientific literature identified case reports, case series reports, clinical trials, and other studies associating sex with sunitinib outcomes. The results suggest male patients may respond better to renal cell carcinoma treatment and female patients may have better brain tumor treatment outcomes but a higher incidence of adverse events. Although more high-quality evidence is needed, these results, as anticipated by the preclinical data, may indicate possible sunitinib sex-divergent therapeutic outcomes in patients. In addition, we propose the systematic analysis of sex-based outcomes in clinical trial reports and their inclusion and review in the ethics committees and review boards to prevent, amongst others, patient burden in upcoming clinical trials.

Bioequivalence Study of Two Long-Acting Formulations of Oxytetracycline Following Intramuscular Administration in Bovines

The aim of this study was to evaluate the bioequivalence of two commercial long-acting formulations based on oxytetracycline (OTC) hydrochloride between the reference formulation (Terramycin LA, Pfizer) and a test formulation (Cyamicin LA, Fort Dodge Saude Animal). Both formulations were administered in a single intramuscular route at a dose of 20 mg OTC/kg of body weight in clinically healthy bovines. The study was carried out according to a one-period parallel design. Plasma samples were analyzed by high-pressure liquid chromatography. The limit of quantitation was 0.050 μg/mL with an accuracy of 101.67% with a coefficient of variation of 13.15%. Analysis of variance and 90% confidence interval tests were used to compare the bioavailability parameters (maximum plasma concentration, C max, and the area under the concentration-versus-time curve extrapolated to infinity, AUC0-∞) of both products. In the case of the time to maximum concentration (T max), non-parametric tests based on Wilcoxon's signed rank test were preferred. The comparison of the mean AUC0-∞ values did not reveal any significant differences (311.40 ± 93.05 μg h/mL and 287.71 ± 45.31 μg h/mL, respectively). The results were similar for the T max (3.58 ± 0.90 h versus 3.42 ± 0.51 h). However, when comparing the mean C max some significant differences were found (8.73 ± 3.66 μg/mL and 10.43 ± 3.84 μg/mL, respectively). The 90% confidence intervals for the ratio of AUC0-∞ and T max values for the reference and test product are within the interval 80-125%, but the 90% confidence intervals for the ratio of C max falls outside the proposed interval. It was concluded that C max of test product are not within the 20% of those of the reference, thus suggesting that test OTC is not bioequivalent to the reference formulation.

Is the pharmacokinetics of bupivacaine equivalent after lumbar epidural administration through a needle or a catheter in male and female adults?

We assessed possible pharmacokinetic modifications due to different epidural injection techniques using either a needle or a catheter. Adult patients (n=23) undergoing lower abdominal or lower extremity surgery were randomly assigned a single bupivacaine epidural injection anesthesia (0.5%, 15 mL, 0.3 mL/s) through needle or catheter device. Plasma bupivacaine concentration was quantified using a validated HPLC method and non-compartmental pharmacokinetic parameters estimated. CMAX and TMAX were similar in both groups: 952 ± 346 ng/mL, 0.65 ± 0.5 1h in the needle group; 810 ± 307 ng/mL, 0.43 ± 0.29 h in the catheter group respectively. Plasma AUC₀→∞ was also similar in both groups: 3868 ± 1687 ngh/mL for needle versus 4096 ± 1748 ngh/mL using catheter. The catheter group showed slower disposition than the needle group: t₁/₂=3.9 ± 2.3 h, MRT=6.0 ± 3.1 h versus 2.7 ± 1.03 h and 4.5 ± 1.2 h with needle administration respectively though it did not reach statistical significance, Cl/F and V/F were also similar. Lastly, female patients showed significant longer t1/2 after administration through catheter (5.7 ± 2.0 h) than needle (2.7 ± 0.6 h) group (P=0.0279). The device type does not affect the pharmacokinetics which is similar in both groups although sex-based differences might exist.

