Electrically–transduced sensors, with their simplicity and compatibility with standard electronic technologies, produce signals that can be efficiently acquired, processed, stored, and analyzed. Two dimensional (2D) nanomaterials, including graphene, phosphorene (BP), transition metal dichalcogenides (TMDCs), and others, have proven to be attractive for the fabrication of high–performance electrically-transduced chemical sensors due to their remarkable electronic and physical properties originating from their 2D structure. This review highlights the advances in electrically-transduced chemical sensing that rely on 2D materials. The structural components of such sensors are described, and the underlying operating principles for different types of architectures are discussed. The structural features, electronic properties, and surface chemistry of 2D nanostructures that dictate their sensing performance are reviewed. Key advances in the application of 2D materials, from both a historical and analytical pers...

Electrically-Transduced Chemical Sensors Based on Two-Dimensional Nanomaterials

Optimization and validation of a quantitative liquid chromatography-tandem mass spectrometric method covering 295 bacterial and fungal metabolites including all regulated mycotoxins in four model food matrices.

Methods to determine limit of detection and limit of quantification in quantitative real-time PCR (qPCR).

Pharmaceutical Statistics: Practical and Clinical Applications

This paper reports turn-off fluorescence sensor for Fe3 + ion in water using fluorescent N-doped carbon dots as a probe. A simple and efficient hydrothermal carbonization of Prunus avium fruit extract for the synthesis of fluorescent nitrogen-doped carbon dots (N-CDs) is described. This green approach proceeds quickly and provides good quality N-CDs. The mean size of synthesized N-CDs was approximately 7 nm calculated from the high-resolution transmission electron microscopic images. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy revealed the presence of –OH, –NH2, –COOH, and –CO functional groups over the surface of CDs. The N-CDs showed excellent fluorescent properties, and emitted blue fluorescence at 411 nm upon excitation at 310 nm. The calculated quantum yield of the synthesized N-CDs is 13% against quinine sulfate as a reference fluorophore. The synthesized N-CDs were used as a fluorescent probe towards the selective and sensitive detection of biologically important Fe3 + ions in water by fluorescence spectroscopy and for bio-imaging of MDA-MB-231 cells. The limit of detection (LOD) and the Stern–Volmer quenching constant for the synthesized N-CDs were 0.96 μM and 2.0958 × 103 M of Fe3 + ions. The green synthesized N-CDs are efficiently used as a promising candidate for the detection of Fe3 + ions and bio-imaging.

Turn-off fluorescence sensor for the detection of ferric ion in water using green synthesized N-doped carbon dots and its bio-imaging.

The quality of an analytical method developed is always appraised in terms of suitability for its intended purpose, recovery, requirement for standardization, sensitivity, analyte stability, ease of analysis, skill subset required, time and cost in that order. It is highly imperative to establish through a systematic process that the analytical method under question is acceptable for its intended purpose. Limit of detection (LOD) and limit of quantification (LOQ) are two important performance characteristics in method validation. LOD and LOQ are terms used to describe the smallest concentration of an analyte that can be reliably measured by an analytical procedure. There has often been a lack of agreement within the clinical laboratory field as to the terminology best suited to describe this parameter. Likewise, there have been various methods for estimating it. The presented review provides information relating to the calculation of the limit of detection and limit of quantitation. Brief information about differences in various regulatory agencies about these parameters is also presented here.

Methods for the determination of limit of detection and limit of quantitation of the analytical methods

In benign prostatic hyperplasia (BPH) there will be a sudden impact on overall quality of life of patient. This disease occurs normally at the age of 40 or above and also is associated with sexual dysfunction. Thus, there is a need of update on current medications of this disease. The presented review provides information on medications available for BPH. Phytotherapies with some improvements in BPH are also included. Relevant articles were identified through a search of the English-language literature indexed on MEDLINE, PUBMED, Sciencedirect and the proceedings of scientific meetings. The search terms were BPH, medications for BPH, drugs for BPH, combination therapies for BPH, Phytotherapies for BPH, Ayurveda and BPH, BPH treatments in Ayurveda. Medications including watchful waitings, Alpha one adrenoreceptor blockers, 5-alpha reductase inhibitors, combination therapies including tamsulosin-dutasteride, doxazosin-finasteride, terazosin-finasteride, tolterodine-tamsulosin and rofecoxib-finasteride were found. Herbal remedies such as Cernilton, Saxifraga stolonifera, Zi-Shen Pill (ZSP), Orbignya speciosa, Phellodendron amurense, Ganoderma lucidum, Serenoa Repens, pumpkin extract and Lepidium meyenii (Red Maca) have some improvements on BPH are included. Other than these discussions on Ayurvedic medications, TURP and minimally invasive therapies (MITs) are also included. Recent advancements in terms of newly synthesized molecules are also discussed. Specific alpha one adrenoreceptor blockers such as tamsulosin and alfuzosin will remain preferred choice of urologists for symptom relief. Medications with combination therapies are still needs more investigation to establish as preference in initial stage for fast symptom relief reduced prostate growth and obviously reduce need for BPH-related surgery. Due to lack of proper evidence Phytotherapies are not gaining much advantage. MITs and TURP are expensive and are rarely supported by healthcare systems.

Various treatment options for benign prostatic hyperplasia: A current update

The current study was carried out with an attempt to separate similarly structured title drugs by liquid chromatography. Spectrophotometric techniques were generally insufficient under these conditions because of the spectral overlapping of drugs with similar functional groups. The pharmaceutical drugs prazosin, terazosin, and doxazosin contain the same parent quinazoline nucleus, thus making it especially difficult to separate the former two drugs because of their very similar structures. A simple and sensitive method for the routine determination of these drugs in pharmaceutical formulations was attempted. We found that the mobile phase consisting of A: ACN–diethylamine (0.05 ml), B: methanol, and C: 10 mM Ammonium acetate separated these drugs effectively. Separations were carried out on a new Kromasil C18 column (250 × 4.6 mm, 5.0 μm) at 254 nm wavelength. The calibration curve was found to be linear in the range of 2–500 μg/ml. The stated method was then validated in terms of specificity, linearity, precision, and accuracy. Additionally, the proposed method reduced the duration of the analysis.

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Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Prazosin, Terazosin, and Doxazosin in Pharmaceutical Formulations.

A new spectrophotometric method for the estimation of tamsulosin hydrochloride in pharmaceutical dosage forms has been developed and validated. The method is based on reaction between drug and bromophenol blue and complex was measured at 421 nm. The slope, intercept and correlation coefficient was found to be 0.054, -0.020 and 0.999, respectively. Method was validated in terms of specificity, linearity, range, precision and accuracy. The developed method can be used to determine drug in both tablet and capsule formulations. Reaction was optimized using three parameters i.e., concentration of the dye, pH of the buffer, volume of the buffer and shaking time. Maximum stability of the chromophore was achieved by using pH 2 and 2 ml volume of buffer. Shaking time kept was 2 min and concentration of the dye used was 2 ml of 0.05% w/v solution. Method was validated in terms of linearity, precision, range, accuracy, LOD and LOQ and stochiometry of the method was also established using Mole ratio and Job's method of continuous variation. The dye benzonoid form (blue color) of dye ionized into quinonoid form (purple color) in presence of buffer and reacts with protonated form of drug in 1:1 ratio and forms an ion-pair complex (yellow color).

Spectrophotometric estimation of tamsulosin hydrochloride by acid-dye method

Background: Although initially introduced for the management of hypertension, � l-adrenergic-receptor antagonists (� l- blockers) have become the standard of care for the medical management of benign prostatic hyperplasia (BPH) related lower urinary tract symptoms (LUTS). Alpha-blockers (alfuzosin, tamsulosin, doxazosin, prazosin and terazosin) relax the smooth muscles in the prostate and are indicated for the symptomatic treatment of BPH due to evidence of their positive and rapid effect on LUTS. However, these agents have the potential to produce orthostatic hypotension and other blood pressure-related adverse effects in normotensive patients and in those receiving concurrent treatment with other antihyper- tensive agents. As a result, more "uroselective," less vasoactivel-blockers have been developed such as tamsulosin and alfuzosin. Objective: The presented review provides information about the various analytical methods available in the literature to the scientists and health professionals engaged in research relating these drugs such as clinical trials or developing new formulations. Various analytical methods for the estimation of these drugs in bulk or in various matrices like blood, se- rum, plasma, alone or in combination with other drugs is discussed. Methods: Relevant articles were identified through a search of the English-language literature indexed in MEDLINE, PubMed, Sciencedirect and the proceedings of scientific meetings from 1977 to 2010. The search terms were benign esti- mation of alpha one blockers, determination of prazosin, terazosin, tamsulosin, doxazosin, alfuzosin. Similarly HPLC and Spectroscopy methods for estimation of prazosin, terazosin, tamsulosin, doxazosin, alfuzosin. Results: Total 57 analytical methods were found. 11 spectrophotometry, 39 chromatographic methods including 2 ESI MS/MS, 1 ESI MS, 2 HPTLC, 3 TLC, 17 HPLC with UV, 9 with fluorescence, 1 with electrochemical detection, 4 with MS detector. Other than this 3 voltametry, 1 method each for radioreceptor assay, polarography, capillary electrophoresis and potentiometry titrations were found. Conclusion: Radioreceptor assay, LC-MS, UPLC-MS methods were found to be the most sensitive for prazosin, terazosin and doxazosin respectively. Likewise, HPLC-MS-MS methods was found as most sensitive method for estimation of tam- sulosin and alfuzosin.

Vipin B. Gupta

Papers

Methods for the determination of limit of detection and limit of quantitation of the analytical methods

Various treatment options for benign prostatic hyperplasia: A current update

Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Prazosin, Terazosin, and Doxazosin in Pharmaceutical Formulations.

Spectrophotometric estimation of tamsulosin hydrochloride by acid-dye method

A Review on Various Analytical Methods on Some Alpha Adrenergic Antagonists