Evaluation of tacrolimus sorption to PVC- and non-PVC-based tubes in administration sets: Pump method vs. drip method

A proof of principle study using radiopharmaceuticals to quantify and localize container-content interactions in medical syringes

The sorption of drugs onto their contents is a known phenomenon that is difficult to analyse precisely. The purpose of this study was to present a non-invasive method for locating and quantifying sorption phenomena using radiopharmaceuticals. Radiopharmaceutical are medicines armed with a radionuclide enabling quantification and imaging using dedicated scanners. The sorption of nine different radiopharmaceuticals on 2- and 3-part syringes was investigated. These syringes were filled with the studied radiopharmaceutical solutions and stored immobile for 3 h. At different times ranging from 0 to 180 min, 10 µL were taken from the syringes and the radioactivity of these samples was determined by a gamma counter. 5 radiopharmaceuticals exhibited no significant sorption at any time point in both 2 and 3-parts syringes, but 4 radiopharmaceuticals exhibited sorption losses varying from 20 to 33% after 3 h contact with 3-part-syringes, but no sorption on 2-part syringes at any time point. [^99mTc]Tc-tetrofosmine Single Photon Emission Computed Tomography/Computed Tomography imaging indicated clearly that the interactions were located on the rubber plunger of the 3-part-syringes. The specific nature of radiopharmaceuticals allowed their use as an innovative method to quantify and localize drug sorption phenomena.

Low dose rabbit antithymocyte globulin is non-inferior to higher dose in low-risk pediatric kidney transplant recipients

BACKGROUND

Currently, there is no consensus among pediatric kidney transplant centers regarding the use and regimen for immunosuppressive induction therapy.

METHODS

In this single center, retrospective cohort study, pediatric kidney transplant recipients transplanted between 1 May 2013 and 1 May 2018 with rabbit antithymocyte globulin (rATG) induction were included. We stratified patients based on immunological risk, with high risk defined as those with repeat transplant, preformed donor specific antibody, current panel-reactive antibodies > 20%, 0 antigen match and/or African-American heritage. Outcome of interest was the incidence of biopsy proven acute rejection by 1 year.

RESULTS

A total of 166 patients met inclusion criteria. Age of patients was 12 years (11 mo-21 y), (median, range), 21.5% received a living donor transplant and 50.6% were female. Low-immunologic-risk patients were divided into 2 groups, those who received the lower cumulative rATG dose of ≤ 3.5 mg/kg (n = 52) versus the higher cumulative dose of > 3.5 mg/kg (n = 47). The median total dose in the lower dose group was 3.1 (IQR 0.3) and 4.4 (IQR 0.8) in the higher dose group, P < 0.001. Rejection rate did not differ significantly between the 2 treatment groups (7/52 vs. 6/47). None in the lower dose group developed BK nephropathy versus 3 in the higher dose group. Graft loss due to BK nephropathy occurred in 1 patient in the higher dose group. Graft loss in the whole cohort at 12 months was a rare event (n = 1) with 99.5% graft survival and 100% patient survival.

CONCLUSIONS

Reduced rATG dosing (≤ 3.5 mg/kg) when compared to higher dosing (> 3.5 mg/kg) is safe and effective in low-risk pediatric kidney transplant recipients without increasing risk of rejection. A higher resolution version of the Graphical abstract is available as Supplementary information.

Insulin Adsorption onto PE and PVC Tubings

We investigate the adsorption of insulin onto PE and PVC materials by using HPLC measurements and computer simulations. We interpret the experiments by calculating the Gibbs free energy profiles during the adsorption process. The values of free energy of adsorption show a good agreement with the experimental measurements. The adsorption of insulin onto the different materials is characterized through the conformational changes with respect to its conformation in water and the interfacial regions, which are described by specific arrangements of polymer chains, water, insulin, and plasticizer molecules.

Physicochemical Stability of a Novel Tacrolimus Ophthalmic Formulation for the Treatment of Ophthalmic Inflammatory Diseases

Tacrolimus is an immunosuppressant used to treat a large variety of inflammatory or immunity-mediated ophthalmic diseases. However, there are currently no commercial industrial forms available that can provide relief to patients. Various ophthalmic formulations have been reported in the literature, but their stability has only been tested over short periods. The objective of this study was to evaluate the physicochemical stability of a preservative-free tacrolimus formulation (0.2 and 1 mg/mL) at three storage temperatures (5 °C, 25 °C and 35 °C) for up to nine months in a multidose eyedropper. Analyses performed were the following: visual inspection and chromaticity, turbidity, viscosity, size of micelles, osmolality and pH measurements, tacrolimus quantification by a stability-indicating liquid chromatography method, breakdown product research, and sterility assay. In an in-use study, tacrolimus quantification was also performed on the drops emitted from the eyedroppers. All tested parameters remained stable during the nine month period when the eyedrops were stored at 5 °C. However, during storage at 25 °C and 35 °C, several signs of chemical instability were detected. Furthermore, a leachable compound originating from a silicone part of the eyedropper was detected during the in-use assay. Overall, the 0.2 mg/mL and 1 mg/mL tacrolimus ophthalmic solutions were physicochemically stable for up to nine months when stored at 5 °C.

