Leaching of 2-(2-hydroxyethylmercapto) benzothiazole into contents of disposable syringes

Impact of blood collection devices on clinical chemistry assays

Blood collection devices interact with blood to alter blood composition, serum, or plasma fractions and in some cases adversely affect laboratory tests. Vascular access devices may release coating substances and exert shear forces that lyse cells. Blood-dissolving tube additives can affect blood constituent stability and analytical systems. Blood tube stoppers, stopper lubricants, tube walls, surfactants, clot activators, and separator gels may add materials, adsorb blood components, or interact with protein and cellular components. Thus, collection devices can be a major source of preanalytical error in laboratory testing. Device manufacturers, laboratory test vendors, and clinical laboratory personnel must understand these interactions as potential sources of error during preanalytical laboratory testing. Although the effects of endogenous blood substances have received attention, the effects of exogenous substances on assay results have not been well described. This review will identify sources of exogenous substances in blood specimens and propose methods to minimize their impact on clinical chemistry assays.

The effects of different types of syringes on equine spermatozoa

Control extender was incubated at 4 degrees C for 24 hours. Rubber or plastic syringe plungers were separately incubated in semen extender for 24 hours at 4 degrees C. Following incubation, the extender was stored at -20 degrees C until the time of semen collection. The treatments consisted of the following: Group A = equine semen plus control extender; Group B=equine semen plus extender incubated with rubber plungers and Group C=equine semen plus extender incubated in plastic plungers; Group D=equine semen plus control extended in rubber plunger syringes and Group E=equine semen plus control extender in plastic plunger syringer. Each group contained a 5-ml volume of semen and extender at a concentration of 1.0 x 10(8) sperm/ml. The number of live spermatozoa, percentage of progressively motile spermatozoa and rate of progressive motility were taken following collection and every 15 minutes for 1 hour following application of treatments. In experiment 2, treatments were allowed to incubate with semen for 45 minutes, then the extender was removed and was replaced with fresh extender. The rate of progressive motility and the percentage of progressively motile spermatozoa were taken immediately, at 45 minutes, and then every 15 minutes for 1 hour. In experiment 1, the number of live spermatozoa was not affected among the 5 groups. However, there was a decrease (P<0.01) in the rate of progressive motility and in the percentage of progressively motile spermatozoa in Group B compared with the remaining 4 treatment groups at 30, 45 and 60 minutes, with no differences noted when semen was held in syringes with a rubber or a plastic plunger. In experiment 2, the percentage of progressively motile spermatozoa increased after the addition of the control extender.

Artificial insemination and preservation of semen

Artificial insemination is an effective technique for improving utilization of stallions in breeding programs. When proper semen handling and insemination procedures are used, optimal pregnancy rates are attainable. When AI techniques are employed for mares and stallions with marginal fertility, pregnancy rates may be improved in comparison with natural mating. Preservation of stallion semen in the liquid or frozen state reduces the costs and potential health hazards incurred by transporting mares and provides easier access to genetic material that may otherwise be unavailable. Acceptable pregnancy rates are consistently obtained with cooled semen. Conversely, techniques for cryopreservation of stallion semen will require more refinement before the procedure can be considered commercially viable on a wide scale.

Comparative studies by cell culture and in vivo implantation test on the toxicity of natural rubber latex materials

Colony assay using V79 cells, the agar diffusion assay with L929 cells, and the 7-day rabbit muscle implantation test were employed to evaluate the cytotoxicity and tissue toxicity of natural rubber latex (NRL) materials. The in vivo implantation test showed that, among 13 histological parameters, thickness of inflammatory layer was the most useful index to evaluate tissue responses quantitatively. A comparison of the in vivo and in vitro parameters revealed the following correlations between the thickness of the inflammatory layer and cytotoxicity indices: Colony assay of the extracts, IC50: r = 0.80; Agar diffusion assay, Zone index: r = 0.73; Lysis index: r = 0.61. From these results, it appears that the colony assay provides a more reliable prediction of the tissue response than the agar diffusion assay.

Methods for predicting migration to packaged pharmaceuticals

The compatibility of the pharmaceutical product with packaging materials is an important parameter which must be evaluated during the product development process. This paper discusses the possibility that pertinent FDA methodology can be modified in a more efficient way using currently available analytical techniques. Several studies on potential migrants from packaging materials, such as heat-seal adhesives, amber polyethylene terephthalate (PET) containers, and rubber gaskets of aerosol valves, are presented to show that commonly encountered questions with regard to packaging materials used during product stability studies can also be answered in the same way.

