Stability of Vancomycin in Icodextrin Peritoneal Dialysis Solution

Background:

Icodextrin is a glucose polymer used as an alternative osmotic agent in peritoneal dialysis (PD) solutions. There are few data regarding the long-term stability of vancomycin in icodextrin PD solution.

Objective:

To determine the chemical stability of vancomycin in icodextrin PD solution in polyvinyl chloride containers over a 7 day period at 4, 24, and 37 °C.

Methods:

Study samples were prepared by adding 2000 mg vancomycin HCl to commercially available 2.0 L bags of icodextrin 7.5% PD solution. Nine bags were prepared and stored in the following conditions: 3 under refrigeration (5 °C), 3 at room temperature (24 °C), and 3 at body temperature (37 °C). Samples were withdrawn from each bag immediately after preparation and at predetermined intervals over the subsequent 7 days. Solutions were visually inspected for precipitation, cloudiness, or discoloration at each sampling interval. Total concentration of vancomycin in dialysate fluid was determined by high performance liquid chromatography.

Results:

Under refrigeration, a mean ± SD of 99.7% ± 0.5% of the initial vancomycin concentration remained at 168 hours (7 days). At room temperature, 97.5% ± 3.4% remained at 168 hours. At body temperature, 94.3% ± 3.9% remained at 24 hours. Stability was not assessed beyond these time points.

Conclusions:

Premixed vancomycin-icodextrin PD solutions, whether stored refrigerated or at room temperature, were found to be stable for up to 7 days. However, we recommend that these solutions be kept refrigerated whenever possible. Solutions stored at body temperature were stable for up to 24 hours, permitting the practice of prewarming solutions prior to administration.

In-line ultrasonic monitoring for sediments stuck on inner wall of a polyvinyl chloride pipe

This research verified the applicability and effectiveness of the ultrasonic monitoring of sediments stuck on the inner wall of polyvinyl chloride (PVC) pipes. For identifying the transmittance of acoustic energy and the speed of sound in the PVC material, the pulse-echo ultrasonic testing was conducted for PVC sheets of different thicknesses. To simulate the solidified sediment, the hot melt adhesive (HMA) was covered on the inner wall of the PVC pipe in different heights. From the experiment, the speeds of sound in the PVC and the HMA materials were obtained as about 2258 and 2000 m/s, respectively. The thickness of the materials was calculated through the signal processing such as taking the absolute value and low pass filtering, the echo detection, and the measurement of the time of flight. The errors between actual and measured thicknesses of PVC sheets were below 5%. In the case of the substance stuck on the inner wall, the errors were below 2.5%. Since the pulse-echo ultrasonic inspection is available on the outer surface and its measurement accuracy was over 95%, it can be an efficient and effective in-service structural health monitoring for the sediment on the wall of PVC pipes.

Stability of stock and diluted rituximab

PURPOSE

The stability of two rituximab preparations stored in polyvinyl chloride (PVC) bags at 4 °C for up to 14 days was investigated.

METHODS

Two types of test samples were prepared: (1) 10 mL of rituximab solution (10 mg/mL) drawn directly from the original manufacturer's vial and injected into sterile glass vials and (2) 3 mL of rituximab 10 mg/mL mixed with 17 mL of 0.9% sodium chloride injection and injected into sterile PVC bags. Samples were analyzed immediately after preparation and after storage at 4 °C for 3, 7, and 14 days. Rituximab activity at the designated time points was measured using a validated enzyme-linked immunosorbent assay (ELISA) method. Chemical stability was defined as the retention of ≥85% of the drug's initial activity. Physical stability was evaluated through visual inspection for color changes or precipitate formation under normal laboratory lighting.

RESULTS

The results of ELISA testing (with spectrophotometric absorbance assessment) indicated that the percentage of initial rituximab activity retained was over 85% for both test preparations under the storage conditions evaluated; no changes in color or turbidity were observed in any of the test samples. These findings suggest that extending the expiration dating of both stock and diluted rituximab solutions beyond the manufacturer-specified limit of 24 hours is feasible.

