Setting occupational exposure limits for antimicrobial agents: A case study based on a quaternary ammonium compound-based disinfectant.

Antimicrobial agents have become an essential tool in controlling the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and guidelines on their use have been issued by various public health agencies. Through its Emerging Viral Pathogen Guidance for Antimicrobial Pesticides, the US Environmental Protection Agency has approved numerous surface disinfectant products for use against SARS-CoV-2. Despite their widespread use and range of associated health hazards, the majority of active ingredients in antimicrobial products, such as surface disinfectants, lack established occupational exposure limits (OELs) to assist occupational health professionals in characterizing risks from exposures to these chemicals. Based on established approaches from various organizations, a framework for deriving OELs specific to antimicrobial agents was developed that relies on a weight-of-evidence evaluation of the available data. This framework involves (1) a screening-level toxicological assessment based on a review of the existing literature and recommendations, (2) identification of the critical adverse effect(s) and dose-response relationship(s), (3) identification of alternative health-based exposure limits (HBELs), (4) derivation of potential OELs based on identified points of departure and uncertainty factors and/or modification of existing alternative HBELs, and (5) selection of an appropriate OEL. To demonstrate the use of this framework, a case study is described for selection of an OEL for a disinfectant product containing quaternary ammonium compounds (quats). Three potential OELs were derived for this product based on irritation toxicity data, developmental and reproductive toxicity (DART) data, and modification of an existing HBEL. The final selected OEL for the quats-containing product was 0.1 mg/m3, derived from modification of an existing HBEL. This value represented the lowest resulting value of the three approaches, and thus, was considered protective of irritation and potential DART.

Synthesis, Comparison, and Optimization of a Humic Acid-Quat10 Polyelectrolyte Complex by Complexation-Precipitation versus Extrusion-Spheronization.

A novel humic acid and polyquaternium-10 polyelectrolyte complex (PEC) was synthesized utilizing two methods and the solubility and permeability of efavirenz (EFV) were established. Complexation-precipitation and extrusion-spheronization were used to synthesize and compare the drug-loaded PECs. The chemical integrity, thermo-mechanical differences, and morphology between the drug-loaded PECs produced by the two methods were assessed by attenuated total reflectance-Fourier transform infrared, differential scanning calorimetry, and SEM. The extent of drug solubilization was determined using the saturation solubility test while the biocompatibility of both PECs was confirmed by cytotoxicity studies on human adenocarcinoma cells (caco2). Bio-relevant media was used for the solubility and permeability analysis of the optimized PEC formulations for accurate assessment of formulation performance. Ritonavir (RTV) was loaded into the optimized formulation to further corroborate the impact of the PEC on the solubility and permeability properties of a poorly soluble and poorly permeable drug. The optimized EFV-loaded PEC and the RTV-loaded PEC exhibited 14.16 ± 2.81% and 4.39 ± 0.57% increase in solubility, respectively. Both PECs were compared to currently marketed formulations. Intestinal permeation results revealed an enhancement of 61.24 ± 6.92% for EFV and 38.78 ± 0.50% for RTV. Although both fabrication methods produced PECs that enhanced the solubility and permeability of the model Biopharmaceutics Classification System Class II and IV drugs, extrusion-spheronization was selected as most optimal based on the higher solubility and permeability improvement and the impact on caco2 cell viability.

Accessibility and potency of uterotonic drugs purchased by simulated clients in four districts in India.

