Fast HPLC-MS/MS Method for Determining Penicillin Antibiotics in Infant Formulas Using Molecularly Imprinted Solid-Phase Extraction

Harnessing biotechnology for penicillin production: Opportunities and environmental considerations

Since the discovery of antibiotics, penicillin has remained the top choice in clinical medicine. With continuous advancements in biotechnology, penicillin production has become cost-effective and efficient. Genetic engineering techniques have been employed to enhance biosynthetic pathways, leading to the production of new penicillin derivatives with improved properties and increased efficacy against antibiotic-resistant pathogens. Advances in bioreactor design, media formulation, and process optimization have contributed to higher yields, reduced production costs, and increased penicillin accessibility. While biotechnological advances have clearly benefited the global production of this life-saving drug, they have also created challenges in terms of waste management. Production fermentation broths from industries contain residual antibiotics, by-products, and other contaminants that pose direct environmental threats, while increased global consumption intensifies the risk of antimicrobial resistance in both the environment and living organisms. The current geographical and spatial distribution of antibiotic and penicillin consumption dramatically reveals a worldwide threat. These challenges are being addressed through the development of novel waste management techniques. Efforts are aimed at both upstream and downstream processing of antibiotic and penicillin production to minimize costs and improve yield efficiency while lowering the overall environmental impact. Yield optimization using artificial intelligence (AI), along with biological and chemical treatment of waste, is also being explored to reduce adverse impacts. The implementation of strict regulatory frameworks and guidelines is also essential to ensure proper management and disposal of penicillin production waste. This review is novel because it explores the key remaining challenges in antibiotic development, the scope of machine learning tools such as Quantitative Structure-Activity Relationship (QSAR) in modern biotechnology-driven production, improved waste management for antibiotics, discovering alternative path to reducing antibiotic use in agriculture through alternative meat production, addressing current practices, and offering effective recommendations.

Long-Term Study of Antibiotic Presence in Ebro River Basin (Spain): Identification of the Emission Sources

Water monitoring is key to determining the presence of potentially hazardous substances related to urban activities and intensive farming. This research aimed to perform a long-term (four years) quantitative monitoring of selected antibiotics (azithromycin, enrofloxacin, trimethoprim and sulfadiazine) both in rivers and wastewaters belonging to the Ebro River basin (North of Spain). The target antibiotics were chosen on the basis of a preliminary multispecies screening. The analysis of the antibiotics was carried out by LC-MS/MS on wastewater-treatment plant (WWTP) effluent, effluents of a slaughterhouse and hospital, rivers downstream and upstream of these WWTPs, and rivers close to extensive farming areas. The ANOVA test was performed to study the significant differences between the points exposed to concrete emission sources and antibiotic concentration. The monitoring, carried out from 2018 to 2020, has been essential to illustrating the presence of the most abundant antibiotics that were detected in the Ebro River basin. Enrofloxacin has appeared in river waters in significant concentrations, especially near intensive farming, meanwhile azithromycin has been frequently detected in wastewaters.

LC-MS/MS methodology development and validation for the screening and quantification of five antibiotics in water

The generalized use of antibiotics in veterinary medicine may cause the development of antibiotic resistance, namely, in farmed fish, and subsequently, transmission of such resistance to humans. To overcome this serious problem, it is necessary to improve the efficiency of antibiotic removal processes from water, and a route for attaining that goal is the use of hydrophobic ionic liquids. LC-MS/MS is an analytical technique with proven utility for pharmaceutical identification and quantification. A methodology for the identification and quantification of five antibiotics, namely ampicillin, amoxicillin, chloramphenicol, enrofloxacin and oxytetracycline, from four families, namely β-lactams, phenicols, quinolones and tetracyclines, was developed and validated using one SPE extraction and clean-up step for detection analysis by LC-MS/MS. The selected linear range for each analyte is as follows: 5-200 ng mL^-1 for ampicillin; 0.1-200 ng mL^-1 for amoxicillin and chloramphenicol; and 1-200 ng mL^-1 for enrofloxacin and oxytetracycline, respectively. The limits of detection for each target analyte vary between 0.01 ng mL^-1 and 0.81 ng mL^-1, and the limits of quantification for each target analyte vary between 0.1 ng mL^-1 and 5 ng mL^-1 for the five antibiotics under study. The extraction recovery value range is between 89.91% and 100.33%. The validation proved that the developed methodology is suitable for the identification and quantification of ampicillin, amoxicillin, chloramphenicol, enrofloxacin and oxytetracycline. After validation, this new assay was successfully applied to a liquid-liquid extraction process using a hydrophobic ionic liquid.

