The combined effects of pH and temperature on penicillin G decomposition and its stability modeling

An Adsorption Based Downstream Processing Approach for Penicillin V from a Penicillium chrysogenum BIONCL I22 Culture Filtrate

Penicillin V (phenoxy methyl penicillin) is highly sought after among natural penicillins because of its exceptional acid stability and effectiveness against common skin and respiratory infections. Given its wide-ranging therapeutic uses, there is a need to establish a greener method for its maximum recovery to reduce the carbon footprint. Here, we have identified and validated optimized operational conditions for resin-based penicillin V recovery. It was observed that Amberlite XAD4 had the highest penicillin V hydrophobic adsorption capacity among the other screened resins. Kinetic and isothermal studies using linear and nonlinear regression analysis showed that the adsorption process well fitted with pseudo-second-order kinetics (R 2 = 0.9816) and the Freundlich adsorption isotherm model (R 2 = 0.9871). Adsorption equilibrium was attained within 4 h, while maximum adsorption was observed at 3 mg/mL penicillin V concentration. Furthermore, the optimized extraction protocol was compared with the conventional butyl acetate-based downstream processing. Under optimum conditions resin-based penicillin V recovery was 2-fold higher as compared to the solvent extraction method and the resin could be reused for over six cycles without compromising the yield. These findings signify substantial progress toward the development of an environmentally sustainable approach for penicillin V recovery and a potentially viable method for extractive fermentation.

Cu2+ coordination-induced in situ photo-to-heat on catalytic sites to hydrolyze β-lactam antibiotics pollutants in waters

For degradation of β-lactam antibiotics pollution in waters, the strained β-lactam ring is the most toxic and resistant moiety to biodegrade and redox-chemically treat among their functional groups. Hydrolytically opening β-lactam ring with Lewis acid catalysts has long been recognized as a shortcut, but at room temperature, such hydrolysis is too slow to be deployed. Here, we found when Cu2+ was immobilized on imine-linked COF (covalent organic framework) (Cu2+/Py-Bpy-COF, Cu2+ load is 1.43 wt%), as-prepared composite can utilize the light irradiation (wavelength range simulated sunlight) to in situ heat anchored Cu2+ Lewis acid sites through an excellent photothermal conversion to open the β-lactam ring followed by a desired full-decarboxylation of hydrolysates. Under 1 W/cm2 simulated sunlight, Cu2+/Py-Bpy-COF powders placed in a microfiltration membrane rapidly cause a temperature rising even to ~211.7 °C in 1 min. It can effectively hydrolyze common β-lactam antibiotics in waters and even antibiotics concentration is as high as 1 mM and it takes less than 10 min. Such photo-heating hydrolysis rate is ~24 times as high as under dark and ~2 times as high as Cu2+ homogenous catalysis. Our strategy significantly decreases the interference from generally coexisting common organics in waters and potential toxicity concerns of residual carboxyl groups in hydrolysates and opens up an accessible way for the settlement of β-lactam antibiotics pollutants by the only energy source available, the sunlight.

Investigating freezing-induced acidity changes in citrate buffers

Citrate buffers are commonly utilized in the field of biomolecule stabilization. We investigate their applicability in the frozen state within a range of initial pHs (2.5 to 8.0) and concentrations (0.02 to 0.60 M). Citrate buffer solutions subjected to various cooling and heating temperatures are examined in terms of the freezing-induced acidity changes, revealing that citrate buffers acidify upon cooling. The acidity is assessed with sulfonephthalein molecular probes frozen in the samples. Optical cryomicroscopy combined with differential scanning calorimetry was employed to investigate the causes of the observed acidity changes. The buffers partly crystallize and partly vitrify in the ice matrix; these processes influence the resulting pH and allow designing the optimal storage temperatures in the frozen state. The freezing-induced acidification apparently depends on the buffer concentration; at each pH, we suggest pertinent concentration, at which freezing causes minimal acidification.

