HPLC Method Research Articles

Systematic Development of a Gradient Elution HPLC Method for the Analysis of Voxelotor and Its Structurally Related Substances Applying Analytical Quality by Design Approach

Systematic Development of a Gradient Elution HPLC Method for the Analysis of Voxelotor and Its Structurally Related Substances Applying Analytical Quality by Design Approach

Chemical Composition of Extracts from Various Parts of Feverfew (Tanacetum parthenium L.) and Their Antioxidant, Protective, and Antimicrobial Activities

Tanacetum parthenium is a medicinal plant from the Asteraceae family that can be applied externally in the case of various skin diseases. The aim of the study was to perform a phytochemical analysis of hydroethanolic extracts from the aerial parts (herb), flower heads, and leaves of feverfew and to assess their biological properties. Hydrodistilled oils were analyzed using GC-MS. The chemical composition of the extracts was estimated using spectrophotometry and the HPLC method. Moreover, the extracts were evaluated to determine their antioxidant potential using DPPH and FRAP and measuring the intracellular level of ROS. The cytotoxicity of extracts toward keratinocytes and fibroblasts was also analyzed, as well as their antimicrobial properties against 12 microorganisms. The results of the research revealed that chrysanthenone and α-thujone were the dominant volatile compounds in the essential oil from the flowers, while camphor, trans-chrysanthenyl acetate, and camphene were predominant in the essential oil from the leaves and herb. The results of HPLC showed that the major polyphenol compounds present in the hydroethanolic extracts from various parts of T. parthenium were 3,5-dicaffeoyl-quinic acid, chlorogenic acid, and 3,4-dicaffeoyl-quinic acid. The extract from feverfew flowers was shown to have the highest content of total polyphenols, flavonoids, and phenolic acids, as well as the highest antioxidant potential. In turn, the herb extract had the highest content of condensed tannins and terpenoids and exhibited the most effective antimicrobial properties against the 12 bacterial and fungal strains. Moreover, the hydroethanolic extracts from different parts of T. parthenium plants were shown to have a potent protective effect on skin cells. The present study supports the potential applications of Tanacetum parthenium in the cosmetic and pharmaceutical industries.

A General Strategy to Rapid and Sensitive Determination of Five High Boiling Point Solvents in Pharmaceuticals by RP-HPLC Combined with Precipitation Method.

The difficulty on determination of high boiling point solvents, always exist due to their low vapor pressure in headspace (HS) vial. What's worse, the commonly used GC diluents, such as N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, N, N-dimethylformamide and N-methylpyrrolidone are often remained in HS instrument after frequent injection into HS, thus would result in terrible positive interference problem. In this work, a fast and sensitive HPLC method in combination with a sample precipitation method, was proposed for the determination of above five high boiling point solvents in drug substances within 14.5min. The final method was validated with regard to limit of detection and limit of quantitation, precision, linearity and accuracy in accordance with ICH Q2 (R1). Finally, the proposed strategy was successfully applied for the analysis of high boiling point solvents used in three active pharmaceutical ingredients. The established generic strategy would provide another choice for the determination of high boiling point solvents in pharmaceuticals.

Kratom Alkaloids: A Blood–Brain Barrier Specific Membrane Permeability Assay-Guided Isolation and Cyclodextrin Complexation Study

Mitragynine is an “atypic opioid” analgesic with an alternative mechanism of action and a favorable side-effect profile. Our aim was to optimize the alkaloid extraction procedure from kratom leaves and to determine and isolate the most relevant compounds capable of penetrating the central nervous system. The PAMPA-BBB study revealed that mitragynine and its coalkaloids, speciociliatine, speciogynine, and paynantheine, possess excellent in vitro BBB permeability. An optimized sequence of CPC, flash chromatography, and preparative HPLC methods was used to isolate the four identified BBB+ alkaloids. To improve the bioavailability of the isolated alkaloids, their cyclodextrin (CD) complexation behavior was investigated via affinity capillary electrophoresis using almost 40 CD derivatives. The apparent alkaloid–CD complex stability constants were determined and compared, and the most relevant CDs phase-solubility studies were also performed. Both the neutral and negatively charged derivatives were able to form complexes with all four kratom alkaloids. It was found that cavity size, substituent type, and degree of substitution also influenced complex formation. The negatively charged Sugammadex, Subetadex, and the sufoalkylated-beta-CD analogs were able to form the most stable complexes, exceeding 1000 M−1. These results serve as a good basis for further solubility and stability enhancement studies of kratom alkaloids.

