Kitasamycin Research Articles

Hydrogel for slow-release drug delivery in wound treatment

Abstract When skin comes into direct contact with the outside environment, it becomes extremely prone to injury and external factors can make wounds difficult to heal. Traditional medical dressings often cause secondary injury and are poorly resistant to infection. Hydrogels offer a promising alternative to overcome these difficulties. In this study, chitosan (CS)/gelatin (GEL)/polyvinyl alcohol (PVA) hydrogels were developed by chemical cross-linking and loaded with the drug kitasamycin (KM) for testing. The hydrogels’ in vitro drug release and wound-healing properties were assessed. For 48 h, the drug release from the hydrogel in vitro persisted, which was significantly longer than the release time of the KM solution. Antimicrobial activity tests showed that the loaded KM hydrogel maintained its bacteriostatic ability at the same concentration as the KM solution, and during in vitro bacteriostatic inhibition, the duration of bacteriostatic inhibition of the KM hydrogel was significantly prolonged compared to that of the KM solution. This confirms the controlled release capability of the hydrogel. In addition, the hydrogel reduced the wound size in mice by 96 % and histopathological tests showed complete re-epithelialization of the wound. The prepared hydrogels successfully demonstrated their potential ability to control drug release and promote skin wound healing.

Subtherapeutic Kitasamycin Promoted Fat Accumulation in the Longissimus Dorsi Muscle in Growing-Finishing Pigs.

Kitasamycin (KM), a broad-spectrum macrolide antibiotic, has implications for growth performance and residue in animals and humans. This study aimed to explore the effects of different KM doses on intramuscular fat accumulation, cecal microflora, and short-chain fatty acids (SCFAs) using a growing-finishing pig model. Forty-two pigs were divided into three groups: control, subtherapeutic KM (50 mg/kg, KM50), and therapeutic KM (200 mg/kg, KM200) diets over 8 weeks. KM50 led to increased back fat thickness, fat content in the longissimus dorsi muscle (LM), and elevated plasma total cholesterol (TC) levels (p < 0.05), supported by upregulated lipid synthesis gene expression (Acc1, Fas, Scd1) (p < 0.05) in the LM. KM50 altered cecal microflora, reducing Lactobacillus spp. and Bifidobacterium spp. abundance, while increasing SCFA concentrations (acetic acid, propionic acid, total SCFAs) (p < 0.05). KM200 had minimal effects on intestinal weight and density, with increased apparent digestibility of nutrients. These findings highlight the dose-dependent impact of KM on intramuscular fat deposition. Subtherapeutic KM induced ectopic fat deposition, emphasizing potential risks in disease treatment for humans and animals.

Dispersive Solid-Phase Extraction and Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry-A Rapid and Accurate Method for Detecting 10 Macrolide Residues in Aquatic Products.

The amount of macrolide (MAL) residues in aquatic products, including oleandomycin (OLD), erythromycin (ERM), clarithromycin (CLA), azithromycin (AZI), kitasamycin (KIT), josamycin (JOS), spiramycin (SPI), tilmicosin (TIL), tylosin (TYL), and roxithromycin (ROX), was determined using solid-phase extraction and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The residues were extracted with 1% ammonia acetonitrile solution and purified by neutral alumina adsorption. Chromatographic separation was completed on an ACQUITY UPLC BEH C18 column with acetonitrile-0.1% formic acid aqueous solution as the mobile phase, and mass spectrometry detection was performed by multiple reaction monitoring scanning with the positive mode in an electrospray ion source (ESI+). Five isotopically labeled compounds were used as internal standards for quality control purposes. The findings indicated that across the mass concentration span of 1.0-100 μg/L, there was a strong linear correlation (R2 > 0.99) between the concentration and instrumental response for the 10 MALs. The limit of detection of UPLC-MS/MS was 0.25-0.50 μg/kg, and the limit of quantitation was 0.5-1.0 μg/kg. The added recovery of blank matrix samples at standard gradient levels (1.0, 5.0, and 50.0 μg/kg) was 83.1-116.6%, and the intra-day precision and inter-day precisions were 3.7 and 13.8%, respectively. The method is simple and fast, with high accuracy and good repeatability, in line with the requirements for accurate qualitative and quantitative analysis of the residues for 10 MALs in aquatic products.

