LC method development for ibuprophen and validation in different pharmaceuticals

Enhanced degradation of bisphenol A and ibuprofen by an up-flow microbial fuel cell-coupled constructed wetland and analysis of bacterial community structure

This study aims to demonstrate that an up-flow microbial fuel cell-coupled constructed wetland (UCW-MFC) can effectively treat synthetic wastewater that contains a high concentration of pharmaceutical and personal care products (PPCPs, 10 mg L^-1 level), such as ibuprofen (IBP) and bisphenol A (BPA). A significant decline in chemical oxygen demand (COD) and ammonia nitrogen (NH₄⁺-N) removal was observed when BPA was added, which indicated that BPA was more toxic to bacteria. The closed circuit operation of UCW-MFC performed better than the open circuit mode for COD and NH₄⁺-N removal. Similarly, the removal rates of IBP and BPA were increased by 9.3% and 18%, respectively, compared with the open circuit mode. The majority of PPCPs were removed from the bottom and anode layer, which accounted for 63.2-78.7% of the total removal. The main degradation products were identified. The removal rates of IBP and BPA decreased by 14.6% and 23.7% due to a reduction in the hydraulic detention times (HRTs) from 16 h to 4 h, respectively. Electricity generation performance, including voltage and maximum power density, initially increased and then declined with a decrease in the HRT. Additionally, both the current circuit operation mode and the HRT have an impact on the bacterial community diversity of the anode according to the results of high-throughput sequencing. The possible bacterial groups involved in PPCP degradation were identified. In summary, UCW-MFC is suitable for enabling the simultaneous removal of IBP and BPA and successful electricity production.

Multi-functional electrospun antibacterial core-shell nanofibrous membranes for prolonged prevention of post-surgical tendon adhesion and inflammation

The possibility of endowing an electrospun anti-adhesive barrier membrane with multi-functionality, such as lubrication, prevention of fibroblast attachment and anti-infection and anti-inflammation properties, is highly desirable for the management of post-surgical tendon adhesion. To this end, we fabricated core-shell nanofibrous membranes (CSNMs) with embedded silver nanoparticles (Ag NPs) in the poly(ethylene glycol) (PEG)/poly(caprolactone) (PCL) shell and hyaluronic acid (HA)/ibuprofen in the core. HA imparted a lubrication effect for smooth tendon gliding and reduced fibroblast attachment, while Ag NPs and ibuprofen functioned as anti-infection and anti-inflammation agents, respectively. CSNMs with a PEG/PCL/Ag shell (PPA) and HA core containing 0% (H/PPA), 10% (HI10/PPA), 30% (HI30/PPA) and 50% (HI50/PPA) ibuprofen were fabricated through co-axial electrospinning and assessed through microscopic, spectroscopic, thermal, mechanical and drug release analyses. Considering nutrient passage through the barrier, the microporous CSNMs exerted the same barrier effect but drastically increased the mass transfer coefficients of bovine serum albumin compared with the commercial anti-adhesive membrane SurgiWrap®. Cell attachment/focal adhesion formation of fibroblasts revealed effective reduction of initial cell attachment on the CSNM surface with minimum cytotoxicity (except HI50/PPA). The anti-bacterial effect against both Gram-negative and Gram-positive bacteria was verified to be due to the Ag NPs in the membranes. In vivo studies using H/PPA and HI30/PPA CSNMs and SurgiWrap® in a rabbit flexor tendon rupture model demonstrated the improved efficacy of HI30/PPA CSNMs in reducing inflammation and tendon adhesion formation based on gross observation, histological analysis and functional assays. We conclude that HI30/PPA CSNMs can act as a multifunctional barrier membrane to prevent peritendinous adhesion after tendon surgery.