Sunitinib tissue distribution changes after coadministration with ketoconazole in mice

Sunitinib is a multitargeted tyrosine kinase inhibitor approved for gastrointestinal stromal tumor (GIST), advanced renal cell carcinoma (RCC) and pancreatic neuroendocrine tumors. It is metabolized via CYP3A4 and has low brain penetration due to efflux transporters ABCB1B and ABCG2. We studied the interaction with ketoconazole (50 mg/kg), antifungal drug which shares metabolic pathways and efflux transporters, in ICR female mice after oral coadministration (30 min apart) of 60 mg/kg sunitinib (study group) versus sunitinib alone (control group). Plasma, liver, kidney and brain sunitinib concentrations were measured by HPLC at 2, 5, 10, 20, 40 min, 1, 2, 4, 6, 12 h post-sunitinib administration, and non-compartmental pharmacokinetic parameters estimated. In plasma, ketoconazole coadministration increased plasma maximum concentration (C MAX) 60 %, delayed time to C MAX (T MAX); 1.6-fold greater area under the curve AUC0→∞ (p < 0.001); lower apparent steady-state volume of distribution (V SS/F) and oral clearance (Cl/F) 40 and 61 %, respectively; and shorter elimination half-life (t 1/2). Sunitinib exhibited extensive tissue distribution which increased after ketoconazole coadministration: total area under the curve (AUC0→∞) increased 1.8-, 2.8- and 1.2-fold in kidney, liver and brain, respectively (all p < 0.001). Sunitinib presented high tissue-to-plasma AUC0→∞ ratio in liver (17.8 ± 1.2), kidney (14.6 ± 1.52) and brain (2.25 ± 0.18) which was modified after coadministration: AUC0→∞ ratio increased in liver (31.4 ± 4.7; p < 0.001), kidney (17.1 ± 2.2; p > 0.05) and decreased in brain (1.70 ± 0.23, p > 0.05). The results showed a significant ketoconazole-sunitinib interaction that affected plasma, tissue pharmacokinetics and tissue uptake mechanisms. The study portrays the risk to increase toxicity and potential clinical translatability to treat tumors in tissues.

A Learning Activity to Introduce Undergraduate Students to Bioethics in Human Clinical Research

We developed a pharmacology practicum assignment to introduce students to the research ethics and steps involved in a clinical trial. The assignment included literature review, critical analysis of bioethical situations, writing a study protocol and presenting it before a simulated ethics committee, a practice interview with a faculty member to obtain informed consent, and a student reflective assessment and self-evaluation. Students were assessed at various steps in the practicum; the learning efficiency of the activity was evaluated using an independent survey as well as students’ reflective feedback. Most of the domains of Bloom’s and Fink’s taxonomies of learning were itemized and covered in the practicum. Students highly valued the translatability of theoretical concepts into practice as well as the approach to mimic professional practice. This activity was within a pharmacy program, but may be easily transferable to other medical or health sciences courses.

Potential protective effect of sunitinib after administration of diclofenac: biochemical and histopathological drug-drug interaction assessment in a mouse model

Sunitinib is a tyrosine kinase inhibitor for GIST and advanced renal cell carcinoma. Diclofenac is used in cancer pain management. Coadministration may mediate P450 toxicity. We evaluate their interaction, assessing biomarkers ALT, AST, BUN, creatinine, and histopathological changes in the liver, kidney, heart, brain, and spleen. ICR mice (male, n = 6 per group/dose) were administered saline (group A) or 30 mg/kg diclofenac ip (group B), or sunitinib po at 25, 50, 80, 100, 140 mg/kg (group C) or combination of diclofenac (30 mg/kg, ip) and sunitinib (25, 50, 80, 100, 140 mg/kg po). Diclofenac was administered 15 min before sunitinib, mice were euthanized 4 h post-sunitinib dose, and biomarkers and tissue histopathology were assessed. AST was 92.2 ± 8.0 U/L in group A and 159.7 ± 14.6 U/L in group B (p < 0.05); in group C, it the range was 105.1-152.6 U/L, and in group D, it was 156.0-209.5 U/L (p < 0.05). ALT was 48.9 ± 1.6 U/L (group A), 95.1 ± 4.5 U/L (p < 0.05) in group B, and 50.5-77.5 U/L in group C and 82.3-115.6 U/L after coadministration (p < 0.05). Renal function biomarker BUN was 16.3 ± 0.6 mg/dl (group A) and increased to 29.9 ± 2.6 mg/dl in group B (p < 0.05) and it the range was 19.1-33.3 mg/dl (p < 0.05) and 26.9-40.8 mg/dl in groups C and D, respectively. Creatinine was 5.9 pmol/ml in group A; 6.2 pmol/ml in group B (p < 0.01), and the range was 6.0-6.2 and 6.2-6.4 pmol/ml in groups C and D, respectively (p < 0.05 for D). Histopathological assessment (vascular and inflammation damages) showed toxicity in group B (p < 0.05) and mild toxicity in group C. Damage was significantly lesser in group D than group B (p < 0.05). Spleen only showed toxicity after coadministration. These results suggest vascular and inflammation protective effects of sunitinib, not shown after biomarker analysis.