CONCLUSION

Rituximab 10 mg/mL undiluted in glass vials and 1.5 mg/mL diluted in 0.9% sodium chloride injection in PVC bags are stable at 4 °C for up to 14 days.

Experimental study on infusion devices containing polyvinyl chloride: to what extent are they di(2-ethylhexyl)phthalate-free?

The use of medical devices containing highly criticized phthalates including di(2-ethylhexyl) phthalate (DEHP) has been challenged by European directive 2007/47/CE, put into effect in March 2010. New plasticizers are now being used to soften PVC in medical devices: trioctyltrimellitate (TOTM), di-isononyl-cyclohexan-1,2-dicarboxilate (DINCH) and di(2-ethylhexyl) terephthalate (DEHT). To quantify DEHP in nine DEHP-free medical devices made of PVC softened by alternative plasticizers, high performance liquid chromatography analysis with ultraviolet detection at 220 nm wavelength was achieved. An NMR spectroscopy was performed to confirm DEHP presence. Only two medical devices out of the nine tested were truly without DEHP. One of them showed traces of DEHP exceeding the threshold contamination of 0.1% in plastic mass set by REACH regulations. TOTM plasticizer is still incriminated when polyvinyl-chloride (PVC) is contaminated with DEHP. Manufacturers must verify the purity of their raw material, not only on PVC, but also on other soft plastics entering into the composition of medical infusion devices. The clinical consequences of exposure to certain levels of DEHP have not been evaluated. A solution could be to use alternative PVC-free materials.

Effects of polyvinyl chloride overwrap film, high-oxygen modified atmosphere packaging, or ultra-low-oxygen modified atmosphere packaging on bone marrow discoloration in beef humerus, rib, thoracic vertebra, and scapula1

Meat retailers have reported bone marrow discoloration to be a problem, especially in modified atmosphere packages (MAP). Therefore, it is important to determine the prevalence and cause(s) of bone marrow discoloration in different beef bones and packaging systems. Thirty-six beef humeri, ribs, scapulas, and thoracic vertebrae from USDA Select and Choice carcasses were obtained from a commercial abattoir, cut into 2.54-cm-thick sections at 4 d postmortem, and packaged into 1 of 3 systems: 1) polyvinyl chloride film (PVC) overwrap; 2) high-oxygen (80% O2, 20% CO2) MAP; and 3) ultra-low-oxygen (70% N2, 30% CO2) MAP. Instrumental reflectance and visual color scores were taken on d 0, 2, and 4, and on d 0 to 4 of display, respectively. Bone marrow was extracted from humeri, ribs, and thoracic vertebrae for analysis but not from scapulas. Ribs, scapulas, and thoracic vertebrae packaged in PVC and high-oxygen MAP developed undesirable gray or black discoloration. In ultra-low-oxygen MAP, mean visual color scores were acceptable throughout the entire display period. Discoloration (darkening) was more extensive for ribs, scapulas, and thoracic vertebrae than for humeri, especially for bones packaged in PVC and high-oxygen MAP. Humeri had lower (P < 0.05) a* values (larger positive a* values indicate a redder color) than the other bones. The a* values for ribs, scapulas, and thoracic vertebrae decreased (P < 0.05) over time. Chroma showed that bone marrow discolored during display, but graying was dramatically less for all bones packaged in ultra-low-oxygen MAP and for humeri in PVC and high-oxygen MAP. Humeri marrow had lower (P < 0.05) 2-thiobarbituric acid reactive substances (TBARS) than did ribs and thoracic vertebrae marrow. Ultra-low-oxygen MAP resulted in the least amount of change in TBARS from d 0 to 4, whereas thoracic vertebrae marrow had greater (P < 0.05) TBARS values at d 4 of display than at d 0 in PVC and high-oxygen MAP. Humeri marrow had dramatically less total Fe and hemoglobin than did that of ribs and thoracic vertebrae for all packaging systems. Myoglobin was undetectable in humeri marrow. The much larger amounts of Fe and hemoglobin in ribs and thoracic vertebrae likely contribute to marrow discoloration. Bone marrow discoloration was distinct in ribs, scapulas, and thoracic vertebrae packaged in PVC or high-oxygen MAP. Bones packaged in ultra-low-oxygen MAP had minimal discoloration.