Optimization of a medium composition for the heterologous production of Alcaligenes faecalis penicillin G acylase in Bacillus megaterium

Penicillin G acylase (PGA) is a strategic enzyme in the production processes of beta-lactam antibiotics. High demand for β-lactam semisynthetic antibiotics explain the genetic and biochemical engineering strategies devoted towards novel ways for PGA production and application. This work presents a fermentation process for the heterologous production of PGA from Alcaligenes faecalis in Bacillus megaterium with optimization. The thermal stability from A. faecalis PGA is considerably higher than other described PGA and the recombinant enzyme is secreted to the culture medium by B. megaterium, which facilitates the separation and purification steps. Media optimization using fractional factorial design experiments was used to identify factors related to PGA activity detection in supernatant and cell lysates. The optimized medium resulted in almost 6-fold increased activity in the supernatant samples when compared with the basal medium. Maximum enzyme activity in optimized medium composition achieves values between 135 and 140 IU/ml. The results suggest a promising model for recombinant production of PGA in B. megaterium with possible extracellular expression of the active enzyme.

Quantifying Antibiotic Distribution in Solid and Liquid Fractions of Manure Using a Two-Step, Multi-Residue Antibiotic Extraction

Antibiotic distribution and analysis within liquid and solid fractions of manure are highly variable due to each compound’s respective physiochemical properties. This study developed and evaluated a uniform method extracting 10 antibiotics from 4 antibiotic classes (tetracycline, sulfonamides, macrolides, and β-lactam) from unprocessed manure, solid−liquid separated manure, and composted solids. Through systematic manipulation of previously published liquid chromatography tandem mass spectrometry methods; this study developed an extraction protocol with optimized recovery efficiencies for varied manure substrates. The method includes a two-step, liquid-solid extraction using 10 mL of 0.1 M EDTA-McIlviane buffer followed by 10 mL of methanol. Antibiotics recoveries from unprocessed manure, separated liquids, separated solids, and heat-treated solids using the two-step extraction method had relative standard deviations < 30% for all but ceftiofur. Total antibiotic recoveries were 67−131% for tetracyclines, 56% for sulfonamide, 49−53% for macrolides, and 1.3−66% for β-lactams. This is the first study to use one protocol to assess four classes of antibiotics in liquid and solid manure fractions. This study allowed for more precise risk assessment of antibiotic transport in manure waste stream applied to fields as a liquid or solid compost.

Effects of pH and Metal Ions on the Hydrothermal Treatment of Penicillin: Kinetic, Pathway, and Antibacterial Activity

Antibiotic residues lead to the risk of resistance gene enrichment, which is the main reason why penicillin mycelial dreg (PMD) is defined as hazardous waste. Hydrothermal treatment (HT) is an effective method to treat penicillin mycelial dreg, but the degradation mechanism of penicillin is unclear. In the study, we researched the effects of pH (4-10) at 80-100 °C and metal ions (Mn²⁺, Fe²⁺, Cu²⁺, and Zn²⁺) at several concentrations on the HT of penicillin, identified the degradation products (DPs) under different conditions, and evaluated the antibacterial activity of hydrothermally treated samples. The results show that penicillin degradation kinetics highly consistent with pseudo-first-order model (R² = 0.9447-0.9999). The degradation rates (k) at pH = 4, 7, and 10 were 0.1603, 0.0039, and 0.0485 min^-1, indicating acidic conditions were more conducive to penicillin degradation. Among the four tested metal ions, Zn²⁺ had the most significant catalytic effect. Adding 5 mg·L^-1 Zn²⁺ caused 100% degradation rate at pH = 7 after HT for 60 min. Six degradation products (DPs) with low mass-to-charge (m/z ≤ 335) were detected under acidic condition. However, only two and three DPs were observed in the samples catalyzed by Zn²⁺ and alkali, respectively, and penilloic acid (m/z = 309) was the main DPs under these conditions. Furthermore, no antibacterial activity to Bacillus pumilus was detected in the medium with up to 50% addition of the treated samples under acidic condition. Even though acid, alkali, and some metal ions can improve the degradation ability of penicillin, it was found that the most effective way for removing its anti-bacterial activity was under the acidic condition. Therefore, resistance residue indicates the amount of additive in the process of resource utilization, and avoids the enrichment of resistance genes.

Stability of benzylpenicillin for continuous intravenous infusions: An isotonic formulation for therapeutic use and a low-dose formulation for clinical trial

INTRODUCTION

The objectives of this study were to develop a stability-indicating high performance liquid chromatography (HPLC) assay for benzylpenicillin (BPC) in pharmaceutical fluids, and to investigate the stability of (i) isotonic citrate-buffered BPC solutions at the clinically relevant concentration of 30 mg/mL, and (ii) low concentration citrate-buffered BPC intravenous infusions (5-30 μg/mL).

