Surface plasmon resonance (SPR) offers exceptional advantages such as label-free, in-situ and real-time measurement ability that facilitates the study of molecular or chemical binding events. ...Besides, SPR lacks in the detection of various binding events, particularly involving low molecular weight molecules. This drawback ultimately resulted in the development of several sensitivity enhancement methodologies and their application in the various area. Among graphene materials, graphene-based nanocomposites stands out owing to its significant properties such as strong adsorption of molecules, signal amplification by optical, high carrier mobility, electronic bridging, ease of fabrication and therefore, have established as an important sensitivity enhancement substrate for SPR. Also, graphene-based nanocomposites could amplify the signal generated by plasmon material and increase the sensitivity of molecular detection up to femto to atto molar level. This review focuses on the current important developments made in the potential research avenue of SPR and fiber optics based SPR for chemical and biological sensing. Latest trends and challenges in engineering and applications of graphene-based nanocomposites enhanced sensors for detecting minute and low concentration biological and chemical analytes are reviewed comprehensively. This review may aid in futuristic designing approaches and application of grapheneous sensor platforms for sensitive plasmonic nano-sensors.
Graphene nanocomposites based sensitivity enhancement methodologies for chemical and biological sensing. (a) oxidant and reducing gases sensing by oxygen atom of GO with surface reaction mechanism. (b) Protein binding interaction directly on GNC (grapheneous nanocomposites) surface. (c) Antigen: antibody (Ag:Ab) reaction of directly immobilized Ag:Ab on to GNC. (d) pi-pi stacking for planer structure. (e) Hydrogen or electrostatics attraction based binding (f) direct sensing of molecules (shown here for ammonia gas). Display omitted
•Presents graphene nanocomposite based SPR sensors.•Recent progresses in SPR signal enhancement by graphene nanocomposites has been overviewed.•Graphene nanocomposites based sensitivity enhancement methodologies for chemical and biological sensing is reviewed.•In this review, we discussed future trends and perspectives to lay down the future SPR based plasmonic nano-sensors.
Monoamine oxidase (MAO) enzyme inhibition is a crucial target for the management of depression and Alzheimer disease and inhibitors of MAO are the most important drugs for their management. Coumarins ...are a large family of compounds, of natural and synthetic origin, that exhibit a variety of pharmacological activities, including MAO inhibition. The current review highlights the design and synthetic methods of coumarin derivatives as well as coumarins obtained from plant source as MAO inhibitors for treatment of depression and Alzheimer disease with salient finding related to structure–activity relationship. The aim of present review is to find out natural as well as synthetic coumarins as MAO inhibitors.
Topical route of administration is very important and the most commonly used method of drug delivery for treatment of ocular diseases. However, due to unique anatomical and physiological barriers of ...eye, it is difficult to achieve the therapeutic concentration in the targeted tissue within the eye. To overcome the effect of these barriers in absorption and to provide targeted and sustained drug delivery, various advances have been made in developing safe and efficient drug delivery systems. Various formulation strategies for ocular drug delivery are used, like basic formulation techniques for improving availability of drugs, viscosity enhancers, and use of mucoadhesives for drug retention and penetration enhancers to promote drug transport to the eye. In this review, we present a summary of the current literature to understand the anatomical and physiological limitations in achieving adequate ocular bioavailability and targeted drug delivery of topically applied drugs and use of new techniques in formulating dosage forms in overcoming these limitations. The recent and future advances in nanocarrier-mediated drug delivery may have the potential to provide patient-friendly and noninvasive techniques for the treatment of diseases related to the anterior and posterior segments of the eye.
Nasal delivery is the promising approach for rapid onset of action and avoids the first pass metabolism. The main aim of present study was to develop a novel mucoadhesive in situ gel of salbutamol ...sulphate using gellan gum and hydroxylpropyl methyl cellulose (HPMC) for nasal administration. The formulations were prepared so as to have gelation at physiological ion content after nasal administration. Developed formulations were evaluated for gelation, viscosity, drug content, in vitro mucoadhesion, in vitro drug release study, ex vivo permeation, and histopathology. Formulations showed pH in the range of nasal cavity and optimum viscosity for nasal administration. The mucoadhesive force depends upon concentration of HPMC and drug release was found to be 97.34% in 11h. The histopathology did not detect any damage during ex vivo permeation studies. Hence, in situ gel system of gellan gum may be a promising approach for nasal delivery of salbutamol sulphate for therapeutic improvement.
•Nebivolol hydrochloride is an antihypertensive BCS class II drug.•Cocrystals with 4-hydroxy benzoic acid and nicotinamide were prepared.•Liquid assisted grinding and solvent evaporation method was ...used.•The problem of low solubility and dissolution can be solved with cocrystals.
Nebivolol hydrochloride is BCS class II drug with low solubility and high permeability prescribed as antihypertensive. Crystal engineering was applied to prepare novel cocrystal forms of nebivolol hydrochloride with general GRAS (Generally regarded as safe) molecules. Pharmaceutical cocrystals of nebivolol hydrochloride were prepared with GRAS molecules, such as 4-hydroxybenzoic acid and nicotinamide (NA), with different ratios like 1:1, 1:2, 1:3. Liquid assisted grinding and solvent evaporation method was used to prepare nebivolol hydrochloride cocrystals. All prepared crystalline forms were characterized by X-ray diffraction, differential scanning calorimetry, and FT-IR to confirm their purity and formation of cocrystals. X-ray crystal data provided details of hydrogen bonding and interactions between drug and co-formers and differential scanning calorimetry provided changes in thermal behaviour and formation of cocrystals. Physicochemical properties such as solubility and dissolution rate were measured and found that all the co-crystals dissolved faster and their equilibrium solubility is higher than the parent drug. Nebivolol hydrochloride - 4-hydroxy benzoic acid cocrystals showed highest solubility among all crystalline forms.