The Antibiotic Kitasamycin-A Potential Agent for Specific Fibrosis Preventing Therapy after Fistulating Glaucoma Surgery?

One major complication after fistulating glaucoma surgeries are fibroblast-mediated scarring processes and their specific prevention is key in the development of novel pharmaceutical concepts. Within this study a possible antifibrotic potential of kitasamycin (KM) in a transforming growth factor (TGF)-β1-mediated fibroblast model was evaluated in vitro. Primary ocular fibroblasts were isolated, cultivated and a dose-response test including determination of the half maximal effective concentration (EC50) for KM was conducted. Transformation of fibroblasts into myofibroblasts was induced by TGF-β1and immunofluorescence (IF), and Western blot (WB) analyses were performed with fibroblasts and myofibroblasts. IF analyses were carried out using antibodies against α-smooth muscle actin (α-SMA) and fibronectin, and protein detection of intracellular and extracellular proteins was performed by WB. Using the dose-response test, the viability, cytotoxicity and EC50 of KM after 24 and 48 h were determined. Fibroblasts exposed to various KM concentrations showed no increase in α-SMA and extracellular matrix expression. In TGF-ß1-stimulated myofibroblasts, KM inhibited the expression of α-SMA and fibronectin in a concentration-dependent manner. These findings demonstrate that KM could impair the transformation of fibroblasts into myofibroblasts and the expression of proteins involved in fibrotic processes, representing a potential agent for specific fibrosis prevention in future therapeutic concepts.

Highly selective removal of kitasamycin from the environment by molecularly imprinted polymers: Adsorption performance and mechanism

A newly green molecularly imprinted polymer (MIP) for kitasamycin (KITA) was synthesized in water by using 1-allyl-3-vinylimidazolium chloride ionic liquid and 2-acrylamide-2-methylpropanesulfonic acid as co-functional monomer on the surface of poly (styrene-divinylbenzene) particles. The prepared MIP has excellent selectivity for KITA in mixed solution, and approximately 90% of KITA can be bounded onto MIP within the first 30 min. And the MIP exhibited powerful affinity towards KITA with the maximum adsorption amount of 127.06 mg g -1 with the recovery of 92.3–108.8%, and the binding capacity increased within the contact temperature of 25–45 °C. The adsorption mechanism revealed that the synergistic effect of hydrogen bond, π-π interaction and molecule structure was attributed to selectivity of the MIP. Under the optimized condition, a MIP-SPE cartridge coupled with high performance liquid chromatography (HPLC) was developed to determine the residues of KITA in soil, water and muscle samples, and the MIP-SPE cartridge can be regenerated at least 25 cycles. Therefore, the developed MIP-SPE-HPLC strategy can be used as a specific, cost-effective and environmentally-friendly method for identification and determination KITA in environmental samples. A novel eco-friendly molecularly imprinted polymer (MIP) was proposed in water by using 1-allyl-3-vinylimidazolium chloride and 2-acrylamide-2-methylpropanesulfonic acid as bifunctional monomer for the specific adsorption of kitasamycin (KITA). The obtained MIP had excellent selectivity towards KITA and can be used as solid phase extraction for recognizing and separating trace KITA in soil, water and muscle samples. • An eco-friendly hydrophilic kitasamycin MIP was synthesized. • The MIP showed excellent selectivity and adsorption capacity to KITA in water. • The excellent practicability and reusability of MIP-SPE were also demonstrated.

Development of a monoclonal-based ic-ELISA for the determination of kitasamycin in animal tissues and simulation studying its molecular recognition mechanism

To monitor the residue of kitasamycin (KIT), a monoclonal antibody against KIT was prepared, and a 50% inhibition concentration (IC50) of 5.7 ± 1.4 μg/L was achieved with the most sensitive antibody, KA/2A9, by optimizing ELISA conditions. The LODs for KIT in different animal tissues ranged from 22.47 μg/kg to 29.32 μg/kg, and the recoveries of the fortified tissues were 70% ~ 120% with coefficients of variation below 20%. Then, KIT-specific scFv KA/2A9/3 was prepared for the first time. Homologous modeling and molecular docking results indicated that the key amino acids of KA/2A9/3 scFv are TYR-92 (CDRL3), SER-93 (CDRL3), ASP-155 (CDRH1) and GLY-226 (CDRH3), and the hydrogen bond is the main force. And then, virtual mutation provides a method to evolve KA/2A9/3 scFv antibodies. These results contribute to comprehending the antigen–antibody binding mechanism and provide effective information for in vitro affinity maturation of anti-KIT scFv.

