Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
1.
Mol Cell Proteomics ; 22(6): 100547, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37059366

RESUMO

Basal cell carcinomas (BCCs) and cutaneous squamous cell carcinomas (SCCs) are the most frequent types of cancer, and both originate from the keratinocyte transformation, giving rise to the group of tumors called keratinocyte carcinomas (KCs). The invasive behavior is different in each group of KC and may be influenced by their tumor microenvironment. The principal aim of the study is to characterize the protein profile of the tumor interstitial fluid (TIF) of KC to evaluate changes in the microenvironment that could be associated with their different invasive and metastatic capabilities. We obtained TIF from 27 skin biopsies and conducted a label-free quantitative proteomic analysis comparing seven BCCs, 16 SCCs, and four normal skins. A total of 2945 proteins were identified, 511 of them quantified in more than half of the samples of each tumoral type. The proteomic analysis revealed differentially expressed TIF proteins that could explain the different metastatic behavior in both KCs. In detail, the SCC samples disclosed an enrichment of proteins related to cytoskeleton, such as Stratafin and Ladinin-1. Previous studies found their upregulation positively correlated with tumor progression. Furthermore, the TIF of SCC samples was enriched with the cytokines S100A8/S100A9. These cytokines influence the metastatic output in other tumors through the activation of NF-kB signaling. According to this, we observed a significant increase in nuclear NF-kB subunit p65 in SCCs but not in BCCs. In addition, the TIF of both tumors was enriched with proteins involved in the immune response, highlighting the relevance of this process in the composition of the tumor environment. Thus, the comparison of the TIF composition of both KCs provides the discovery of a new set of differential biomarkers. Among them, secreted cytokines such as S100A9 may help explain the higher aggressiveness of SCCs, while Cornulin is a specific biomarker for BCCs. Finally, the proteomic landscape of TIF provides key information on tumor growth and metastasis, which can contribute to the identification of clinically applicable biomarkers that may be used in the diagnosis of KC, as well as therapeutic targets.


Assuntos
Carcinoma Basocelular , Carcinoma de Células Escamosas , Neoplasias Cutâneas , Humanos , Neoplasias Cutâneas/metabolismo , Líquido Extracelular/metabolismo , NF-kappa B/metabolismo , Proteômica , Carcinoma Basocelular/metabolismo , Carcinoma Basocelular/patologia , Carcinoma de Células Escamosas/metabolismo , Queratinócitos/metabolismo , Biomarcadores Tumorais/metabolismo , Microambiente Tumoral
2.
J Am Acad Dermatol ; 90(1): 66-73, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37704106

RESUMO

BACKGROUND: Evidence regarding long-term therapeutic outcomes and disease-specific survival (DSS) in Extramammary Paget's disease (EMPD) is limited. OBJECTIVES: To assess the DSS and outcomes of surgical and nonsurgical therapeutic modalities in a large cohort of EMPD patients. METHODS: Retrospective chart review of EMPD patients from 20 Spanish tertiary care hospitals. RESULTS: Data on 249 patients with a median follow-up of 60 months were analyzed. The estimated 5-, 10-, and 15-year DSS was 95.9%, 92.9%, and 88.5%, respectively. A significantly lower DSS was observed in patients showing deep dermal invasion (≥1 mm) or metastatic disease (P < .05). A ≥50% reduction in EMPD lesion size was achieved in 100% and 75.3% of patients treated with surgery and topical therapies, respectively. Tumor-free resection margins were obtained in 42.4% of the patients after wide local excision (WLE). The 5-year recurrence-free survival after Mohs micrographic surgery (MMS), WLE with tumor-free margins, WLE with positive margins, radiotherapy, and topical treatments was 63.0%, 51.4%, 20.4%, 30.1%, and 20.8%, respectively. LIMITATIONS: Retrospective design. CONCLUSIONS: EMPD is usually a chronic condition with favorable prognosis. MMS represents the therapeutic alternative with the greatest efficacy for the disease. Recurrence rates in patients with positive margins after WLE are similar to the ones observed in patients treated with topical agents.