The present work aims to develop mucoadhesive thermosensitive nasal
gel for Promethazine hydrochloride using quality by design (QbD) approach. It can reduce nasal mucociliary clearance (MCC) and ...increase residence of the drug on nasal mucosa. This might increase drug absorption to improve bioavailability of the drug as compared to oral dosage form.
Promethazine hydrochloride is an antiemetic drug administered by oral, parenteral and rectal routes. These routes have poor patient compliance or low bioavailability. Nasal route is a better alternative as it has large surface area, high drug absorption rate and no first pass effect. Its only limitation is short drug retention time due to MCC. By formulating a mucoadhesive
gel, the MCC can be reduced, and drug absorption will be prolonged. Thus, improving bioavailability.
gel was prepared by cold method having material attributes as concentration of Poloxamer 407 (X
) as gelling agent and hydroxypropyl methyl cellulose K4M (X
) as mucoadhesive agent. Critical Quality Attributes (CQA) were gelation temperature, mucoadhesive force and
diffusion. Central composite design (CCD) was adopted for optimization.
Optimized formulation satisfied all the CQA significant for nasal administration. Moreover, the formulation was found to be stable in accelerated stability studies for 3 months.
It can be concluded that since the drug can easily permeate through nasal mucosa and can gain access directly in the brain without undergoing first pass metabolism along with increased residence due to mucoadhesion, mucoadhesive
gel has potential to increase drug bioavailability.
This paper presents the identification and classification of Indian agricultural crop species using a novel combined local binary histogram pattern of gradient (LBHPG) image feature extraction ...technique. Initially, a partition of the leaf image background is done through the newly developed fast adaptive fuzzy C-mean clustering (FAFCM) technique. After that, leaf objects within the image are identified using the LBHPG method. For the classification, KNN, PNN, and SVM shallow machine learning classifiers are used for crop species identification. The performance evaluation is done using LBP and HOG individually along with the new proposed LBHPG technique for classification using KNN, PNN, and SVM Classifiers. The performance evaluation is based on six metrics parameters of the confusion matrix, viz., accuracy, sensitivity, specificity, precision, recall, and F-measure. The experimental results show that the proposed novel LBHP feature extraction technique with PNN Classifier gives the highest accuracy of 94.58%.
The natural stilbenoids combretastatin A-4 (CA4) and combretastatin A-1 (CA1) are potent antitubulin agents demonstrating antimitotic activity as well as tumor vascular disruption property. Due to ...structural simplicity and potent cytotoxicity of CA4 and CA1, they are considered as promising leads for the development of potent anticancer agents. In fact, scientific fraternity is motivated to synthesize several derivatives of CA4 and CA1 as novel therapeutic agents. In the literature, several studies have been carried out to evaluate the medicinal chemistry, pharmacology and structure-activity relationships (SAR) of a variety of modified combretastatin derivatives. The present report aimed at comprehensively revising the recent advancements (2006-2014) in the medicinal chemistry and SAR of diversified combretastatin analogues. The published data concerning new combretastatin A-4 analogues as antimitotic anticancer agents are presented and SAR is reviewed and discussed.
Stimuli-sensitive layer-by-layer (LbL) self-assembly systems have generated much interest among researchers worldwide due to the simplicity of the process by which they are produced and their ...numerous applications in drug delivery. LbL self-assembly systems involve simple alternative adsorption of oppositely charged polyelectrolytes on core materials and are thus considered to be promising tools for drug delivery and biosensing. Here, we discuss the latest findings from research into LbL systems, with special emphasis on drug delivery systems. This review highlights various stimuli-responsive LbL systems and their targeting and biosensory applications. For the convenience of readers, these stimuli-responsive LbL systems are classified as exogenous stimuli-responsive LbL systems and endogenous stimuli-responsive LbL systems.
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Rheumatoid arthritis is a chronic condition that is characterized by joint pain and inflammation. It is an autoimmune disorder in which the body tissues are erroneously attacked by the immune system ...of the host itself. It has been evident that rheumatoid arthritis symptoms follow a 24 h circadian rhythm and exhibit high thresholds of pain, functional disability, and stiffness predominantly early in the morning. Colon-specific drug delivery systems can be utilized in the formulations to be used in the treatment of rheumatoid arthritis. The colon-specific drug delivery system has shown promising results in the treatment of different diseases at the colonic site like Crohn’s disease, ulcerative colitis, colon cancer, etc. The colon-specific drug delivery is capable of delivering the formulation at the predetermined location and predetermined time. The early morning symptoms of rheumatoid arthritis like pain and inflammation can be treated using the various approaches of the colon-specific drug delivery system because it will lead to patient compliance as the patient will not require administering the formulation immediately after waking up in the morning. This review also explains the immunological factors which may trigger rheumatoid arthritis in human beings. It further explores conventional approaches like pH-dependant, microorganisms-driven, pressure-controlled, and time-dependant formulations. By employing two or more conventional approaches given above the various novel approaches have been designed to eliminate the drawbacks of individual techniques.