Gold immunochromatographic assay for kitasamycin and josamycin residues screening in milk and egg samples

ABSTRACT In this study, a kitasamycin (KIT) hapten was prepared through the o-carboxymethoxylamine method and used to produce a monoclonal antibody against KIT and josamycin (JOS). The half inhibition concentration for an indirect competitive enzyme-linked immunosorbent assay was 1.49 and 2.67 ng/mL, respectively. Based on this antibody, a gold immunochromatographic assay (GICA) was developed for the detection of KIT and JOS residues in milk and egg samples. A hand-held strip scanner was used for quantitative analysis, with limits of detection for KIT and JOS of 1.51 and 1.91 μg/L in milk, and 3.0 and 2.72 μg/kg in eggs. The proposed GICA was validated by LC–MS/MS, which indicated that the GICA method would be a useful tool for the on-site detection of KIT and JOS residues in milk and egg samples.

Epidemiological studies on drug-resistance patterns, coagulase types, and MRSA-phage types of MRSA isolates during 1990-1994

We examined drug-resistance patterns, coagulase types, and MRSA-phage types of 125 MRSA strains isolated from clinical specimens during the period of January 1990 and December 1994. No vancomycin-resistant strain was isolated. Twenty one antibiotics were divided into three classes, low-intermediate- and high-isolation-frequency class, based on isolation frequencies of resistant strains. Minocycline, chloramphenicol, streptomycin, and imipenem were found to be included in low-isolation-frequency class (16.8-40%). In intermediate-isolation-frequency class (45.6-62.9%), cefmetazole, amikacin, gentamicin, and tetracycline were included. Oxacillin, ampicillin, piperacillin, ceftizoxime, cefoperazone, cefazolin, erythromycin, oleandomycin, kitasamycin, clindamycin, kanamycin, tobramycin, and ofloxacin belonged to high-isolation-frequency class (97.6-100%). MIC90s of vancomycin and minocycline (1.56 and 25 micrograms/ml) were lower than that of other 13 drugs. Comparing medical ward with dental ward, imipenem-, gentamicin-, and minocycline-resistant strains at medical ward, chloramphenicol- and streptomycin-resistant strains at dental ward were isolated dominantly on each ward, MRSA isolates were classified to 39 types by drug-resistance patterns. The isolation frequencies of coagulase type II and type IV strains were 65.6% and 29.6%, respectively. At dental ward, the isolation frequency of coagulase type IV strains was higher than that of coagulase type II strains during 1990-1992. However, coagulase type II strains were isolated considerably more than type IV strains during 1993-1994. By MRSA-phage typing, MRSA isolates were grouped into 18 MRSA-phage types. One hundred and twenty five MRSA isolates were divided into 56 types by using drug-resistance patterns, coagulase typing, and MRSA-phage typing. It was considered that such classification in combination of three methods is useful to make decision of epidemic by the same MRSA strain.

A multiresidue method for the simultaneous determination of ten macrolide antibiotics in human urine based on gradient elution liquid chromatography coupled to coulometric detection (HPLC–ECD)

A new generation of coulometric detector coupled to a high performance liquid chromatograph (HPLC) was used in this work with the aim of developing a multiresidue method allowing for the first time the separation, in a single run, of ten commercially available macrolide antibiotics, erythromycin (ERY), dirithromycin (DIR), tylosin (TYL), tilmicosin (TILM), spiramycin (SPI), josamycin (JOS), kitasamycin (KIT), rosamicin (ROS), roxithromycin (ROX) and oleandomycin (OLE). The procedure was therefore fully optimised for the separation of standard mixtures of the ten macrolides using a gradient elution on a C8 reversed phase HPLC column, and very reasonable resolution was achieved among the thirteen signals, arising from these ten. In the following step, the quantification of all the macrolides was achieved in standard mixtures, using ROX as an internal standard (I.S.), with detection limits, on column, below 2.5 ng for each. The method was then applied to the determination of macrolides in human urine, after a simple and fast sample preparation procedure involving liquid–liquid extraction. Calibration curves were carried out using the method of matrix-matching. The detection limits for each drug, in the human urine, were below 3 ng injected (equivalent to an initial concentration in the urine below 0.06 mg l −1). Overall recoveries of the entire method were estimated for each drug in human urine fortified at different levels of concentration within the linear range and averaged values were between 49.9 and 81.2% for low concentration levels and between 53.2 and 92.0% for high concentration levels for all macrolides.