Assuntos
Doença de Paget Extramamária , Humanos , Estudos Retrospectivos , Doença de Paget Extramamária/cirurgia , Cirurgia de Mohs , Análise de Sobrevida , Margens de Excisão , Resultado do Tratamento , Recidiva Local de Neoplasia/epidemiologia , Recidiva Local de Neoplasia/terapia , Recidiva Local de Neoplasia/patologia
3.
Clin Exp Dermatol ; 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38531692

RESUMO

BACKGROUND: Topical imiquimod has shown to be an effective treatment for EMPD, although available evidence supporting its use is based on case reports and small series of patients. OBJECTIVES: To investigate the therapeutic outcomes and analyze potential clinico-pathological factors associated with imiquimod response in a large cohort of EMPD patients. METHODS: Retrospective chart review of 125 EMPD patients treated with imiquimod at 20 Spanish tertiary-care hospitals. RESULTS: During the study period, patients received 134 treatment regimens with imiquimod, with 70 (52.2%) cases achieving complete response (CR), 41 (30.6%) partial response and 23 (17.2%) no response. The cumulative CR rates at 24 and 48 weeks of treatment were 46.3% and 71.8%, respectively, without significant differences between first-time and previously treated EMPD. Larger lesions (≥6 cm; p = 0.038) and EMPD affecting >1 anatomical site (p = 0.002) were significantly associated with a worse treatment response. However, the CR rate did not differ significantly by the number of treatment applications (≤4 vs. > 4 times/week; p = 0.112). Among patients who achieved CR, 30 (42.9%) developed local recurrences during a mean follow-up period of 36 months, with an estimated 3 and 5-year recurrence free-survival of 55.7% and 36.4%, respectively. CONCLUSIONS: Imiquimod appears as an effective therapeutic alternative for both first-line and previously treated EMPD lesions. However, a less favorable therapeutic response could be expected in larger lesions and those affecting >1 anatomical site. Based on our results, a 3-4 times weekly regimen of imiquimod with a treatment duration of at least 6 months could be considered an appropriate therapeutic strategy for EMPD patients.

4.
J Am Acad Dermatol ; 89(1): 119-127, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36907554

RESUMO

BACKGROUND: Satellitosis or in-transit metastasis (S-ITM) has clinical outcomes comparable to node-positivity in cutaneous squamous cell carcinoma (cSCC). There is a need to stratify the risk groups. OBJECTIVE: To determine which prognostic factors of S-ITM confer an increased risk of relapse and cSCC-specific-death. METHODS: A retrospective, multicenter cohort study. Patients with cSCC developing S-ITM were included. Multivariate competing risk analysis evaluated which factors were associated with relapse and specific death. RESULTS: Of a total of 111 patients with cSCC and S-ITM, 86 patients were included for analysis. An S-ITM size of ≥20 mm, >5 S-ITM lesions, and a primary tumor deep invasion was associated with an increased cumulative incidence of relapse (subhazard ratio [SHR]: 2.89 [95% CI, 1.44-5.83; P = .003], 2.32 [95% CI, 1.13-4.77; P = .021], and 2.863 [95% CI, 1.25-6.55; P = .013]), respectively. Several >5 S-ITM lesions were also associated with an increased probability of specific death (SHR: 3.48 [95% CI, 1.18-10.2; P = .023]). LIMITATIONS: Retrospective study and heterogeneity of treatments. CONCLUSION: The size and the number of S-ITM lesions confer an increased risk of relapse and the number of S-ITM an increased risk of specific-death in patients with cSCC presenting with S-ITM. These results provide new prognostic information and can be considered in the staging guidelines.


