Acid Degradation Products Research Articles

Analysis and Formation of Polycyclic Aromatic Hydrocarbons in Canned Minced Chicken and Pork during Processing.

Polycyclic aromatic hydrocarbons (PAHs) represent important toxic compounds formed in meat products during processing. This study aims to analyze 22 PAHs by QuEChERS coupled with GC-MS/MS in canned minced chicken and pork during processing. After marinating raw minced chicken and pork separately with a standard flavoring formula used for canning meat in Taiwan, they were subjected to different processing conditions including stir-frying, degassing and sterilizing at 115 °C/60 min (low-temperature-long-time, LTLT) and 125 °C/25 min (high-temperature-short-time, HTST). The quantitation of PAHs in these meat products revealed the formation of only three PAHs including acenaphthylene (AcPy), acenaphthene (AcP) and pyrene (Pyr) in canned minced chicken and pork during processing with no significant difference in total PAHs between the meat types. Analysis of PAH precursors showed the presence of benzaldehyde at the highest level, followed by 2-cyclohexene-1-one and trans,trans-2,4-decadienal in canned minced chicken and pork, suggesting PAH formation through the reaction of benzaldehyde with linoleic acid degradation products and of 2-cyclohexene-1-one with C4 compounds through the Diels-Alder reaction, as well as the reaction of trans,trans-2,4-decadienal with 2-butene. Monounsaturated and polyunsaturated fatty acids were present in the largest proportion in LTLT-sterilized chicken/pork, followed by HTST-sterilized chicken/pork and raw chicken/pork, and their levels did not show a high impact on PAH formation, probably due to an insufficient heating temperature and length of time. A two-factorial analysis suggested that PAH formation was not significantly affected by the sterilization condition or meat type. Principal component analysis corroborated the observed results implying the formation of PAHs in canned minced chicken/pork under different processing conditions with an insignificant difference (p > 0.05) between them, with the individual PAH content following the order of Pyr > AcPy > AcP.

FAMS-A Targeted Fatty Acid Mass Spectrometry Method for Monitoring Free Fatty Acids from Polysorbate Hydrolysis.

Polysorbates are the predominant surfactants used to stabilize protein formulations. Unfortunately, polysorbates can undergo hydrolytic degradation, which releases fatty acids that can accumulate to form visible particles. The detection and quantitation of these fatty acid degradation products are critical for assessing the extent of polysorbate degradation and the associated risks of particle formation. We previously developed a user-friendly mass spectrometric method called Fatty Acids by Mass Spectrometry (FAMS) to quantify the free fatty acids. The FAMS method was validated according to ICH Q2 (R1) guidelines and is suitable for a wide range of products, buffers and protein concentrations. The end-to-end workflow can be automated from sample preparation to data analysis. To broaden method accessibility, the QDa detector selected for fatty acid measurement does not require specific mass spectrometry experience. We provide here a detailed procedure for both manual and automated sample preparation for high-throughput analysis. In addition, we highlight in this protocol the critical operational details, procedural watchouts and troubleshooting tips to support the successful execution of this method in another laboratory.

HPTLC method for determination of anti-hypertensive drug combination metoprolol succinate and dapagliflozin

Combination of Metoprolol Succinate and Dapagliflozin is recommended in the treatment of Hypertension. Accurate and precise thin layer chromatographic method has been developed for the determination of Metoprolol Succinate and Dapagliflozin in combination. Pre-coated silica gel G60—F254 aluminium sheet (10 × 10 cm),0.2 mm layer thickness used as stationary phase and n-Butanol: Ethyl acetate: Triethylamine (6:4:0.1 v/v/v) used as mobile phase. The method was found to be linear with a range of 200–1200 ng/band for DAP and 1000–6000 ng/band for MET with correlation coefficient (r2) 0.996 for both DAP and MET. The proposed method was validated as per ICH Q2 (R2) guideline with respect to linearity, accuracy and precision. Stress degradation was carried out to find out the intrinsic stability of the molecules. Both the drugs were highly susceptible to acid and base hydrolysis and degradation products were well separated with drug peak. The method was successfully used for determination of metoprolol succinate and dapagliflozin in combination.

