Syringe Filter Research Articles

Microfunnel-filter-based emulsification microextraction followed by gas chromatography for simple determination of organophosphorus pesticides in environmental water samples.

A simple and fast method named microfunnel-filter-based emulsification microextraction is introduced for an efficient determination of some organophosphorus pesticides including diazinon, malathion, and chlorpyrifos in the environmental samples including the river, sea, and well water. This method is based upon the dispersion of a low-toxicity organic solvent (dihexyl ether), as the extractant, in a high volume of an aqueous sample solution (45mL). It is implemented without a centrifugation step, and using a syringe filter and a micro-funnel, the phase separation and transfer of the enriched analytes to the gas chromatograph are simply achieved. By filtration of the extractant phase, a suitable sample clean-up is obtained, and the total extraction time is just a few minutes. The factors influencing the extraction efficiency are optimized, and under the optimal conditions, the proposed method provides a good linearity (in the range of 15-1500ng/mL (R2 >0.996). A high enrichment factor is obtained (in the range of 306-342), and the method provides low limits of detection and quantification (in the ranges of 4-8 and 15-25ng/mL, respectively).

Rapid and in-situ detection of fecal indicator bacteria in water using simple DNA extraction and portable loop-mediated isothermal amplification (LAMP) PCR methods

Contamination of water by fecal matter and potential human enteric pathogens is a serious health concern. Microbiological water quality has been assessed by conventional culture-based methods of fecal indicator bacteria (FIB). Recently, molecular techniques for FIB have been introduced as alternative tools for rapid detection. However, such molecular techniques require a modern laboratory setting, expensive equipment, and skilled personnel. In this study, we developed a simple and rapid DNA extraction method based on a syringe filter without any specialized equipment. Furthermore, loop-mediated isothermal amplification (LAMP) PCR for fecal indicator bacteria (FIB) (i.e. E. coli and E. faecalis) was carried out using the DNA extracts from the syringe-filter based DNA extraction method. The efficiency of the extracted DNA from the syringe-filter based method was comparable to the results of the commercial kit method. We also tested fresh and marine-water collected directly from different locations in Singapore that were spiked with E. coli or E. faecalis. The LAMP assays combined with our DNA extraction method showed higher sensitivity and more tolerance to PCR inhibitors than that of conventional PCR methods. We further developed a portable LAMP device to conduct isothermal PCR reactions for rapid on-site measurement of FIB. As the color changes in the end point of the LAMP reaction can be observed with the naked eye, the portable LAMP device was easily operated and quick, obtaining results in 30 min. The simple, portable and user-friendly platform can be used as an initial screening for the rapid detection of the presence FIB in lower-resource settings. In conclusion, the portable LAMP device coupled with a syringe-filter based DNA extraction method enables us to detect the presence of FIB for assessing microbial water quality within 1 h without any sophisticated laboratory equipment or highly trained personnel.

Bioaerosol biomonitoring: Sampling optimization for molecular microbial ecology.

Bioaerosols (or biogenic aerosols) have largely been overlooked by molecular ecologists. However, this is rapidly changing as bioaerosols play key roles in public health, environmental chemistry and the dispersal ecology of microbes. Due to the low environmental concentrations of bioaerosols, collecting sufficient biomass for molecular methods is challenging. Currently, no standardized methods for bioaerosol collection for molecular ecology research exist. Each study requires a process of optimization, which greatly slows the advance of bioaerosol science. Here, we evaluated air filtration and liquid impingement for bioaerosol sampling across a range of environmental conditions. We also investigated the effect of sampling matrices, sample concentration strategies and sampling duration on DNA yield. Air filtration using polycarbonate filters gave the highest recovery, but due to the faster sampling rates possible with impingement, we recommend this method for fine ‐scale temporal/spatial ecological studies. To prevent bias for the recovery of Gram‐positive bacteria, we found that the matrix for impingement should be phosphate‐buffered saline. The optimal method for bioaerosol concentration from the liquid matrix was centrifugation. However, we also present a method using syringe filters for rapid in‐field recovery of bioaerosols from impingement samples, without compromising microbial diversity for high ‐throughput sequencing approaches. Finally, we provide a resource that enables molecular ecologists to select the most appropriate sampling strategy for their specific research question.

