[Determination of the presence of an antibiotic in implant-bone biopsy specimens by Raman spectroscopy in experiment]. / Opredelenie nalichiya antibiotika v implantato-kostnykh bioptatakh metodom ramanovskoi spektroskopii v eksperimente.

THE AIM OF THE STUDY: Was to determine the presence of an amoxicillin-based antibiotic in bone implant biopsies by Raman spectroscopy in an experiment. MATERIALS AND METHODS: Experimental animals (n=10, a miniature pig of the Svetlogorsk breed) were divided into 2 groups of 5 animals. Groups 1 and 2 were injected with amoxicillin 2 ml per 20 kg of body weight 30 minutes before dental implantation surgery, then group 2 was additionally injected with 1 ml per 20 kg of body weight for 5 days. Each animal has 6 implants installed. On the 1st, 3rd, 7th, 14th day, an implant-bone biopsy was removed from each animal, micro-preparations were made and Raman spectroscopy was performed to assess the peak matching of the Raman spectrum. RESULTS: In animals of the 1st and 2nd groups, the main peak of the Raman spectrum, which is closest to the values of the antibiotic spectrum of interest to us, is located closer to 1448 cm-1 and 1446 cm-1, respectively. At the same time, in both observations, the peaks relate to the spectrum of bone tissue, which cannot indicate the content of an antibiotic in the drug. CONCLUSION: No scattering spectra corresponding to the antibiotic molecule were found in any animal from both groups, regardless of the mode of administration and dosage of amoxicillin. The detected peaks corresponded to bone tissue without an antibiotic.

Adsorption of antibiotics on different microplastics (MPs): Behavior and mechanism.

MPs can adsorb antibiotics to coexist and accumulate in the aquatic environment in the form of complexes, resulting in unforeseeable adverse consequences. The adsorption behavior and mechanism of three antibiotics amoxicillin (AMX), ciprofloxacin (CIP), and tetracycline (TC) by four MPs Polyvinyl chloride (PVC), polystyrene (PS), polypropylene (PP), and polyethylene (PE) were studied. Results showed that the adsorption of antibiotics onto MPs follows the pseudo-second-order kinetic and the Freundlich isotherm model, indicating a multilayer chemical adsorption. Combined with FTIR, XRD, and SEM analyses, the adsorption behavior was simultaneously governed by physical processes. Additionally, the equilibrium adsorption capacity was inhibited in the research concentration range of NaCl from 10 mg/L to 10 g/L. The higher the salt concentration, the more pronounced the inhibition phenomenon was. The high (9) and low (3) pH also inhibited the adsorption of antibiotics to MPs. The humic acid (HA) concentration in the range of 0-20 mg/L generally inhibited the MPs-antibiotics adsorption, but the higher HA concentration showed less inhabitation than the lower one. The adsorption inhibition of TC on the four MPs by SA also followed the above rule. However, the adsorption inhibition of sodium alginate (SA) on AMX and CIP on the four MPs was enhanced with its concentration (0-50 mg/L).

Determination of amoxicillin and cotrimoxazole concentrations in sputum of patients with cystic fibrosis.

In the management of cystic fibrosis, treatments against Staphylococcus aureus and Haemophilus influenzae such as amoxicillin or cotrimoxazole have to be prescribed and the antibiotherapy's efficacy may be linked to the concentration that reaches the infected site. As cystic fibrosis patients present disturbed pharmacokinetics parameters, drug monitoring would be relevant to assess the lung distribution of antibiotics and to optimize dosing regimens. In this context, the aim of the study was to develop and validate HPLC-based methods for the determination of both antibiotics in bronchial sputum from cystic fibrosis patients, in order to assess the distribution of the drugs into the lungs. Plasma proteins were precipitated by acetonitrile and amoxicillin concentrations in sputum were determined by HPLC coupled with tandem-mass spectrometry. Following liquid extraction with ethyl acetate, cotrimoxazole was quantified by HPLC using ultraviolet detection. Both methods were rapid, specific, accurate and reproducible. The method was applied to patient samples. In three treated patients, concentrations of amoxicillin in sputum were similar and below the lower limit of quantification (0.1 µg/g) and in six patients, sputum concentrations up to 11.1 and 6.4 µg/g were measured for sulfamethoxazole and trimethoprim, respectively.

Fabrication of multi-walled carbon nanotubes and carbon black co-modified graphite felt cathode for amoxicillin removal by electrochemical advanced oxidation processes under mild pH condition.