Carbon dots-embedded N-acetylneuraminic acid and glucuronic acid-imprinted polymers for targeting and imaging of cancer cells

Diagnosis, treatment, and prediction of cancer progression require new targeting agents to specifically target cell surface receptors. Herein, we demonstrated fluorescent carbon quantum dots-molecularly imprinted polymer (CQD-MIP) for selective targeting and imaging of cancer cells. Carbon quantum dots (CQDs) were synthesized and characterized. The synthesized CQDs had average size of 1.5 nm and show intense fluorescence emission at wavelength of 450 nm with excitation at 370 nm. CQD-MIP nanoparticles imprinted with N-acetylneuraminic acid and glucuronic acid were prepared and characterized. CQD-MIPs were successfully applied for selective targeting and imaging of MCF-7, HepG-2, and NIH-3T3 cell lines. Non-imprinted polymer (NIP) showed no binding properties toward a target molecule. Non-imprinted polymer (NIP) and non-cancerous human cell lines were used for controlling the imprinting and targeting effects, respectively. Acceptable results were obtained with imprinted polymers on cancer cells.

Towards the Removal of Antibiotics Detected in Wastewaters in the POCTEFA Territory: Occurrence and TiO2 Photocatalytic Pilot-Scale Plant Performance

This research aims to assess the presence of four antibiotic compounds detected in the influent and effluent of wastewater treatment plants (WWTPs) in the POCTEFA territory (north of Spain and south of France) during the period of 2018–2019, and to relate the removal of antibiotic compounds with the processes used in the WWTPs. The performance of a photocatalytic TiO2/UV-VIS pilot-scale plant was then evaluated for the degradation of selected antibiotics previously detected in urban treated effluent. The main results reflect that azithromycin had the highest mass loadings (11.3 g/day per 1000 inhabitants) in the influent of one of the selected WWTPs. The results also show considerable differences in the extent of antibiotics removal in WWTPs ranging from 100% for sulfadiazine to practically 0% for trimethoprim. Finally, the photocatalytic TiO2/UV-VIS pilot-scale plant achieved the removal of the four antibiotics after 240 min of treatment from 78%–80% for trimethoprim and enrofloxacin, up to 100% for amoxicillin, sulfadiazine and azithromycin. The catalyst recovery via mechanical coagulation–flocculation–decantation was almost total. The Ti concentration in the effluent of the TiO2/UV-VIS pilot-scale plant was lower than 0.1% (w/w), and its release into the environment was subsequently minimized.

A model study by using polymeric molecular imprinting nanomaterials for removal of penicillin G

We aimed to develop a molecularly imprinted polymeric systems with using penicillin G as a template molecule for removal of the antibiotic residues from environmental samples. Firstly, Pen-G-imprinted poly (2-hydroxyethyl methacrylate-N-methacryloyl-L-alanine) [p(HEMA-MAAL)] nanopolymers were synthesized by surfactant-free emulsion polymerization method. Then, template molecule (Pen-G) was extracted from nanopolymers. Synthesized nanopolymers were characterized by different methods such as Fourier-transform infrared spectroscopy (FTIR), elemental and zeta-size analysis, scanning electron microscope (SEM), and surface area calculations. Nanopolymers have 60.38 nm average size and 1034.22 m²/g specific surface area. System parameters on Pen-G adsorption onto Pen-G imprint nanopolymers were investigated at different conditions. The specific adsorption value (Q_max) of molecularly impirinted p(HEMA-MAAL) nanopolymers was found 71.91 g/g for Pen-G in 5 mg/mL Pen-G initial concentration. Pen-G adsorption of molecularly imprinted nanopolymers was 15 times more than non-imprinted polymer. It is shown that obtained p(HEMA-MAAL) nanopolymer was a reuseable product which protected its adsorption capacity of 98.9% after 5th adsorption-desorption cycle. In conclusion, we suggest a method to develop a nanostructure, selective, low-cost molecularly imprinted polymeric systems with using penicillin G as a template molecule for removal of the antibiotic residues.

Impedimetric electronic tongue based on molybdenum disulfide and graphene oxide for monitoring antibiotics in liquid media

Antibiotics are considered emerging pollutants which indiscriminate use has led to the development of antibiotic-resistant bacteria, while their improper disposal has caused adverse effects to the environment and human health. Thus, the development of devices or techniques capable of detecting antibiotics with high sensitivity, low detection limits, and reasonable cost becomes of prime importance. In this work, an electronic tongue (e-tongue) based on molybdenum disulfide (MoS₂) and graphene oxide (GO) was developed and employed to detect four distinct antibiotics, namely cloxacillin benzathine, erythromycin, streptomycin sulfate, and tetracycline hydrochloride. The five sensing units of the e-tongue were obtained using the drop-casting method to modify gold interdigitated electrodes with MoS₂ and GO. Using Principal Component Analysis to process the experimental data allowed the e-tongue to recognize samples contaminated with distinct antibiotics at varied concentrations from 0.5 to 5.0 nmol L^-1. Analyses with real samples were also performed using river water and human urine and the electronic tongue was able to differentiate the samples at a nanomolar level. The proposed system represents a sensitive and low-cost alternative for antibiotic analyses in different liquid media.

Preparation of Restricted Access Media-Molecularly Imprinted Polymers for the Detection of Chloramphenicol in Bovine Serum

Chloramphenicol- (CAP-) restricted access media-molecularly imprinted polymers (CAP-RAM-MIPs) were prepared by precipitation polymerization using CAP as a template molecule, 2-diethylaminoethyl methacrylate (DEAEM) as a functional monomer, ethylene glycol dimethyl acrylate (EDMA) as a crosslinking agent, glycidyl methacrylate (GMA) as an outer hydrophilic functional monomer, and acetonitrile as a pore former and solvent. The CAP-RAM-MIPs were successfully characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The adsorption performance was investigated in detail using static, dynamic, and selective adsorption experiments. Adsorption equilibrium could be reached within 11 min. The CAP-RAM-MIPs had a high adsorption rate and good specific adsorption properties. Scatchard fitting curves indicated there were two binding sites for CAP-RAM-MIPs. Adsorption was Freundlich multilayer adsorption and consistent with the quasi-second kinetic model. Using CAP-RAM-MIPs for selective separation and enrichment CAP in bovine serum in combination with high-performance liquid chromatography (HPLC), CAP recovery ranged from 94.1 to 97.9% with relative standard deviations of 0.7-1.5%. This material has broad application prospects in enrichment and separation.

Preparation of Ampicillin Surface Molecularly Imprinted Polymers for Its Selective Recognition of Ampicillin in Eggs Samples

Surface-imprinted polymers (MIPs) microspheres with the ability to specifically recognize water-soluble molecules were prepared using self-made monodisperse porous poly(chloromethylstyrene-co-divinylbenzene) beads as the solid-phase matrix and ampicillin (AMP) as the template molecule. MIPs were synthesized using different template molecule: monomer: crosslinker ratios and the optimum preparation ratio were obtained by measuring adsorption. The maximum equilibrium amount of adsorption by the MIPs reached 115.62 mg/g. Scatchard analysis indicated that the MIPs contained two types of recognition sites: specific and nonspecific. Based on the adsorption kinetics, adsorption equilibrium was reached after 30 minutes. Penicillin G, amoxicillin, and sulbactam acid were used as competitive molecules to research the selective adsorption capacity of the MIPs. The imprinted material was found to have good selectivity with selectivity coefficients for penicillin G, amoxicillin, and sulbactam acid of 5.74, 6.83, and 7.25, respectively. The MIPs were used as solid-phase extraction filler, resulting in successful enrichment and separation of ampicillin residue from egg samples. Standard addition recovery experiments revealed that recovery was good with recoveries from the spiked samples ranging from 91.5 to 94.9% and relative standard deviations from 3.6 to 4.2%. The solid-phase extraction MIPs microcolumn was reused 10 times, where it maintained a recovery rate of over 80%. This work presents a sensitive, fast, and convenient method for the determination of trace ampicillin in food samples.

Preparation of Imazethapyr Surface Molecularly Imprinted Polymers for Its Selective Recognition of Imazethapyr in Soil Samples

A novel strategy based on imazethapyr (IM) molecular-imprinting polymers (MIPs) grafted onto the surface of chloromethylation polystyrene resin via surface-initiated atom transfer radical polymerization (SI-ATRP) for specific recognition and sensitive determination of trace imazethapyr in soil samples was developed. The SI-ATRP was performed by using methanol-water (4 : 1, v/v) as the solvent, acrylamide as the functional monomer, trimethylolpropane trimethacrylate (TRIM) as the cross-linker, imazethapyr as the template, and CuBr/2,2'-bipyridine as the catalyst. The resulting MIPs were characterized by elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Then, the binding selectivity, adsorption capacity, and reusability of the MIPs were evaluated. The results indicated that the prepared MIPs exhibited specific recognition and high selectivity for imazethapyr. The MIPs were further used as solid-phase extraction (SPE) materials coupled with high-performance liquid chromatography (HPLC) for selective extraction and detection of trace imazethapyr from soil samples. The results showed that good linearity was observed in the range of 0.10-5.00 μg/mL, with a correlation coefficient of 0.9995. The limit of detection (LOD) of this method was 15 ng/g, and the extraction recoveries of imazethapyr from real samples were in the range of 91.1-97.5%, which proved applicable for analysis of trace imazethapyr in soils. This work proposed a sensitive, rapid, and convenient approach for determination of trace imazethapyr in soil samples.