The Effect of Cinnamon Essential Oil on Lactobacillus species

Antimicrobial properties of cinnamon essential oil solutions (EO) have been identified against pathogenic bacteria, but its effects on commensal microorganisms have not yet been described. In previous studies in our laboratory, cinnamon EO was tested against Salmonella Typhimurium and Escherichia coli utilizing the disc diffusion method. Zones of inhibition were measured, and cinnamon EO at 2 and 4% displayed great effectiveness against these microorganisms. Both microorganisms are Gram negative rods and have the capability to cause disease. Thus, the main objective of this study is to evaluate the effect of cinnamon EO on the commensal Gram positive microorganisms Lactobacillus acidophilus and Lactobacillus rhamnosus.The Lactobacillus acidophilus (ATCC® 4356™) and Lactobacillus rhamnosus (ATCC® 7469™) inoculums were prepared by growing the bacteria in MRS (De Man, Rogosa and Sharpe) broth for 24h under microaerophilic conditions (5% CO2) at 37°C, yielding 6.9 ×108 CFU/ml. One hundred microliters of starting bacterial culture was spread onto MRS agar plates and dried for 15 minutes. Treatments were formed by creating cinnamon EO solutions of 0, 0.5, 1, 2 and 4% using 70% ethyl alcohol as the diluent. Each EO was vortexed and filtered using a 0.2 microliter sterile syringe filter. Twenty microliters of each EO were pipetted into a sterile paper disc and left to dry for 1h. Five paper discs of each treatment containing the EO were placed on standardized locations on each inoculated plate in duplicate. Additionally, three manufactured standard antibiotic paper discs of 5 mcg ciprofloxacin, 10mcg ampicillin, and 10mcg streptomycin were placed on separate plates in duplicate as controls. The zone of inhibition created by each EO or antibiotic was measured using a calibrated digital caliper. All data were analyzed using GLM procedure for ANOVA and Person correlation analysis.The antimicrobial property of the EO observed as the zone of inhibition increased as the concentration of the EO increased for Lactobacillus acidophilus (r=0.86, p<0.0001). EO at 4% showed the greatest antimicrobial effect against Lactobacillus acidophilus compared to 2.0, 1.0, and 0.5% (2.59, 2.11, 0.0 and 0.0mm, respectively; p<0.0001). Lactobacillus rhamnosus showed resistance to EO at all concentrations studied with no zones of inhibition observed. All antibiotics had some effect against Lactobacillus rhamnosus, where ampicillin had the greatest effect compared to ciprofloxacin and streptomycin (6.62, 6.27, and 2.33mm, respectively; p<0.0001). Ampicillin had the greatest effect against Lactobacillus acidophilus compared to streptomycin (9.72 vs. 2.8mm, respectively; p<0.0001). However, L. acidophilus was shown to be resistant to ciprofloxacin with no zone of inhibition formed.In conclusion, Lactobacillus species were generally resistant to cinnamon EO. These Lactobacillus species are commonly used as probiotics and are often adversely affected by antibiotic intake. Using cinnamon essential oil as an antibiotic alternative has shown to be a promising option with limited detrimental effects against the commensal bacteria. Further evaluation of the effects of cinnamon EO on commensal bacteria is needed to further determine the benefits of utilizing a natural alternative.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The Effect of Cinnamon Essential Oil on Escherichia coli