METHODS

The stability of isotonic BPC solutions containing 3.4 or 7.2 mg/mL sodium citrate was compared against contemporary hypertonic solutions. The HPLC assay was shown to be stability-indicating following acidic, alkali, oxidative and elevated temperature stress testing.

RESULTS

After 7 d storage at 4 °C and 24 h at 35 °C, the concentrations of isotonic BPC 30 mg/mL solutions containing 3.4 and 7.2 mg/mL sodium citrate were 96% and 95% respectively, compared to day 0. After 3 d at 4 °C and 24 h at room temperature (22 °C), the concentrations of isotonic BPC solutions with 3.4 and 7.2 mg/mL sodium citrate were 99% and 96% respectively, compared to day 0. These data were comparable to the hypertonic solutions and meet pharmacopeial stability requirements. Low concentration BPC infusions showed 0.5% and 2.5% degradation after 24 h storage at 22 °C and 35 °C, respectively.

CONCLUSIONS

The isotonic BPC 30 mg/mL formulation is simple to prepare and may offer clinical benefits in settings where hypertonic solutions are problematic. This study provides assurance that high- and low-dose isotonic BPC infusions are stable at room temperature and our findings may be applicable to in vitro studies of BPC.

Design and Optimization of a Novel Strategy for the Local Treatment of Helicobacter pylori Infections

Infections with Helicobacter pylori are a global challenge. Currently, H. pylori infections are treated systemically, but the eradication rates of the different therapy regimens are declining due to the growing number of bacterial strains resistant to major antibiotics. Here, we present a strategy for the local eradication of H. pylori by the use of Penicillin G sodium (PGS). In vitro experiments revealed that PGS shows high antibiotic activity against resistant strains of Helicobacter pylori with a minimum inhibitory concentration (MIC) of 0.125 μg/ml. In order to provide luminal concentrations above the MIC for longer periods of time, an extended release tablet was developed. Alkalizers were included to prevent acidic degradation of PGS within the tablet matrix. Out of the tested alkalizers MgO, l-Lysine, NaHCO3, and Na2CO3 NaHCO3 provided the strongest rise in pH inside the hydrated matrix when tested in simulated gastric fluid. Better PGS stability can mainly reasoned from that, addition of MgO resulted in high pH values within the matrix, causing basic degradation of PGS. This work is a first step towards the use of extended release tablets containing PGS for the local treatment of H. pylori as a safe and cost-effective alternative to common systemic treatment regimens.

Hydrophobic Adsorption Followed by Desorption with Ethanol-Water for Recovery of Penicillin G from Fermentation Broth

The hydrophobic adsorption is an alternative to traditional organic solvent extraction for the recovery and purification of Penicillin G (PenG). However, there is a lack of information concerning the effect of process variables and technical feasibility while balancing product degradation. After assessing the integrity of PenG under different conditions, Amberlite XAD-4 was selected from among three different adsorbents. During the batch process using only 0.05 g_XAD-4/mL_medium, the adsorption yield increased from 36% at pH 6 to 44% at pH 4. More than 90% of the antibiotic was captured from the fermentation broth using 0.083 g_XAD-4/mL_medium in a 45 min batch performed at pH 4 and 4 °C. Moreover, there was no PenG degradation. The desorption conditions were evaluated, and 95% of the antibiotic could be recovered in only one batch using water-ethanol, which is an unexplored PenG desorption process. The results showed selective adsorption, indicating that the process can also be useful for purification purposes. Hydrophobic adsorption with ethanol desorption is efficient, scalable, and green and could be used in place of traditional methods or in extractive fermentation.