Stability of morphine solutions in plastic syringes determined by reversed-phase ion-pair liquid chromatography

A reversed-phase ion-pair HPLC assay has been developed for quantitating morphine, codeine, apomorphine, and pseudomorphine in aqueous solutions. Using two types of plastic syringes, the effect of light (25 W) and temperature (22 and 3 degrees C) on the stability of morphine, over a 12-week period, has been investigated in the presence and absence of preservative and antioxidant. The leaching of contaminants from the plastic syringes to water stored in them, for a period of up to 12 weeks, has also been investigated. The results indicate that less than 3% of the morphine is degraded in both types of plastic syringes, stored in light at 22 +/- 2 degrees C. The degradation is even less prominent in the dark or at 3 degrees C. Pseudomorphine has been identified as the major degradation product. Using 5% degradation of drug as the criterion for the determination of the shelf-life of morphine, it was found that in one brand of plastic syringes, morphine has a shelf-life of the order of 20 and 33 weeks, in the absence and presence of preservative and antioxidant, respectively. In the other brand of plastic syringe, the drug has a shelf-life of greater than 1 year. Some unidentified leached contaminants have been detected in water stored in both brands of syringes.

The influence of drug sorption on pharmacokinetic studies of chlormethiazole and lignocaine

The influence of drug sorption on the measurement of dose and blood concentrations during pharmacokinetic studies of chlormethiazole and lignocaine in a chronically catheterized sheep preparation has been examined. There was no sorption to soda glass tubes, borosilicate glass volumetric flasks or soda glass microlitre syringes but minor sorption to polypropylene syringes, polypropylene pipette tips and rubber bottle stoppers after 240 min contact. During infusions through administration sets including either polyvinyl chloride or polyethylene catheters, no significant loss of lignocaine occurred, but only 41.7-63.9% of the chlormethiazole dose was delivered. No significant decreases in either drug occurred from blood sampled through an intravascular catheter and stopcock system. There was negligible degradation of the samples over 4 h. Sorption of chlormethiazole or lignocaine to the laboratory equipment used was not a significant source of error but polyvinyl chloride infusion catheters could result in significant reductions in chlormethiazole dose.

Avoidable accumulation of potentially toxic levels of benzothiazoles in babies receiving intravenous therapy

Large amounts of a compound of exogenous origin were present in the serum of premature babies receiving prolonged intravenous therapy. This compound, identified as 2-(carboxymethylthio)benzothiazole (CMB) is derived from oxidation of 2-(hydroxyethylthio)benzothiazole which is leached out of rubber components of intravenous administration sets and syringes. Serum concentrations of CMB after prolonged exposure can exceed 500 mumol/l; concentrations over 35 mumol/l were observed in 91 babies over a period of twenty-seven months. This potentially toxic accumulation can be largely avoided by judicious choice of equipment.

Mass spectral identification of benzothiazole derivatives leached into injections by disposable syringes

Five benzothiazole derivatives leached into injections by the rubber plunger-seals of disposable syringes were identified by electron impact (EI) and chemical ionization (CI) mass spectrometry. These are 2-hydroxybenzothiazole, 2-mercaptobenzothiazole, 2-(methylmercapto)benzothiazole, 2-(2-hydroxyethoxy)benzothiazole and 2-(2-hydroxyethylmercapto)benzothiazole. 2-Mercaptobenzothiazole is used as a vulcanization accelerator. The other four compounds are formed from the zinc derivative of 2-mercaptobenzothiazole during sterilization with ethylene oxide. Toxicological, technological and legal consequences of the leaching are discussed briefly.

Contamination of injectable solutions with 2-mercaptobenzothiazole leached from rubber closures

An impurity, discovered in a sample of digoxin injectable solution commercially packaged in a syringe for single-dose delivery, was found to originate from the rubber closure of the syringe and was identified as 2-mercaptobenzothiazole, a common accelerator for rubber vulcanization. Several similarly packaged injectable solutions of a variety of drugs from various manufacturers were examined and over half contained 2-mercaptobenzothiazole. The compound was identified by UV spectrophotometry (including a pH-dependent shift in its absorbance maximum), by mass spectrometry, and by comparison with standard 2-mercaptobenzothiazole using silica gel and reverse-phase high-performance liquid chromatography (HPLC). The presence of this impurity in injectable solutions may have implications with regard to toxicity and may interfere with the assay of digoxin injectable solution by HPLC.

Phenylacetic acid stimulation of cellulose digestion by Ruminococcus albus 8

The rate of cellulose digestion by Ruminococcus albus 8 grown on a defined medium could be increased by adding a minimum of 6.6% (vol/vol) rumen fluid. Strain 8 was grown on half this concentration, and the culture medium before and after growth was analyzed by gas chromatography-mass spectrometry to determine which components of the rumen fluid were used. Phenylacetic acid was identified as the component needed to make the defined medium nutritionally equivalent to one supplemented with rumen fluid. [14C]phenylacetic acid fed to cultures of strain 8 was primarily incorporated into protein. Hydrolysis of protein samples and separation of the resulting amino acids showed that only phenylalanine was labeled. The results indicate that cellulose digestion by strain 8 was probably limited by phenylalanine biosynthesis in our previously reported medium. The data obtained on the utilization of other rumen fluid components, as well as on the production of metabolites, illustrate the potential usefulness of this method in formulating defined media to simulate those in nature.