Hydrogen peroxide (H2O2) electrogenerated via two-electron oxygen reduction reaction at cathode plays an important role in electrochemical advanced oxidation processes for organic pollutants removal from wastewater. Herein, multi-walled carbon nanotubes and carbon black co-modified graphite felt electrode (MWCNTs-CB/GF) was prepared as an efficient cathode for H2O2 electrogeneration and amoxicillin removal by anodic oxidation with hydrogen peroxide (AO-H2O2) and electro-Fenton (EF) under mild pH condition. Besides, the physicochemical and electrochemical properties of MWCNTs-CB/GF were characterized by scanning electron microscopy, N2 adsorption and desorption experiment, contact angle measurement, X-ray photoelectron spectroscopy, and linear sweep voltammetry. Compared with GF, MWCNTs-CB/GF showed a higher H2O2 generation of 309.0 mg L-1 with a current efficiency of 60.9% (after 120 min) and more effective amoxicillin removal efficiencies of 97.5% (after 120 min) and 98.7% (after 30 min) in AO-H2O2 and EF (with 0.5 mM Fe2+) processes, under the condition of current density 12 mA cm-2 and initial pH 5.5. Meanwhile, the TOC removal efficiency was 45.2% during EF process after 120 min. Anodic oxidation, H2O2 oxidation, and methanol capture indicated that ∙OH generated via electro-activation reaction at MWCNTs-CB/GF and Fenton reaction in solution played the dominant role in amoxicillin removal. Moreover, the TOC removal was associated with ∙OH generated during Fenton reaction in the solution. The major intermediates of AMX degradation by EF process were identified using LC-MS and the possible degradation pathways were proposed containing of ß-lactam ring opening, hydroxylation reaction, decarboxylation reaction, methyl groups in the thiazolidine ring oxidation reaction, bond cleavage, and rearrangement processes. All of the above results proved that MWCNTs-CB/GF was an excellent cathode for AMX degradation under mild pH condition.

Evaluation of the amoxicillin concentrations in amniotic fluid, placenta, umbilical cord blood and maternal serum two hours after intravenous administration.

OBJECTIVES: The aims of this study were to evaluate amoxicillin concentrations in amniotic fluid, placenta, umbilical cord blood and maternal blood two hours after intravenous administration to assess obstetric and non-obstetric factors that could have influences on the penetration of the antibiotic into the examined tissues and to analyze the sensitivity to amoxicillin of the most common pathogens isolated from the genital tract. METHODS: A total of 35 full-term pregnant women who qualified for elective Caesarean delivery were included in the study. Amoxicillin at a dose of 1000 mg was administered prior to surgery. Amoxicillin levels were determined by diffusion microbial assay. RESULTS: The drug concentration was highest in umbilical cord blood compared with amniotic fluid, maternal blood and placenta (4.20±1.06 µg/g versus 3.96±0.79 µg/g, 3.22±0.64 µg/g and 2.81±0.64 µg/g, respectively). Obstetric and non-obstetric factors had no influence on the amoxicillin concentration. The most common bacteria isolated from the genital tracts of pregnant women (Streptococcus agalactiae, Enterococcus faecalis, Escherichia coli) were sensitive to amoxicillin. The MIC for the sensitive strain of Streptococcus agalactiae was seen in the majority of tissues of all of the patients; however, the MICs for E. faecalis and E. coli were not observed in any compartment. CONCLUSIONS: Amoxicillin proved to have good penetration into the fetal tissues and placenta after intravenous administration. The most common bacteria isolated from the genital tracts of pregnant women were sensitive to amoxicillin. Pregnancy complications were not found to have an influence on the amoxicillin concentrations in the examined tissues.

Interactions between Microcystis aeruginosa and coexisting amoxicillin contaminant at different phosphorus levels.

Microcystis aeruginosa was cultured with 0.05-5 mg L(-1) of phosphorus and exposed to 200-500 ng L(-1) of amoxicillin for seven days. Amoxicillin presented no significant effect (p>0.05) on the growth of M. aeruginosa at phosphorus levels of 0.05 and 0.2 mg L(-1), but stimulated algal growth as a hormesis effect at phosphorus levels of 1 and 5 mg L(-1). Phosphorus and amoxicillin affected the contents of chlorophyll-a, adenosine triphosphate (ATP) and malondialdehyde, the expression of psbA and rbcL, as well as the activities of adenosinetriphosphatase and glutathione S-transferase in similar manners, but regulated the production and release of microcystins and the activities of superoxide dismutase and peroxidase in different ways. Increased photosynthesis activity was related with the ATP consumption for the stress response to amoxicillin, and the stress response was enhanced as the phosphorus concentration increased. The biodegradation of amoxicillin by M. aeruginosa increased from 11.5% to 28.2% as the phosphorus concentration increased. Coexisting amoxicillin aggravated M. aeruginosa pollution by increasing cell density and concentration of microcystins, while M. aeruginosa alleviated amoxicillin pollution via biodegradation. The interactions between M. aeruginosa and amoxicillin were significantly regulated by phosphorus (p<0.05) and led to a complicated situation of combined pollution.