Assuntos
Carcinoma de Células Escamosas , Neoplasias Cutâneas , Humanos , Carcinoma de Células Escamosas/patologia , Estudos de Coortes , Estudos Retrospectivos , Prognóstico , Neoplasias Cutâneas/patologia , Recidiva Local de Neoplasia/epidemiologia , Recidiva Local de Neoplasia/patologia , Fatores de Risco , Recidiva , Estadiamento de Neoplasias
5.
Sci Justice ; 59(2): 190-198, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30798868

RESUMO

Over the past decades, consume of slimming agents considerably increased in several countries, including Brazil, due to weight-loss and stimulant properties. Since these drugs are controlled to prevent illicit and indiscriminate use, there is a parallel illegal market that uses the Internet and irregular pharmacies in order to distribute these formulations. Slimming agents produced by these illegal sources are known for being manufactured with little or none quality control resulting in uncertain and unknown formulations. For forensic purposes, apprehended pharmaceuticals have to undergo a process of chemical identification that can be difficult due to its complex matrix. In this sense, application of assisted energies in the extraction step such as microwave irradiation can be a promising method to increase the recuperation of the target molecules of the sample. Therefore, the aim of this research was to identify four slimming agents apprehended in Brazil by means of visual inspection, Fourier Transform Infrared Spectroscopy, Differential Scanning Calorimetry and Gas Chromatography - Mass Spectrometry. Moreover, the efficiency of solid-liquid extraction and microwave-assisted extraction was compared. It should be noted that our work was one of the few to use Differential Scanning Calorimetry and the application of microwave irradiation in the analysis of apprehended materials. Results showed that the majority of the samples was counterfeit being composed of one or several adulterants or contaminants. Initially, visual inspection resourcefully screened the slimming agents for possible signs of falsification, however it failed to detect fraudulent products that were very similar to veridical medicines. Sequentially, Fourier Transform Infrared Spectroscopy detected functional groups present in the samples while the presence or absence of the alleged active ingredients were successfully measured with Differential Scanning Calorimetry and, thus, providing a full chemical screening of the apprehended materials. Gas Chromatography- Mass Spectrometry confirmed the presence of adulterants such as caffeine, fluoxetine and phenolphthalein as well as contaminants such as sulfurol in the falsified samples. Finally, comparison of extraction procedures indicated that microwave-assisted extraction increased the recovery of compounds detected in chromatographic analysis to a greater extent than solid-liquid extraction.


Assuntos
Depressores do Apetite/análise , Varredura Diferencial de Calorimetria , Medicamentos Falsificados/química , Contaminação de Medicamentos , Micro-Ondas , Brasil , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Infravermelho com Transformada de Fourier
6.
Sci Justice ; 56(1): 35-41, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26746824

RESUMO

Cannabis sativa L. is cultivated in most regions of the world. In 2013, the Brazilian Federal Police (BFP) reported 220 tons of marijuana seized and about 800,000 cannabis plants eradicated. Efforts to eradicate cannabis production may have contributed to the development of a new form of international drug trafficking in Brazil: the sending of cannabis seeds in small amounts to urban centers by logistics postal. This new and increasing panorama of cannabis trafficking in Brazil, encouraged the chemical study of cannabis seeds cultivated in greenhouses by gas-chromatography coupled with mass spectrometry (GC-MS) associated with exploratory and discriminant analysis. Fifty cannabis seeds of different varieties and brands, seized by the BFP were cultivated under predefined conditions for a period of 4.5 weeks, 5.5 weeks, 7.5 weeks, 10 weeks and 12 weeks. Aerial parts were analyzed and cannabigerol, cannabinol, cannabidiol, cannabichromene Δ9-tetrahydrocannabinol (THC) and other terpenoids were detected. The chromatographic chemical profiles of the samples were significantly different, probably due to different variety, light exposition and age. THC content increased with the age of the plant, however, for other cannabinoids, this correlation was not observed. The chromatograms were plotted in a matrix with 50 rows (samples) and 3886 columns (abundance in a retention time) and submitted to PCA, HCA and PLS-DA after pretreatment (normalization, first derivative and autoscale). The PCA and HCA showed age separation between samples however it was not possible to verify the separation by varieties and brands. The PLS-DA classification provides a satisfactory prediction of plant age.