Critical Drug Loss Induced by Silicone and Polyurethane Implantable Catheters in a Simulated Infusion Setup with Three Model Drugs

Silicone and polyurethane are biocompatible materials used for the manufacture of implantable catheters, but are known to induce drug loss by sorption, causing potentially important clinical consequences. Despite this, their impact on the drugs infused through them is rarely studied, or they are studied individually and not part of a complete infusion setup. The aim of this work was to experimentally investigate the drug loss that these devices can cause, on their own and within a complete infusion setup. Paracetamol, diazepam, and insulin were chosen as models to assess drug sorption. Four commonly used silicone and polyurethane catheters were studied independently and as part of two different setups composed of a syringe, an extension set, and silicone or polyurethane implantable catheter. Simulated infusion through the catheter alone or through the complete setup were tested, at flowrates of 1 mL/h and 10 mL/h. Drug concentrations were monitored by liquid chromatography, and the silicone and polyurethane materials were characterized by ATR-IR spectroscopy and Zeta surface potential measurements. The losses observed with the complete setups followed the same trend as the losses induced individually by the most sorptive device of the setup. With the complete setups, no loss of paracetamol was observed, but diazepam and insulin maximum losses were respectively of 96.4 ± 0.9% and 54.0 ± 5.6%, when using a polyurethane catheter. Overall, catheters were shown to be the cause of some extremely high drug losses that could not be countered by optimizing the extension set in the setup.

[Infusion sets in neonatology: What practices in France?]

OBJECTIVES

Therapeutic management of ill newborns can require complex infusion practices using medical devices (MD). Currently, there does not exist any recommendations concerning these infusion practices. The objective of this work was to study and characterise French infusion methods neonatal and neonatal intensive care units.

MATERIALS AND METHODS

The study was performed in 2019, during 6 months. French hospitals possessing high (type 3) or medium (type 2B) grade maternity ward were contacted and asked to complete a 5 part online survey, to gather general information about the hospital/ward, infusion methods (overall and detailed), and detailed information about the medications and MD used.

RESULTS

The participation level was of 19.6 % Type 3 maternities use overall two-times more MD than those of type 2B. The vascular access device most commonly used was a single lumen catheter (80.6 % of infusion methods). 100 % of the hospitals having answered used multi-access devices (three-way tap, multiport infusion manifold, Y-extension lines) and 93.5 % used a pump-infusor. Lipidic filters for parenteral nutrition were used in 78.6 % of the hospitals. Two general standard of infusion methods were isolated: a simple version with two access points (type 2B hospitals), and a complex one with five access points (from hospitals with type 3 maternities).

CONCLUSIONS

Neonatal infusion practices in France are very heterogeneous, thus exposing the patients to a degree of variability during their therapeutic management. This work is a first step forwards to help analyse and anticipate the risks of content/container interactions caused by infusion practices.

Understanding and Characterizing the Drug Sorption to PVC and PE Materials

Characterizing the sorption of drugs onto polyvinylchloride (PVC) and polyethylene (PE) materials in terms of thermodynamic adsorption properties and atomistic details (local arrangements, orientation, and diffusion) is fundamental for the development of alternative materials that would limit drug sorption phenomena and plasticizer release. Here, a combination of experiments and sophisticated calculations of potential of mean forces are carried out to investigate the sorption of paracetamol and diazepam to PE and PVC surfaces. The simulated Gibbs free energies of adsorption are in line with the experimental interpretations. The polymer-drug-water interface is then characterized at the molecular scale by an in-depth investigation of local properties such as density, orientation, and diffusion.

Assessment of efficacy of postinfusion tubing flushing in reducing risk of cytotoxic contamination

PURPOSE

Infusion of cytotoxic drugs carries the risk of occupational exposure of healthcare workers. Since disconnecting an infusion line is a source of contamination, flushing of tubing after infusion of cytotoxic agents is recommended, but the optimal volume of rinsing solution is unknown. The objective of this study was to assess whether postinfusion line flushing completely eliminates cytotoxics.

