Stability of clozapine tablets repackaged in dose administration aids using repackaging machines.

BACKGROUND: The use of dose administration aids in automated ward dispensing devices requires the repackaging of medications, which may impact their stability compared with the original manufacturer's packaging. OBJECTIVES: This study aimed to assess the physical and chemical stability of clozapine tablets for up to 84 days after repackaging. METHODS: A total of 900 tablets of clozapine 100 mg (Viatris) were repackaged and stored under five different conditions to conduct physical and chemical stability tests on days 0, 28, 56 and 84. The results were compared with control tablets in their original packaging. Visual inspections of tablet appearance were performed. Physical tests included assessments of mass uniformity, friability and resistance to crushing, following the standards of the European Pharmacopoeia 11th edition. The chemical stability was determined using ultra-high performance liquid chromatography with tandem-mass spectrometry detection (UHPLC-MS/MS) to measure clozapine concentration, N-desmethyl-clozapine, and monitor clozapine degradation to detect formation of any degradation products other than N-desmethyl-clozapine. RESULTS: Visual examination showed changes in the appearance of tablets only in those stored under UV light. Mass uniformity met standards for all tablets over 84 days. None passed the friability test due to tablet cracking after tumbling. A gradual deterioration in tablet hardness was observed with the resistance to crushing test. In terms of chemical stability, N-desmethyl-clozapine was undetected in any of the tablets stored under all conditions, and the mean concentration of clozapine remained within the target range over 84 days. CONCLUSION: N-desmethyl-clozapine was not detected and clozapine concentrations remained stable under all storage conditions. The tablets were compliant with the mass uniformity test in each condition. However, the tablets were cracked in the friability test and gradual deterioration in tablet hardness was observed. In the light of these results, the Vinatier Hospital pharmacy has chosen to establish a shelf life for clozapine tablets of 84 days.

Comparative study between direct analysis in whole blood, oral fluid, and declaration of consumption for the prevalence of nonsteroidal anti-inflammatory drugs and acetaminophen in ultratrail runners.

Ultratrail running is a sport with growing number of adherents. To complete ultratrail despite physical issues such as joint and muscle pain, many runners use nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen. Studies asking participants about their consumption of drugs during ultratrail revealed a prevalence of NSAIDs and acetaminophen up to 70% and 25%, respectively. The aims of the present study were to determine the prevalence of NSAIDs and acetaminophen for 81 runners during the 2021 Ultratrail du Mont Blanc® (UTMB®) using direct analysis of dried blood spots (DBS) and oral fluid (OF) and to compare results with the declaration of consumption by runners; this is to identify the most relevant method to study the prevalence of drugs. Our results show a prevalence of NSAIDs of 46.6% using DBS, 18.5% using OF, and 13.8% based on a questionnaire. Prevalence of acetaminophen were 30.1%, 30.9%, and 22.5% using DBS, OF, and questionnaire, respectively. From this study, we conclude that the analysis of drugs directly in DBS is the most relevant tool to determine the prevalence in ultratrail events.

Serum Concentrations of Lidocaine During Bariatric Surgery.

Lidocaine has been shown to be clinically beneficial during bariatric surgery. However, information about lidocaine serum concentrations in this setting is scarce. This prospective clinical trial included 42 obese patients undergoing laparoscopic bariatric surgery. They received lidocaine based on adjusted body weight. Administration began with a 1.5 mg·kg bolus of intravenous lidocaine followed by a continuous infusion of 2 mg·kg·hour. After skin closure, administration was decreased to 1 mg·kg·hour until discharge from the recovery room. No serum concentrations of lidocaine were outside the usual accepted range (1.5-5 µg·mL).

[Accreditation of the toxicological screening: recommendations of the SFBC-SFTA group]. / Accréditation du criblage toxicologique : recommandations du groupe SFBC-SFTA.

Toxicological screening is a specific approach to analytical toxicology that uses analytical tools such as GC-MS, LC-UV (diode array) or LC-MS. Toxicological screening allows the detection and simultaneous identification of a large number of compounds. The results may be based on the use of one or more techniques. As part of the accreditation process for medical biology examinations according to standard NF EN ISO 15189, the group from SFTA and SFBC recommends an approach to accredit toxicological screening. Indeed, the complexity of the accreditation of this analysis comes in particular from the high number of compounds that can be detected. Validation parameters are discussed in the specific context of toxicological screening by considering two distinct approaches: the simple identification of compounds, or the identification and estimation of a range of concentration related to clinical outcomes.