Development and validation of HPLC-DAD method for the simultaneous determination of amoxicillin, metronidazole and rabeprazole sodium. Application to spiked simulated intestinal fluid samples.

This work deals with the development, validation and application of an HPLC-DAD method for the determination of a ternary mixture containing amoxicillin (AX), metronidazole (MZ) and the proton pump inhibitor rabeprazole sodium (RB). This triple therapy is used for treatment of Helicobacter pylori infection. Effective chromatographic separation between the three drugs was achieved using Thermo Hypersil BDS-C8 (4.6×250mm, 5µm particle size) column and a mobile phase composed of phosphate buffer pH 7 and acetonitrile (70: 30, by volume). The mobile phase was pumped isocratically at a flow rate of 1 mL/min. Quantification of the analytes was based on measuring their peak areas at 230nm for both AX and RB, and at 319nm for MZ. AX, MZ and RB eluted at retention times 2.36, 3.55 and 8.72min respectively. The reliability and analytical performance of the proposed HPLC procedure were statistically validated with respect to linearity, ranges, precision, accuracy, selectivity, robustness, detection and quantification limits. The linear dynamic ranges were 25-250, 25-250 and 5-50µg/mL for AX, MZ and RB respectively with correlation coefficients>0.9998. The validated method was successfully applied to the analysis of several laboratory-prepared mixtures as well as simulated intestinal fluid samples spiked with the three drugs.

Avaliacão do uso da amoxicilina em, diferentes períodos no tratamento de abscessos dentoalveolares / Evaluation ot use of amoxicillin in different periods for the treatment of dentaolveolar abscess

O objetivo foi avaliar a eficácia da amoxicilina em diferentes periodos (3 e 7 dias) no tratamento coadjuvante de abscessos dentoalveolares após realização de drenagem. Foram avaliados 20 voluntários divididos em 2 grupos (n=10): G1 - 19 de amoxicilina, antes do procedimento de drenagem e 500mg de 8/8h por 3 dias; G2 - 1 9 de amoxicilina antes do procedimento e 500mg de 8/8h por 7 dias. Foram avaliados o edema, dor, febre, supuração e trismo, e os voluntários tiveram acompanhamento clínico diário. O edema foi avaliado em duas medidas (Tragus a Asa do Nariz e Tragus a Comissura Labial). A abertura bucal e o edema foram avaliados antes da drenagem, 1, 2, 3 e 7 dias após. Para a avaliação de dor foi utilizada a escala analógica visual (EAV) antes e nos intervalos O, 1 h, 2h, 4h, 12h, 1 dia, 2 dias, 3 dias e 1 semana após. Os resultados fora m su bmetidos à a ná I ise estatística (Kruska II-Wa II is), com n ivel de sig n ificâ ncia de 5%. Quanto aos parâmetros clínicos avaliados, não foram observadas diferenças estatisticamente significantes entre os grupos [p>0,05), e nenhum dos voluntários apresentou complicações no período do pós-atendimento. Concluiu-se que, após a intervenção clínica, a eficácia da amoxicilina nos períodos avaliados foi similar na amostra avaliada

The aim of this study was to compare the use of amoxicillin for different time intervals (3 and 7 days) for treatment of acute dentoalveolar abscesses after performing drainage. Twenty volunteers were divided into two groups (n = 10): G 1 - The volunteers received 1 9 of amoxicillin before the drainage procedure, and 500mg of amoxicillin every 8 hours for 3 days; G2 - The volunteers received 19 of amoxicillin before the drainage procedure, and 500mg of amoxicillin every 8 hours for 7 days. For each patient followed-up, acute infectious conditions were investigated, and pain, edema, fever, suppuration and trismus were evaluated. To evaluate pain was used a visual analog scale [VAS) in the intervals O, 1 h, 2h , 4h , 12 h , 1,2 and 3 days and 1 week after the drainage. The results were submmited to statistical analysis [Kruskal - Wallisl. with a significance levei of 5 %. There was no statistically significant difference between the groups considering the parameters evaluated [p>0.05). None of the volunteers had complications in the post clinical care assessed. It was concluded that after clinical intervention, the effectiveness of the use of amoxicillin in periods of 3 and 7 days was similar in the evaluated volunteers

Modification of TiO(2) nanotube surfaces by electro-spray deposition of amoxicillin combined with PLGA for bactericidal effects at surgical implantation sites.