Microbiota diversity of three Brazilian native fishes during ice and frozen storage

This study aimed to assess the bacterial microbiota involved in the spoilage of pacu (Piaractus mesopotamics), patinga (female Piaractus mesopotamics x male Piaractus brachypomus), and tambacu (female Colossoma macropomum × male Piaractus mesopotamics) during ice and frozen storage. Changes in the microbiota of three fish species (N = 22) during storage were studied through 16S rRNA amplicon-based sequencing and correlated with volatile organic compounds (VOCs) and metabolites assessed by nuclear magnetic resonance (NMR). Storage conditions (time and temperature) affected the microbiota diversity in all fish samples. Fish microbiota comprised mainly of Pseudomonas sp., Brochothrix sp., Acinetobacter sp., Bacillus sp., Lactiplantibacillus sp., Kocuria sp., and Enterococcus sp. The relative abundance of Kocuria, P. fragi, L. plantarum, Enterococcus, and Acinetobacter was positively correlated with the metabolic pathways of ether lipid metabolism while B. thermosphacta and P. fragi were correlated with metabolic pathways involved in amino acid metabolism. P. fragi was the most prevalent spoilage bacteria in both storage conditions (ice and frozen), followed by B. thermosphacta. Moreover, the relative abundance of identified Bacillus strains in fish samples stored in ice was positively correlated with the production of VOCs (1-hexanol, nonanal, octenol, and 2-ethyl-1-hexanol) associated with off-flavors. 1H NMR analysis confirmed that amino acids, acetic acid, and ATP degradation products increase over (ice) storage, and therefore considered chemical spoilage index of fish fillets.

Isolation, Identification, and Characterization of Forced Degradation Products of Bosentan by Using Advanced Analytical Techniques

ABSTRACTThe present study explains the degradation behavior of bosentan (BOS), active pharmaceutical ingredient (API) (BOS monohydrate), a Food and Drug Administration (FDA)–approved drug used for the treatment of chronic heart failure, subarachnoid hemorrhage, and Raynaud's syndrome pulmonary hypertension. The stress study was performed under various stress conditions such as acid hydrolysis, base hydrolysis, oxidation, thermal degradation, and photolysis as per International Council for Harmonization (ICH) guidelines and found three degradation products (DPs) under acid hydrolysis conditions (1 N HCl/4 h/60°C reflux conditions) (the net degradation of API ∼ 21.39%). The drug was found to be stable under the remaining conditions (thermal, photolytic, oxidative, and basic hydrolytic conditions). Mechanisms for forming the three acid DPs were also proposed and discussed. The DPs were initially detected by ultrahigh‐performance liquid chromatography–mass spectrometry analysis. These DPs were isolated by preparative HPLC and then characterized by high‐resolution mass spectrometry and nuclear magnetic resonance spectroscopy techniques. Based on the structural characterization study, all these DPs are new and not reported elsewhere in the literature to my knowledge. Many reports were found in the literature for the quantification of the drug in the APIs and formulation products. However, there is no report published yet for the identification and characterization of DPs of the BOS drug.

An nMgO containing scaffold: Antibacterial activity, degradation properties and cell responses.

Bone repair failure caused by implant-related infections is a common and troublesome problem. In this study, an antibacterial scaffold was developed via selective laser sintering with incorporating nano magnesium oxide (nMgO) to poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The results indicated the scaffold exerted high antibacterial activity. The antibacterial mechanism was that nMgO could cause oxidative damage and mechanical damage to bacteria through the production of reactive oxygen species (ROS) and direct contact action, respectively, which resulted in the damage of their structures and functions. Besides, nMgO significantly increased the compressive properties of the scaffold including strength and modulus, due to its excellent mechanical properties and uniform dispersion in the PHBV matrix. Moreover, the degradation tests indicated nMgO neutralized the acid degradation products of PHBV and benefited the degradation of the scaffold. The cell culture demonstrated that nMgO promoted the cellular adhesion and proliferation, as well as osteogenic differentiation. The present work may open the door to exploring nMgO as a promising antibacterial material for tissue engineering.