Red Blood cell IMPDH activity in adults and children with or without azathioprine: Relationship between thiopurine metabolites, ITPA and TPMT activities.

Inosine monophosphate dehydrogenase (IMPDH) is considered as the limiting enzyme of thiopurine metabolism for the formation of 6-thioguanine nucleotides (6-TGN). No data are available on the influence of RBC IMPDH activity on the metabolism of thiopurine drugs in individuals with IBD. The aims of this study were as follows: (a) to carry out a phenotypic study of RBC IMPDH activity in adults and children treated or not with azathioprine (AZA) for autoimmune diseases, and (b) to investigate the relationship between the activities of IMPDH, thiopurine metabolites, inosine triphosphatase (ITPA) and thiopurine methyltransferase (TPMT). IMPDH activity was determined in 97 adults and 67 children treated or not with AZA. 6-Thioguanine nucleotides (6-TGN), 6-methylmercaptopurine nucleotide (6-MeMPN) levels, and ITPA as well as TPMT activities were measured in RBCs by HPLC. Using the Gaussian mixture model, distribution of IMPDH activity was evaluated. Influence of age, sex and AZA treatment on IMPDH activity was also assessed. A bimodal distribution in IMPDH activity was found with 87% of patients exhibiting normal activity and 13% of patients with high activity. No influence of age, sex and AZA therapy was found. There is no relationship between TPMT, ITPA and IMPDH activities. A negative correlation between IMPDH activity and 6-MeMPN was shown in adults and children (rs = -0.335 P = 0.014 and rs = -0.383 P = 0.012, respectively). Our results suggest that AZA-treated patients exhibiting lower IMPDH activity could have higher Me-6MPN levels with higher risk of hepatotoxicity. We demonstrated that RBC matrix could be an interesting alternative to lymphocyte matrix to monitor thiopurine metabolites and enzyme activity.

ITPA Activity in Children Treated by Azathioprine: Relationship to the Occurrence of Adverse Drug Reactions and Inflammatory Response.

Azathioprine (AZA), a thiopurine drug, is widely used in the treatment of children with immunological diseases such as inflammatory bowel disease (IBD) and autoimmune hepatitis (AIH); however, interindividual variability in the occurrence of adverse drug reactions (ADRs) and drug response is observed. This study investigated (i) the relationships between inosine triphosphate pyrophosphatase (ITPA) activity, an enzyme involved in thiopurine metabolism, and the occurrence of ADRs in children with immunological disease on AZA therapy, and (ii) the relationship between ITPA activity and the inflammatory activity observed in children with IBD. ITPA and TPMT activities were determined in 106 children with immunological disease on AZA therapy. Markers of hepatotoxicity, myelotoxicity, pancreatitis and inflammation as well as clinical information were retrospectively collected during regular medical visits. No significant association was found between ITPA activity and hepatotoxicity or clinical ADRs such as cutaneous reactions, arthralgia, flulike symptoms and gastrointestinal disorders. Concerning myelotoxicity, a significant relation was observed between ITPA activity and RBC mean corpuscular volume (MCV; p=0.003). This observation may be related to the significant relationship found between high ITPA activity and the increase in γ-globulin level reflecting inflammation (p=0.005). In our study, ITPA activity was not associated with occurrence of ADRs, but a relationship between high ITPA activity and γ-globulin, a marker of inflammation, was found in children with IBD. Therefore, measurement of ITPA activity may help to identify children with IBD predisposed to residual inflammation on AZA therapy. Further prospective studies are needed to confirm this result.

ITPA Activity in Adults and Children Treated With or Without Azathioprine: Relationship Between TPMT Activity, Thiopurine Metabolites, and Co-medications.