Toxoplasma gondii: determination of the onset of chronic infection in mice and the in vitro reactivation of brain cysts

Toxoplasma gondii is an intra-cellular parasite that infects humans through vertical and horizontal transmission. The cysts remain dormant in the brain of infected humans and can reactivate in immunocompromised hosts resulting in acute toxoplasmic encephalitis which may be fatal. We determined the onset and progression of brain cysts generation in a mouse model following acute toxoplasmosis as well as the ability of brain cysts to reactivate in vitro. Male Balb/c mice, (uninfected control group, n = 10) were infected orally (study group, n = 50) with 1000 tachyzoites of T. gondii (ME49 strain) and euthanized at 1, 2, 4, 8 and 16 weeks post infection. Brain tissue was harvested, homogenized, stained and the number of brain cysts counted. Aliquots of brain homogenate with cysts were cultured in vitro with confluent Vero cells and the number of cysts and tachyzoites counted after 1 week. Brain cysts but not tachyzoites were detected at week 2 post infection and reached a plateau by week 4. In vitro Vero cells culture showed similar pattern for cysts and tachyzoites and reactivation of cyst in vitro was not influenced by the age of the brain cysts.

Reduced exposure of imatinib after coadministration with acetaminophen in mice

Purpose:

Imatinib is an efficacious drug against chronic myeloid leukemia (CML) and gastrointestinal stromal tumor (GIST) due to selective inhibition of c-KIT and BCR-ABL kinases. It presents almost complete bioavailability, is eliminated via P450-mediated metabolism and is well tolerated. However, a few severe drug-drug interactions have been reported in cancer patients taking acetaminophen.

Materials and Methods:

Male ICR mice were given 100 mg/kg single dose of imatinib orally or imatinib 100 mg/kg (orally) coadministered with acetaminophen intraperitoneally (700 mg/kg). Mice were euthanized at predetermined time points, blood samples collected, and imatinib plasma concentration measured by HPLC.

Results:

Imatinib AUC_0-12 was 27.04 ± 0.38 mg·h/ml, C_max was 7.21 ± 0.99 mg/ml and elimination half-life was 2.3 hours. Acetaminophen affected the imatinib disposition profile: AUC_0-12 and C_max decreased 56% and 59%, respectively and a longer half-life was observed (5.6 hours).

Conclusions:

The study shows a pharmacokinetic interaction between acetaminophen and imatinib which may render further human studies necessary if both drugs are administered concurrently to cancer patients.

Metronidazole leads to enhanced uptake of imatinib in brain, liver and kidney without affecting its plasma pharmacokinetics in mice

Objectives

The pharmacokinetic interaction between metronidazole, an antibiotic–antiparasitic drug used to treat anaerobic bacterial and protozoal infections, and imatinib, a CYP3A4, P-glycoprotein substrate kinase inhibitor anticancer drug, was evaluated.

Methods

Male imprinting control region mice were given 50 mg/kg imatinib PO (control group) or 50 mg/kg imatinib PO, 15 min after 40 mg/kg PO metronidazole (study group). Imatinib plasma, brain, kidney and liver concentrations were measured by HPLC and non-compartmental pharmacokinetic parameters estimated.

Key findings

Metronidazole coadministration resulted in a double-peak imatinib disposition profile. The maximum concentration (Cmax) decreased by 38%, the area under the curve (AUC0–∞) decreased by 14% and the time to Cmax (Tmax) was earlier (50%) in plasma. Apparent volume of distribution (VSS/F) and oral clearance (Cl/F) increased by 21% and 17%, respectively. Imatinib tissue penetration was higher after metronidazole coadministration, with 1.7 and 2.1-fold AUC0–∞ increases in liver and kidney, respectively. Metronidazole increased imatinib's tissue-to-plasma AUC0–∞ ratio in liver from 2.29 to 4.53 and in kidney from 3.04 to 7.57, suggesting higher uptake efficiency. Brain Cmax was 3.9-fold higher than control and AUC0–t last was 2.3-fold greater than plasma (3.5% in control group). No tissue-plasma concentration correlation was found.