Assuntos
Canabinoides/análise , Cannabis/química , Sementes/química , Tráfico de Drogas , Cromatografia Gasosa-Espectrometria de Massas
7.
Sci Justice ; 54(5): 363-8, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25278199

RESUMO

This paper proposes a novel method for selecting subsets of wavenumbers provided by attenuated total reflectance by Fourier transform infrared (ATR-FTIR) spectroscopy able to improve the clustering of medicine samples into two groups; i.e., authentic or fraudulent. For that matter, we apply principal components analysis (PCA) to ATR-FTIR data, and derive two variable importance indices from the PCA parameters. Next, an iterative variable (i.e. wavenumbers) elimination procedure and sample clustering through k-means and Fuzzy C-means techniques are carried out; clustering performance is assessed by the Silhouette Index (SI). The performance of the proposed method is compared with a greedy variable selection method, the "leave one variable out at a time" approach, in terms of clustering quality, percent of retained variables, and computational time. When applied to Viagra ATR-FTIR data, our propositions increased the average SI from 0.5307 to 0.8603 using 0.61% of the original 661 wavenumbers; as for Cialis ATR-FTIR data, clustering quality increased from 0.7548 to 0.8681 when 1.21% of the original wavenumbers were retained in the procedure. The retained wavenumbers, located in the 1091-1046cm(-1) region, comprise the lactose typically hailed as key substance to discriminate between authentic and counterfeit samples.

8.
J Mass Spectrom ; 55(10): e4596, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32729201

RESUMO

The consumption of design drugs, frequently known as new psychoactive substances (NPS), has increased considerably worldwide, becoming a severe issue for the responsible governmental agencies. These illicit substances can be defined as synthetic compounds produced in clandestine laboratories in order to act as analogs of schedule drugs mimetizing its chemical structure and improving its pharmacological effects while hampering the control and making regulation more complicated. In this way, the development of new methodologies for chemical analysis of NPS drugs is indispensable to determine a novel class of drugs arising from the underground market. Therefore, this work shows the use of high-resolution mass spectrometry Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) applying different ionization sources such as paper spray ionization (PSI) and electrospray ionization (ESI) in the evaluation of miscellaneous of seized drugs samples as blotter paper (n = 79) and tablet (n = 100). Also, an elucidative analysis was performed by ESI(+)MS/MS experiments, and fragmentation mechanisms were proposed to confirm the chemical structure of compounds identified. Besides, the results of ESI(+) and PSI(+)-FT-ICR MS were compared with those of GC-MS, revealing that ESI(+)MS showed greater detection efficiency among the methodologies employed in this study. Moreover, this study stands out as a guide for the chemical analysis of NPS drugs, highlighting the differences between the techniques of ESI(+)-FT-ICR MS, PSI(+)-FT-ICR MS, and GC-MS.


Assuntos
Drogas Desenhadas/química , Drogas Ilícitas/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Cromatografia Gasosa-Espectrometria de Massas , Papel , Espectrometria de Massas em Tandem
9.
Forensic Sci Int ; 309: 110191, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32092622

RESUMO

The dissemination of falsified medicines is a public health risk. Techniques such as attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy are commonly adopted for fraudulent drug detection. However, the spectrum generated by the ATR-FTIR typically results in hundreds of wavenumbers, reducing the performance of classification methods aimed at discriminating between authentic and falsified medicines. This article proposes a novel method for selecting a reduced size subset of wavenumbers that improves the classifier performance. The singular value decomposition SVD is used to generate a wavenumber importance index. An iterative process creates k-nearest neighbor (KNN) models by adding the wavenumbers in a decreasing order according to the importance index. Wavenumbers that increase classification accuracy are selected. When applied to Cialis® ATR-FTIR data, the proposed approach retained average 0.51% of the original wavenumbers with 100% accurate classifications; as for the Viagra® data set, the method yielded perfect classifications retaining average 0.17% of the original wavenumbers.