BACKGROUND: The implication of inosine triphosphate pyrophosphatase (ITPA) on thiopurine drug response variability has been investigated but little data are available on its role on thiopurine metabolites. The ability of ITPA to modify the thiopurine metabolite levels is currently used to optimize azathioprine (AZA) therapy in relation to thiopurine S-methyltransferase (TPMT) activity, the aim of this study is to investigate ITPA phenotype in a large population and to evaluate the relation between ITPA and TPMT activities and thiopurine metabolites. METHODS: ITPA activity was determined in 183 adults and 138 children with or without AZA therapy. 6-thioguanine nucleotides (6-TGN), 6-methylmercaptopurine nucleotides (6-MeMPN) levels, and ITPA as well as TPMT activities were measured in red blood cells. Using the Gaussian mixture model, distribution of ITPA activity was evaluated. Intraindividual variability and influence of age, sex, AZA treatment and associated co-medications on ITPA activity were also assessed. RESULTS: This retrospective study shows a quadrimodal distribution in ITPA activity. No influence of age, sex, AZA therapy, and co-medications was found. In adults, ITPA activity was not significantly associated with 6-TGN or 6-MeMPN concentrations, whereas a weak negative correlation was observed with 6-MeMPN levels in pediatric populations (rs = -0.261; P = 0.024). A weak positive correlation was observed between ITPA and TPMT activities in children (rs = 0.289; P = 0.001). CONCLUSIONS: ITPA activity was poorly influenced by nongenetic parameters and has no influence on 6-TGN and 6-MeMPN concentrations in adults and only a weak correlation with 6-MeMPN and TPMT activity in children. These results demonstrate that ITPA is not a rate-limiting enzyme in the formation of 6-TGN but suggest that a decrease in ITPA activity in children may be a risk factor for accumulation of 6-MeMPN in cells.

Determination of inosine 5'-monophosphate dehydrogenase activity in red blood cells of thiopurine-treated patients using HPLC.

Thiopurine drugs are commonly used in immune diseases and to a lesser extent, in transplant rejection prophylaxis: however interindividual variability in drug response and in the occurrence of adverse events is observed. Genetic variation in thiopurine S-methyltransferase (TPMT) doesn't completely explain the occurrence of all adverse events and drug response variability. The potential implication of other enzymes involved in thiopurine metabolism, such as ITPA, has been investigated over the last decade but little data is available on inosine 5'-monophosphate dehydrogenase (IMPDH) in patients treated with thiopurine drugs. The authors reported a HPLC method to determine IMPDH activity in the red blood cells (RBCs) of thiopurine-treated patients. IMPDH activity was evaluated by enzymatic conversion of inosine 5'-monophosphate (IMP) to xanthosine 5'-monophosphate (XMP). The XMP formed was analyzed on a Luna® NH2 stationary phase, a weak anion exchange phase that exhibits both ionic and hydrophobic properties. XMP was eluted below 15min. Intra-assay and inter-assay precisions were below 9% for RBCs supplemented with 2, 40 and 80µmol/L of XMP. IMPDH activity was measured in adults without thiopurine treatment as well as in adult and paediatric patients treated with thiopurines. A wide interindividual variability in IMPDH activity in RBCs was observed. No difference in IMPDH activity was found between untreated subjects and adult and paediatric patients on thiopurine therapy (median value 11.8, 7.9 and 7.7nmol XPM/g Hb/h respectively). The method described is useful in the determination of IMPDH phenotype from patients on thiopurine therapy and in the investigation of the potential relationship between IMPDH activity in RBCs and the occurrence of adverse events and drug response variability.

Determination of inosine triphosphate pyrophosphatase phenotype in human red blood cells using HPLC.

BACKGROUND: Thiopurine drugs, widely used in cancer chemotherapy, inflammatory bowel disease, and autoimmune hepatitis, are responsible for common adverse events. Only some of these may be explained by genetic polymorphism of thiopurine S-methyltransferase. Recent articles have reported that inosine triphosphate pyrophosphatase (ITPase) deficiency was associated with adverse drug reactions toward thiopurine drug therapy. Here, we report a weak anion exchange high-performance liquid chromatography method to determine ITPase activity in red blood cells and to investigate the relationship with the occurrence of adverse events during azathioprine therapy. METHODS: ITPase activity was assessed by the enzymatic conversion of inosine triphosphate (ITP) to inosine monophosphate (IMP). The reaction was stopped by heating for 3 minutes at 120°C. IMP, inosine diphosphate, and ITP were analyzed on a Hypersil APS-2 column, a weak anion exchange phase that exhibits both ionic and hydrophobic properties. RESULTS: The chromatographic method reported allows the analysis of IMP, inosine diphosphate, and ITP in a single run in <12.5 minutes. The method was linear in the range 5-1500 µmole/L of IMP. Intraassay and interassay precisions were <5% for red blood cell lysates supplemented with 50, 500, and 1000 µmole/L IMP. Km and Vmax evaluated by Lineweaver-Burk plot were 677.4 µmole/L and 19.6 µmole·L·min, respectively. The frequency distribution of ITPase from 73 patients was investigated. CONCLUSIONS: The method described is useful to determine the ITPase phenotype from patients on thiopurine therapy and to investigate the potential relation between ITPase deficiency and the occurrence of adverse events.