Antimicrobial properties of cinnamon essential oil have been identified against foodborne bacteria, but its effectiveness has not yet been fully determined. In a previous study, cinnamon essential oil at concentrations of 2% and 4% showed to be effective against Salmonella enterica serovar Typhimurium. However, its effect on a commensal, opportunistic and specialized pathogen like E. coli has not been completely described. Thus, the main objective of this study is to evaluate the effectiveness of cinnamon essential oil on Escherichia coli.The Escherichia coli (ATCC 25404™) inoculum was prepared by growing the bacteria in Luria‐Bertani (LB) broth for 24 hours at 37°C, yielding 8.7×109 CFU/ml. One hundred microliters of the starting bacterial culture were spread onto LB agar plates and left to dry for 15 minutes. Treatments were formed by creating cinnamon essential oil solutions (EO) of 0, 0.5, 1, 2 and 4% using 70% ethyl alcohol as the diluent. Each EO was vortexed and filtered using a 0.2 microliter sterile syringe filter. Twenty microliters of each EO was pipetted into a sterile paper disc (weight ranged of 0.0086–0.0090g) and left to dry for one hour. Five paper discs of each treatment containing the EO were placed on standardized locations on each inoculated plate in duplicate. The plates were then incubated at 37°C for 24 hours. Additionally, three manufactured standard antibiotic paper discs of 5 mcg ciprofloxacin, 10mcg ampicillin, and 10mcg streptomycin were placed on separate plates in duplicate as positive controls. The zone of inhibition created by each EO or antibiotic was measured using a calibrated digital caliper. All data were analyzed using the general linear model procedure for analysis of variance (ANOVA) and Pearson correlation analysis.The antimicrobial property of the EO observed as the zone of inhibition increased as the concentration of the EO increased (r= 0.922, p<0.0001). EO at 4% showed the greatest antimicrobial effect against Escherichia coli compared to 2, 1, and 0.5% (6.7, 5.0, 0.88 and 0.0mm, respectively; p<0.0001). There was no significant difference (p>0.05) between the zone of inhibition of 0% and 0.5% EO. However, 2% EO showed increasing effectiveness against Escherichia coli with a zone of inhibition of 5.1mm (p<0.0001). The 2% EO concentration showed a greater zone of inhibition against E. coli than the ampicillin treatment (5.1 vs. 2.3mm, p<0.0001). All antibiotics had some effect against E. coli, and ciprofloxacin had the greatest effect; its effect was even greater than the 4% EO (7.6 vs. 6.7mm, p<0.0001). The 4% EO was not as effective as ciprofloxacin, but it was more effective than both streptomycin and ampicillin (6.7 vs. 6.1 and 2.3mm, respectively; p<0.0001).In conclusion, cinnamon EO showed increasing antimicrobial properties against Escherichia coli as the concentration of oil increased. It proved to be more effective than two of the antibiotic controls at 4% concentration. Further evaluation of the effects of cinnamon EO is needed to determine the extent of its effectiveness against additional commensal and pathogenic organisms.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Antimicrobial Properties of Cinnamon Essential Oil on Salmonella Typhimurium

Essential oils have a wide range of properties due to various chemical compounds in their composition. Potential applications have been identified in areas such as food preservation, natural alternatives to antibiotics, and disease prevention and treatments. More specifically, the antimicrobial properties of cinnamon (Cinnamomum sp.) oil have been established against foodborne bacteria, but the effectiveness has not yet been defined at various concentrations under standardized conditions. Therefore, the main objective of this study was to evaluate the effect of cinnamon essential oil on Salmonella enterica ser. Typhimurium (Salmonella Typhimurium) using the disc diffusion procedure.The Salmonella Typhimurium (ATCC® 53648™) inoculum was prepared by growing the bacteria in tryptic soy broth for 24 hours at 37°C, yielding 6.9 × 108 CFU/ml. One hundred microliters of the starting bacterial culture were spread onto Mueller Hinton agar plates and left to dry for 15 minutes. Treatments were formed by creating cinnamon essential oil solutions (EO) of 0, 0.5, 1, 2 and 4% using 70% ethyl alcohol as the diluent. Each EO was vortexed and filtered using a 0.2 microliter sterile syringe filter. Twenty microliters of each EO was pipetted into a sterile paper disc (weight ranged of 0.0086–0.009g) and left to dry for one hour. Five paper discs of each treatment containing the EO were placed on standardized locations on each inoculated plate in duplicate. The plates were then incubated at 37°C for 24 hours. Additionally, three manufactured standard antibiotic paper discs of 5 mcg Ciprofloxacin, 10 mcg Ampicillin, and 10 mcg Streptomycin were placed on separate plates in duplicate as controls. The zone of inhibition created by each EO or antibiotic was measured using a calibrated digital caliper. All data were analyzed using the general linear model procedure for analysis of variance (ANOVA).The antimicrobial property of the EO observed as the zone of inhibition increased as the concentration of the EO increased (R= 0.884, P < 0.0001). EO at 4% showed the greatest antimicrobial effect against Salmonella Typhimurium compared to 2.0, 1.0, and 0.5% (10.5, 6.0, 4.2 and 4.6 mm, respectively; P < 0.0001). There was no significant difference (P=0.4) between the zone of inhibition of 0.5% and 1% EO. However, 2% EO showed a significantly larger zone of inhibition than 0.5% and 1% EO (P<0.01). The 2% EO concentration showed a greater zone of inhibition against Salmonella than ampicillin and streptomycin treatments (6.0 versus 4.7 and 3.4 mm respectively; P< 0.0001). All antibiotics had some effect against Salmonella where ciprofloxacin had the greatest effect; its effect was even greater than the 4% EO (14.0 vs. 10.5 mm, P< 0.0001).In conclusion, cinnamon EO showed increasing antimicrobial properties against Salmonella Typhimurium as the concentration of oil increased. It proved to be more effective than two of the antibiotic controls as low as 2% concentration. Further evaluation of the effects of cinnamon EO is needed to determine the extent of its effectiveness against additional foodborne pathogens.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Highly selective determination of some anti‐depressant drugs in complicated matrices by dual emulsification liquid‐phase microextraction based on filtration followed by high‐performance liquid chromatography