High and long-term antibacterial activity against Escherichia coli via synergy between the antibiotic penicillin G and its carrier ZnAl layered double hydroxide

Antibiotic-resistant bacterial infections are a global health problem. A commonly-used antibiotic Penicillin G was incorporated into ZnAl-layered double hydroxides (PNG/LDH) with a varied amount of PNG. PNG/LDH nanocomposites were well characterized in structure and composition using elemental analysis, X-ray diffraction pattern, Fourier transform infrared spectroscopy and TEM images, revealing that PNG were mostly adsorbed on the LDH surfaces at a lower PNG loading but some were intercalated into LDH interlayers at a higher PNG loading. The typical release profile of PNG and Zn²⁺ from PNG/LDH was a quick release, followed by a sustainable slow release. The antibacterial tests against Escherichia coli demonstrated that PNG/LDH with a suitable composition synergistically improved bacterial inhibition compared with free PNG and pristine LDHs. In specific, PNG/LDH with much higher cost-effectiveness showed a potent antimicrobial activity and maintained the activity for up to 10 days, significantly elongating the antibacterial effect compared with just 1 day for free PNG in the same conditions. Our results suggest suitable composition of nanoparticle carriers and antibiotics could significantly enhance antibacterial activity of antibiotics for a long period via the synergistic effect between carrier and antibiotics, a potential approach to overcome the bacterial resistance to antibiotics.

UHPLC-MS/MS method for the quantitation of penicillin G and metabolites in citrus fruit using internal standards

Penicillin G has been applied to citrus trees as a potential treatment in the fight against Huanglongbing (HLB). Here, we have developed and validated a method to identify and quantitate penicillin G and two of its metabolites, penillic acid and penilloic acid, in citrus fruit using ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). This method improves upon a previous method by incorporating isotopically labeled internal standards, namely, penillic acid-D₅, and penilloic acid-D₅. These standards greatly enhanced the accuracy and precision of our measurements by compensating for recovery losses, degradation, and matrix effects. When 2g of citrus fruit sample is extracted, the limits of detection (LOD) were determined to be 0.1ng/g for penicillin G and penilloic acid, and 0.25ng/g for penillic acid. At fortification levels of 0.1, 0.25, 1, and 10ng/g, absolute recoveries for penillic and penilloic acids were generally between 50-70%. Recoveries corrected with the isotopically labeled standards were approximately 90-110%. This method will be useful for the identification and quantitation of drug residues and their degradation products using isotopically labeled standards and UHPLC-MS/MS.

Identification of Penicillin G Metabolites under Various Environmental Conditions Using UHPLC-MS/MS

In this work, we investigate the stability of penicillin G in various conditions including acidic, alkaline, natural acidic matrices and after treatment of citrus trees that are infected with citrus greening disease. The identification, confirmation, and quantitation of penicillin G and its various metabolites were evaluated using two UHPLC-MS/MS systems with variable capabilities (i.e., Thermo Q Exactive Orbitrap and Sciex 6500 QTrap). Our data show that under acidic and alkaline conditions, penicillin G at 100 ng/mL degrades quickly, with a determined half-life time of approximately 2 h. Penillic acid, penicilloic acid, and penilloic acid are found to be the most abundant metabolites of penicillin G. These major metabolites, along with isopenillic acid, are found when penicillin G is used for treatment of citrus greening infected trees. The findings of this study will provide insight regarding penicillin G residues in agricultural and biological applications.

Maturity and security assessment of pilot-scale aerobic co-composting of penicillin fermentation dregs (PFDs) with sewage sludge

In this work, penicillin fermentation dregs (PFDs) and sewage sludge (SWS) were co-composted to analyze the possibility of recycling nutrients in PFDs. The temperature was maintained above 55°C for more than 3 days, and the final electrical conductivity (EC), pH and C/N all met the national standards in maturity. A nearly 100% removal of the residual penicillin was achieved, and the seed germination index (GI) increased from 0.02% to 83.54±3.1% by the end of the composting process. However, monitoring the quantity of antibiotic resistance genes (ARGs) showed that the logarithm of the number of copies of blaTEM increased from 4.17±0.19 at the initial phase to 8.92±0.27 by the end of the composting process, which means that there is a high risk for land use when using PFD compost products.