Sensitive HPLC Method to Support Pre-formulation Studies and to Determine Critical Quality Attributes of Therapeutic Contact Lenses Containing Dorzolamide Hydrochloride

Background: Dorzolamide hydrochloride (DRZ) is a carbonic anhydrase inhibitor used to treat glaucoma and ocular hypertension. Drug-eluting contact lenses, such as Acuvue Theravision ™ with Ketotifen, offer improved drug delivery and reduced side effects compared to eye drops. Drug-loaded nanoparticle-loaded contact lenses can sustain drug release and enhance comfort for extended wear. Objective: High buffer concentration and low pH increase the risk of damage to silica-bonded columns. Therapeutic contact lenses face challenges related to critical lens parameters, including the estimation of drug incorporation and release due to interference of lens matrix leaching. There is currently no analytical method available for estimating DRZ in contact lenses. Method: The HPLC method, which was developed and validated using ICH Q2 (R1) criteria, used a C18 column (250 mm × 4.6 mm, 5 μm) as a stationary phase and methanol:water (70:30 v/v) as the mobile phase. The detecting wavelength was 253 nm. Moreover, to support the efficiency of the developed method, the marketed formulation of DRZ eye drops, drug purity, and loading in contact lenses were analysed. The method was also employed to determine the Critical Quality Attributes (CQAs) of therapeutic contact lenses and drug release and drug leaching during the sterilization process. Result: The developed HPLC method shows Rt for DRZ at 2.881 minutes with good linearity (r2 > 0.998) between 2-32μg/mL, precision (RSD < 2%), accuracy (Recovery > 99.5%), sensitivity, and specificity for quantifying DRZ in marketed formulations and therapeutic contact lenses. The developed method is devoid of any buffer or modifier in the mobile phase, making it safer for the stationary phase. This method mitigates the interference of lens matrix leaching, which induces an overestimation of DRZ. All the result for therapeutic contact lenses was found to be closely aligned with theoretically expected results, confirming the reliability of the developed HPLC method for therapeutic contact lenses. Conclusion: This method is specific, accurate, and precise for quantifying DRZ in commercial formulations and newly developed therapeutic contact lenses. It effectively evaluates the critical quality attributes of these lenses, demonstrating their reliability for assessing their performance and ensuring quality in therapeutic applications.

Green metrics-based HPLC method for quantification of three antidiabetic drugs in tablet dosage form using Box–Behnken design

Green metrics-based HPLC method for quantification of three antidiabetic drugs in tablet dosage form using Box–Behnken design

Possibilities and limitations of computer assisted chiral HPLC method development for ozanimod on polysaccharide based chiral stationary phases.

In this study, a direct HPLC method was developed to determine the enantiomeric purity of the immunomodulatory drug, ozanimod. A systematic method development process was followed, incorporating risk assessment, identification of critical analytical procedure parameters, initial screening of stationary phases, and software-assisted optimization of method parameters. Eight different polysaccharide-based chiral columns were selected to assess chiral separation of enantiomers under polar organic elution mode. The most promising results were obtained using a methanol:2-propanol mixture on the amylose-based Chiralpak AD column. Following this, systematic modeling was conducted using DryLab software to optimize method conditions, including isocratic eluent composition, temperature, and flow rate. Baseline separation was achieved within fifteen minutes using the optimized parameters: Chiralpak AD column thermostated at 10°C, and a mobile phase of methanol:2-propanol: diethylamine, 70:30:0.1 (v/v/v %), delivered at a flow rate of 0.8 mL/min. The developed method was validated according to current guidelines and in silico robustness testing was conducted to determine tolerance limits for critical separation parameters and their impact on enantioresolution. Our findings demonstrate the utility of DryLab, typically employed for reversed-phase achiral separations, in optimizing chiral methods even in polar organic mode. Limitations of the selected approach the development of chiral separation methods are also highlighted.

Urothelial Urinary Bladder Cancer Is Characterized by Stage-Dependent Aberrations in Metabolism of Bioactive Sphingolipids

Although dysregulated sphingolipid metabolism was observed in many malignant tumors, bladder cancer has not yet been examined in this regard. This study aims to investigate the metabolism of bioactive sphingolipids across different stages of urothelial urinary bladder cancer (UBC). Forty-eight patients with UBC were included in this study. The neoplasms were classified as either non-muscle-invasive (NMIBC, n = 24) or muscle-invasive (MIBC, n = 24). Samples of the healthy bladder tissue were taken from the patients who underwent radical cystectomy. The content of sphingolipids was measured using an HPLC method, and the mRNA expression of sphingolipid transporters and metabolizing enzymes was evaluated using RT-PCR. Compared to the healthy bladder tissue, the UBC, regardless of the stage, showed an elevated expression of SphK1, Spns2, and ABCC1. The changes in the level of bioactive sphingolipids were strongly stage-dependent. MIBC showed accumulation of sphingosine-1-phosphate (S1P) and ceramide, whereas the content of these sphingolipids in the NMIBC tumor was not different from that of healthy tissue. Moreover, MIBC, compared to NMIBC, was characterized by higher levels of sphingosine and dihydroceramide. We conclude that profound alterations in sphingolipid metabolism develop upon UBC transition from non-muscle-invasive to muscle-invasive. They include the accumulation of S1P, resulting from the increased availability of sphingosine generated from ceramide, which also builds up due to a further activation of its de novo synthesis. We hypothesize that the dysregulation of S1P metabolism leading to the accumulation of this tumor-promoting sphingolipid contributes to the progression of UBC.

Development of a molecularly imprinted poly‐pyrrole biosensor for rapid and accurate estimation of liothyronine: Toward point‐of‐care quality assessment

AbstractLiothyronine (T3) is a thyroid hormone, which is frequently administered alongside thyroxine in the treatment of hypothyroidism. However, several market withdrawals have been called for due to persistent quality issues with liothyronine tablets. Given its narrow therapeutic index, maintaining optimal liothyronine levels is imperative, highlighting the criticality of ensuring quality both during manufacturing and at the patient's bedside. In this study, we introduce a pioneering electroanalytical biosensor designed for liothyronine estimation using molecularly imprinted poly‐pyrrole (MIP‐Ppy). Notably, the sensor demonstrates linear response within the concentration range of 50–300 pg/mL (r2 = 0.986) with a remarkable limit of detection (LOD) of 80 pg/mL. Interference studies were performed to validate the sensor's robustness, displaying negligible response alterations. This method was used for the assay of liothyronine tablets and was compared with the traditional HPLC method. The MIP‐Ppy biosensor showed 90.7% recovery with a minimal relative standard deviation of 0.093 whereas HPLC showed 91.2% recovery with RSD 0.052. These findings underscore the biosensor's potential as a cost‐effective alternative to sophisticated chromatographic methods for liothyronine estimation in pharmaceutical tablets. This advancement lays the groundwork for the development of a user‐friendly point‐of‐care device.

Application of Reversed-Phase HPLC Method for the Simultaneous Determination of Lenacapavir and Bictegravir in Tablets Dosage Form

Application of Reversed-Phase HPLC Method for the Simultaneous Determination of Lenacapavir and Bictegravir in Tablets Dosage Form

Solvent-Based and Matrix-Matched Calibration Methods on Analysis of Ceftiofur Residues in Milk and Pharmaceutical Samples Using a Novel HPLC Method.

The matrix effect is accepted as one of the critical factors that affect trueness, and it is especially important in the analysis of critical compounds, such as drugs, toxins and pesticides, in complex matrices. Ceftiofur (CEF) is a leading drug used in dairy industry for pulmonary infections. Because milk has a complex matrix, which is rich in fats, proteins and many other compounds, the determination of CEF in milk products deals with issues of trueness. On the other hand, pharmaceuticals also have a complex composition as they contain not only the active pharmaceutical ingredient but also many excipients, such as preservatives and pH modifiers. Due to its frequent use, its residues can be found in meat products or exist as an excreted compound in urine, milk and so on. The aim of this study was to investigate the effect of different calibration methods on quantitative estimation of CEF in milk and pharmaceutical samples. CEF was analysed using a new HPLC method, in which separation was achieved on a C18 bonded fused-core silica particle column by using isocratic elution; the method was optimized by testing different chromatographic conditions and validated according to the ICH Q2(R1) and United States Pharmacopeia guidelines. Interestingly, it was found that CEF signals in milk samples were higher than the ones at the same level prepared in calibration solutions with a ratio of 11.28:1. This finding reveals the necessity of matrix-matched calibration for accurate quantitative determination of CEF in milk samples. Moreover, the milk in the market and the most used pharmaceutical formulations were analysed using the current method.

DEVELOPMENT OF NOVEL SINGLE HPLC METHOD FOR SIMULTANEOUS SEPARATION OF MULTIPLE IMPURITIES IN DEXAMETHASONE DRUG PRODUCT

Objective: A simple, reliable, and rapid HPLC method has been established for the detection of Dexamethasone (DEX) and its related impurities. The proposed method has been validated for specificity, linearity, system suitability, accuracy, precision, robustness, LOD, and LOQ as per International Council for Harmonisation (ICH) guidelines. All parameters were found to be within the accepted limits, affirming the method's reliability. Methods: Analysis was conducted using HPLC on X-Bridge C18 column (250 mm×4.6 mm id, 3.5 µm) with a mobile phase-A comprising buffer and acetonitrile (90:10, v/v), mobile phase-B comprising buffer and acetonitrile (25:75, v/v) and a flow rate of 0.8 ml/min by following gradient elution. The detection was performed with a UV detector set at 240 nm. The method has been employed to investigate DEX and DEX-related impurities. These studies were conducted in tablet formulations of DEX. Results: The Retention Time (tR) of DEX was about 41.589 min, and all parameters met acceptable limit values. The response exhibited linearity over a concentration range of 0.162 to 3.052 µg/ml (R2= 0.9999). The percentage of DEX recovered from the pharmaceutical tablet dosage form ranged from 96.3 % to 100.4 %. Sensitivity levels for the developed method were indicated by LOD and LOQ values of 0.081–0.162 µg/ml. The proposed method was validated according to ICH guideline. Conclusion: Hence, a simple, reliable, accurate, and precise HPLC method was developed, proving suitable for the separation of DEX and DEX-related impurities in commercial formulations.

Hypothesizing the Oleic Acid-Mediated Enhanced and Sustained Transdermal Codelivery of Pregabalin and Diclofenac Adhesive Nanogel: A Proof of Concept.

Pregabalin (PG) and diclofenac diethylamine (DEE) are anti-inflammatory molecules that are effective in relieving inflammation and pain associated with musculoskeletal disorders, arthritis, and post-traumatic pain, among others. Intravenous and oral delivery of these two molecules has their limitations. However, the transdermal route is believed to be an alternate viable option for the delivery of therapeutic molecules with desired physicochemical properties. To this end, it is vital to understand the physicochemical properties of these drugs, dosage, and strategies to enhance permeation, thereby surmounting the associated constraints and concurrently attaining a sustained release of these therapeutic molecules when administered in combination. The present work hypothesizes the enhanced permeation and sustained release of pregabalin and diclofenac diethylamine across the skin, entrapped in the adhesive nano-organogel formulation, including permeation enhancers. The solubility studies of pregabalin and diclofenac diethylamine in combination were performed in different permeation enhancers. Oleic acid was optimized as the best permeation enhancer based on in vitro studies. Pluronic organogel containing pregabalin and diclofenac diethylamine with oleic acid was fabricated. Duro-Tak® (87-2196) was added to the organogel formulation as a pressure-sensitive adhesive to sustain the release profile of these two therapeutic molecules. The adhesive organogel was characterized for particle size, scanning electron microscopy, and contact angle measurement. The HPLC method developed for the quantification of the dual drug showed a retention time of 3.84 minutes and 9.69 minutes for pregabalin and diclofenac, respectively. The fabricated nanogel adhesive formulation showed the desired results with particle size and contact angle of 282 ± 57 nm and ≥120⁰, respectively. In vitro studies showed the percentage cumulative release of 24.90 ± 4.65% and 33.29 ± 4.81% for pregabalin and diclofenac, respectively. In order to accomplish transdermal permeation, the suggested hypothesis of fabricating PG and DEE nano-organogel in combination with permeation enhancers will be a viable drug delivery method. In comparison to a traditional gel formulation, oleic acid as a permeation enhancer increased the penetration of both PG and DEE from the organogel formulation. Notably, the studies showed that the use of pressure-sensitive adhesives enabled the sustained release of both PG and DEE.Therefore, the results anticipated the hypothesis that the transdermal delivery of adhesive PG and DEEbased nanogel across the human skin can be achieved to inhibit inflammation and pain.

Lanthanide coordination polymers as luminescent laccase mimics for ratiometric sensing of dopamine

Some metal ions, with inner enzyme-like catalytic activity, could be doped into lanthanide coordination polymers (Ln CPs) through coordination, which has been proved as a facile strategy to prepare the luminescent nanozymes. In this study, Cu-doped Ln CPs with laccase-mimic activity and double luminescence were rationally designed and synthesized by self-assembly of guanine monophosphate (GMP), 2-aminoterephthalic acid (ATA), Cu2+ and Tb3+ in buffer solution at room temperature. The obtained probes Tb/Cu-GMP/ATA CPs not only emitted green fluorescence of Tb3+ and blue fluorescence of ATA simultaneously under irradiation at the same wavelength, but also processed enhanced laccase-like activity for catalyzing the oxidation of phenolic substrates. Upon dopamine (DA), the probes catalyzed the oxidation of DA to polydopamine (PDA), which effectively quenched the fluorescence of Tb3+ due to the internal filtration effect. Based on this, a ratiometric fluorescent sensor for DA was constructed accordingly, and the corresponding fluorescence intensity ratio of Tb3+to ATA (F547/F427) was linearly correlated with the DA concentration in the range of 1 to 400 μM, with a detection limit of 0.44 μM. Besides, this sensor could be used to detect DA in human serum samples with good recovery, which results were highly consistent with that of HPLC method. The constituent and luminescence tunability, as well as the extraordinarily facile synthesis, made Ln CPs a potential platform for designing and preparing the integrated multifunctional probe for special target in sensing applications.

Stability indicating RP-HPLC method development and validation for quantification of impurities in gonadotropin-releasing hormone (Elagolix): Robustness study by quality by design.

The purpose of this research was to establish and validate a reverse phase HPLC method for the determination of Elagolix impurities in pharmaceutical dosage form. Mobile phase A, consisting of 10mM sodium dihydrogen phosphate (pH6.0) and acetonitrile in a 95:5v/v ratio, and mobile phase B, containing 85:10:5v/v/v of acetonitrile, Milli-Q water, and methanol, were used to achieve the method's specificity in the analytical column Kromasil 100-C18 (250 mm × 4.6mm, 5μm). The gradient program includes (%B/Time [min]: 36/0, 36/10, 38/15, 85/55, 85/65, 36/67, and 36/75). The flow rate is 0.8mL/min. The overall run duration is 75.0min, the injection volume is 10.0μL, and the detection is at 210 nm in UV. The samples were subjected to hydrolysis, oxidation, and heat conditions in order to facilitate their forced degradation. The procedure was validated and determined with the standards of ICH guidelines. From the LOQ to a concentration level of 200%, the linearity of the technique was ascertained. An accuracy range of LOQ to 150% was established for the method, and the average recovery was acceptable. Design of experiments, part of the quality by design idea, was used to prove the method's reliability.

Chitosan Nanoparticles Embedded in In Situ Gel for Nasal Delivery of Imipramine Hydrochloride: Short-Term Stage Development and Controlled Release Evaluation.

Imipramine hydrochloride (IMP), a tricyclic antidepressant used for major depression, enuresis, and neuropathic pain, is limited by gastrointestinal complications, low oral bioavailability (44%), and complex dosing requirements. This study aimed to explore a novel non-invasive nasal delivery system using chitosan nanoparticles (Cs NPs) embedded in an in situ gel to address the limitations of oral IMP administration. Cs NPs loaded with IMP were synthesized via ionic gelation and assessed for precision in drug concentration using a validated HPLC method. The particles were integrated into a thermoresponsive polymer, Pluronic F127, to form an in situ gel suitable for nasal administration. The formulation was characterized for gelation temperature, duration, viscosity, mucoadhesive strength, and overall gel robustness. Drug release kinetics and the controlled release mechanism were studied using ex vivo permeation tests with Franz diffusion cells and nasal sheep mucosa. The optimized nanoparticle formulation (F4-50) exhibited a consistent PS of 141.7 ± 2.2 nm, a zeta potential (ZP) of 16.79 ± 2.1 mV, and a high encapsulation efficiency of 67.71 ± 1.9%. The selected in situ gel formulation, F4-50-P1, demonstrated a gelation temperature of 33.6 ± 0.94 °C and a rapid gelation time of 48.1 ± 0.7 s. Transform-attenuated total reflectance infrared spectroscopy (ATR-IR) confirmed the compatibility and effective encapsulation of IMP within the formulation. The release profile of F4-50 included an initial burst release followed by a sustained release phase, with F4-50-P1 showing improved control over the burst release. The flux rates were 0.50 ± 0.01 mg/cm2/h for F4-50 and 0.33 ± 0.06 mg/cm2/h for F4-50-P1, indicating effective permeation. The developed chitosan nanoparticle-based in situ gel formulation provides a promising approach for the controlled release of IMP, enhancing therapeutic efficacy and patient compliance while mitigating the disadvantages associated with oral delivery.

Investigation of the impact of diverse climate conditions on the cultivation suitability of Cinnamomum cassia using the MaxEnt model, HPLC and chemometric methods in China

Cinnamomum cassia Presl. is a subtropical plant that is used for food and medicine. Climate change has changed the suitable habitats of medicinal plants, which might have repercussions for the efficacy of herbal remedies. In this study, the potential distribution in each period of Cinnamomum cassia was predicted and the quality in different suitable habitats was evaluated. According to the results, (1) precipitation, temperature, and soil are the primary environmental variables influencing C. cassia distribution. (2) The high-suitable habitats of current climate scenarios were predominantly located in the southern regions (Guangdong and Guangxi etc.) of China, with an area of 706,129.08 km2. Under future climate scenarios, suitable habitats will increasingly move northward, with a greater concentration south of the Yangtze River, particularly in the 2090s SSP585 scenario, the total area of newly extended suitable habitat reaches 312,963.53 km2. (3) HPLC and FTIR, combined with chemometrics, can be effective methods for identifying different suitable habitats of C. cassia. The content of trans-cinnamaldehyde (0.85%) is significantly higher in the high suitability habitat compared to the medium-low suitability habitat (0.30%). Our findings can offer valuable guidance for the identification of suitable C. cassia cultivation areas in China, as well as for the evaluation of C. cassia resource quality and the rational use of resources in different suitable habitats.

Physicochemical Stability of Nab-Paclitaxel (Pazenir) Infusion Dispersions in Original Glass Vials and EVA Infusion Bags

Background/Objectives: The study objective was to determine the physicochemical stability of nab-paclitaxel (Pazenir) ready-to-use (RTU) dispersion for infusion in original glass vials and ready-to-administer (RTA) infusion dispersion in EVA infusion bags. Methods: Triplicate test dispersions were prepared and stored light protected for a maximum of 28 days either in the original glass vials (RTU) at 2–8 °C or in EVA infusion bags (RTA) at 2–8 °C and at 25 °C. Directly after reconstitution and on days 1, 3, 5, 7, 14, 21, and 28 samples were withdrawn and paclitaxel concentrations assayed by a stability-indicating HPLC method. In parallel, pH and osmolality were measured. In a second series, test dispersions were stored over a 14-day period and inspected daily for visible particles and colour changes. Samples were taken daily for particle size analysis. Integrity and particle size distribution of the nanoparticles were determined by dynamic light scattering (DLS) and albumin monomers, dimers, oligomers, or polymers by size-exclusion-chromatography (SEC). Results: Non-redispersible particles were observed in test dispersions on day 5 (RTA 25 °C), day 7 (RTA 2–8 °C), and day 11 (RTU 2–8 °C). DLS analysis revealed out-of-specification results for the polydispersity index from day 7 (RTA 25 °C) and day 12 (RTU, RTA refrigerated). Paclitaxel concentrations remained >95% of the initial concentrations for 7 days (RTU 2–8 °C, RTA 25 °C) and for 14 days (RTA 2–8 °C). All test dispersions met the specifications regarding the oligomeric status of albumin, pH, and osmolality over the investigation periods. Conclusions: Stability of nab-paclitaxel dispersions is limited by the release of water-insoluble paclitaxel from the nanoparticles and subsequent crystallisation and by formation of insoluble albumin aggregates. Based on our overall results, shelf life of refrigerated RTU and RTA nab-paclitaxel dispersions is limited to 7 days. Shelf life of RTA nab-paclitaxel dispersions stored at room temperature is limited to 4 days. Careful visual inspection of nab-paclitaxel dispersions after reconstitution and prior to administration is highly recommended to detect non-redispersible particles.

Identification and characterization of Morganella morganii strain YC12-C3 and Enterococcus faecalis strain YC12-C10 and elucidation of its deoxynivalenol-degrading potential.

Deoxynivalenol ( DON) is one of the most harmful mycotoxins in food or feed or Traditional Chinese Medicine. An efficient and applicable method for the detoxification of DON is urgently developed. 1152 strains were isolated from the intestinal contents of crucian. Morganella morganii YC12-C3 and Enterococcus faecalis YC12-C10 were screened with the highest degradation rate of DON via HPLC methods. The optimal degradation condition of YC12-C3 and YC12-C10 is co-cultured 24 h and 36 h at 28 ℃ in LB medium with pH 7 and 1.0% inoculation dosage, respectively. LC-MS/MS and 1H NMR results show that YC12-C10 and YC12-C3 can transform DON to 3-deoxy-6-demethanol-DON, a new metabolite biotransformed from DON, by deoxidization at C3 hydroxy and de-methanal reaction at methanol moiety of C6. In addition, the DON-degradation in agricultural material assay showed that YC12-C10 and YC12-C3 can degrade 150 μg·kg-1 DON in Coix lacryma-jobi, with a degradation rate of 68.89% and 59.94%, respectively. This result shows that YC12-C10 and YC12-C3 have a sound efficiency in removing DON ability in Coix lacryma-jobi, providing a new strain resource and application technique for biological detoxification of DON in food or feed or TCM industry.

Spectrophotometric Determination of 4-n-butylresorcinol in Cosmetics by Decolorization of Oxidized 3,3',5,5'-tetramethylbenzidine

Background: 4-n-butylresorcinol (4nBR) was widely used in the treatment of chloasma and skin whitening cosmetics. As a decolorizing agent, it can effectively control the activity of tyrosinase. Market regulatory authorities require truthful labeling of ingredients in cosmetics. Therefore, the quantitative determination of 4nBR is of great practical significance. Hypothesis: At present, the main detection method of 4nBR reported in the literature is HPLC. Compared with the HPLC method, optical methods offer several advantages, including low cost, and simplicity, which make them suitable for on-field detection applications. A convenient spectrophotometric method was established for 4nBR detection. Methods: Fe3+ can oxidize the common colorless chromogenic substrate 3,3',5,5'- tetramethylbenzidine (TMB) to blue oxTMB. Based on the fact that 4-n-butyl resorcinol (4nBR) can reduce oxTMB, a convenient and rapid spectrophotometric method for the determination of 4nBR was proposed. Results: Under the optimum conditions, the absorbance at 652 nm has a good linear relationship with the concentration of 4nBR in the range of 1.2 - 16 μM. The linear equation for the detection of 4nBR was ΔA = 0.0546 c (μM) - 0.0026 (r2=0.9962), and the detection limit was 0.33 μM. The accuracy of this method is comparable to that of HPLC. Conclusion: This method has good selectivity for 4nBR and good anti-interference ability for common additives in cosmetics. The proposed method can be applied to the determination of 4nBR in thereal samples. other: Optical methods offer several advantages, including low cost, simplicity, which make them suitable for on-field detection application.