AbstractAn efficient microextraction method is applied for the determination of some anti‐depressant drugs in complex matrices. The method consists of two steps. In the first step, an organic extraction solvent is dispersed into an aqueous sample solution (20 mL, pH 12), and the resulting mixture is subsequently passed through a hydrophilic polytetrafluoroethylene syringe filter that is permeable to aqueous solutions, and thus the organic phase is retained by the membrane. In the second step, the filter is detached from the syringe and attached to another syringe containing an aqueous solution (pH 2, 150 μL). By the in‐syringe dispersion of the organic phase into the aqueous phase, the target analytes are ionized and selectively back‐extracted into the aqueous phase. In addition to the preconcentration of the analytes in the aqueous phase, which can cause the elimination of the problem of injection of the organic solvent into the final instrument analyzer as well, the method provides a high sample clean‐up since acidic compounds, large molecules, and neutral components are not extracted into the acceptor phase. Under the optimized experimental conditions, the method provides a good linearity (in the range of 5–2000 ng mL−1) and a low limit of detection (1.5–3.0 ng mL−1).

Optimized Analysis of Ergot Alkaloids in Rye Products by Liquid Chromatography-Fluorescence Detection Applying Lysergic Acid Diethylamide as an Internal Standard.

Analysis of ergot alkaloids remains a topic of importance and the European Food Safety Authority (EFSA) has encouraged laboratories to provide monitoring data for the further evaluation of their occurrence in food and feed. While LC-MS/MS has dominated developments in recent years, LC-FLD is still more widespread, especially in developing countries. To improve the analysis of ergot alkaloids by LC-FLD, we developed an improved protocol introducing lysergic acid diethylamide (LSD) for internal standardization. Several aspects such as the composition and pH of the extraction medium, type of sorbent and conditions applied for solid-phase extraction/clean-up, use of a keeper during final evaporation and the type of syringe filter used for filtration prior to injection were thoroughly investigated. Optimized conditions comprise extraction by ethyl acetate, methanol and 28% aqueous ammonia in combination with basic aluminum oxide for extract clean-up. Use of a keeper was found inappropriate as LC-FLD analysis was significantly affected by co-eluting keeper components. Similar observations were made with some of the investigated syringe filters, where polytetrafluoroethylene (PTFE) proved to be the most suitable. Validation and application of the optimized methodology to real samples provided limits of detection and quantification suitable for the evaluation of relevant ergot alkaloid contaminations in rye and bakery products with superior precision that was facilitated by the introduced internal standard, LSD.

Enhancing the efficiency of disc membrane chromatography modules by using a flow directing layer