OBJECTIVE: To fabricate the antibiotic-releasing coatings on TiO(2) nanotube surfaces for wide applications of implant and bone plate in medical and dental surgery, the optimal deposition time of amoxicillin/PLGA solution simultaneously performing non-toxicity and a high bactericidal effect for preventing early implant failures was found. MATERIALS AND METHODS: FE-SEM, ESD and FT-IR were used for confirming deposition of amoxicillin/PLGA on the TiO(2) surface. Also, the elution of amoxicillin/PLGA in a TiO(2) nanotube surface was measured by a UV-VIS spectrophotometer. The bactericidal effect of amoxicillin on the TiO(2) nanotube surface was evaluated by using Staphylococcus aureus (S. aureus). The cytotoxicity and cell proliferation were observed by WST assay using MC3T3-E1 osteoblast cells. RESULTS: The results indicated that the TiO(2) nanotube surface controlled by electro-spray deposition time with amoxicillin/PLGA solution could provide a high bactericidal effect against S. aureus by the bactericidal effect of amoxicillin, as well as good osteoblast cell proliferation at the TiO(2) nanotube surface without toxicity. CONCLUSIONS: This study used electro-spray deposition (ESD) methodology to obtain amoxicillin deposition in nanotube structures of TiO(2) and found the optimal deposition time of amoxicillin/PLGA solution simultaneously performing non-toxicity and a high bactericidal effect for preventing early implant failures.

A novel voltammetric sensor for amoxicillin based on nickel-curcumin complex modified carbon paste electrode.

The electrocatalytic oxidation of amoxicillin was investigated on a nickel-based (Ni(II)-curcumin) chemically modified electrode. This modified electrode was prepared by electropolymerization of complex (curcumin = 1,7-bis[4-hydroxyl-3-methoxyphenyl]-1,6-heptadiene-3,5-dione) in alkaline solution. For the first time, the catalytic oxidation of amoxicillin was demonstrated by cyclic voltammetry, chronoamperometry, chronocoulometry and amperometry methods at the surface of this modified carbon paste electrode. The obtained results showed that NiOOH acts as an electrocatalyst for oxidation of amoxicillin. This electrocatalytic oxidation exhibited a good linear response for amoxicillin concentration over the range of 8 × 10⁻6-1×10⁻4 M with a detection limit of 5 × 10⁻6 M. Therefore, this electrocatalytic method was used as a simple, selective and rapid method able to determine amoxicillin in pharmaceutical preparations and biological media.

Immunocytochemistry for bestatin and its application to drug accumulation studies in rat intestine and kidney.

The in vivo role of transporters in drug disposition, in the context of other transporters, and metabolism has not been established. We prepared an anti-bestatin serum against bestatin conjugated to albumin with glutaraldehyde (GA). The antiserum was specific for GA-conjugated bestatin and weakly reacted with free bestatin, but no reaction occurred with structurally unrelated compounds according to both the inhibition and binding ELISAs. The antiserum allowed us to develop an immunocytochemical (ICC) method for detecting the uptake of bestatin in the rat intestine and kidney. Three hours after a single oral administration of bestatin, the ICC method revealed that the drug distributed in the microvilli, cytoplasm and nuclei of the absorptive epithelial cells at much larger amounts than in all other cell types in the small intestine. However, no drug was detected in the mucin goblets in the epithelium. In the kidney, the drug distributed to a greater extent in the S3 segment than in the S1 and S2 segments of the proximal tubule, and also was detected in the microvilli of the proximal tubule cells (S1, S2 and S3). These findings that bestatin accumulated in large amounts, especially in the cells and/or at the sites where the transporters PEPT1 and PEPT2 occur, corresponded well to those observed with ß-lactam amoxicillin in the previous ICC studies. Thus, this may indicate a possibility that both the transporters might be involved, at least in part, in the distribution of bestatin in the small intestine and kidney under the conditions examined.

[Synthesis of artificial antigens of amoxicillin and preparation of monoclonal antibody to amoxicillin].

AIM: To synthesize two kinds of amoxicillin artificial antigen and to establish hybridoma cell lines secreting monoclonal antibody against amoxillin. METHODS: Amoxicillin were respectively coupled with ovalbumin(OVA) and bovine serum albumin(BSA) by using N-hydroxysuc-cinimide active ester (NHS) method to prepared the immunogen and detection antigen. Molar ratio of conjugates were detected by ultraviolet spectrum analysis. BALB/c mice was immunized with AMX-OVA. The hybridomas were obtained by fusing mouse myeloma cells Sp2/0 with splenocytes from the mice immunized with AMX-OVA. The aseites with mAb were purified by octanoic acid-saturated ammonium sulphate method. Isotype was determined by Mouse Isotype kit (Bio-RadLabs.). RESULTS: UV spectra shows overlay features between a small molecular compound and carrier protein. Five hybridoma cell strains secreting specific mAb against amoxicillin were obtained and the five Amb belong to IgG1 kappa isotype. The limit of detection of AMX was 0.25 ng/mL and but there is mild degree of cross-reactions with ampicillin with same structure of ß-lactam ring. CONCLUSION: The anti-AMX Amb could be used to develop immunoassay for detection of residues.

Determination of water content by capillary gas chromatography coupled with thermal conductivity detection.

This article presents some experience obtained by applying capillary gas chromatography coupled with thermal conductivity detection (GC/TCD) to the determination of water in substances for pharmaceutical use. This technique represents a useful, orthogonal tool complementary to water determination methods based on volumetric or coulometric titration. It can also represent an alternative technique when such titrations are not applicable. This article presents the preliminary results obtained in a number of case studies where a GC/TCD procedure was applied in comparison with pharmacopoeial methods to substances with different water contents.

Antibiotic removal from water: elimination of amoxicillin and ampicillin by microscale and nanoscale iron particles.

Zerovalent iron powder (ZVI or Fe(0)) and nanoparticulate ZVI (nZVI or nFe(0)) are proposed as cost-effective materials for the removal of aqueous antibiotics. Results showed complete removal of Amoxicillin (AMX) and Ampicillin (AMP) upon contact with Fe(0) and nFe(0). Antibiotics removal was attributed to three different mechanisms: (i) a rapid rupture of the beta-lactam ring (reduction), (ii) an adsorption of AMX and AMP onto iron corrosion products and (iii) sequestration of AMX and AMP in the matrix of precipitating iron hydroxides (co-precipitation with iron corrosion products). Kinetic studies demonstrated that AMP and AMX (20 mg L(-1)) undergo first-order decay with half-lives of about 60.3+/-3.1 and 43.5+/-2.1 min respectively after contact with ZVI under oxic conditions. In contrast, reactions under anoxic conditions demonstrated better degradation with t(1/2) of about 11.5+/-0.6 and 11.2+/-0.6 min for AMP and AMX respectively. NaCl additions accelerated Fe(0) consumption, shortening the service life of Fe(0) treatment systems.

Early wound healing following one-stage dental implant placement with and without antibiotic prophylaxis: a pilot study.

BACKGROUND: One-stage implant placement has clinically acceptable treatment outcomes. Among other advantages, it may allow investigation of early wound healing. The purpose of this pilot study was to determine whether peri-implant crevicular fluid (PICF) can be used to detect early changes around implants placed with one-stage surgical protocol following 1 week of healing. METHODS: Twenty subjects (11 males and nine females; aged 22 to 72 years; two smokers) were included. Exclusion criteria were allergies to amoxicillin and systemic conditions that may affect healing. Subjects had a healthy periodontium and needed a single implant; eight received antibiotic prophylaxis, and 12 served as controls. Clinical healing was evaluated with plaque and gingival indices (PI and GI, respectively). Gingival crevicular fluid (GCF) from the surgical site was obtained prior to the surgery, whereas PICF was collected at the 1-week visit. Enzyme-linked immunosorbent assay was used to determine GCF/PICF interleukin (IL)-1beta and -8 concentrations. Peripheral blood and GCF antibiotic levels were measured by high-performance liquid chromatography. RESULTS: Postoperative PI and GI were slightly increased. Total GCF and PICF volumes did not show a significant difference between appointments. There was an increase in PICF IL-1beta and -8 levels at 1 week postoperatively. Mean amoxicillin serum concentration was 5.1 +/- 2 microg/ml at 1 to 4 hours following the initial dose, whereas GCF amoxicillin levels were below the limit of detection. Antibiotic prophylaxis had a modest effect on clinical indices (PI and GI) and no appreciable effect on biomarkers. CONCLUSIONS: PICF content can be studied as early as 1 week following one-stage implant placement. The results raise doubts regarding the clinical usefulness of amoxicillin prophylaxis.