Acid Hydrolytic Degradation Profiling of Ezetimibe: Identification, Isolation, and Structural Elucidation of Its Degradants

ABSTRACTEzetimibe (EZE) is a dyslipidemic agent used to treat hyperlipidemia along with statins and diet changes. To ascertain the drug's degradation profile, stress tests were conducted on it in accordance with International Council for Harmonization recommendations. An ultrahigh‐performance liquid chromatography–mass spectrometry method was developed and validated for the identification and quantification of EZE and its degradants. Using preparative high‐performance liquid chromatography, all impurities were isolated, and their structures were characterized thoroughly using advanced spectral techniques. The drug was relatively stable in basic, peroxide, photolytic, and thermal conditions; however, five degradants were observed in acid degradation. Among the five degradants, three degradation products eluted as Peak‐1, Peak‐2, and Peak‐3 which were found to be novel impurities that were not reported previously. However, the remaining two impurities were identified as Peak‐4 and Peak‐5, despite the insufficient information available. The present study has focused on the isolation of these five acid degradation products and the structural confirmation of these degradants by highly efficient spectral techniques. Moreover, the possible degradation mechanism of the azetidinone ring in the presence of acid has been explained, which might be helpful in determining the quality and purity of EZE and similar pharmaceutical compounds.

Effects of Bacillus altitudinis inoculants on cigar tobacco leaf fermentation.

Microbial succession and metabolic adjustment during cigar tobacco leaf (CTL) fermentation are key factors to improve the quality and flavor of CTLs. However, the interactions in the above processes remain to be further elucidated. Bacillus altitudinis inoculants were added to the CTLs, and metagenomics and metabolomics were used to analyze the effects of the inoculants on regulating microbial succession, metabolic shift, and aroma production during fermentation. The addition of the inoculants reinforced the CTL macromolecule transformation and facilitated the aroma production efficiently, and the total aroma production was increased by 43% compared with natural fermentation. The omics analysis showed that Staphylococcus was a main contributor to fatty acid degradation, inositol phosphate metabolism, energy supply (oxidative phosphorylation), nutrient transport (ABC transporter and phosphotransferase system [PTS]), and aroma production (terpenoid backbone biosynthesis, phenylalanine metabolism, and degradation of aromatic compounds). Furthermore, Staphylococcus was positively correlated with TCA cycle intermediates (citric acid, fumaric acid, and aconitic acid), cell wall components, peptidoglycan intermediates (GlcNAc-1-P and UDP-GlcNAc), and phytic acid degradation products (inositol). The characteristics collectively showed Staphylococcus to be the most dominant in the microbial community at the genus level during microflora succession. The addition of the inoculants supplemented the nutritional components of the CTLs, enhanced the metabolic activity and diversity of bacteria such as Corynebacterium, improved their competitive advantages in the microflora succession, and facilitated the richness of microbial communities. Additionally, a metabolic shift in nicotine degradation and NAD + anabolism from Staphylococcus to Corynebacterium in fermentation with inoculants was first observed. Meanwhile, the significantly correlative differential metabolites with Staphylococcus and Corynebacterium were a metabolic complement, thus forming a completely dynamic fermentation ecosystem. The results provided evidence for CTL fermentation optimization.

Structure, spectral properties and antioxidant activity of melanoidins extracted from high temperature sterilized lotus rhizome juice

Melanoidins are complex macromolecular compounds closely associated with the browning phenomenon in high-temperature sterilized lotus rhizome juice (HTSL). This study aimed to preliminarily investigate the structural properties of melanoidins extracted from HTSL. Results showed that the average molecular weight of HTSL melanoidins ranged from 1.48 to 41.40 kDa. Medium and high molecular weight melanoidins were the main contributors to the brown color of HTSL. Sugars, proteins, and phenolics were present in HTSL, among which sugar was the most abundant, with glucose being the predominant monosaccharide in acid degradation products of melanoidins. Through fluorescence and ultraviolet spectral analysis, we found that the melanoidins contained carboxyl and carbonyl compounds, as well as furan and pyran heterocyclic compounds. The infrared spectra and nuclear magnetic resonance spectra revealed a prominent sugar absorption peak, indicating that sugar was the main component of the melanoidins of HTSL. Furthermore, in vitro antioxidant experiments showed that the antioxidant activity of melanoidins was significantly positively correlated with phenolic compounds. Our results indicated that there were differences in the structural properties of melanoidins fractions with different molecular weights. MW-H fraction significantly impacted the color and antioxidant activity of HTSL.

Profiling of 3-Formyl rifamycin (3-FR) from sintered fixed dose combinations (SDCs) of rifampicin and isoniazid by using RP-HPLC, LC-ESI-QTOF and UPLC/MS/MS

The rapid and severe decomposition of rifampicin in the presence of isoniazid (INH) in a gastric acidic pH environment is a well-reported phenomenon. It is important to note that the significant decomposition problem of RIF has an impact on its bioavailability, which becomes a major issue in fixed dose combinations (FDCs). In this degradation process, RIF will undergo acid hydrolysis and form 3-FR, an acid degradation product of RIF. Further, it will react with INH and form an insoluble iso-nicotinoyl hydrazone (HYD). The formed HYD is probably not stable in the acidic condition, so it will further convert into INH and 3-FR. Consequently, the generation of 3-FR in the acidic stomach environment can be a critical factor contributing to a substantial decline in RIF bioavailability and warrants careful consideration. Hence, it is imperative to explore the presence of 3-FR not only in in vitro dissolution samples but also in in vivo plasma samples. Therefore, the current study focused on the chemical analysis of 3-FR using additively manufactured sintered drug combinations (SDCs) to evaluate its formation, release and qualitative absorption in both in vitro and in vivo settings. High-performance liquid chromatography (HPLC) and liquid chromatography-electrospray ionization quadrupole time-of-flight high-resolution mass spectrometry (LC-ESI-QTOF-MS/MS) were employed for analytical investigations. The developed LC/MS-MS method was employed to investigate the presence of 3-FR in the rabbit's plasma following a single oral administration of SDCs. The study revealed the significant presence of 3-FR in both the in vitro and in vivo plasma samples obtained from the SDCs of RIF and INH. This finding indicates the potential of altering the strategy through additive manufacturing of pH-dependent SDCs to address the critical issue of RIF.

Stability indicating eco-friendly quantitation of terbutaline and its pro-drug bambuterol using quantitative proton nuclear magnetic spectroscopy

Quantitative 1H-NMR became an increasingly important issue in pharmaceutical analytical chemistry. This study used NMR spectroscopy to assay the bronchodilator drug terbutaline sulfate and its pro-drug bambuterol hydrochloride in pure form and pharmaceutical preparations. The technique proceeded using deuterium oxide (D2O) as an 1H-NMR solvent and phloroglucinol anhydrous as an internal standard (IS). Comparatively, to the phloroglucinol signal at 5.9 ppm, the resulting quantitative signals of the studied drugs were corrected. The terbutaline singlet signal at 6.3 ppm was chosen for quantification, while the bambuterol quantitative singlet signal was at 2.9 ppm. The two drugs were rectilinear over the concentration range of 1.0–16.0 mg/mL. LOD values were 0.19 and 0.21 mg/mL while LOQ values were 0.58 and 0.64 mg/mL for terbutaline and bambuterol respectively. The developed method has been validated according to the International Conference of Harmonization (ICH) regarding linearity, accuracy, precision, specificity, and robustness. A greenness profile assessment was applied, and the method proved to be green. The method enables the assay of the two drugs in pure drug and pharmaceutical preparations. The method also enables the assay of the two drugs in the presence of each other; thus, it is considered a stability-indicating method where terbutaline is an acid degradation product of bambuterol.

Development and Validation of Stability Indicating RP-HPLC Method and Characterization of Degradation Products of Anti-neoplastic Agent by LCMS-MS

In present research a stability indicating reversed-phase high-performance liquid chromatography (RP-HPLC) was developed and validated for quantification of azacitidine and its degradants. The chromatographic isolation of azacitidine carried out using Phenominex C18 (150×4.6 mm, 5 μ) column, movable phase of 0.1% HCOOH in water and acetonitrile (30:70 v/v), at a flowing rate of 1-mL/min analyzed at 210 nm. The %recovery findings ranged between of 99.13–99.41%. The limit of detection (LoD), and limit of quantitation (LoQ)values were assessed from the rectilinear plot and were found to be 3.78 and 15.12 μg/mL. The regression equation of the linearity curve was found to be y = 851.76x + 310.38 and r2 value of 0.9998. The samples were subjected to stress degradation and characterized by three acid degradation products by liquid chromatography-mass spectrometry (LC-MS/MS) - DPI, DPII, and DPIII. The stationary phase and movable system attained excellent resolution as chromatographic isolation and structure identification was accomplished using LC-MS/MS fragmentation

Cerebrospinal fluid findings in patients with obsessive–compulsive disorder, Tourette syndrome, and PANDAS: A systematic literature review

BackgroundObsessive-compulsive disorder (OCD) and Tourette syndrome (TS) are related mental disorders that share genetic, neurobiological, and phenomenological features. Pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections (PANDAS) is a neuropsychiatric autoimmune disorder with symptoms of OCD and/or TS associated with streptococcal infections. Therefore, PANDAS represents a strong link between OCD, TS, and autoimmunity. Notably, cerebrospinal fluid (CSF) analyses can provide insight into the central nervous processes in OCD, TS, and PANDAS. MethodsA systematic literature search according to the PRISMA criteria was conducted to collect all CSF studies in patients with OCD, TS, and PANDAS. The total number of cases and the heterogeneity of the low number of studies were not sufficient for a meta-analysis to provide a high level of evidence. Nevertheless, meta-analytical statistics could be performed for glutamate, 5-hydroxyindoleacetic acid (degradation product of serotonin), homovanillic acid (degradation product of dopamine), 3-methoxy-4-hydroxyphenylglycol (major metabolite of noradrenaline), and corticotropin-releasing hormone (CRH) in OCD. A risk-of-bias assessment was implemented using the Cochrane ROBINS-E tool. ResultsMeta-analytical testing identified elevated glutamate levels in the CSF of OCD patients compared with healthy controls, while no significant differences were found in other neurotransmitters or CRH. Single studies detected novel neuronal antibodies in OCD patients and elevated oligoclonal bands in TS patients. For TS and PANDAS groups, there was a dearth of data. Risk of bias assessment indicated a substantial risk of bias in most of the included studies. ConclusionsThis systematic review of available CSF data shows that too few studies are currently available for conclusions with good evidence. The existing data indicates glutamate alterations in OCD and possible immunological abnormalities in OCD and TS. More CSF studies avoiding sources of bias are needed.

Validated green high performance liquid chromatographic and capillary electrophoretic methods for estimation of dinitolmide in presence of its acid-degradation product

This study describes two new, green, fast, specific and highly sensitive stability-indicating techniques for determination of Dinitolmide (DM) in presence of its acid induced degradation product without prior separation; Acid degradation was carried out by hydrolysis with 0.1 N HCl; and the acidic degradation pathway was established by IR, and MS techniques. The first is a HPLC-Diode Array detector was performed by isocratic mode on BDS Hypersil C18 column (150 mm × 4.6 mm × 5 μm particle size) at ambient temperature with a mobile phase consisting of 5 mM sodium acetate buffer (pH 5.5): acetonitrile (40:60, v/v), flow rate of 1 mL/min and detection at 210 nm. DM and its acid degradant were eluted at 4.3 and 2.8 min, respectively offering quick analysis. Linearity of the calibration curves confirm good correlation in range of 1–15 μg/mL with recovery % of 100.02 ± 0.460. The LOD and LOQ were 0.243 and 0.737, respectively. The second method is CE -Diode Array detector was carried out at 25 °C using borate buffer (30 mM, pH 9) as background electrolyte solution and detection at 225 nm. The migration times were 2.26 and 2.97 min for DM and its acid degradant, respectively. The linearity range was 5–50 μg/mL with recovery % of 99.55 ± 0.910, LOD and LOQ were 1.010 and 3.050, respectively. The small LOD and LOQ values for both methods confirm high sensitivity of the methods The developed methods were validated according to the ICH guidelines demonstrating good accuracy and precision. The results were statistically compared with those obtained by a reported method in terms of accuracy, precision, and no significant difference was found. Both methods were successfully applied for estimating DM and its acid degradant in pure and pharmaceutical dosage forms. In addition, the methods were assessed for their greenness profile and CE was greener owing to using safer solvents and less energy consumption.

Personalized Response of Parkinson's Disease Gut Microbiota to Nootropic Medicinal Herbs In Vitro: A Proof of Concept.

Parkinson's disease (PD) is a neurodegenerative disease characterized by the loss of dopaminergic neurons. Although the etiology of PD remains elusive, it has been hypothesized that initial dysregulation may occur in the gastrointestinal tract and may be accompanied by gut barrier defects. A strong clinical interest in developing therapeutics exists, including for the treatment of gut microbiota and physiology. We previously reported the impact of healthy fecal microbiota anaerobic cultures supplemented with nootropic herbs. Here, we evaluated the effect of nootropic Ayurvedic herbs on fecal microbiota derived from subjects with PD in vitro using 16S rRNA sequencing. The microbiota underwent substantial change in response to each treatment, comparable in magnitude to that observed from healthy subjects. However, the fecal samples derived from each participant displayed unique changes, consistent with a personalized response. We used genome-wide metabolic reconstruction to predict the community's metabolic potential to produce products relevant to PD pathology, including SCFAs, vitamins and amino acid degradation products. These results suggest the potential value of conducting in vitro cultivation and analyses of PD stool samples as a means of prescreening patients to select the medicinal herbs for which that individual is most likely to respond and derive benefit.

Stability indicating LC-MS/MS method and validation of Selexipag impurities and identification of its force degradation products

Selexipag belongs to a class of medicines known as IP prostacyclin receptor agonists used to treat pulmonary arterial hypertension.A simple and sensitive LC-MS/MS method has been developed for the identification of process related impurities in Selexipag API. The method was developed using a Zorbax C18 15 × 0.46 cm, 5μ column with a gradient program at 35 0C and flow rate of 1.0 mL/min. Detection was carried out by MS/MS with an ESI detector. Stress conditions were established by exposing the drug to acidic, alkaline, oxidative, thermal and photolytic stress condition. Identified and unidentified impurity was found when the fractions of acid and alkaline degradation product was analyzed by LC-MS/MS. The suggested methodology can be used to test the quality of Selexipag and identify the process-related impurities in pharmaceutical products.

Sustainable Stability-Indicating spectra manipulations for the concurrent quantification of a novel Anti-COVID-19 drug and its active Metabolite: Green profile assessment

Millions of individuals have lost their lives and changed their routines as a direct consequence of exposure to the coronavirus (Covid-19). Molnupiravir (MOL) is an orally bioavailable tiny molecule antiviral prodrug that is effective for curing the coronavirus that produces serious acute respiratory disorder (SARS-CoV-2). Fully green-assessed stability-indicating simple spectrophotometric methods have been developed and fully validated as per ICH criteria. The potential impact of degradation products of drug components on the safety and efficacy of a medication's shelf life is likely to be negligible. The field of pharmaceutical analysis necessitates various stability testing under different conditions. The conduct of such inquiries affords the prospect of predicting the most probable routes of degradation and ascertaining the inherent stability characteristics of the active drugs. Consequently, a surge in demand arose for the creation of an analytical methodology that could consistently measure the degradation products and/or impurities that may be present in pharmaceuticals. Herein, five smart and simple spectrophotometric data manipulation techniques have been produced for the concurrent estimation of MOL and its active metabolite as its possible acid degradation product namely; N-hydroxycytidine (NHC). Structure confirmation of NHC build-up through IR, MS and NMR analyses. All current techniques verified linearity ranging from 10 to 150 μg/ml and 10–60 μg/ml for MOL and NHC, respectively. The limit of quantitation (LOQ) values were in the range of 4.21–9.59 μg/ml, while the limit of detection (LOD) values were ranging from 1.38 − 3.16 μg/ml. The current methods were evaluated in terms of greenness by four assessing methods and confirmed to be green. The significant novelty of these methods depends on their being the first environmentally soundness stability-indicating spectrophotometric approaches for the concurrent estimation of MOL and its active metabolite, NHC. Also, the preparation of purified NHC delivers significant cost savings, instead of purchasing an expensive ingredient. These smart methods were utilized for analyzing the pharmaceutical dosage form which may be of great benefit to the pharmaceutical market.