METHODS

Infusions were simulated with 3 cytotoxics (gemcitabine, cytarabine, and paclitaxel) diluted in 5% dextrose injection or 0.9% sodium chloride injection in 250-mL infusion bags. Infusion lines were flushed using 5% dextrose injection or 0.9% sodium chloride solution at 2 different flow rates. The remaining concentration of cytotoxics in the infusion line was measured by a validated high-performance liquid chromatography (HPLC) method after passage of every 10 mL of flushing volume until a total of 100 mL had been flushed through.

RESULTS

All cytotoxics remained detectable even after line flushing with 80 mL of flushing solution (a volume 3-fold greater than the dead space volume within the infusion set). Gemcitabine and cytarabine were still quantifiable via HPLC even after flushing with 100 mL of solution. Efficacy of flushing was influenced by the lipophilicity of drugs but not by either the flushing solvent used or the flushing flow rate. After 2-fold dead space volume flushing, the estimated amount of drug remaining in the infusion set was within 0.19% to 0.56% of the prescribed dose for all 3 cytotoxics evaluated.

CONCLUSION

Complete elimination of cytotoxics from an infusion line is an unrealistic objective. Two-fold dead space volume flushing could be considered optimal in terms of administered dose but not from an environmental contamination point of view. Even when flushed, the infusion set should still be considered a source of cytotoxic contamination.

Impact of alternative materials to plasticized PVC infusion tubings on drug sorption and plasticizer release

Medical tubings in plasticized polyvinylchloride (PVC) are widely used for the infusion of medications but are known in some cases to cause content-container interactions (drug sorption and plasticizer release). The aim of this study was to assess interactions between drugs and five alternative materials to a reference plasticized PVC intravenous (IV) infusion tubing: three were PVC coextruded with polyethylene (PE), polyurethane (PU) or a thermoplastic elastomer (Styrene-EthyleneButadiene-Styrene (SEBS)) and two were SEBS or thermoplastic olefin (TPO) monolayer tubings. Diazepam and insulin were chosen as respective reference of absorption and adsorption while paracetamol acted as a negative control. The concentration of each drug was quantified with liquid chromatography to evaluate a potential loss after a static contact condition and simulated infusion at 1 mL/h and 10 mL/h dynamic condition by an electric syringe pump. A characterization of each material's surface was performed by Fourier transform infrared spectroscopy in attenuated total reflection mode (ATR-FTIR) and by measurement of surface zeta potential. Plasticizer release was quantified by gas chromatography coupled with mass spectrometry (GC-MS). For all tubings except PVC/PU, no loss of paracetamol was observed in any condition. Diazepam sorption appeared to be less important with PVC/PE, PVC/SEBS, SEBS and TPO tubings than with PVC, but was more important when using PVC/PU tubings. PVC tubings induced the least loss of insulin amongst all the studied materials. Surface analysis by ATR-FTIR highlighted the presence of a plasticizer (that could be attributed to Tris (2-Ethylhexyl) Trimellitate (TOTM)) in the coextruded SEBS layer of PVC/SEBS, which could have influenced drug sorption, probably as a consequence of a migration from the PVC layer. Coextruded PVC/SEBS and PVC/PE presented the lowest zeta potential of all studied materials with respective values of -39 mV and -36 mV and were related to the highest sorption of insulin while PVC/PU with the highest zeta potential (about -9 mV) presented the highest absorption of diazepam. Coextruded layered materials appeared to have a lower plasticizer release than PVC alone. As a conclusion, PVC/PE and thermoplastic elastomers alone or coextruded with PVC could be interesting alternatives to PVC tubings with regards to sorption phenomena and plasticizer release.

Assessment of Patient Exposure to Leachables From Lyophilized Drug Formulations Following Reconstitution, Storage, and Administration via Polymeric Packaging/Delivery Systems

It has been demonstrated that lyophilized drug formulations have an increased propensity to leach substances from the rubber stoppers comprising their primary packaging system when compared to aqueous liquid formulations stored in the same manner. Unfortunately, patient exposure to leachables originating in lyophilized drug products is not known. To that end, the goal of this study was to assess patient exposure to these leachables after reconstitution, storage, and administration of the lyophilized drug. To achieve this goal, several leachables present in 2 commercial lyophilized drug products were quantified after contact with polyvinyl chloride and non-polyvinyl chloride medication bags as well as an infusion set for durations of 15 min to 7 days at refrigerated and ambient temperature. The results obtained from this study showed that the bag's material of construction and the drugs formulation did not impact the mass of the leachables administered. Conversely, the mass of each leachable administered to the patient was reduced or eliminated as the contact duration with the intravenous bag and the temperature increased. However, for shorter contact durations, refrigerated storage, and higher molecular weight compounds, the patient would be exposed to a majority of the leachables originating from the vial.