Streamlining methodology for the multiresidue analysis of beta-lactam antibiotics in bovine kidney using liquid chromatography-tandem mass spectrometry.

A previously reported multiresidue method for the analysis of 11 important beta-lactams (amoxicillin, ampicillin, cefazolin, cephalexin, cloxacillin, desfuroylceftiofur cysteine disulfide (DCCD), deacetylcephapirin, dicloxacillin, nafcillin, oxacillin, and penicillin G) in bovine kidney has been further streamlined. The method is based on a simple extraction using acetonitrile-water (4:1, v/v), followed by dispersive solid-phase extraction clean-up with C(18) sorbent, concentration of an extract aliquot, and filtration of the final extracts using syringeless filter vials, which are used for the sample introduction in the liquid chromatographic-tandem mass spectrometric (LC-MS/MS) analysis. The recoveries have been improved by adding the internal standard [(13)C(6)]sulfamethazine to the homogenized sample before the extraction step, which enabled a proper control of the volume changes during the sample preparation. Average recoveries of fortified samples were 87-103% for all beta-lactams, except for DCCD, which had an average recovery of 60%. Based on the results of the stability study and LC mobile phase tests, methanol has been eliminated from the entire method, including the LC-MS/MS analysis. The best overall LC-MS/MS (electrospray positive ionization) performance was achieved by using 0.1% formic acid as an additive in both parts of the mobile phase, in water and in acetonitrile. To prevent carry-over in the LC-MS/MS analysis, the LC method was divided into two parts: one serving as an analytical method for injection of the sample and elution of the analytes and the other one, starting at a highly organic mobile phase composition, being dedicated for injection of a solvent, washing of the system, and equilibration of the column to the initial conditions of the analytical method. In this way, a blank solvent is injected after each sample, but these in-between injections contribute minimally to the overall sample throughput.

Determination of amoxicillin content in powdered pharmaceutical formulations using DRIFTS and PLS

The amount of amoxicillin in pharmaceutical formulations was determined using spectra of diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), in association with partial least squares (PLS) regression. The spectra of 24 different samples (17 for the calibration set and 7 for the validation set), which had been registered using a Nicolet Magna 550 spectrophotometer, contained 76.7-94.3 percent of amoxicillin in starch. The PLS models were constructed with auto-scaled or variance-scaled data, and multiplicative scatter correction (MSC). The best model presented R²=0.9936, RMSEC=0.441 and RMSEV=0.790. The analytical method proposed is non-destructive and the cost and time of analysis are very much reduced, allowing for the fast and direct determination of amoxicillin content.

Neste trabalho propõe-se a quantificação de amoxicilina em formulações farmacêuticas empregando espectroscopia por refletância difusa no infravermelho com transformada de Fourier (DRIFTS) e regressão por mínimos quadrados parciais (PLS). Foram coletados em um espectrômetro Nicolet Magna 550 os espectros de 24 amostras (17 para o conjunto de calibração e 7 para o conjunto de validação) contendo de 76,7-94,3 por cento de amoxicilina em amido. Para a construção dos modelos PLS foi empregada a correção do espalhamento de luz (MSC) e os dados foram autoescalados ou escalados pela variância. Foi obtido um excelente modelo para a previsão da amoxicilina o qual apresentou R²=0,9936, RMSEC=0,441 e RMSEV=0,790. O método proposto além de não destrutivo apresenta baixo tempo de análise e baixo custo podendo ser facilmente empregado no controle de qualidade das indústrias farmacêuticas.

Flow injection-chemiluminescence determination of amoxycillin using potassium permanganate and formaldehyde system.

It was found that amoxycillin can react with potassium permanganate in an acidic medium to produce chemiluminescence, which is greatly enhanced by formaldehyde. The optimum conditions for this chemiluminescent reaction were studied in detail using a flow-injection system. The experimental results indicate that, under optimum conditions, the chemiluminescence intensity is linearly related to the concentration of amoxycillin in the range 5.48 x 10(-8)-2.74 x 10(-6) mol/L, with a detection limit (3sigma) of 4.1 x 10(-8) mol/L. The relative standard deviation was 1.0% at 1.1 x 10(-6) mol/L amoxycillin (n = 11 measurements). This method has the advantages of high sensitivity, fast response and ease of operation. The method was successfully applied to the determination of amoxycillin in raw medicines and capsules.