Assuntos
Medicamentos Falsificados/química , Algoritmos , Humanos , Análise de Componente Principal , Espectroscopia de Infravermelho com Transformada de Fourier
10.
J Pharm Biomed Anal ; 174: 198-205, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31174131

RESUMO

In this paper, we propose a novel framework to select the most relevant X-Ray Fluorescence (XRF) energy values (i.e., features) to enhance the clustering (grouping) of counterfeit and illicit medical tablets. The framework is based on the integration of multidimensional scaling (MDS) and Procrustes analysis (PA) multivariate techniques. MDS provides a projection of the original data into a lower dimension, while PA finds a projection matrix from the original data. Such outputs give rise to a feature importance index that guides an iterative feature selection process; after each feature is inserted in the subset, an optimization procedure based on a greedy search method is carried out to maximize the clustering quality assessed through the Silhouette Index (SI). The inorganic chemical fingerprinting of 41 commercial samples (Viagra®, Cialis®, Lazar®, Libiden®, Maxfil®, Plenovit®, Potent 75®, Rigix®, V-50®, Vimax® and Pramil®) and 56 seized counterfeit samples (Viagra and Cialis) was used to validate the proposed framework. From the original 2048 data points in the full spectra, we identified a subset comprised of 41 energy values that substantially improved clustering quality; the obtained groups were assessed by visual inspection of the PCA plots.


Assuntos
Medicamentos Falsificados/análise , Inibidores da Fosfodiesterase 5/análise , Espectrometria por Raios X/métodos , Análise por Conglomerados , Análise Multivariada , Análise de Componente Principal , Citrato de Sildenafila/análise , Comprimidos , Tadalafila/análise
11.
J Pharm Biomed Anal ; 166: 304-309, 2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-30685655

RESUMO

Erectile dysfunction medicines such as Cialis and Viagra are very popular worldwide and are between the most prevalent counterfeit medicines in Brazil. A range of analytical methods has been used to analyze Cialis and Viagra, such as ATR-FTIR, GCMS and UPLC-MS. Until now, there are no data available of DSC methods for analysis of counterfeit medicines of Cialis and Viagra. DSC is a thermal analysis that provides useful information of physico-chemical events, and however is almost not used for forensic purposes. In this study, thermal analysis of 25 counterfeit Viagra and Cialis seized by Brazilian Federal Police were performed by DSC and compared to their authentic medicines and analytical standards, along with chemometric tools. Authentic samples of Viagra displayed a similar thermal profile with the API, while Cialis were different with additional endothermic peaks, that could be related to excipients interference. Thermograms of Viagra counterfeit samples were similar to authentic samples, while Cialis showed an enlargement and displacement of endothermic peaks. Also, some Cialis counterfeit samples showed melting peaks attributed to sildenafil, the API of Viagra, instead tadalafil, confirming previous results obtained by UPLC-MS. Multivariate analysis with application of Hierarchical Cluster Analysis classified different groups of samples, including a cluster with counterfeit Cialis and Viagra, indicating the use of same API for both counterfeit medicines and possibly the same illicit production; and a cluster with authentic Viagra and counterfeit Cialis, confirming the addition of sildenafil instead tadalafil to Cialis counterfeit samples. Here for the first time we described the use of DSC for chemical profiling of Cialis and Viagra and showed that even when applied to a small group of samples, DSC along with chemometric tools can be considered as a good auxiliary method in forensic casework samples. DSC provided useful data to perform the identification of counterfeit and authentic medicines, with low cost and a simple method.


Assuntos
Varredura Diferencial de Calorimetria , Medicamentos Falsificados/análise , Inibidores da Fosfodiesterase 5/análise , Citrato de Sildenafila/análise , Tadalafila/análise , Brasil , Análise por Conglomerados , Disfunção Erétil/tratamento farmacológico , Excipientes/química , Humanos , Masculino , Inibidores da Fosfodiesterase 5/normas , Análise de Componente Principal , Citrato de Sildenafila/normas , Tadalafila/normas
12.
Drug Test Anal ; 9(8): 1172-1181, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27860446

