1,720,981 research outputs found
Development of dissolving and hydrogel-forming microneedles for delivery of vancomycin hydrochloride
No full textPemanfaatan Nanoteknologi dalam Sistem Penghantaran Obat Baru untuk Produk Bahan Alam
Get PDFSejak dahulu banyak ekstrak dari bahan alam yang secara empiris dimanfaatkan untuk pengobatan. Ekstrak-ekstrak tersebut digunakan karena mengandung senyawa bioaktif yang dapat memberikan efek farmakologis. Isolat dari ekstrak tersebut diuji baik secara in vitro maupun in vivo untuk mengetahui efek dan bioavailabilitas dalam tubuh secara ilmiah. Namun demikian diperkirakan lebih dari 40% senyawa bahan alam memiliki kelarutan yang rendah di dalam air atau bahkan memberikan toksisitas yang tinggi. Kelarutan yang rendah di dalam air serta kurangnya kemampuan permeabilitas menembus barrier absorpsi dapat mempengaruhi bioavailabilitas senyawa bahan alam di dalam tubuh. Tidak hanya itu, bioavailabilitas suatu senyawa juga sangat dipengaruhi oleh stabilitas terhadap pH lambung dan kolon, metabolisme oleh mikroflora normal dalam saluran pencernaan, absorpsi melalui dinding usus, mekanisme aktif pompa efflux dan metabolisme lintas pertama. Solusi dari permasalahan tersebut adalah dengan mengembangkan sistem penghantaran obat yang dikenal dengan sistem penghataran obat baru (novel drug delivery system). Sistem penghantaran obat baru merupakan suatu sistem penghantaran obat yang lebih modern dengan cara mengontrol pelepasan obat sehingga aktivitas farmakologis menjadi lebih baik. Pembuatan sediaan berbasis teknologi baru ini dapat menjadi alternatif dalam pembuatan produk herbal dan diharapkan bioavailabilitas produk herbal dalam tubuh menjadi lebih baik sehingga dapat memberikan efek terapi yang lebih baikNatural products have been known to have a major role in maintaining health. Some studies reported that they demonstrated various pharmacological activities and provided a lead compound or drug candidate. Isolated compounds from the extracts have been studied both in vitro and in vivo to determine their effects and bioavailability in the body. However, more than 40% natural products have low solubility in water, or even give a high toxicity. Low solubility in water and the lack of ability to penetrate the absorption barrier may affect the bioavailability in the body. Furthermore, the bioavailability of a compound is also influenced by the stability of drugs in the pH of the stomach and colon, metabolism by normal microflora in the digestive tract, absorption through the intestinal wall, efflux pumps mechanism and first-pass metabolism. Solution to overcome these problems is by developing a drug delivery system known as a novel drug delivery system (NDDS). The NDDS is a more modern system to control the release of drugs so that it will give better pharmacological activity. Making dosage forms based on this novel technology can be an alternative for manufacturing herbal products. It can increase their bioavailability in the body so that it can provide a better therapeutic effect
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
THE EFFECT OF ANTICOAGULANT TYPES ON THE IN VITRO ANALYSIS OF CLOPIDOGREL IN HUMAN PLASMA USING LIQUID CHROMATOGRAPHY TANDEM-MASS SPECTROMETRY
Get PDFObjective: The aim of this study was to optimize and validate a plasma clopidogrel analysis method using liquid chromatography tandem-massspectrometry.Methods: Plasma samples were analyzed using a BEH C18 column (1.7 μm; 100 mm×2.1 mm), the mobile phase was 0.1% formic acid in acetonitrile(30:70, v/v). The flow rate was 0.2 mL/min, with a column temperature set to 35°C, an injection volume of 5 μL, an analysis time of 4 min, andirbesartan as the internal standard. Aliquots were obtained by liquid-liquid extraction using ammonium acetate and diethyl ether. The stability andpeak area ratio of the respective plasma area responses were evaluated using ANOVA.Results: No significant differences (p>0.05) were observed between anticoagulants regarding analyte stability. However, the peak area ratioshowed significant differences (p<0.05) between the anticoagulants. The accuracy and precision of the analysis with citrate, heparin, andethylenediaminetetraacetic acid (EDTA) plasma met the quality requirements, and a linear calibration curve was created with concentrations rangingfrom 0.02 to 5.0 ng/mL.Conclusion: The results showed that improved analysis of clopidogrel was achieved using citrate or heparin plasma compared with EDTA plasma
FORMULATION OF A CREAM CONTAINING ETHOSOMAL GREEN TEA (CAMELLIA SINENSIS L. KUNTZE) LEAF EXTRACTS FOR IMPROVED DERMAL PENETRATION