Characterization of estrogenic compounds in medical polyvinyl chloride tubing by gas chromatography-mass spectrometry and estrogen receptor binding assay

BACKGROUND

In 2001, the U.S. Food and Drug Administration (FDA) convened to conduct a safety assessment of a plasticizer, di(2-ethylhexyl) phthalate (DEHP), released from polyvinyl chloride (PVC) medical devices. Hospitalized patients may be exposed to high concentrations of plasticizers, antioxidants, and chemical contaminants in PVC medical devices during blood transfusion or hemodialysis, thus, making them vulnerable to more potentially adverse effects of these chemicals than healthy people. At the same time, recently, the effect of endocrine-disrupting chemicals on hospitalized patients has attracted a great deal of attention. This study aims to investigate the harmful effects of estrogenic compounds in medical PVC tubing by two approaches of gas chromatography-mass spectrometry (GC-MS) and estrogen receptor (ER) binding assay.

METHODS

Residual plasticizers, antioxidants, and chemical contaminants in PVC tubing were subjected to GC-MS in the full-scan mode with an original library for plastic additives. Such residual compounds in PVC tubing were screened at very low concentrations (10(-2)-10(5) nmol/l) to determine whether they competed with fluorescein-labeled estradiol for ER (alpha).

RESULTS

DEHP, 2-ethylhexanol, butylated hydroxytoluene, and 4-nonylphenol (NP) were detected in medical PVC tubing. In addition, only NP in PVC tubing was found to bind with ER.

CONCLUSIONS

The current study proves that the main residual chemical for estrogenic effect was NP in medical PVC tubing.

Loss of factor VIII activity during storage in PVC containers due to adsorption

Recombinant factor VIII concentrates are stable when administered in a reconstituted form according to the manufacturer's specifications, and undiluted via infusion with syringe mini-pumps. However many Haemophilia centres administer recombinant factor VIII further diluted in intravenous fluids for greater ease of administration. To investigate the stability of recombinant factor VIII during administration as a diluted infusion, reconstituted factor VIII was stored in polyvinylchloride (PVC) mini-bags undiluted (146 IU mL-1) and at factor VIII concentrations of 10 IU mL-1 and 2 IU mL-1. After 48 h of storage at room temperature in PVC mini-bags, the recoveries of factor VIII activity were 41.9% of the initial activity for the undiluted (146 IU mL-1) product and 43.7% of the initial activity for factor VIII diluted to 10 IU mL-1. For factor VIII diluted to 2 IU mL-1, the amount of factor VIII activity remaining at 48 h was only 1.8% of the initial activity. In contrast, 100% of factor VIII activity was recovered after 48 h when undiluted reconstituted product (146 IU mL-1) was stored in a syringe. To investigate the mechanism of factor VIII activity loss during storage, factor VIII samples collected after 0, 3 and 48 h of storage were analysed by immunoblotting with factor VIII antibodies. No evidence of factor VIII proteolytic degradation during storage was found, however, large amounts of factor VIII antigen were recovered from the empty PVC mini-bags following elution with denaturing detergent. We conclude that clinically significant losses of factor VIII activity occur during storage in PVC mini-bags and that the loss of activity is most likely due to protein adsorption onto the plastic surface. This loss of factor VIII activity during storage in PVC containers may substantially affect the safety and potential cost savings of administering recombinant factor VIII by continuous infusion.

PVC as a biomedical polymer--plasticizer and stabilizer toxicity

During the last 40 years PVC has become the most widely studied and understood polymeric biomaterial. The success of PVC compounds is due to their ability to fulfill the complex needs of the medical device industry. The range of properties they possess, which includes flexibility and low toxicity, is achieved by their various formulations. Plasticizers are used to meet many of the requirements and because of their ability to be extracted into biofluids they present the greatest toxicological risk. In his discussion, the author looks at the ingredients of compound formulations and the influence of plasticizers on the toxicity. A detailed report is provided of studies carried out in connection with di(2-ethylhexyl)phthalate (DEHP), the most extensively used plasticizer, and the author questions the validity of using the results of animal tests for the assessment of risk to humans. A description of the commercial production of PVC polymers and a review of the various pharmocopoeia and national standards and requirements are also included.

Effect of three plastic catheters on survival and growth of Pseudomonas aeruginosa

The effect of polyvinylchloride (PVC), polyurethane (PU) and siliconized latex (SL) catheters on the survival and growth of six non-mucoid and three mucoid strains of Pseudomonas aeruginosa was evaluated. Pseudomonas aeruginosa (1 x 10(8)) was incubated in PBS alone (control) or with 30 1-cm length segments of each catheter and the number of viable microorganisms was determined after 8 h, 1, 2, 5, 7 and 10 days. The presence of PVC catheters significantly favoured the survival and growth of non-mucoid strains in comparison to the control (P less than 0.05 at 5 days, P less than 0.01 at 7 days and thereafter); a similar result was observed with SL catheters (P less than 0.05 at 2 days, P less than 0.01 at 5 days and thereafter). No differences were observed with PU catheters. The number of mucoid microorganisms decreased with time in all controls and suspensions containing segments of catheter, but non-mucoid revertants appeared and quickly increased in the presence of PVC and SL (but not PU) catheters. Eluates of PBS previously containing PVC or SL segments induced a 100- to 500-fold increase in the growth of a non-mucoid strain in comparison with PBS alone. It is concluded that some plastic catheters can release substance(s) that favour the viability of P. aeruginosa.

Evaluation of long sampling tubes for remote monitoring by mass spectrometry

The long sampling tubes required for remote mass spectrometry alter the sampling system's performance characterized by sample flow, residence time, and 10 to 90% response time. We searched for an easy-to-handle tube with (1) a length of 30 m, (2) sample flow less than 50 ml.min-1, and (3) residence and response times approaching those predicted by our mathematical model. We tested tubes of various geometries and various commercially available materials by using them as inlet catheters for a quadrupole mass spectrometer (Centronic 200 MGA, Centronic Ltd, Craydon, UK). We measured their responses at 0 to 10% (on transients) and 10 to 0% (off transients) step changes in gas concentration for nitrogen, argon, nitrous oxide, oxygen, and carbon dioxide and 0 to 3% and 3 to 0% for halothane, enflurane, and isoflurane. With 5 polyethylene tubes, halothane response times were up to 38 times longer than predicted. One 30-m polyethylene tube combined a 158-ms response time for nitrogen and argon with a 2,205-ms response time for halothane. Teflon, polyvinyl chloride, and stainless steel also proved to be unsuitable because of unacceptable signal distortion: the carbon dioxide response time for a 30-m Teflon tube was 2,600 ms. A glass tube showed the least signal distortion but was hard to handle. Our requirements were fulfilled by a 29.77-m tube made from nylon with a 1.00-mm inside diameter to which a 0.23-m length of nylon with a 0.25-mm inside diameter was added at the patient end. It offers (1) sample flow equals 46 ml.min-1, (2) residence time equals 11.1 seconds, and (3) response times approaching our theoretical predictions, that is, 159, 164, 180, 159, 188, 302, 298, and 300 ms (means of on and off transients) for nitrogen, argon, nitrous oxide, oxygen, carbon dioxide, halothane, enflurane, and isoflurane, respectively. This tube allows the accurate monitoring of breathing frequencies up to 25 and 50 breaths/min for volatile agents and gases, respectively.