RESUMO

In forensic and pharmaceutical scenarios, the application of chemometrics and optimization techniques has unveiled common and peculiar features of seized medicine and drug samples, helping investigative forces to track illegal operations. This paper proposes a novel framework aimed at identifying relevant subsets of attenuated total reflectance Fourier transform infrared (ATR-FTIR) wavelengths for classifying samples into two classes, for example authentic or forged categories in case of medicines, or salt or base form in cocaine analysis. In the first step of the framework, the ATR-FTIR spectra were partitioned into equidistant intervals and the k-nearest neighbour (KNN) classification technique was applied to each interval to insert samples into proper classes. In the next step, selected intervals were refined through the genetic algorithm (GA) by identifying a limited number of wavelengths from the intervals previously selected aimed at maximizing classification accuracy. When applied to Cialis®, Viagra®, and cocaine ATR-FTIR datasets, the proposed method substantially decreased the number of wavelengths needed to categorize, and increased the classification accuracy. From a practical perspective, the proposed method provides investigative forces with valuable information towards monitoring illegal production of drugs and medicines. In addition, focusing on a reduced subset of wavelengths allows the development of portable devices capable of testing the authenticity of samples during police checking events, avoiding the need for later laboratorial analyses and reducing equipment expenses. Theoretically, the proposed GA-based approach yields more refined solutions than the current methods relying on interval approaches, which tend to insert irrelevant wavelengths in the retained intervals. Copyright © 2016 John Wiley & Sons, Ltd.


Assuntos
Anestésicos Locais/química , Cocaína/química , Medicamentos Falsificados/química , Citrato de Sildenafila/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Tadalafila/química , Vasodilatadores/química , Algoritmos , Anestésicos Locais/classificação , Cocaína/classificação , Medicamentos Falsificados/classificação , Drogas Ilícitas/química , Drogas Ilícitas/classificação , Citrato de Sildenafila/classificação , Tadalafila/classificação , Vasodilatadores/classificação
13.
Forensic Sci Int ; 262: 56-65, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26970868

RESUMO

Thin layer chromatography (TLC) is a simple and inexpensive type of chromatography that is extensively used in forensic laboratories for drugs of abuse analysis. In this work, TLC is optimized to analyze cocaine and its adulterants (caffeine, benzocaine, lidocaine and phenacetin) in which the sensitivity (visual determination of LOD from 0.5 to 14mgmL(-1)) and the selectivity (from the study of three different eluents: CHCl3:CH3OH:HCOOHglacial (75:20:5v%), (C2H5)2O:CHCl3 (50:50v%) and CH3OH:NH4OH (100:1.5v%)) were evaluated. Aiming to improve these figures of merit, the TLC spots were identified and quantified (linearity with R(2)>0.98) by the paper spray ionization mass spectrometry (PS-MS), reaching now lower LOD values (>1.0µgmL(-1)). The method developed in this work open up perspective of enhancing the reliability of traditional and routine TLC analysis employed in the criminal expertise units. Higher sensitivity, selectivity and rapidity can be provided in forensic reports, besides the possibility of quantitative analysis. Due to the great simplicity, the PS(+)-MS technique can also be coupled directly to other separation techniques such as the paper chromatography and can still be used in analyses of LSD blotter, documents and synthetic drugs.


Assuntos
Cocaína/química , Contaminação de Medicamentos , Entorpecentes/química , Benzocaína/análise , Cafeína/análise , Cromatografia em Camada Fina , Humanos , Lidocaína/análise , Espectrometria de Massas/métodos , Fenacetina/análise
14.
Forensic Sci Int ; 242: 111-116, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25047218

RESUMO

ATR-FTIR spectra may include a large number of noisy and correlated wavenumbers that tend to affect and reduce the performance of exploratory and classificatory multivariate techniques. We propose a method based on Partial Least Square Discriminant Analysis (PLS-DA) for identifying the relevant subsets of ATR-FTIR wavenumbers aimed at classifying Viagra and Cialis into authentic or fraudulent categories. In our propositions, the PLS-DA is applied to ATR-FTIR data, and four indices aimed at evaluating wavenumber importance are derived from PLS-DA parameters. Next, an iterative wavenumber elimination and classification procedure integrating PLS-DA and the proposed indices is carried out: the wavenumber with the smallest index is removed, and a new classification is performed using the remaining wavenumbers. The classification performance is assessed through multiple criteria, i.e., sensitivity, specificity and percent of wavenumbers retained; the recommended wavenumber subset is chosen based on the distance between the candidate subsets and a hypothetical ideal solution. The proposed method significantly reduced the percent of wavenumbers to be assessed, and slightly improved classification performance for Viagra and Cialis data when compared to classification on all the original wavenumbers.