Cu(II)-catalyzed transformation of benzylpenicillin revisited: the overlooked oxidation

Penicillins, a class of widely used β-lactam antibiotics, are known to be susceptible to catalyzed hydrolysis by metal ions such as Cu(II). However, new results in this study strongly indicate that the role of Cu(II) is not merely a hydrolysis catalyst but also an oxidant. When benzylpenicillin (i.e., penicillin G (PG)) was exposed to Cu(II) ion at an equal molar ratio and pH 7, degradation of PG occurred rapidly in the oxygen-rich solution but gradually slowed down to a halt in the oxygen-limited solution. In-depth studies revealed that Cu(II) catalyzed hydrolysis of PG to benzylpenicilloic acid (PA) and oxidized PA to yield phenylacetamide and other products. The availability of oxygen played the role in reoxidizing Cu(I) back to Cu(II), which sustained fast degradation of PG over time. The overall reaction was also influenced by pH, with Cu(II)-catalyzed hydrolysis of PG occurring throughout pH 5, 7 and 9, while Cu(II) oxidation of PA occurring at pH 7 and 9. Note that the potential of Cu(II) to oxidize penicillins was largely overlooked in the previous literature, and catalyzed hydrolysis was frequently assumed as the only reaction. This study is among the first to identify the dual roles of Cu(II) in the entire degradation process of PG and systematically investigate the overlooked oxidation reaction to elucidate the mechanism. The new mechanistic knowledge has important implications for many other β-lactam antibiotics for their interactions with Cu(II), and significantly improves the ability to predict the environmental fate and transformation products of PG and related penicillins in systems where Cu(II) species are also present.

A new and general model to describe, characterize, quantify and classify the interactive effects of temperature and pH on the activity of enzymes

The common approachvs.the modern approach to analyze the effects of temperature and pH on the activity of enzymes.

A Proposal for Six Sigma Integration for Large-Scale Production of Penicillin G and Subsequent Conversion to 6-APA

Six Sigma methodology has been successfully applied to daily operations by several leading global private firms including GE and Motorola, to leverage their net profits. Comparatively, limited studies have been conducted to find out whether this highly successful methodology can be applied to research and development (R&D). In the current study, we have reviewed and proposed a process for a probable integration of Six Sigma methodology to large-scale production of Penicillin G and its subsequent conversion to 6-aminopenicillanic acid (6-APA). It is anticipated that the important aspects of quality control and quality assurance will highly benefit from the integration of Six Sigma methodology in mass production of Penicillin G and/or its conversion to 6-APA.

Modeling solubility, acid-base properties and activity coefficients of amoxicillin, ampicillin and (+)6-aminopenicillanic acid, in NaCl(aq) at different ionic strengths and temperatures

The total solubility of three penicillin derivatives was determined, in pure water and NaCl aqueous solutions at different salt concentrations (from ∼0.15 to 1.0 mol L(-1) for ampicillin and amoxicillin, and from ∼0.05 to 2.0 mol L(-1) for (+)6-aminopenicillanic acid), using the shake-flask method for generating the saturated solutions, followed by potentiometric analysis. The knowledge of the pH of solubilization and of the protonation constants determined in the same experimental conditions, allowed us to calculate, by means of the mass balance equations, the solubility of the neutral species at different ionic strength values, to model its dependence on the salt concentration and to determine the corresponding values at infinite dilution. The salting parameter and the activity coefficients of the neutral species were calculated by the Setschenow equation. The protonation constants of ampicillin and amoxicillin, determined at different temperatures (from T=288.15 to 318.15K), from potentiometric and spectrophotometric measurements, were used to calculate, by means of the Van't Hoff equation, the temperature coefficients at different ionic strength values and the corresponding protonation entropies. The protonation enthalpies of the (+)6-aminopenicillanic acid were determined by isoperibol calorimetric titrations at T=298.15K and up to I=2.0 mol L(-1). The dependence of the protonation constants on ionic strength was modeled by means of the Debye-Hückel and SIT (Specific ion Interaction Theory) approaches, and the specific interaction parameters of the ionic species were determined. The hydrolysis of the β-lactam ring was studied by spectrophotometric and H NMR investigations as a function of pH, ionic strength and time. Potentiometric measurements carried out on the hydrolyzed (+)6-aminopenicillanic acid allowed us to highlight that the opened and the closed β-lactam forms of the (+)6-aminopenicillanic acid have quite different acid-base properties. An analysis of literature solubility, protonation constants, enthalpies and activity coefficients is reported too.