STATEMENT OF SIGNIFICANCE

A multi-functional anti-adhesion barrier membrane that could reduce fibroblasts attachment and penetration while simultaneously prevent post-surgical infection and inflammation is urgently needed. To this end, we prepared electrospun core-shell hyaluronic acid + ibuprofen/polyethylene glycol + polycaprolactone + Ag nanoparticles nanofibrous membranes by co-axial electrospinning as an ideal anti-adhesive membrane. The core-shell structure could meet the need of a desirable anti-adhesion barrier through release of ibuprofen and Ag nanoparticles to reduce infection and inflammation while hyaluronic acid can reduce fibroblasts adhesion. The superior performance of this multi-functional core-shell nanofibrous membrane in preventing peritendinous adhesion and post-surgical inflammation was demonstrated in a rabbit flexor tendon rupture model.

Esterification of Ibuprofen in Soft Gelatin Capsules Formulations-Identification, Synthesis and Liquid Chromatography Separation of the Degradation Products

Unknown impurities were identified in ibuprofen (IBU) soft gelatin capsules (SGCs) during long-term stability testing by a UHPLC method with UV detection and its chemical formula was determined using high resolution/accurate mass (HRAM) LC-MS. Reference standards of the impurities were subsequently synthesized, isolated by semi-preparative HPLC and characterized using HRAM LC-MS, NMR and IR. Two impurities were formed by esterification of IBU with polyethylene glycol (PEG), which is used as a fill of the SGCs, and were identified as IBU-PEG monoester and IBU-PEG diester. Two other degradants arised from reaction of IBU with sorbitol and sorbitan, which are components of the shell and serves as plasticizers. Thus, IBU sorbitol monoester (IBU-sorbitol) and IBU sorbitan monoester (IBU-sorbitan ester) were identified. An UHPLC method was further optimized in order to separate, selectively detect and quantify the degradation products in IBU SGCs.

Fast photocatalytic degradation of pharmaceutical micropollutants and ecotoxicological effects

Aqueous solutions of ciprofloxacin (CP) and ibuprofen (IBP) in the presence of LaFeO₃ photocatalyst, of H₂O₂, and of both LaFeO₃ and H₂O₂ were irradiated under visible light. The degradation rate in the presence of both LaFeO₃ and H₂O₂ after 5 h irradiation was more than 90 % for CP and 40 % for IBP, much higher than that with only H₂O₂ under visible light. For the sake of comparison, the experiments were also carried out in the dark, and both CP and IBP were not significantly converted. The degradation rate was enhanced by the simultaneous presence of small concentration of LaFeO₃ (130 mg L^-1) and H₂O₂ (0.003 M). However, tests on the aquatic acute toxicity indicate that the degradation products of CP and IBP induce toxic effects on aquatic organisms, consequently indicating incomplete detoxification after 5 h irradiation. The main degradation product of IBP was 4-isobutylacetophenone (4-IBAP), detected in the irradiated solutions by using UV/vis spectrophotometry. 4-IBAP was more toxic and showed a slower photocatalytic degradation than the parent compound. On the contrary, the toxicity of CP degradation products, although not negligible, was comparable to that of CP itself.

One-step method for plasma determination of ibuprofen by chemiluminescence-coupled ultrafiltration and application in a pharmacokinetic study

A simple one-step method is established for plasma determination of ibuprofen and its pharmacokinetic study. The method involves simple sample pre-treatment by dilution, rapid separation by ultrafiltration (UF) and online sensitive detection by chemiluminescence (CL) based on significant intensity enhancement of ibuprofen on the weak CL of potassium permanganate and sodium sulphite in an acidic system. The calibration curve for ibuprofen is linear in the range 0.1-50.0 µg/mL in rat plasma. Average recoveries of ibuprofen at 0.80, 12.0 and 40.0 µg/mL amounted to 98.0 ± 4.2%, 101.2 ± 3.6% and 99.3 ± 5.4%, respectively. Standard deviations of intra- and inter-day measurement precision and accuracy are within ±10.0%. The detection limit for ibuprofen is 10.0 µg/L in plasma samples. Pharmacokinetic study of ibuprofen by the validated method shows that the mean plasma drug concentration-time course confirms to a classical two-compartment open model with first-order absorption. The proposed method will be an alternative for pre-clinical pharmacokinetic study of ibuprofen and other non-steroidal anti-inflammatory drugs.