15.
Forensic Sci Int ; 235: 1-7, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24447444

RESUMO

Several analytical techniques aimed at profiling drugs are deemed costly and time consuming, and may not be promptly available for analysis when required. This paper proposes a method for identifying the analytical techniques providing the most relevant data for classification of drug samples into authentic and unauthentic categories. For that matter, we integrate principal components analysis (PCA) to k-Nearest Neighbor (KNN) and Support Vector Machine (SVM) classification tools. PCA is first applied to data from five techniques, i.e., physical profile, X-ray fluorescence (XRF), direct infusion electrospray ionization mass spectrometry (ESI-MS), active pharmacological ingredients profile (ultra performance liquid chromatography, UPLC-MS), and infrared spectroscopic profile (ATR-FTIR). Subsets of PCA scores are then combined with a "leave one subset out at a time" approach, and the classification accuracy using KNN and SVM evaluated after each subset is omitted. Subsets yielding the maximum accuracy indicate the techniques to be prioritized in profiling applications. When applied to data from Viagra and Cialis, the proposed method recommended using the data from UPLC-MS, physical profile and ATR-FTIR techniques, which increased the categorization accuracy. In addition, the SVM classification tool is suggested as more accurate when compared to the KNN.

16.
J Anal Toxicol ; 38(7): 432-7, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25038769

RESUMO

Brazil is considered one of the countries with the highest number of amphetamine-type stimulant (ATS) users worldwide, mainly diethylpropion (DIE) and fenproporex (FEN). The use of ATS is mostly linked to diverted prescription stimulants and this misuse is widely associated with (ab)use by drivers. A validated method was developed for the simultaneous analysis of amphetamine (AMP), DIE and FEN in plasma samples employing direct immersion-solid-phase microextraction, and gas chromatographic/mass spectrometric analysis. Trichloroacetic acid 10% was used for plasma deproteinization. In situ derivatization with propylchloroformate was employed. The linear range of the method covered from 5.0 to 100 ng/mL. The detection limits were 1.0 (AMP), 1.5 (DIE) and 2.0 ng/mL (FEN). The accuracy assessment of the control samples was within 85.58-108.33% of the target plasma concentrations. Recoveries ranged from 46.35 to 84.46% and precision was <15% of the value of relative standard deviation. This method is appropriate for screening and confirmation in plasma forensic toxicology analyses of these basic drugs.


Assuntos
Anfetaminas/sangue , Estimulantes do Sistema Nervoso Central/sangue , Dietilpropiona/sangue , Detecção do Abuso de Substâncias/métodos , Adulto , Anfetamina/sangue , Brasil , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Limite de Detecção , Masculino , Reprodutibilidade dos Testes , Microextração em Fase Sólida
17.
J Pharm Biomed Anal ; 83: 209-14, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23770779

RESUMO

Attenuated total reflectance (ATR), a sampling technique by Fourier transform infrared (FTIR) spectroscopy, has been adopted as an analytical tool for detecting fraudulent medicines. The spectrum generated by FTIR-ATR typically relies on hundreds of equally spaced wavenumbers which may reduce the performance of techniques tailored to classify samples into classes, i.e., authentic or fraudulent. This paper proposes a novel method for selecting subsets of wavenumbers (variables) that better classify samples into such classes. For that matter, principal components analysis (PCA) is integrated to the k-nearest neighbor (KNN) classification technique. PCA is applied to FTIR-ATR data, and a variable importance index is built on the PCA outputs. An iterative backward variable elimination is started guided by that index; after each variable removal, samples are categorized into authentic or fraudulent classes using KNN, and the classification accuracy is measured. The wavenumber subset compromising high accuracy and reduced percent of retained variables is chosen. When applied to Cialis FTIR-ATR data, the proposed approach retained only average 1.84% of the original variables and increased the classification accuracy average 2.1%, to 0.9897 from 0.9689; as for Viagra data, the method increased average classification accuracy 1.56%, from 0.9135 to 0.9278, using only 7.72% of the original variables.