Determination of macrolide antibiotics in meat and fish by liquid chromatography–electrospray mass spectrometry

A simple and reliable method using liquid chromatography–electrospray ionization-mass spectrometry (LC–ESI-MS) has been developed for the determination of macrolide antibiotics, erythromycin (EM), oleandomycin (OM), kitasamycin (KT), josamycin (JM), mirosamicin (MRM), spiramycin (SPM), tilmicosin (TLM) and tylosin (TS) in meat. The LC separation was performed on a TSKgel Super ODS column ( 100 mm×2 mm i.d.) with a gradient system of 0.2% acetic acid–acetonitrile (containing 0.2% acetic acid) as the mobile phase at the flow rate of 0.2 ml/min. The positive ionization produced the molecular related ions, (M+2H) 2+, at m/ z 422 and 435 for SPM and TLM, and (M+H) +, at 734, 688, 772, 828, 728 and 916 for EM, OM, KT, JM, MRM and TS, respectively. The calibration graphs for each drug were rectilinear from 0.05 to 25 ng with selected ion monitoring (SIM). The drugs were extracted with 0.2% metaphosphoric acid–methanol (6:4), and the extracts were cleaned up on an Oasis HLB cartridge (60 mg). The recoveries of the drugs from meat and fish fortified at the 0.2 μg/g level was 70.4–93.2% with high precision. The limits of quantification of the drugs in meat and fish were 0.01 μg/g.

Development of a Multiresidue Liquid Chromatography Method with Electrochemical Detection (HPLC‐ECD) for the Determination of Macrolide Antibiotics

AbstractA multiresidue high performance liquid chromatography procedure with electrochemical detection (amperometric) (HPLC‐ECD) using a C18 narrow bore column was fully optimized for the separation of a standard mixture of macrolides. Up to five macrolides, josamycin (JOS), kitasamycin (KIT), rosamicin (ROS) roxithromycin (ROX) and oleandomycin (OLE), the latter being selected as internal standard for the quantification, were properly separated using an isocratic elution mode. The influence of classical chromatographic and instrumental parameters was investigated in order to optimize them before the calibration assay. The method was succesfully applied to the determination of ROS and ROX in human urine.

Analytical Methods for Residues of Macrolides in the Muscle and Liver of Swine

Analytical methods for macrolide antibiotics (Macs.) in the muscle and liver of swine were examined.Tylosin (TS), erythromycin (EM), spiramycin (SP), oleandomycin (OM) and kitasamycin (KT) were well extracted with methyl alcohol after deproteinization by means of salt solutions, then adsorbed on an Amberlite XAD-2 resin column and eluted with methyl alcohol. The eluate was concentrated to dryness and dissolved in phosphate buffer (pH 8.0) to prepare a test solution. The cup plating method with Micrococcus luteus as the test organism was employed for the assay, and the average recoveries were more than 93.2% and 92.5% from muscle and liver, respectively. As little as 0.05μg/g (TS, SP, OM, KT) or 0.01μg/g (EM) was detectable.The extraction and the column chromatography were carried out on samples to which other antibiotics had been added in order to check the specificity of the present method. Chlortetracycline (5.0μg/g), fradiomycin (5.0μg/g), kanamycin (5.0μg/g), monensin (5.0μg/g) and colistin (5.0μg/g) showed no inhibition zone in the cup plating method, but bacitracin (5.0μg/g), ampicillin (5.0μg/g) and oxytetracycline (5.0μg/g) showed an inhibition zone.Bioautography was suitable for both separation and confirmation of the identity of Macs.