Conclusions

Metronidazole slightly decreased imatinib systemic exposure but enhanced liver, kidney and brain penetration, probably due to metronidazole-mediated inhibition of P-glycoprotein and other efflux transporters. The high brain exposure opens possibilities for treatment of glioma and glioblastoma. Renal and hepatic functions may need to be monitored due to potential renal and hepatic toxicity.

Histopathology and biochemistry analysis of the interaction between sunitinib and paracetamol in mice

Background

Sunitinib, a tyrosine kinase inhibitor to treat GIST and mRCC may interact with paracetamol as both undergo P450 mediated biotransformation and P-glycoprotein transport. This study evaluates the effects of sunitinib-paracetamol coadministration on liver and renal function biomarkers and liver, kidney, brain, heart and spleen histopathology. ICR male mice (n = 6 per group/dose) were administered saline (group-A) or paracetamol 500 mg/kg IP (group-B), or sunitinib at 25, 50, 80, 100, 140 mg/kg PO (group-C) or coadministered sunitinib at 25, 50, 80, 100, 140 mg/kg PO and paracetamol IP at fixed dose 500 mg/kg (group-D). Paracetamol was administered 15 min before sunitinib. Mice were sacrificed 4 h post sunitinib administration.

Results

Group-A serum ALT and AST levels were 14.29 ± 2.31 U/L and 160.37 ± 24.74 U/L respectively and increased to 249.6 ± 222.7 U/L and 377.1 ± 173.6 U/L respectively in group-B; group-C ALT and AST ranged 36.75-75.02 U/L and 204.4-290.3 U/L respectively. After paracetamol coadministration with low sunitinib doses (group-D), ALT and AST concentrations ranged 182.79-221.03 U/L and 259.7-264.4 U/L respectively, lower than group-B. Paracetamol coadministration with high sunitinib doses showed higher ALT and AST values (range 269.6-349.2 U/L and 430.2-540.3 U/L respectively), p < 0.05. Hepatic histopathology showed vascular congestion in group-B; mild congestion in group-C (but lesser than in group-B and D). In group-D, at low doses of sunitinib, lesser damage than in group-B occurred but larger changes including congestion were observed at high sunitinib doses. BUN levels were higher (p < 0.05) for group-B (33.81 ± 5.68 mg/dL) and group-D (range 35.01 ± 6.95 U/L to 52.85 ± 12.53 U/L) compared to group-A (15.60 ± 2.17 mg/dL) and group-C (range 17.50 ± 1.25 U/L to 26.68 ± 6.05 U/L). Creatinine remained unchanged. Renal congestion and necrosis was lower in group-C than group-B but was higher in group-D (p > 0.05). Mild cardiotoxicity occurred in groups B, C and D. Brain vascular congestion occurred at high doses of sunitinib administered alone or with paracetamol. Hepatic and renal biomarkers correlated with histopathology signs.

Conclusions

Paracetamol and sunitinib coadministration may lead to dose dependent outcomes exhibiting mild hepatoprotective effect or increased hepatotoxicity. Sunitinib at high doses show renal, cardiac and brain toxicity. Liver and renal function monitoring is recommended.

Differential effects of ketoconazole and primaquine on the pharmacokinetics and tissue distribution of imatinib in mice

Imatinib, a selective inhibitor of c-KIT and Bcr-Abl tyrosine kinases, approved for the treatment of chronic myelogenous leukemia and gastrointestinal stromal tumors, shows further therapeutic potential for gliomas, glioblastoma, renal cell carcinoma, autoimmune nephritis and other neoplasms. It is metabolized by CYP3A4, is highly bound to alpha-1-acid glycoprotein and is a P-glycoprotein substrate limiting its brain distribution. We assess imatinib's protein binding interaction with primaquine, which also binds to alpha-1-acid glycoprotein, and its metabolic interaction with ketoconazole, which is a CYP3A4 inhibitor, on its pharmacokinetics and biodistribution. Male ICR mice, 9-12 weeks old were given imatinib PO (50 mg/kg) alone or co-administered with primaquine (12.5 mg/kg), ketoconazole (50 mg/kg) or both, and imatinib concentration in the plasma, kidney, liver and brain was measured at prescheduled time points by HPLC. Noncompartmental pharmacokinetic parameters were estimated. Primaquine increased 1.6-fold plasma AUC(0)--> infinity, C(Max) decreased 24%, T(Max) halved and t(1/2) and mean residence time were longer. Ketoconazole increased plasma AUC(0)-->infinity 64% and doubled the C(Max), but this dose did not affect t(1/2) or mean residence time. When ketoconazole and primaquine were co-administered, imatinib AUC(0)-->infinity and C(Max) increased 32 and 35%, respectively. Ketoconazole did not change imatinib's distribution efficiency in the liver and kidney, primaquine increased it two-fold and it was larger when both the drugs were co-administered with imatinib. Ketoconazole did not change brain penetration but primaquine increased it approximately three-fold. Ketoconazole and primaquine affect imatinib clearance, bioavailability and distribution pattern, which could improve the treatment of renal and brain tumors, but also increase toxicity. This would warrant hepatic and renal functions monitoring.

Disposition and tissue distribution of imatinib in a liposome formulation after intravenous bolus dose to mice

Imatinib is an efficacious anticancer drug with a spectrum of potential antitumour applications limited by poor biodistribution at therapeutic concentrations to the tissues of interest. We assess the pharmacokinetic and tissue distribution profile of imatinib in a liposome formulation. Its single dose (6.25 mg x kg(-1)) in a liposome formulation was administered iv to male mice. Imatinib concentration was measured in plasma, spleen, liver, kidney and brain using a HPLC assay. Non-compartmental pharmacokinetic approach was used to assess the disposition parameters. The plasma disposition profile was biphasic with a plateau-like second phase. The AUC(0-->infinity) was 11.24 microg x h x mL(-1), the elimination rate constant (k(el)) was 0.348 h(-1) and the elimination half life (t(1/2)) was 2.0 h. The mean residence time (MRT) was 2.59 h, V(SS) was 1.44 L x kg(-1) and clearance was 0.56 L x h x kg(-1). Liver achieved the highest tissue exposure: CMAX = 18.72 microg x mL(-1); AUC(0-->infinity)= 58.18 microg x h x mL(-1) and longest t(1/2) (4.29 h) and MRT (5.31 h). Kidney and spleen AUC(0-->infinity) were 47.98 microg x h x mL(-1) and 23.46 microg x h x mL(-1), respectively. Half-life was 1.83 h for the kidney and 3.37 h for the spleen. Imatinib penetrated into the brain reaching approximately 1 microg x g(-1). Upon correction by organ blood flow the spleen showed the largest uptake efficiency. Liposomal imatinib presented extensive biodistribution. The drug uptake kinetics showed mechanism differences amongst the tissues. These findings encourage the development of novel imatinib formulations to treat other cancers.

Histopathological study of the hepatic and renal toxicity associated with the co-administration of imatinib and acetaminophen in a preclinical mouse model

Imatinib, a selective tyrosine kinase inhibitor, is the first line treatment against chronic myelogenous leukaemia (CML) and gastrointestinal stromal tumors (GIST). Several fatal cases have been associated with imatinib hepatotoxicity. Acetaminophen, an over-the-counter analgesic, anti-pyretic drug, which can cause hepatotoxicity, is commonly used in cancer pain management. We assessed renal and hepatic toxicity after imatinib and acetaminophen co-administration in a preclinical model. Four groups of male ICR mice (30-35 g) were fasted overnight and administered either saline solution orally (baseline control), imatinib 100 mg/kg orally (control), acetaminophen 700 mg/kg intraperitoneally (positive control) or co-administered imatinib 100 mg/kg orally and acetaminophen 700 mg/kg intraperitoneally (study group), and sacrificed at 15 min, 30 min, 1 h, 2 h, 4 h and 6 h post-administration (n = 4 per time point). The liver and kidneys were harvested for histopathology assessment. The liver showed reversible cell damage like feathery degeneration, microvesicular fatty change, sinusoidal congestion and pyknosis, when imatinib or acetaminophen were administered separately. The damage increased gradually with time, peaked at 2 h but resolved by 4 h. When both drugs were administered concurrently, the liver showed irreversible damage (cytolysis, karyolysis and karyorrhexis) which did not resolve by 6 h. Very minor renal changes were observed. Acetaminophen and imatinib co-administration increased hepatoxicity which become irreversible, probably due to shared P450 biotransformation pathways and transporters in the liver.

HPLC determination of imatinib in plasma and tissues after multiple oral dose administration to mice

Imatinib inhibits Bcr-Abl, c-KIT and PDGFR kinases. It is approved for the treatment of chronic myeloid leukemia (CML), gastrointestinal stromal tumors (GIST) and has further therapeutic potential. Male ICR mice were given imatinib PO (50 or 25 mg/kg, 5 doses every 2 h); euthanized 2 h after the last dose administration; plasma, liver, brain, spleen and kidney were collected and imatinib concentration measured by an optimized HPLC method for quantification in tissues. Methanol (1:1 v/v plasma) and pH 4, 40:30:30 (v/v/v) water-methanol-acetonitrile at 5 ml/g (brain) and 10 ml/g (spleen, kidney, liver) ratio was added to the samples, homogenized, sonicated, centrifuged (15,000 rpm, 5 min, 2 degrees C) and the supernatant injected into an Inertsil CN-3 column (4.6 mm x 150 mm, 5 microm) using 64:35:1 (v/v/v) water-methanol-triethylamine (pH 4.8), flow rate 1 ml/min, 25 degrees C. Imatinib eluted at 7.5 min (268 nm). Linearity: 0.1-50 microg/ml; precision, accuracy, inter- and intra-day variability was within 15%. Recovery was above 95% (plasma), 80% (brain) and 90% (kidney, liver, spleen). Imatinib tissue concentrations were 6-8 folds higher than plasma except brain, where the ratio decreased from 0.24 to 0.08 suggesting limited brain penetration, likely due to blood brain barrier efflux transporters. The extensive distribution supports the expansion of therapeutic applications.

Pharmacokinetics and tissue distribution after intravenous administration of a single dose of amphotericin B cochleates, a new lipid-based delivery system

Model independent pharmacokinetic analysis of intravenous (iv) amphotericin B cochleates (CAMB), a new lipid-based drug delivery system, in mice (0.625 mg/kg) shows a two-phase disposition profile in blood [area under the curve of concentration versus time from time zero to infinity (AUC(0-infinity)) = 1.01 microg. h/mL, half-life (t((1/2))) = 11.68 h, volume of distribution at steady state (V(ss)) = 9.59 L/kg, clearance (CL) = 10.36 mL/min/kg and mean residence time from time 0 to infinity (MRT(0-infinity)) = 15.41 h). In target tissues, maximum time (t(max)) ranged from 2 min (spleen and lung) to 10 min (liver) and lungs presented the highest AMB concentration (16.4 microg. h/g) followed by liver (8.56 microg/g), and spleen (6.63 microg/g). In addition, liver and spleen presented the longest elution half-life (75.03 and 66.71 h, respectively), MRT(0-infinity) (98.4 and 86.3 h, respectively), and AMB exposure:liver AUC(0-infinity) = 474 and 116.4 microg. h/g for the spleen. The large V(ss) and the extensive tissue AUC indicate large and efficient ability of cochleates to penetrate and deliver AMB. Differences in tissue uptake mechanism and pharmacokinetic data suggest a crucial role of macrophages in CAMB clearance from blood as well as an essential role of the liver and the spleen in AMB distribution to target tissues.

Coadministration of neoral and the novel rapamycin analog, SDZ RAD, to rat lung allograft recipients: potentiation of immunosuppressive efficacy and improvement of tolerability of staggered versus simultaneous treatment

BACKGROUND

Neoral and rapamycin derivative (RAD) have complementary mechanisms for inhibition of lymphocyte activation and are substrates for the same pathways of drug metabolism. Therefore, we investigated treatment regimens designed to minimize pharmacokinetic interactions and to potentiate immunosuppressive efficacy in a highly stringent rat lung allograft model.