Assuntos
Medicamentos Falsificados/química , Preparações Farmacêuticas/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise de Componente Principal/métodos
18.
Forensic Sci Int ; 226(1-3): 282-9, 2013 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-23422165

RESUMO

This paper proposes a direct and efficient method to discriminate between counterfeit and authentic Cialis and Viagra samples by combining attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy with multivariate techniques. The chemical profile of 53 commercial samples (Viagra(®), Cialis(®)) and 104 counterfeit samples (Viagra and Cialis) from distinct seizures were obtained from ATR-FTIR data derived from 10mg of crushed core tablets. Principal component analysis (PCA) technique was employed to classify samples based on the fingerprint region mid-infrared spectra (1800-525 cm(-1)) using OMNIC v.7.2 software; PCA enabled categorizing samples in groups with different chemical profiles, successfully distinguishing between authentic and counterfeits samples in forensic routine. The existence of active pharmaceutical ingredients (API) and technological adjuvant others than specified on the medicine package were also detected in counterfeit samples. In addition, we applied the similarity match (SM) method to demonstrate that a mixture of pharmaceutical powders deriving from a common origin may have been used to manufacture both counterfeit Cialis and Viagra tablets from distinct seizures.

19.
Forensic Sci Int ; 229(1-3): 13-20, 2013 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-23683904

RESUMO

In this work, the chemical profile of 43 commercial samples of tablets for male erectile dysfunction (Viagra, Cialis, Lazar, Libiden, Maxfil, Plenovit, Potent 75, Rigix, Vimax, Pramil 75 and Pramil) and 65 counterfeit samples (Viagra and Cialis) were obtained from UPLC-MS data. Methanol extracts of crushed tablets were investigated by ultra performance liquid chromatography (UPLC) with diode array detection (DAD) coupled with eletrospray ionization in the positive ion mode (ESI(+)) quadrupole time-of-flight (Q-Tof) mass spectrometry (MS). A validated method was employed for the simultaneous determination of sildenafil citrate (SLD) and tadalafil (TAD). The ultra-chromatograms obtained with method provide high resolution of MS, and are a quick (less to 1.5 min) and reliable tool in the distinction between authentic and counterfeit tablets. It was observed in most cases the presence of other active pharmaceutical ingredients (APIs) than specified on the package (TAD and SLD). Additionally, high concentrations of TAD and SLD were detected in counterfeit samples when compare with observed values for a typical commercial product. Chemometric methods were employed and the samples were grouped in five groups as function of API content.

20.
Forensic Sci Int ; 229(1-3): 23-6, 2013 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-23683905

RESUMO

Brazil is one of the world's highest users of anorectic drugs, mainly diethylpropione, fenproporex and sibutramine. The present work focuses on physical and chemical characteristics of 17 counterfeited capsules containing amphetamine-type stimulants (ATS) from three seizures conducted by Brazilian Federal Police. The physical profile was useful in indicating forgery, bring complementary information, but the use of this data singly was not sufficient to distinguish between authentic and counterfeited medicines. The chemical analysis revealed that the seizures capsules labeled as Desobesi-M (fenproporex 25mg), actually contained the active pharmaceutical ingrediente (API) sibutramine. The amount of this API ranged from 1/3 to 2 times the amount of drug found in commercial product, may reach twice the recommended daily dose. Multivariate analysis with application of principal component analysis on data from spectroscopy attenuated total reflectance Fourier transform infrared classified the samples according to their similarities, indicating that two seizures had common origin. This study represents the first step in the elucidation of falsification of ATS in Brazil. Considering the forensic intelligence these information are valuable in order to develop and establish a database that enables correlate samples from different locations and/or suppliers and to map the profile and trends of trafficking.

SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa