Evaluating the persistence of malachite green residues in tilapia and pacu fish

Although banned in food-producing animals, residues of malachite green (MG) and its primary metabolite, leucomalachite green (LMG), have been found in fish due to illegal use in aquaculture and the release of industrial wastewater, which represent a serious risk to food and environmental securities. This study aimed to investigate the residue depletion profile of MG and LMG in edible tissues of Nile tilapia (Oreochromis niloticus) and pacu (Piaractus mesopotamicus) cultured simultaneously under the same environmental conditions to support control measures in case of abuse. An analytical method involving QuEChERS sample preparation and liquid chromatography coupled to tandem mass spectrometry was developed, validated, and applied to quantify MG and LMG residues in fish fillets from two depletion experiments after treatment by immersion bath (MG at 0.10 mg L-1 for 60 min). During the experiment, the average water temperature was 30 ºC, while the pH was 6.9. The method is selective, precise (CV = 0.4 - 22%) and accurate (recovery 92 - 114%). The limits of detection and quantification are 0.15 and 0.5 ng g-1, respectively. In both species, the sum of MG and LMG residues were quantified up to the 32nd day post-exposure, and the concentrations were significantly higher in the pacu fillets (up to 3284 ng g-1) than in Nile tilapia (up to 432 ng g-1). The sums of MG and LMG residues were below 2 ng g-1 at 44 days and 342 days for Nile tilapia and pacu, respectively - the Minimum Required Performance Limit (MRPL) for analytical methods intended to monitor forbidden substances in food according to old European Commission guidelines. The persistence of MG residues in pacu may be attributed to its higher lipid content, which favors the accumulation of the non-polar metabolite LMG. These results provide insights into the concern about human, animal, and environmental health risks resulting from unauthorized use or aquatic contamination by industrial wastewater containing MG residues.

Levamisole incorporation in fish feed - Ensuring the medication dose and avoidance of leaching into the water

Levamisole, an anthelmintic and immunostimulant drug, has been studied as a promising alternative for aquaculture use. While oral administration through feeding is the main route of administration in fish farming, no studies evaluating methods of levamisole incorporation into the feed have been reported so far. Therefore, this study aimed to evaluate potential procedures for levamisole incorporation in extruded fish feed using ethyl cellulose, gelatin, or vegetable oil, to avoid drug leaching to the water during the animal's medication. A suitable LC-MS/MS method was optimized (full factorial design), validated, and applied to evaluate the efficiency of the process, the homogeneity of the drug concentration, and the leaching rate. The method has been demonstrated to be selective, precise (RSD < 4.9%), accurate (recovery > 98.4%), and linear (r > 0.99, 125-750 mg kg-1). The incorporation procedures using the three coating agents showed high incorporation efficiency (70%) and a homogeneous drug concentration among the extruded feed pellets. A low levamisole leaching rate was verified in the feed prepared using the ethyl cellulose coating procedure (4.3% after 15 min of immersion in the water). On the other hand, fish feed coated with gelatin and oil resulted in a high leaching rate (30-35% after 15 min). Thus, this study shows that coating ethyl cellulose may be a promising procedure for levamisole incorporation in fish feed and with the potential to enhance its use in animal production while reducing environmental contamination.

Residue Depletion Profile and Estimation of Withdrawal Period for Sulfadimethoxine and Ormetoprim in Edible Tissues of Nile Tilapia (Oreochromis sp.) on Medicated Feed

Sulfadimethoxine (SDM) and ormetoprim (OMP) are antimicrobials used in combination to treat bacterial infections in fish farming. The use of this drug combination is not yet regulated in some countries, such as Brazil. Due to the lack of regulated drugs for aquaculture in Brazil, this study investigated the residue depletion profile of SDM and OMP in Nile tilapia (Oreochromis sp.) after oral administration. Fish were treated with medicated feed containing a 5:1 ratio of SDM:OMP at the dose of 50 mg kg BW-1 for five consecutive days with an average water temperature of 28 °C. The drugs were incorporated into the feed by using a gelatin coating process which promoted homogeneity in drug concentration and prevented the drug leaching into the water during medication. The SDM and OMP determination in fish fillets (muscle plus skin in natural proportions) was performed using the QuEChERS approach followed by LC-MS/MS quantification. The analytical method was validated according to Brazilian and selected international guidelines. A withdrawal period of 9 days (or 252 °C days) was estimated for the sum of SDM and OMP residues at concentration levels below the maximum residue level of 100 µg kg-1.

Combination of extractive techniques followed by HPLC-MS/MS analysis to monitor ent-agathic acid in fish treated with Copaifera duckei Dwyer

Plants are used as therapeutic alternatives in Veterinary Medicine, including therapies for food-producing animals. However, these medicinal resources can sometimes contain dangerous substances, and when used in animals that supply food, they stand out from the point of view of food safety. The diterpene ent-agathic acid, a component of Copaifera duckei oleoresin, is an example of substances already described with toxic activity in mammals. Thus, this study aimed to propose combining two extractive techniques followed by high-performance liquid chromatography coupled mass spectrometry analysis to monitor residues of ent-agathic acid in Piaractus mesopotamicus fillet treated in an immersion bath with Copaifera duckei oleoresin. An optimized combination of solid-liquid extraction (using acidified acetonitrile) and dispersive liquid-liquid microextraction (using acidified water and chloroform as dispersive and extracting solvent, respectively) was performed to recover the target analyte, added to the development of HPLC-MS/MS method with adequate validation parameters to quantify the ent-agathic acid present in the fish fillet. In vivo tests of residual persistence of ent-agathic acid in fishes treated with C. duckei oleoresin were performed, indicating the non-detection of the target diterpene (< 6.1 µg/mL). The combined extractive procedure followed by quantitative analysis in the in vivo test of residual persistence of the target analyte in fish indicated the absence of ent-agathic acid in all samples. Thus, the data found might contribute to understanding the use of oleoresins from C. duckei as an alternative to traditional veterinary products.

Analysis of Organic Impurities of Besifloxacin Hydrochloride by High-Performance Liquid Chromatography with Isocratic and Gradient Elution

Introduction:

Impurity analysis is an important step in the quality control of pharmaceutical ingredients and the final product. Impurities can arise from drug synthesis or excipients and even at small concentrations may affect product efficacy and safety. In this work, two methods using highperformance liquid chromatography (HPLC) were developed and validated for the evaluation of besifloxacin and its impurity synthesis, with isocratic elution and another with gradient elution.

Method:

The analysis by HPLC in isocratic elution mode was performed using a cyano column maintained at 25 °C. The mobile phase was composed of 0.5% triethylamine (pH 3.0): acetonitrile (88:12 v/v) eluted at a flow rate of 1.0 mL/min with detection at 330 nm. The gradient elution method was carried out with the same column and mobile phase components only modifying the rate between organic and aqueous phase during analysis. The procedures have been validated according to internationally accepted guidelines, observing results within acceptable limits.

Results:

The methods presented were found to be linear in the 140 to 260 μg/ mL range for besifloxacin and 0.3 to 2.3 μg/ mL for an impurity named A. The limits of detection and quantification were, respectively, 0.07 and 0.3 μg/ mL for impurity A, with a 20 μL injection volume. The precision achieved for all analyses performed provided RSD inter-day equal to 6.47 and 6.36% for impurity A with isocratic elution and gradient, respectively. The accuracy was higher than 99% and robustness exhibited satisfactory results. In the isocratic method, an analysis time of 25 min and 15 min was obtained for the gradient. For impurity A, the number of theoretical plates in the isocratic mode was about 5000 while in the gradient mode it was about 45000, hence, it made the column more efficient by changing the mobile phase composition during elution. In besifloxacin raw material and in the pharmaceutical product used in this study, other related impurities were present but impurity A was searched for and not detected.

Conclusion:

The proposed methods can be applied for the quantitative determination of impurities in the analysis of the besifloxacin raw material, as well as in ophthalmic suspension of the drug, considering the quantitation limit.

Ethnoveterinary for food-producing animals and related food safety issues: A comprehensive overview about terpenes

Alternatives to the use of conventional veterinary drugs in food-producing animals have gained attention, such as the use of natural products (NPs), mainly to soften the risks to the animal, the environment, and consumer's health. Although NPs have consistent advantages over conventional drugs, they cannot be considered risk free under food safety matters. In this way, this document presents a comprehensive overview of the importance of considering both the pharmacological and toxicological properties of the constituents of a NP from plants intending the standardization and regulation of its use in food-producing animals. Terpenes are the most diverse class of natural substances present in NP of vegetal origin with a broad range of biological activities that can be explored in veterinary science; however, certain plants and terpenes also have significant toxic effects, a fact that can harm the health of animals and consequently generate economic losses and risks for humans. In this context, this review gathered scientific data of vegetal species of importance to ethnoveterinary for food-producing animals, which produce terpenes, its biological effects, and their implications on food safety issues for consumers. For this, more than 300 documents were selected from different online scientific databases. The present data and discussion may contribute to the rational commercial exploration of this class of NPs in veterinary medicine.