Disc membrane chromatography modules are widely used for laboratory-scale protein separations. These have high radial to axial aspect ratios, with the inlet and the outlet being located at the centre. This results in a huge variability in flow path lengths. Also, the radial velocity in the feed side header decreases very significantly in an outward direction, while that in the permeate side header increases in an inward direction. Therefore, the flow paths closer to the axis of the membrane disc have higher average velocity compared to those closer to the periphery. Consequently, the solute residence time distribution within the disc membrane chromatography module is very large, which results in broad flow-through and eluted peaks and early breakthrough of bound solutes. In this paper, we discuss a simple but effective solution to this problem which involves the incorporation of a flow directing layer (FDL) within the membrane module. The FDL could be placed either in the front or at the rear of the membrane disc. The presence of FDL results in equalization of path lengths within the module, leading to narrowing of residence time distribution, and thereby improvement in separation efficiency. Modules housing strong cation exchange membrane discs having two different bed volumes of 0.4 mL (40 mm diameter) and 4.7 mL (60 mm diameter) were designed and fabricated in-house. The impact of using FDL on both the front side (F-FDL) and the rear side (R-FDL) was investigated. The separation efficiency of the membrane modules was assessed using salt tracer experiments, breakthrough protein binding, and ternary protein separation carried out in the bind-and-elute mode. The results confirmed that the use of the FDL significantly enhanced the separation efficiency. In addition to membrane chromatography, this approach of using an FDL could be extended to other membrane disc based modules such as in-line and syringe filters and membrane reactors.

Determination of acidic drugs in biological and environmental matrices by membrane-based dual emulsification liquid-phase microextraction followed by high-performance liquid chromatography.

A simple method is introduced providing a highly clean microextraction for the determination of some anti-inflammatory drugs as the model analytes in human urine and environmental matrices. This method is based upon the implementation of two consecutive emulsification liquid-phase microextractions, which are separated by a syringe filtration step. In this method, the organic extraction solvent (dihexyl ether) is dispersed into the aqueous sample solution (20mL), and the resulting cloudy mixture is passed through a hydrophilic polytetrafluoroethylene syringe filter. By this action, the extraction phase containing the analytes and many interfering species that could be transferred into the organic phase is retained behind the hydrophilic membrane. The filter is then detached from the syringe and attached to another syringe containing an aqueous solution (pH 12.0, 150 μL), and by the in-syringe dispersion of the organic phase into the aqueous phase, the analytes are selectively back-extracted into the aqueous phase. The developed method is centrifuge-free and very simple, and provides a high sample clean-up in a few minutes. Under the optimized experimental conditions, the developed method provided a linearity in the range of 2.0-2000ng/mL, a low limit of detection (0.5ng/mL), and enrichment factors of 47-53.

Partitioning of potentially toxic elements among two colloidal fractions and relevance for their mobility in different water types

Potentially toxic elements are mobilized in aquatic systems in solution or bounded to colloids of different sizes, which may include nanometer particles. The present work studies the distribution of elements (Al, Fe, Zn, Mn, Co, Cd, Ni, Cu, and As) between small (<0.20 μm) and larger (0.45–0.20 μm) colloids in different waters sources in a world class metallogenic province (Iberian Pyrite Belt), including the acid mine waters. Syringe filters with pore-size ratings of 0.20 μm and 0.45 μm have been used to assess the transport and fate of these potentially toxic elements. The results show the contribution of colloids for mobility of arsenic and most metals, evidencing the role of the small ones in acid mine drainage.

Extractable impurities from fluoropolymer-based membrane filters – interference in high-throughput, untargeted analysis

The removal of particles using fluoropolymer-based membrane filters is usually done so to prolong the life span of an analytical column, prevent hardware damage, and reduce signal suppression. Ironically, these membrane filters tend to leach impurities into the samples as the samples are filtered through them. These impurities have the potential to affect the researcher's interpretation in high-throughput, non-targeted analysis. In this study, extractable impurities from different brands of fluoropolymer-based membrane filters present in the filtrate filtered using the said filters were investigated. The results demonstrated that different brand membrane filters and materials tend to elute vastly different numbers of impurities. There were instances whereby the extractable impurities persisted in both the membrane filter and the filtrate despite the filter being pre-conditioned (up to 3 times). Principle component analysis revealed that filtrates at different purge intervals are distant from the unfiltered samples. Pre-conditioning of the PTFE membrane filters could potentially reduce the number of extractable impurities across the tested brands. PVDF filtrates, however, tend to co-cluster with their respective brands, thus suggesting that dissimilarity persists in brands following conditioning. As such, pre-conditioning of the PTFE membrane filters should be encouraged so as to reduce false positive results, while the use of PVDF membrane filters for mass-spectrometry-based untargeted analysis is not advisable as extractable impurities would still persist after 3 rounds of conditioning. Neither the use of different filter brands, nor the use of different filter materials in a sample batch are encouraged as different membrane materials or brands could potentially elute varying impurities.

Comparative Observation of the Use of Combi 10 and Filter Paper in the Diagnosis of Schistosoma haematobium Infections

Urinary Schistosomiasis is neglected tropical disease (NTDs) caused by the trematode, Schistosoma haematobium. This Study was designed to comparatively observe the use of Combi 10 and filter paper in the diagnosis of Schistosoma hameatobium, and to determine the prevalence and intensity of the Infection among Primary School Pupils in Makurdi Metropolis. A survey involving 202 pupils from four different primary schools within the Makurdi Metropolis was conducted. Urine samples were collected from pupils between the ages 5 to 19 and examined for hematuria and Ova of Schistosoma haematobium using Medi Test Combi 10 and Polycarbonate Filters in Urine Syringe Filtration Technique (USFT) respectively. The prevalence of Schistosoma haematobium based on microscopic examination of Filter papers was 25.7% while prevalence of Hematuria was 35%. Prevalence of Proteinuria was observed to be 50% Infection Intensity varied from Light to heavy. In general infection was higher among males (26.3%) than females (25.8%; P>0.05) although statistically non-significant. The age specific prevalence ranged from 11.1% to 40% in 5-9 years and 15-19 years respectively (P >0.05), and showed no significant difference. There was also a strong positive correlation between the use Medi-test Combi 10 reagent strips and Poly membrane Filtration technique. A total of 111 urine samples were positive to haematuria using combi 10 while only 52 urine samples were positive to S. haematobium using poly membrane filter paper, hence correlation is significant at 0.05 level. The above finding shows that S. haematobiumis prevalent among primary school pupils and the use of Combi 10 and Filter paper are both diagnostic tools that can be used in S. haematobium diagnosis. They can both ascertain the prevalence of the disease will provide a guide for the treatment and eradicating of the infection. Hence, decisive control measures including administration of praziquantel to pupils are needed.

Viral Enrichment Methods Affect the Detection but Not Sequence Variation of West Nile Virus in Equine Brain Tissue.

West Nile virus (WNV), a small, positive sense, single stranded RNA virus continues to encroach into new locales with emergence of new viral variants. Neurological disease in the equine can be moderate to severe in the face of low to undetectable virus loads. Physical methods of virus enrichment may increase sensitivity of virus detection and enhance analysis of viral diversity, especially for deep sequencing studies. However, the use of these techniques is limited mainly to non-neural tissues. We investigated the hypothesis that elimination of equine brain RNA enhances viral detection without limiting viral variation. Eight different WNV viral RNA enrichment and host RNA separation methods were evaluated to determine if elimination of host RNA enhanced detection of WNV and increase the repertoire of virus variants for sequencing. Archived brain tissue from 21 different horses was inoculated with WNV, homogenized, before enrichment and separation. The protocols utilized combinations of low-speed centrifugation, syringe filtration, and nuclease treatment. Viral and host RNA were analyzed using real-time PCR targeting the WNV Envelope (E) protein and equine G3PDH to determine relative sensitivity for WNV and host depletion, respectively. To determine the effect of these methods on viral variation, deep sequencing of the E protein was performed. Our results demonstrate that additional separation and enrichment methods resulted in loss of virus in the face of host RNA depletion. DNA sequencing showed no significant difference in total sequence variation between the RNA enrichment protocols. For equine brain infected with WNV, direct RNA extraction followed by host RNA depletion was most suitable. This study highlights the importance of evaluating viral enrichment and separation methods according to tissue type before embarking on studies where quantification of virus and viral variants is essential to the outcome of the study.