Get PDFObjective: This study aimed to formulate the epigallocatechin gallate (EGCG) from green tea into ethosomes and measure the resulting increases inskin penetration using a rat model.Methods: Ethosomes were formulated using ethanol concentrations of 25% (F1), 30% (F2), and 35% (F3), and those with favorable characteristicswere then incorporated into a cream for the determination of penetration into Franz diffusion cells.Results: We showed that the formulation F3 had the best spherical morphology, a Z-average value of 73.01 nm, a polydispersity index of 0.26, azeta potential of −47.77±3.93 mV, and the highest percentage of drug entrapment (49.46%±0.62%) compared with the other formulas. The totalcumulative EGCG penetration from the resulting ethosomal cream was 905.75±49.47 μg/cm2, whereas that from the cream containing green tea leafextract was only 413.92±52.83 μg/cm2.Conclusion: These data indicate a higher penetration of EGCG from ethosomal green tea cream than from cream containing non-ethosomal green teaextract
MICROENCAPSULATION OF GRAPE SEED OIL (VITIS VINIFERA L.) WITH GUM ARABIC AS A COATING POLYMER BY CROSSLINKING EMULSIFICATION METHOD
Get PDFObjective: Grape seed oil (GSO) from Vitis vinifera L. is a liquid vegetable oil which has been used mainly for its linoleic acid content. However, there are many efforts to convert the liquid form of the oil into a solid form due to the instability under storage condition. The aim of this study was to convert GSO into the solid microcapsules by emulsion crosslinking method with gum arabic as a coating polymer.Methods: The GSO was formulated with gum arabic in the ratios of 1:2, 1:3, 1:4, and 1:5. Gum arabic solution was emulsified with GSO using Span 80 and glutaraldehyde. The emulsion was dropped into a beaker glass of isopropyl alcohol to form microcapsules. The microcapsules were dried at 70 °C. Then, they were characterized in terms of morphology, particle size, swelling index, water content, and entrapment efficiency.Results: The produced microcapsules of GSO showed white yellowish color and spherical shape. The particle size of F1, F2, F3 and F4 microcapsules were 69 μm, 82 μm, 125 μm, and 131 μm, respectively. The water content of the F1–F4 ranged from 4.37±0.34 to 5.70±0.92% and swelling indexes were ranged from 5.54±0.01 to 5.94±0.04. The value of entrapment efficiency of F1, F2, F3, and F4 were 17.33±0.603, 20.73±0.678, 34.22±1.195, and 67.15±2.019%, respectively.Conclusion: The results of this investigation showed that GSO could be converted into the solid spherical microcapsules by emulsion crosslinking method using gum arabic. Taken together, this study has provided the most promising formulation of GSO microcapsules for further production in pharmaceutical industry
METHOD DEVELOPMENT AND VALIDATION OF CEFOPERAZONE AND SULBACTAM IN DRIED BLOOD SPOTS BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY PHOTODIODE ARRAY DETECTOR
Get PDFObjective: The primary purpose of this research was to develop a simple, precise, fast, and accurate method for measuring cefoperazone and sulbactam simultaneously in dried blood spots (DBS) using HPLC PDA.
Methods: A simplified analytical method for quantifying cefoperazone and sulbactam in DBS samples using a High-Performance Liquid Chromatography photodiode array detector with isocratic elution was developed and validated. The best chromatographic conditions were obtained by using a reversed-phase column (250 x 4.6 mm; 5 mm); phosphate buffer 10 mmol pH 3.2–acetonitrile (83:17, v/v) as a mobile phase; a flow rate of 1.0 ml/min; a column temperature of 35 °C; a photodiode array detector at 210 nm, and cefuroxime as internal standard. Samples were prepared by liquid-liquid extraction with 100 ml hydrochloric acid 0.5 mol/l and 1000 ml ethyl acetate, evaporated with nitrogen and reconstituted with 100 mL phosphate buffer–acetonitrile (4:1).
Results: The total chromatography run time was 15 min, and the elution times for sulbactam, cefoperazone, and IS (cefuroxime) were 3.46, 10.221, and 6.987 min, respectively. A linear response function was established at 0.5-30 mg/ml with (r) 0.995 for sulbactam and 2.5-250 mg/ml with (r) 0.999 for cefoperazone in dried blood spots. The lower limit quantification (LLOQ) concentration of sulbactam 1 mg/ml and cefoperazone were 5 mg/ml.
Conclusion: This method has successfully fulfilled the validation requirement referring to the 2011 EMA and 2018 FDA guidelines
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