The comparative analysis of gastrointestinal toxicity of azithromycin and 3′-decladinosyl azithromycin on zebrafish larvae

The most commonly reported side effect of azithromycin is gastrointestinal (GI) disorders, and the main acid degradation product is 3’-Decladinosyl azithromycin (impurity J). We aimed to compare the GI toxicity of azithromycin and impurity J on zebrafish larvae and investigate the mechanism causing the differential GI toxicity. Results of our study showed that the GI toxicity induced by impurity J was higher than that of azithromycin in zebrafish larvae, and the effects of impurity J on transcription in the digestive system of zebrafish larvae were significantly stronger than those of azithromycin. Additionally, impurity J exerts stronger cytotoxic effects on GES-1 cells than azithromycin. Simultaneously, impurity J significantly increased ghsrb levels in the zebrafish intestinal tract and ghsr levels in human GES-1 cells compared to azithromycin, and ghsr overexpression significantly reduced cell viability, indicating that GI toxicity induced by azithromycin and impurity J may be correlated with ghsr overexpression induced by the two compounds. Meanwhile, molecular docking analysis showed that the highest -CDOCKER interaction energy scores with the zebrafish GHSRb or human GHSR protein might reflect the effect of azithromycin and impurity J on the expression of zebrafish ghsrb or human ghsr. Thus, our results suggest that impurity J has higher GI toxicity than azithromycin due to its greater ability to elevate ghsrb expression in zebrafish intestinal tract.

Stability-indicating HPLC-DAD and TLC-densitometry methods for the quantification of bupivacaine and meloxicam in their co-formulated mixture

The implementation of a novel drug formulation necessitates the assessment of its content stability and the designation of appropriate stability monitoring methodologies. Bupivacaine (BVC) and Meloxicam (MLX) were recently authorized under the name Zynrelef® solution. This novel combination was tested for stability under a variety of stress circumstances for the first time in this study. The basic degradation pathway was shown to affect BVC, while the acidic degradation pathway works for MLX. Identification of the acquired degradation products, including BVC impurity F (BVC IMP-F), 1-buytylpiperidine-2- 2carboxylic acid (1-BPC), MLX acid degradation product (MLX-DEG), and MLX impurity B (MLX IMP-B), was carried out using IR and MS spectroscopic techniques. HPTLC and HPLC, two chromatographic-based stability-indicating methods, have been established. The HPTLC method offered efficient separation upon the usage of silica gel 60 F254 as a stationary phase and ethyl acetate/toluene/triethylamine/acetic acid (4:4:2:0.4, v/v/v/v) as a developing system with densitometric recording at 260 nm. The HPLC method was developed by using Zorbax® SB C18 column as a stationary phase and a mobile phase consisting of acetonitrile: methanol: phosphate buffer, pH 6.5 (20:60:20 v/v/v), at a flow rate of 1.5 mL min-1. Quantification of the analytes was performed at 265 nm using a diode array detector. The current research introduced the first stability-indicating methods for the assay of BVC and MLX which were successfully applied for the determination of the cited drugs in their combined pharmaceutical formulation. Moreover, the HPLC method was further extended for studying the degradation kinetics of the two drugs.

Biodegradable implants based on photo-cross-linked aliphatic polycarbonates for long-acting contraception

In this study, a new class of biodegradable contraceptive implants was prepared via the UV irradiation molding method, among which, progestin levonorgestrel (LNG) was used as a model drug. Photo-cross-linked aliphatic polycarbonates (APCs), namely, poly (trimethylene carbonate-co-2,2′-dimethyltrimethylene carbonate) [P(TMC-co-DTC)] elastomers, were used as the drug delivery matrix. The results obtained from the degradation experiments carried out in Sprague-Dawley (SD) rats showed that the cross-linked elastomer had the degradation characteristics of the surface erosion degradation mechanism, with no generation of acid degradation products, and excellent form-stability, which met the performance requirements of the matrix for a long-acting sustained-release delivery system. The in vitro cytotoxicity tests and histological and immunohistochemical evaluations showed good biocompatibility and biosafety of the elastomer matrix material and contraceptive implants. Subsequently, the implant formulations were screened by in vitro release experiments, and their release kinetics were explored. Finally, in the evaluation study of the in vivo anti-fertility effect, the implants exhibited excellent dimensional stability and were degraded by a surface erosion mechanism. LNG achieved a stable and sustained release in female SD rats, maintaining a long-acting contraceptive duration of up to 4 months. The contraceptive implants obtained in this study could be used to address the limitations of currently available formulations, which required secondary surgical removal and a single means of regulating drug release kinetics. Therefore, these implants could provide a new option for birth control needs and may be of significance in reducing the incidence of induced abortion and protecting female fertility.