Hydrophobic drug adsorption loss to syringe filters from a perspective of drug delivery

Filtering with a syringe filter is a common operation in pharmaceutical analysis. Ophthalmic research often has a limited amount of sample and low amount of drug which is vulnerable to filtering membrane adsorption loss but not well recognized in the research community. Current study investigated drug adsorption by 11 types of syringe filters for 4 hydrophobic compounds commonly encountered in transscleral drug delivery. Among the 11 types of syringe filters surveyed, polytetrafluoroethylene – NBA, polytetrafluoroethylene – NLA, and polypropylene filters caused the least adsorptive drug loss for these four drugs studied. The magnitude of drug adsorption was filter- and drug-specific. Polytetrafluoroethylene-NLA caused the least adsorptive loss (1%) for triamcinolone acetonide, polytetrafluoroethylene-NBA caused the least adsorptive loss (5.4%) for diclofenac, and polypropylene caused the least adsorptive loss for cyclosporine A, 16.8% on average. Tacrolimus had the least adsorptive loss to the filters of polytetrafluoroethylene – NLA and polypropylene; however, the percentage of adsorptive loss from filtration was the highest (32% loss in average) among the four drugs surveyed. ConclusionLow drug concentrations as seen in samples from ophthalmic researches are vulnerable to filtration drug loss. Selecting the right filter via validation is critical to avoid underestimating the drug level and distorting the resultant distribution/clearance profile in the ocular pharmacokinetic analysis.

Sustained-Release Injectable Hydrogel Formulations for Administration of Sodium Salicylate in Broiler Chickens.

We developed injectable hydrogels for the slow release of analgesic drugs in birds as an in vivo model of pharmacokinetics in wild avian species. Hydrogels loaded with sodium salicylate (NaSA) were injected subcutaneously in Ross broiler chickens. The hydrogels were made by dissolving sodium alginate and NaSA in water at 2 different concentrations (low, LALG; high, HALG) and then adding calcium chloride. In vitro drug release studies were performed by swelling the hydrogels in water and analyzing serial samples by ultraviolet-visible (UV-Vis) spectroscopy. Dried hydrogel films of the same formulations of the two alginate concentrations then were dissolved in sterile water for the in vivo pharmacokinetic study conducted in 18 chickens divided into 3 groups of 6 birds. Each of the 2 resultant NaSA hydrogel solutions were filtered with 0.2-µm syringe filters before injecting at a NaSA dose of 150 mg/kg SC in the respective LALG or HALG groups. The control group was injected SC with the same dose of NaSA dissolved in water. Pharmacokinetics parameters calculated by the compartmental and noncompartmental approaches were compared among the 3 groups by the Kruskal-Wallis test. Results of in vitro studies showed that both hydrogels released 80% of the drug during the first 3.5 hours. Results of the pharmacokinetic study indicated that NaSA concentrations remained above the minimum effective concentration (MEC) for analgesia in humans for 24 ± 8.9 (LALG) to 26 ± 4 (HALG) hours for the hydrogel formulations compared to 10 ± 5.6 hours for the aqueous formulation. These hydrogel formulations may have potential in providing long-term analgesia in avian species, but need further evaluation with pharmacodynamic or pharmacokinetic/pharmacodynamic modeling studies.

Use of syringe filters to isolate Campylobacter species from stool samples

We investigated the efficacy of syringe filters and membrane filters with different pore sizes for recovering Campylobacter. A syringe filter with a 0.45 μm pore size achieved the highest recovery rate (0.29%), while polycarbonate membrane filters with pore sizes of 0.6 μm and 0.4 μm recovered less Campylobacter, at 0.01% and 1.3 × 10−3%, respectively. We also tested 601 diarrheic stool samples using membrane and syringe filtration methods. A total of 23 Campylobacter jejuni/coli were isolated from both syringe and membrane filtration; nine and one were isolated from only syringe or only membrane filtration, respectively (p < .05). The syringe filtration technique was better than membrane filtration for the isolation of Campylobacter.

QCM analysis of chlorhexidine interaction with salivary and S. gordonii films on titanium implant surfaces

Background In implant surgery, preoperative and postoperative mouth rinsing with Chlorhexidine (CHX) has been regularly applied for the prophylaxis of peri-implantitis. Studies indicate that titanium (Ti) implant materials might be involved in both uptake and release of CHX, suggesting antiplaque activity through prolonged CHX release. However, during the primary bacterial colonization period, the interactions between bacteria, salivary pellicle films and CHX on Ti surfaces are still unclear in detail. Aim/Hypothesis This study aimed at using a mass-sensitive on-line sensor system to analyze surface interactions of CHX on the adsorption processes of the early oral colonizer S. gordonii (Sg), and the antibacterial efficiency of CHX on planktonic and pre-adsorbed Sg on Ti conditioned with or without saliva. Material and Methods A conventional mass-sensitive quartz crystal microbalance (QCM) device with frequency (f) and dissipation (D) output (qCell T+ 3T Analytik, Germany) and Ti-coated smooth quartz crystal sensors were used in a flow-system for real-time monitoring of dynamic macromolecule surface, bacteria surface, and macromolecule bacteria interactions. Sg was precultured in Schaedler medium overnight and diluted to OD620 = 0.54. CHX mouth rinsing (0.12%) was used. Human saliva (Sal) was collected once from one healthy volunteer for the complete study and sterile-filtered by low protein binding syringe filters. The QCM flow sequences of different groups were- A) CHX-Sg+ B) Sal-CHX-Sg+ C) Sg-CHX+ D) Sal-Sg-CHX+ E) mixed CHX+Sg+ F) Sal-mixed CHX+Sg. Sg was run for 2 hours and CHX, Sal, PBS for 30 minutes, respectively. PBS flow was used as baseline and for washing. After QCM runs, the vitality of Sg on Ti sensor surfaces was analyzed by Live Dead staining and fluorescence microscopy. Results (A) The interaction of CHX on Ti is a “U”-shaped signal indicating reversible interaction- fast f decrease of 361 Hz, fast increase of 332 Hz and final residue of 128 ng/cm2. Subsequent staining revealed a dense, vital (green) bacterial film. (B) CHX interaction with saliva-coated Ti induced a reversible f decrease of 302 Hz and an increase of 338 Hz upon PBS rinsing. Subsequent Sg run results in a dense vital film. (C) On pre-adsorbed Sg films, CHX induced a large f decrease of 985 Hz, which represents a strong CHX adsorption interaction, followed by an increase of 818 Hz caused by desorption upon PBS, ending with a 740 ng/cm2 residue and dense red stained films. (D) On surfaces preconditioned with saliva and Sg, CHX caused a 753 Hz decrease, followed by a reversible 586 Hz increase upon PBS ending with a CHX residue of 737 ng/cm2 and killed bacteria. (E, F) A mix of CHX and planktonic Sg on Ti with or without saliva led to very small f changes and dead bacteria with comparable low film density. Conclusions and Clinical Implications CHX bind rapidly but almost reversibly to Ti, and the small residues cannot kill colonizing Sg. CHX bind similarly fast but stronger to Sg films. Higher amounts of residual CHX were found on Sg films than on pure Ti. This QCM study shows that free CHX inhibits planktonic bacterial binding with bactericidal effect, but cannot remove significant amounts of biofilm on Ti implant abutment surfaces. These online results coincide with earlier findings from conventional, static incubation experiments.

INJECTION SIMULATION FOR THE MOLD PROCESS IN THE MEDICAL INDUSTRY

This paper presents information on the methods of construction and selection of materials, for the manufacturing of a medical device – a syringe filter. The main scope of the research was numerical simulation made in order to optimize the injection process. This simulation comprised of two parts: the first in which the chosen optimal number and position of injection points on the surface, and a second with the chosen optimum wall thickness, using a pre-selected injection points.

Effects of Product Handling Parameters on Particle Levels in a Commercial Factor VIII Product: Impacts and Mitigation

To reduce the risk of immunogenicity that may be caused by therapeutic protein products, it is important to properly characterize subvisible particles and to develop strategies to reduce the levels of particles delivered to patients. In the present study, by using state-of-the-art methods to quantify particle levels, we found that the factor VIII product, Kogenate FS, contained relatively high levels of protein particles and silicone oil droplets, the vast majority of which were submicron in size. In a test of effects of product mishandling, the Kogenate FS vial was shaken instead of swirled during reconstitution. Levels of silicone oil droplets and protein particles were increased. In contrast, these levels were greatly reduced by 2 mitigation strategies tested, using a nonsiliconized syringe for the diluent container or using submicron pore size syringe filters during simulated infusion. Thus, to avoid potential adverse effects due to mishandling-induced increases in particle levels, it is important to educate end-users about proper product handling. Furthermore, effective particle mitigation and reduction strategies should be developed for factor VIII, and other therapeutic protein products. Such efforts could lead to clinically useful approaches to reduce the levels of particles delivered to patients and to an associated reduction in adverse immunogenicity.