BACKGROUND: Surveillance of drug quality for antibiotics, antiretrovirals, antimalarials and vaccines is better established than surveillance for maternal health drugs in low-income countries, particularly uterotonic drugs for the prevention and treatment of postpartum hemorrhage. The objectives of this study are to: assess private sector accessibility of four drugs used for uterotonic purposes (oxytocin, methylergometrine, misoprostol, valethamate bromide); and to assess potency of oxytocin and methylergometrine ampoules purchased by simulated clients. METHODS: The study was conducted in Hassan and Bagalkot districts in Karnataka state and Agra and Gorakhpur districts in Uttar Pradesh state. A sample of 877 private pharmacies was selected (using a stratified, systematic sampling with random start), among which 847 were successfully visited. The target sample size for assessment of accessibility was 50 pharmacies per drug, per district. The target sample size for potency assessment was 100 purchases each of oxytocin and methylergometrine across all districts. Successful drug purchases varied by state. RESULTS: In Agra and Gorakhpur, 90%-100% of visits for each of the drugs resulted in a purchase. In Bagalkot and Hassan, only 29%-52% of visits for each drug resulted in a purchase. Regarding potency, the percent of active pharmaceutical ingredient was assessed using United States Pharmacopeia monograph #33 for both drugs; 193 and 188 ampoules of oxytocin and methylergometrine, respectively, were assessed. The percent of oxytocin ampoules outside manufacturer specification ranged from 33%-40% in Karnataka and from 22%-50% in Uttar Pradesh. In Bagalkot and Hassan, 96% and 100% of the methylergometrine ampoules were outside manufacturer specification, respectively. In Agra and Gorakhpur, 54% and 44% were outside manufacturer specification, respectively. CONCLUSION: Private sector accessibility of uterotonic drugs in study districts in Karnataka warrants attention. Most importantly, interventions to assure quality oxytocin and particularly methylergometrine are needed in study districts in both states.

Evaluation and optimization of solid adsorbents for the sampling of gaseous methylated mercury species.

This study evaluates the suitability of commercially available adsorbents for the measurement of gaseous organic mercury species namely monomethylmercury (MMHg) and dimethylmercury (DMHg). Bond Elut ENV (BE), a new generation of divinylbenzene (DVB), is evaluated the first time for simultaneous sampling and quantification of ultra-trace levels of MMHg and DMHg in air and its performance compared against Carbotrap(®) B (CB) and Tenax(®) TA (TA), two commonly used adsorbents for mercury solid phase adsorption. The suitability of TA as an absorbent for MMHg (recovery 100±8.1%) but less so for DMHg (recovery 64±17.3%) was confirmed while the reverse was observed for CB with an average recovery of 100±0.3% for DMHg but only 61±32.5% for MMHg. BE is the only adsorbent that showed excellent performance for trapping both Hg species with recoveries of 98±9.2% and 95±8.1% for MMHg and DMHg, respectively. Furthermore, BE exhibited much higher sampling capacities (>100L at 4°C) and preservation of sample integrity (>1 month at -20°C in the dark). Overall, BE proves to be the most suitable adsorbent for simultaneous trapping of organic Hg species with high sampling capacity and sample stability but also very good chromatographic properties which are desirable characteristics for both collection traps and analytical traps. Bond Elut ENV is proposed as an alternative to both Tenax(®) TA and Carbotrap(®) B with additional advantages of offering more versatility and sampling options.

Spectrophotometric determination of isopropamide iodide and trifluoperazine hydrochloride in presence of trifluoperazine oxidative degradate.

Four sensitive, selective and precise stability indicating methods for the determination of isopropamide iodide (ISO) and trifluoperazine hydrochloride (TPZ) in their binary mixture and in presence of trifluoperazine oxidative degradate (OXD). Method A is a derivative spectrophotometric one, where ISO was determined by first derivative (D(1)) at 226.4 nm while TPZ was determined by second derivative (D(2)) at 270.2 nm. Method B is the first derivative of the ratio spectra (DD(1)) spectrophotometric method, ISO can be determined by measuring the peak amplitude at 227.4 nm using 5 microg mL(-1) of OXD as a divisor, while TPZ can be determined by measuring the peak amplitude at 249.2 and 261.4 nm using 15 microg mL(-1) of ISO as a divisor. Method C is the isoabsorptive spectrophotometric method. This method allows determination of ISO and TPZ in their binary mixture by measuring total concentration of ISO and TPZ at their isoabsorptive point at lambda(229.8) nm (Aiso1) while TPZ concentration alone can be determined at lambda(max) 311.2 nm, then ISO concentration can be determined by subtraction. On the same basis TPZ can be determined in presence of ISO and OXD, where OXD concentration alone was determined by measuring the peak amplitude at lambda(281.6) and lambda(309.4) nm while total concentration of TPZ and OXD was determined at their isoabsorptive points at (Aiso2 = 270.2 nm), (Aiso3 = 310.6 nm) and (Aiso4 = 331.8 nm) then TPZ concentration was determined by subtraction. Method D is the multivariate calibration techniques [the classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS)], using the information contained in the absorption spectra of ISO, TPZ and OXD mixtures. The selectivity of the proposed methods was checked using laboratory prepared mixtures. The proposed methods have been successfully applied to the analysis of ISO and TPZ in pharmaceutical dosage form without interference from other dosage form additives and the results were statistically compared with the reported method.

Chemical standards in ion mobility spectrometry.

In ion mobility spectrometry (IMS), reduced mobility values (K(0)) are used as a qualitative measure of gas phase ions, and are reported in the literature as absolute values. Unfortunately, these values do not always match with those collected in the field. One reason for this discrepancy is that the buffer gas may be contaminated with moisture or other volatile compounds. In this study, the effect of moisture and organic contaminants in the buffer gas on the mobility of IMS standards and analytes was investigated for the first time using IMS directly coupled to mass spectrometry. 2,4-Dimethylpyridine, 2,6-di-tert-butylpyridine (DTBP), and tetrabutylammonium, tetrapropylammonium, tetraethylammonium, and tetramethylammonium chlorides were used as chemical standards. In general, the mobility of IMS standard product ions was not affected by small amounts of contamination while the mobilities of many analytes were affected. In the presence of contaminants in the buffer gas, the mobility of analyte ions is often decreased by forming ion-molecule clusters with the contaminant. To ensure the measurement of accurate reduced mobility values, two IMS standards are required: an instrument and a mobility standard. An instrument standard is not affected by contaminants in the buffer gas, and provides an accurate measurement of the instrumental parameters, such as voltage, drift length, pressure, and temperature. The mobility standard behaves like an analyte ion in that the compound's mobility is affected by low levels of contamination in the buffer gas. Prudent use of both of these standards can lead to improved measurement of accurate reduced mobility values.

Quantification of erufosine, the first intravenously applicable alkylphosphocholine, in human plasma by isotope dilution liquid chromatography-tandem mass spectrometry using a deuterated internal standard.

A sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of erucylphosphohomocholine (erufosine, ErPC(3)) in pharmacokinetic studies. Nine-fold deuterated ErPC(3) was used as the internal standard. Following protein precipitation, reversed phase chromatography was performed. For analyte detection, electrospray ionization in the positive mode was applied. The mass transition m/z 504.4>139.1 was recorded for ErPC(3), and the transition m/z 513.7>139.1 for the internal standard, respectively. Good linearity with a correlation coefficient >0.99 was found for the range of 0.48-15 mg/L ErPC(3) in plasma (0.93-29.8 microM), the important range for clinical pharmacokinetic analysis. Interassay coefficients (n=10) of variation between 4.2% and 5.5% were found for ErPC(3) pool samples with concentrations between 4.7 mg/L and 44.0mg/L, respectively. The method has been used for analyses during a phase I clinical trial of ErPC(3).

Sensitive determination of bromine and iodine in aqueous and biological samples by electrothermal vaporization inductively coupled plasma mass spectrometry using tetramethylammonium hydroxide as a chemical modifier.

A procedure for the simultaneous determination of bromine and iodine by inductively coupled plasma (ICP) mass spectrometry was investigated. In order to prevent the decrease in the ionization efficiencies of bromine and iodine atoms caused by the introduction of water mist, electrothermal vaporization was used for sample introduction into the ICP mass spectrometer. To prevent loss of analytes during the drying process, a small amount of tetramethylammonium hydroxide solution was placed as a chemical modifier into the tungsten boat furnace. After evaporation of the solvent, the analytes instantly vaporized and were then introduced into the ICP ion source to detect the (79)Br(+), (81)Br(+), and (127)I(+) ions. By using this system, detection limits of 0.77 pg and 0.086 pg were achieved for bromine and iodine, respectively. These values correspond to 8.1 pg mL(-1) and 0.91 pg mL(-1) of the aqueous bromide and iodide ion concentrations, respectively, for a sampling volume of 95 microL. The relative standard deviations for eight replicate measurements were 2.2% and 2.8% for 20 pg of bromine and 2 pg of iodine, respectively. Approximately 25 batches were vaporizable per hour. The method was successfully applied to the analysis of various certified reference materials and practical situations as biological and aqueous samples. There is further potential for the simultaneous determination of fluorine and chlorine.

[Evaluating the effect of quaternary ammonium disinfectants on bacterial strains of animal origin]. / Evaluación de desinfectantes de amonio cuaternario sobre cepas bacterianas de origen animal.

The authors evaluate two quaternary ammonium compounds, first and second generation, using three methods: minimum bactericide concentration, the suspension test of the German Society for Hygiene and Microbiology and the agar gel diffusion test. The compounds were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis from sheep and pigs. The results show that quaternary ammonia compounds with dodecyl chains have greater efficacy than benzalconium chloride, and that quaternary ammonium compounds are more effective against gram-positive bacteria. No resistance linked to the strains used in the tests was detected. Finally, the authors demonstrate that all three techniques are valid for the evaluation of quaternary ammonium disinfectants.

Direct determination of lead in biological samples by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) after furnace-fusion in the sample cuvette-tungsten boat furnace.

The newly conceived electrothermal vaporization (ETV) system using a tungsten boat furnace (TBF) sample cuvette was designed for the direct analysis of solid samples with detection by inductively coupled plasma mass spectrometry (ICP-MS). Into this small sample cuvette, a solid mixture of the biological samples and diammonium hydrogenphosphate powder as a fusion flux was placed and situated on a TBF. Tetramethylammonium hydroxide solution was added to the mixture. After the on-furnace digestion had been completed, the analyte in the cuvette was vaporized and introduced into the ICP mass spectrometer. The solid samples were analyzed by using a calibration curve prepared from the aqueous standard solutions. The detection limit was estimated to be 5.1 pg of lead, which corresponds to 10.2 ng g(-1) of lead in solid samples when a prepared sample amount of 1.0 mg was applied. The relative standard deviation for 8 replicate measurements obtained with 100 pg of lead was calculated to be 6.5%. The analytical results for various biological samples are described.

Development and validation of a near infrared method for the analytical control of a pharmaceutical preparation in three steps of the manufacturing process.

A near infrared diffuse reflectance spectroscopy (NIRS) procedure for the quantitative control analysis of the active compound (otilonium bromide) in a pharmaceutical preparation in three steps of the production process (blended product, cores and coated tablets) and a methodology for its validation are proposed. The analytical procedure is composed by two consecutive steps. First, the sample is identified by comparing its spectrum with a second derivative spectral library. If the sample is positively identified, the active compound is quantified by using a previously established partial least squares (PLS) calibration model. The procedure was validated by studying repeatability, intermediate precision, accuracy and linearity. To this end, an adaptation of ICH (International Conference on Harmonisation) validation methodology to an NIR multivariate calibration procedure is proposed. The relative standard error of prediction (RSEP) was < or = 1% and the suitability of the procedure for control analysis was confirmed by the results obtained analysing new production samples produced over a three-month period.

Test method for the evaluation of virucidal efficacy of three common liquid surface disinfectants on a simulated environmental surface.

The Association of Official Analytical Chemists bacterial use-dilution test for evaluating liquid surface disinfectants was modified to determine the efficacy of three common environmental germicide compounds against representatives of four virus groups. Modifications were made to conform to the Environmental Protection Agency guidelines on virucidal testing procedures. Alterations included: the use of a concentrated tissue culture preparation of virus instead of a standard bacterial culture; HEp-2 tissue culture cells as a visible test system in place of standard nutrient broth; and controls to measure the virus titer end point and the toxicity of the disinfectant to the cell cultures. Comparison of control end points with results from the test proper were the measure of the effectiveness of the germicides against the viruses. Results are described which agree with those based on other methods previously reported.