A novel hollow-fibre microporous membrane liquid–liquid extraction for determination of free 4-isobutylacetophenone concentration at ultra trace level in environmental aqueous samples

In this study, a method was developed for determination of the free concentration of 4-isobutylacetophenone, a toxic degradation product of ibuprofen, in river and sewage water samples from Sweden. Sample preparation and analysis were performed by a hollow-fibre microporous membrane liquid-liquid extraction (HF-MMLLE) set-up and gas chromatography-mass spectrometry (GC-MS), respectively. In this novel approach, only the liquid in the membrane pores is utilised for non-depleting extraction. Several parameters were studied, including: type of organic solvent, sample pH, and salt and humic acid content. The optimised method allowed the determination of the analyte at the ng L(-1) level in river and sewage water. A linear plot gave a correlation coefficient better than 0.992 and resulted in a limit of detection of 7 and 14 ng L(-1) for river and sewage water, respectively. The enrichment factor was over 2000 in the fibre and over 300 after dilution. The repeatability and reproducibility were better than 5% and 10%, respectively. For the first time, 4-isobutylacetophenone was found at free concentrations of 40 ng L(-1) or below in sewage waters, while it could not be quantified in a river downstream from a municipal sewage treatment plant.

Tandem column for the simultaneous determination of arginine, ibuprofen and related impurities by liquid chromatography

Ibuprofen arginate is a rapidly absorbed salt designed to promote more rapid onset of analgesia than commercially available forms of ibuprofen. Ibuprofen and arginine have very different polarities and this becomes in a chromatographic problem, further complicated with the determination of related compounds, which is necessary in stability assays of the pharmaceutical forms. The common solution is the employment of two separate methods, but this is time consuming. A LC method has been developed to determinate both compounds and related impurities in one run. Ibuprofen, arginine and three ibuprofen related impurities (B, E and J) have been baseline separated with isocratic conditions at pH 3.0 and run time under 20 min by employing a tandem combination of two different stationary phases: first a ZORBAX SB-C18 column from Agilent (250 mm x 4.6 mm and 5 microm) and downstream a SUPELCOSIL LC-NH2 column from Supelco (150 mm x 4.6 mm and 3 microm). The octadecyldiisobutylsilane column provides the separation of ibuprofen and its impurities by a hydrophobic mechanism, whereas aminopropyl column offers selective retention of arginine by dipolar interaction mechanism. Method has been successfully validated following ICH guidelines and it has been demonstrated to be reliable for arginine, ibuprofen and related impurities determination in sachets of two different dosages as pharmaceutical forms. Moreover, stress test has proved the selectivity of the method for degradation products, such as those that can emerge throughout long-term stability assays.

Utilization of zirconia stationary phase as a tool in drug control

Zirconia-based stationary phases represent an interesting alternative to silica-based materials. Two zirconia-based stationary phases were studied as an option for use in drug analysis. The different properties of zirconia material, distinct from RP silica-columns, were employed for the development of a novel and rapid stability monitoring HPLC method. This method enables simultaneous control of possible degradation processes of active substance (ibuprofen) as well as antimicrobial excipients (methyl-and propylparaben). The separation of ibuprofen, its two main degradation products 2-(4-isobutyrylphenyl)propionic acid and 4-isobutylacetophenone, parabens, and 4-hydroxybenzoic acid as their degradation product was successfully accomplished on a Zr-CarbonC18 column using a mobile phase consisting of acetonitrile-phosphate buffer (pH 4.8)-propan-2-ol (27:56:17, v/v/v). Detection was performed at 258 nm and the analysis was completed within 17 minutes.

Use of the zirconia-based stationary phase for separation of ibuprofen and its impurities

A new reversed-phase liquid chromatographic method using zirconia-based stationary phase was developed for determination of ibuprofen, its related compounds and its main degradation products. The chromatographic separation was successfully achieved on the Discovery Zr-PS column (150 mm x 4.6 mm i.d., 5 microm), using a mobile phase methanol-phosphate buffer (pH 4.5; 0.05 M)-tetrahydrofurane (21:74:5, v/v/v) and the flow rate 0.5 ml min(-1). The UV detection was performed in dual wavelength mode (219 and 258 nm) to detect all compounds of interest. The column temperature was set on 60 degrees C to shorten the analysis time and improve the peak symmetry. The method is simple, rapid and cuts down the amount of hazardous waste produced in the analysis. The assay is completed within 22 minutes.

Characterization of Caco-2 cell monolayer drug transport properties by cassette dosing using UV/fluorescence HPLC

Cassette dosing is commonly used in pharmacokinetic studies to decrease time, labor and expenditures. Cassette dosing (having several compounds in a mixture) has been used to screen in vitro permeabilities in Caco-2 cell monolayers. The cassette dosing method has accelerated both transport experiments and sample analyses, which are both part of Caco-2 permeability screening. In this study, a cassette dosing method was used for a mixture of heterogeneous test drugs, which are transported by various mechanisms across the Caco-2 cell monolayer. To characterize the Caco-2 cell monolayer absorption properties, we developed a new UV/fluorescence HPLC method for nine heterogeneous drugs. This new analytical method is fast and specific for high throughput analysis. Fluorescence detection was used to analyze the low concentration of drugs while UV detection was suitable for higher concentrations. The permeability results of single drugs and the mixture of drugs showed a high degree of similarity for each individual compound. All drugs can be applied to the Caco-2 cell culture as a mixture, and the cassette dosing method is suitable for permeability studies.

Validation of a liquid chromatographic method for the determination of ibuprofen in human plasma

A simple, rapid method of determining the ibuprofen concentration in small volumes of human plasma (50 microl) by HPLC was developed. The sample was prepared for injection using a solid-phase extraction method, with naproxen as the internal standard. A 96-well extraction plate was used, easing sample preparation and allowing the simultaneous extraction of multiple plasma samples directly into the HPLC injection vials. Samples were stable at room temperature for at least 48 h prior to injection. The HPLC method used an ultraviolet detector with a 5-min run time and measured concentrations across the range typically seen with the clinical use of this drug. The calibration curve was linear across the concentration range of 0.78-100 microg/ml with a limit of quantitation (LOQ) of 1.56 microg/ml. The coefficient of variation for intra-day and inter-day precision was 6% or less with accuracies within 2% of the nominal values for low (4.5 microg/ml), medium (40 microg/ml) and high (85 microg/ml) ibuprofen concentrations. For ibuprofen concentrations at the LOQ, the intra-day and inter-day precision and accuracy were within 10 and 15%, respectively. Recovery was 87% or greater for ibuprofen. This method was used to analyze plasma samples for unknown ibuprofen concentrations in bioequivalence and limited food effect studies of different formulations of ibuprofen. Thus, this method has been fully validated and used in the analysis of unknown plasma samples for ibuprofen.

Simultaneous determination of ibuprofen and hydroxypropylmethylcellulose (HPMC) using HPLC and evaporative light scattering detection

Ibuprofen may be crystallised in the presence of hydroxypropylmethylcellulose (HPMC) to improve its physical properties. This, however, creates problems with the simultaneous analysis of each ingredient. The analytical method developed utilised high performance liquid chromatography (HPLC) with a stationary phase designed for carbohydrate separation (GylcoSep N) and a mobile phase comprising methanol and water. Evaporative light scattering detection (ELSD) proved a suitable method for the analysis of both HPMC and ibuprofen. Data showed that HPMC and ibuprofen could be quantified in each other's presence. Validation studies indicated that the method was adequately accurate and precise. Baseline resolution was achieved between the two components. HPMC (1.1% w/w) was retained in ibuprofen crystals obtained from alcoholic HPMC suspensions.

Spectrofluorometric determination of ibuprofen in pharmaceutical formulations

The spectrofluorometric determination of ibuprofen in pharmaceutical tablets, creams and syrup is described. It involves excitation at 263 nm and emission at 288 nm. the linear range is 2-73 mg L(-1). Other drugs or excipients present in the different formulations do not interfere, except in the case of chlorzoxazone containing tablets. Due to its strong absorbance in the spectral range the chlorzoxazone does interfere, so that in this case the proposed method can't be applied.