Impact of Atrazine Exposure on the Microbial Community Structure in a Brazilian Tropical Latosol Soil

Atrazine is a triazine herbicide that is widely used to control broadleaf weeds. Its widespread use over the last 50 years has led to the potential contamination of soils, groundwater, rivers, and lakes. Its main route of complete degradation is via biological means, which is carried out by soil microbiota using a 6-step pathway. The aim of the present study was to investigate whether application of atrazine to soil changes the soil bacterial community. We used 16S rRNA gene sequencing and qPCR to elucidate the microbial community structure and assess the abundance of the atrazine degradation genes atzA, atzD, and trzN in a Brazilian soil. The results obtained showed that the relative abundance of atzA and trzN, encoding triazine-initiating metabolism in Gram-negative and -positive bacteria, respectively, increased in soil during the first weeks following the application of atrazine. In contrast, the abundance of atzD, encoding cyanuric acid amidohydrolase-the fourth step in the pathway-was not related to the atrazine treatment. Moreover, the overall soil bacterial community showed no significant changes after the application of atrazine. Despite this, we observed increases in the relative abundance of bacterial families in the 4th and 8th weeks following the atrazine treatment, which may have been related to higher copy numbers of atzA and trzN, in part due to the release of nitrogen from the herbicide. The present results revealed that while the application of atrazine may temporarily increase the quantities of the atzA and trzN genes in a Brazilian Red Latosol soil, it does not lead to significant and long-term changes in the bacterial community structure.

Evaluation of linagliptin dissolution from tablets using HPLC and UV methods

Linagliptin (LGT) is used to reduce glucose blood levels in patients with type 2 Diabetes mellitus. The proposed conditions for a biowaiver guide can be applied due to high solubility of linagliptin in aqueous media. The aim of the present study was to develop and validate a dissolution test for 5 mg linagliptin coated tablets. After diverse dissolution procedure evaluation, the selected method was achieved using USP apparatus 1 (basket) at 75 rpm and 900 mL of citrate buffer pH 3.5 as dissolution medium. The conditions proposed by biowaiver guide were also applied to this drug, using USP apparatus 2 (paddle) and 900 mL of 0.1 M HCl, pH 4.5 acetate buffer and pH 6.8 phosphate buffer as dissolution medium. HPLC and UV spectrophotometry were used to LGT quantitation and validated for this purpose. The chromatographic and spectrophotometric methods in the dissolution context proved to be linear in 0.5 – 20.0 μg.mL-1 range, precise with RSD values less than 1.0 % and 2.0%, respectively, and accurate (mean recovery 100.29 % and 100.59%). The parameters such as specificity, linearity, accuracy, precision and robustness were according to international guidelines for both methods HPLC and UV. Dissolved linagliptin results were compared using the Student’s t-test and the data found were not significant different (P=0.068). In most dissolution conditions evaluated, LGT presented more than 85% drug dissolved from the tablets in fifteen minutes. The proposed methods can be applied for quality control of this gliptin. According to the results, linagliptin may be a biowaiver candidate.