Detection of β-Lactams and Chloramphenicol Residues in Raw Milk-Development and Application of an HPLC-DAD Method in Comparison with Microbial Inhibition Assays

The present study was carried out to assess the detection sensitivity of four microbial inhibition assays (MIAs) in comparison with the results obtained by the High Performance Liquid Chromatography with Diode-Array Detection (HPLC-DAD) method for antibiotics of the β-lactam group and chloramphenicol in fortified raw milk samples. MIAs presented fairly good results when detecting β-lactams, whereas none were able to detect chloramphenicol at or above the permissible limits. HPLC analysis revealed high recoveries of examined compounds, whereas all detection limits observed were lower than their respective maximum residue limits (MRL) values. The extraction and clean-up procedure of antibiotics was performed by a modified matrix solid phase dispersion procedure using a mixture of Plexa by Agilent and QuEChERS as a sorbent. The HPLC method developed was validated, determining the accuracy, precision, linearity, decision limit, and detection capability. Both methods were used to monitor raw milk samples of several cows and sheep, obtained from producers in different regions of Greece, for the presence of examined antibiotic residues. Results obtained showed that MIAs could be used effectively and routinely to detect antibiotic residues in several milk types. However, in some cases, spoilage of milk samples revealed that the kits’ sensitivity could be strongly affected, whereas this fact does not affect the effectiveness of HPLC-DAD analysis.

Molecularly Imprinted Polymers as Extracting Media for the Chromatographic Determination of Antibiotics in Milk

Milk-producing animals are typically kept stationary in overcrowded large-scale farms and in most cases under unsanitary conditions, which promotes the development of infections. In order to maintain sufficient health status among the herd or promote growth and increase production, farmers administer preventative antibiotic doses to the animals through their feed. However, many antibiotics used in cattle farms are intended for the treatment of bacterial infections in humans. This results in the development of antibiotic-resistant bacteria which pose a great risk for public health. Additionally, antibiotic residues are found in milk and dairy products, with potential toxic effects for the consumers. Hence the need of antibiotic residues monitoring in milk arises. Analytical methods were developed for the determination of antibiotics in milk, with key priority given to the analyte extraction and preconcentration step. Extraction can benefit from the production of molecularly imprinted polymers (MIPs) that can be applied as sorbents for the extraction of specific antibiotics. This review focuses on the principals of molecular imprinting technology and synthesis methods of MIPs, as well as the application of MIPs and MIPs composites for the chromatographic determination of various antibiotic categories in milk found in the recent literature.

Determination of Aflatoxin M1 and Heavy Metals in Infant Formula Milk Brands Available in Pakistani Markets

Aflatoxin M₁ (AFM₁) after its bioconversion from aflatoxin B₁ in animal liver becomes the part of milk while heavy metals get entry into milk and milk products during handling in the supply chain. Aflatoxin M₁ and heavy metals being toxic compounds are needed to be monitored continuously to avoid any ailments among consumers of foods contaminated with such toxicants. Thirteen commercially available infant formula milk (IFM) brands available in Pakistani markets were analyzed for the quantitative determination of AFM₁ and heavy metals through ELISA and atomic absorption spectrophotometer, respectively. AFM₁ was found positive in 53.84% samples while 30.76% samples were found exceeding the maximum EU limit i.e. 0.025 μg/kg for AFM₁ in IFM. Heavy metals lead (Pb) and cadmium (Cd) were found below the detection limits in any of the sample, whereas the concentrations of iron (Fe), zinc (Zn) and nickel (Ni) ranged between 45.40-97.10, 29.72-113.50 and <0.001-50.90 μg/kg, respectively. The concentration of Fe in all the tested brands was found in normal ranges while the concentrations of Zn and Ni were found exceeding the standard norms. Elevated levels of AFM₁, Zn and Ni in some of the tested IFM brands indicated that a diet completely based on these IFM brands might pose sever health implications in the most vulnerable community i.e., infants.

Selection of DNA aptamers against penicillin G using Capture-SELEX for the development of an impedimetric sensor

This paper describes for the first time the selection of aptamers selective to penicillin. Aptamers were selected using a specific process called Capture-SELEX (Systematic Evolution of Ligands by Exponential Enrichment). This technique is based on the selection of DNA aptamers using penicillin G in solution while the ssDNA library is fixed on a support. One aptamer showing a good affinity to penicillin was finally selected and tested in electrochemical sensor configuration, using electrochemical impedance spectroscopy as detection technique. The developed aptasensor allowed the detection of penicillin in a wide concentration range, comprised between 0.4 and 1000µgL^-1 Such performance was compatible with milk analysis, as the maximum residue limit tolerated in this matrix is 4µgL^-1. The selectivity of the developed sensor was also studied, showing that the sensor was also able to bind other beta-lactam antibiotics, although with a weaker affinity. Finally the sensor was used for detection of penicillin G in milk. It was shown that a simple sample treatment with isopropanol followed by filtration was sufficient to eliminate matrix effects, allowing the determination of penicillin in milk at concentrations compatible with legislation requirements.