A preparative method for the purification of isopenicillin N from genetically blocked Acremonium chrysogenum strain TD189: studies on the degradation kinetics and storage conditions

A protocol for preparative isopenicillin N (IPN) purification, a highly interesting and hitherto unavailable intermediate of the penicillin and cephalosporin biosynthetic pathway due to its high unstability, is described. Culture broths of Acremonium chrysogenum TD189, a strain blocked in cephalosporin biosynthesis that accumulates this metabolite, were treated with acetone and filtered though charcoal and a hydrophobic resin in a single step as tandem columns. The cleared broth was then lyophilized and passed though a Sephadex G-25 column. The last step was the purification to homogeneity of IPN in a semipreparative HPLC equipment and, optionally, a desalting step by Sephadex G-10 column. Once purified, a complete analysis of the stability of the compound and the conditions for its long-term storage was carried out. Our results suggest a first-order model for IPN decomposition for all the pH and temperature analyzed. IPN is more stable at neutral pH, and once lyophilized, can be stored under vacuum and -75 ° C with a half-life of 770 days.

Insights into the reaction of beta-lactam antibiotics with copper(II) ions in aqueous and micellar media: kinetic and spectrometric studies

Degradation of beta-lactam antibiotics by means of metallic cations seems to have a very complex chemistry, involving not only the catalytic effect of the metal ion but also complex formation. Many different compounds, such as methylpyrazines, oxazolones, penicilloic, penicillenic, and penicillonic acids, have been reported as degradation products of such antibiotics, although not many details about the progress of the reaction can be found in the literature. Two novel fluorimetric and spectrophotometric methods previously published by the authors, as well as kinetic studies, have been used to propose a possible reaction mechanism for the ampicillin degradation in the presence of copper(II) ions. Likewise, we have proposed the chemical structure required by the beta-lactam antibiotics to develop absorption or fluorescence properties. Kinetics in micellar and aqueous media shows that the copper-ampicillin reaction proceeds through different pathways depending on the reaction medium.

Toxicity and biodegradability assessment of raw and ozonated procaine penicillin G formulation effluent

The effect of O3 (applied dose = 1440 mg h(-1); pH 7 and pH 12) and H2O2/O3 (applied dose = 1440 mg h(-1); pH 7; 10 mM H2O2) pretreatment of procaine penicillin G (PPG) formulation effluent on its biodegradability and acute toxicity was investigated. For that purpose ISO 8192 activated sludge inhibition and Daphnia magna acute toxicity tests were conducted. BOD5 measurements that were carried out to preevaluate the biocompatibility of untreated, ozonated, and perozonated PPG effluent have shown that BOD5 alone was not a very correct or useful tool to predict the actual biodegradability of PPG effluent. No significant correlation existed between the BOD5 and the toxicity test results. Acute toxicity studies carried out with D. magna and synthetic municipal sewage sludge have demonstrated the inhibitory effect of H2O2/O3 oxidation. COD removal of pharmaceutical wastewater containing PPG effluent with acclimated sewage sludge decreased from 79% to 50% after H2O2/O3 pretreatment.

Ozonation of Procaine Penicillin G formulation effluent Part I: Process optimization and kinetics

Ozonation characteristics of synthetic Procaine Penicillin G (PPG) formulation effluent were investigated in a semi-batch ozone reactor at different pH (3, 7 and 12), ozone feed rates (600-2600 mg h-1) and COD values (200-600 mg l-1). Ozonation of aqueous PPG effluent resulted in 37 (82)% COD removal after 60 (120) min ozonation when the reaction pH was kept constant at pH=7.900 mg l-1 (corresponding to 50% of the total introduced) ozone was absorbed during a reaction period of 1 h. The effects of increasing the applied ozone dose and the initial COD on the COD abatement rates of PPG effluent were also studied. Results have indicated that increasing the ozone dose and decreasing the COD content both have positive effects on COD removal rates. The significant contribution of the free radical (.OH) reaction pathway to PPG ozonation could be traced using tert-butyl alcohol as the .OH probe compound at varying concentrations. The bimolecular reaction rate constants for the direct reaction of PPG with ozone were found as 152 and 2404 M-1 h-1 at pH=3 and 7, respectively, using the gas phase ozone partial pressures determined from of the outlet gas stream analysis. It could be demonstrated that ozone decomposition to free radicals being triggered by increasing the pH from 3 to 7 is essential for the rate enhancement of PPG effluent ozonation.