METHODS

Lewis recipients of Brown Norway lungs received the following daily oral doses: (A) RAD at 2.5 mg/kg (n=9); (B) Neoral at 7.5 mg/kg (n=8); (C) RAD at 2.5 mg/kg + Neoral at 7.5 mg/kg simultaneously (n=8); or (D) RAD at 2.5 mg/kg + Neoral at 7.5 mg/kg (n=6) staggered 6 hr apart. Rats were assessed by daily weights, chest radiographs, drug trough levels (high-performance liquid chromatography/mass spectrometry), and blinded scoring of graft histology at death (day 21).

RESULTS

Radiographs were completely opacified in all grafts of control and RAD monotherapy groups on days 7 and 14, respectively. Grafts were mildly opacified (Neoral monotherapy) and completely clear (both RAD + Neoral groups) on day 21. Simultaneous or staggered combined treatment dramatically reduced histologic rejection compared with treatment with either drug alone. Simultaneous treatment caused poor tolerability (poor grooming, lethargy) and significantly higher day-14 RAD and cyclosporine (CsA) trough levels (49+/-5 and 638+/-106 ng/ml; P<0.04) than in the staggered group (28+/-3 and 318+/-25 ng/ml) in which all animals were clinically normal. RAD and CsA day-14 trough levels in the staggered group were the same or lower than trough levels in animals treated with either drug alone (RAD 27+/-3/Neoral 815+/-67 ng/ml).

CONCLUSIONS

(1) Administration of RAD + Neoral suppressed lung rejection more effectively than treatment with either drug alone. (2) Trough levels did not differ between monotherapy and staggered combination therapy for RAD but were lower for CsA. These results suggested that pharmacological, rather than pharmacokinetic, interactions between the parent drugs were responsible for the potentiation of immunosuppression when these drugs were coadministered. 3) Staggered administration of RAD+Neoral avoided the pharmacokinetic interactions that caused the elevated drug blood levels and poor tolerability caused by simultaneous administration. Thus, we could potentiate efficacy and improve tolerability by staggering administration of RAD and Neoral.

Development of a high-performance liquid chromatographic-electrospray mass spectrometric assay for the specific and sensitive quantification of the novel immunosuppressive macrolide 40-O-(2-hydroxyethyl)rapamycin

It was our objective to develop a rapid, sensitive and specific assay to quantify the immunosuppressive macrolide 40-O-(2-hydroxyethyl)rapamycin (SDZ-RAD) in blood of transplant patients. SDZ-RAD was extracted from blood by solid-liquid extraction. SDZ-RAD and its internal standard 28,40-diacetyl rapamycin were quantified using HPLC-electrospray MS. The assay was linear from 0.1 to 100 microg/l (r2 = 0.99). The mean recovery was 83% for SDZ-RAD and 80.5% for the internal standard. The mean day-to-day precision was 8.0%. Extracted samples were stable at 20 degrees C for at least 48 h and SDZ-RAD blood samples at -80 degrees C for at least six months.

Granulocyte-specific monoclonal antibody technetium-99m-BW 250/183 and indium-111 oxine-labelled leucocyte scintigraphy in inflammatory bowel disease

Thirty-three patients suspected of suffering from inflammatory bowel disease were studied. Autologous leucocytes were labelled with indium 111 oxine and re-injected simultaneously with 0.3-0.5 mg of technetium 99m granulocyte-specific monoclonal antibody BW 250/183. Two scans were obtained, the early scan 3-4 h postinjection (p.i.) and the late scan 18-24 h p.i. Using the endoscopy study as standard, the diagnostic accuracy of both agents was determined. Sensitivity, specificity and accuracy of 111In scans was 88.8%, 100.0% and 93.7% at 4 h and 94.7%, 100.0% and 96.9% at 24 h, respectively. Concerning the results using antibodies, the values were 61.1%, 100.0% and 78.1% at 4 h and 78.9%, 92.8% and 84.8% at 24 h, respectively. Segmental analysis showed concordance in 89.3% and 93.3% of the cases at 4 and 24 h, respectively. Though less sensitive and less accurate than scanning employing indium 111 leucocytes, BW 250/183 granulocyte-specific scintigraphy can be used for inflammatory bowel disease diagnosis and localization.