EVALUATION OF THE STABILITY OF VIGABATRIN IN HOSPITALAR EXTEMPORANEOUS FORMULATIONS

The aim of this study was to analyze the chemical stability of the anticonvulsant vigabatrin extemporaneous formulation from tablets in storage conditions of different temperatures and types of packaging used. The analysis of vigabatrin extemporaneous formulations were performed by high-performance liquid chromatography (HPLC). The method described in British Pharmacopoeia was co-validated for specificity, linearity, precision and accuracy. Vigabatrin extemporaneous solutions were prepared in triplicate and placed in amber glass and PET bottles, which were stored under three different conditions: at room temperature (15 to 30 °C), under refrigeration (2 to 8 °C), and oven (40 °C). Samples of solutions stored at room temperature and refrigeration were collected every 7 days along 35 days. The same was done for solutions kept at 40 °C, but for a period of 28 days. It was also analyzed the solutions pH in each sampling time. Vigabatrin extemporaneous solutions showed variations within the limits of British Pharmacopoeia 2016 up to 21 days in amber PET and glass bottles at room and refrigerated temperatures. Vigabatrin content for formulations kept in oven decreased above 10% after 7 days of study. The lowest pH change occurred in amber glass bottle stored under refrigeration. Results of this study will be applied as a reference for vigabatrin extemporaneous formulation in hospital, once it was demonstrated the reliability of storage time interval and proper conditions for the use. Thus, pediatric patients with fractionated doses or use of nasogastric probe will have adequately prepared extemporaneous formulations, reducing the risk of dilution errors and microbiological contamination, improving the efficacy and safety, and enabling more time for nursing assistance.  

EVALUATION OF THE PRESENCE OF POLYMORPHIC FORMS AND INFLUENCE ON THE DISSOLUTION PROFILE OF TENOXICAM IN ACTIVE PHARMACEUTICAL INGREDIENT AND FORMULATIONS

Polymorphism is a relatively common phenomenon among pharmaceutical compounds, and one of the main aspects to be considered in the production and development of medications. The investigation of polymorphism associated with oxicams, a group belonging to the class of non-steroidal anti-inflammatory drugs (NSAIDs) has increased in recent years and, in the case of tenoxicam, the existence of four polymorphic forms is reported in the literature. The objective of this study was to characterize the presence of different polymorphic forms of tenoxicam in active pharmaceutical ingredient and oral pharmaceutical formulations, as well as to evaluate the influence on in vitro dissolution. The characterization of the three samples of pharmaceutical ingredient of tenoxicam from different suppliers by X-Ray Diffraction (XRD), Infrared (IR) and dissolution profile indicated the presence of a form III crystalline structure, without presenting significant differences between the in vitro dissolution profiles analyzed, and a Dissolution Efficiency (DE%) of 60.30%, 60.70% and 72.34%, respectively. When the four pharmaceutical specialties of tenoxicam were submitted to XRD analysis, they also presented form III crystalline structures. Despite this, the formulations presented different dissolution profiles and a DE% of 75.23%, 83.69%, 78.19% and 90.63%, respectively, without compromising their quality. However, often polymorphism affects physico-chemical properties of drugs, showing the importance of studying this phenomenon, by correlating the presence of crystalline structures to alterations in the quality of active ingredients and pharmaceutical products.

CHARACTERIZATION OF LINAGLIPTIN USING ANALYTICAL TECHNIQUES

Linagliptin (LGT) is a member of the class of gliptins that inhibit the enzyme dipeptidyl-peptidase-4. They are used to reduce glucose blood levels in patients with type 2 Diabetes mellitus. Due to its recent development and launching on the market, LGT has no official compendium monograph, national or international, or available registries for the qualitative determination of this drug. The objective of this work was to characterize LGT by using thermal techniques, nuclear magnetic resonance, mass and infrared spectrometry, liquid chromatography and ultraviolet spectrophotometry to be used as a chemical reference substance. The range and melting point obtained are in accordance with that described in the literature. The main groups of LGT molecule were observed in infrared spectroscopy and the molecular ion m/z 473.25 ratio was found in mass spectroscopy analysis. In UV spectroscopy, the maximum wavelength absorption of the substance in different solvents can be observed. The chromatographic methods provide selectivity for LGT and can be used to analyze it qualitatively. The proposed conditions have been successfully applied for identification and qualitative analysis of LGT as a chemical reference substance, contributing to studies of this gliptin, and to the quality control of medicines that contain it.

STUDY OF FLAVONOIDS PRESENT IN POMELO (Citrus Maxima) BY DSC, UV-VIS, IR, 1H AND 13C NMR AND MS

Flavonoids are among the most important plant metabolites. Due to their potential benefits, there is a considerable interest in this natural product. In genus Citrus, some plants have not yet been much exploited in Brazil, as in the case of grapefruit (Citrus maxima), whose main flavonoids are naringin and their aglycone naringenin. The physico-chemical characteristics are important pre-requisites of reference chemical in future studies. In this context, the objective of this study was to determine the characterization of naringin and naringenin by melting point, DSC, UV-VIS, 1H and 13C NMR, IR and MS. Results revealed that, naringin and naringenin after characterization, can be used as a chemical of reference in future studies and contribute to seeking possible technological applications.