Formulation Optimization and Characterization of Tizanidine Hydrochloride-Loaded Gold Nanoparticles Using Quality by Design Approach.

BACKGROUND: Gold nanoparticles (GNP) have been used extensively in cancer biologics and as drug carrier systems for improved pharmacokinetics and effective therapeutic action. GNPs also ensure reliable diagnosis with sensitive imaging. OBJECTIVE: This study aimed to synthesize tizanidine hydrochloride (TZN)-biodegradable gold (Au) nanoparticles by the reduction of chloroauric acid (HAuCl4) with trisodium citrate using a microwave synthesizer and quality by design approach. METHODS: The formulation method used was optimized using a 32 (two-factor, three-level design) factorial experiment. Temperature (X1) and concentration of gold salt (X2) were the two independent factors, and particle size (Y1), Percent drug entrapment efficiency (Y2), and polydispersity index (Y3) were the responses recorded for the study. RESULT: The results of the study revealed that the optimized nanoparticles (TGN8) had a particle size (Y1) of 195 ± 1.2 nm, a polydispersity index of 0.2, and entrapment efficiency of 99.0 ± 2.9% at an optimized concentration of 14 mM gold salt (X1) and 100 0C temperature (X2). Atomic Force Microscopy showed the spherical shape particles. In vitro drug release was found to be 62.1 ± 0.5% release of TZN in simulated gastric buffer (pH 1.2) and 45.5 ± 2.8% in physiological buffer (pH 7.4). CONCLUSION: Overall, the study identified the optimal formulation conditions for TZN GNPs by considering the effects of independent variables on desired responses.

Plasma Hepcidin Levels in Healthy Children from Chandigarh, Northern India.

Hepcidin is a key molecule involved in iron homeostasis. We measured hepcidin levels in 50 healthy children from Chandigarh, Northern India for establishing normal ranges. Hepcidin ranges (19.96-36.6 ng/mL; 0-2 years) and (9.54-36.15 ng/mL; 2-6 years) with mean (SD) of 32.5 (4.84) ng/mL, and 31.13 (6.62) ng/mL respectively were noted in study participants. The mean (SD) and ranges for plasma hepcidin in boys and girls in the study was 31.01 (6.71) ng/mL (9.54-36.6 ng/mL) and 32.7 (4.14) ng/mL (19-36.2 ng/mL), respectively.

Combination of mTOR and MAPK Inhibitors-A Potential Way to Treat Renal Cell Carcinoma.

Renal cell carcinoma (RCC) is the most common neoplasm that occurs in the kidney and is marked by a unique biology, with a long history of poor response to conventional cancer treatments. In the past few years, there have been significant advancements to understand the biology of RCC. This has led to the introduction of novel targeted therapies in the management of patients with metastatic disease. Patients treated with targeted therapies for RCC had shown positive impact on overall survival, however, no cure is possible and patients need to undergo treatment for long periods of time, which raises challenges to manage the associated adverse events. Moreover, many patients may not respond to it and even response may not last long enough in the responders. Many inhibitors of the Mammalian target of Rapamycin (mTOR) signaling pathway are currently being used in treatment of advanced RCC. Studies showed that inhibitions of mTOR pathways induce Mitogen-Activated Protein Kinase (MAPK) escape cell death and cells become resistant to mTOR inhibitors. Because of this, there is a need to inhibit both pathways with their inhibitors comparatively for a better outcome and treatment of patients with RCC.

Sulphonamido-quinoxalines: search for anticancer agent.

A series of new sulphonamido-quinoxaline derivatives 3(a-p) have been prepared which are structurally similar to the High Throughput Screening (HTS) hit identified by Porter and collaborator. The newly synthesized compounds 3b, 3c, 3f, 3i, 3j, 3l, 3n and 3o were further evaluated in the National Cancer Institute for in vitro cytotoxicity assay among them compound 3l showed highest activity against Leukemia RPMI-8226 cell lines (GI50: 1.11 µM) as compared to other tested compounds. It is to be noted that compound 3l shows significant activity (GI50: 1.11 µM) compared to the High Throughput Screening (HTS) hit identified by Porter and collaborator (IC50 = 1.3 µM). Further docking study confirms the c-Met kinase inhibitory mechanism of the synthesized compounds.

Stability-Indicating LC Method for the Determination of Prasugrel Hydrochloride in Pharmaceutical Dosage Form.

A simple, rapid and precise method was developed for the quantitative estimation of prasugrel hydrochloride in pharmaceutical dosage form. A chromatographic separation of prasugrel and its degradants was achieved with Zorbax XDB C(8), 150 × 4.6 mm, 3.5µm analytical column using aqueous solution of 0.05 M ammonium acetate pH 4.5 with acetic acid-acetonitrile (40:60 v/v). The instrumental settings include flow rate of 1.0 ml/min, column temperature at 30°C and detector wavelength of 254 nm using a photodiode array detector. Theoretical plates for prasugrel were 7023. Tailing factor for prasugrel was 1.11. Prasugrel was exposed to thermal, photolytic, hydrolytic and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. Peak homogeneity data of prasugrel was obtained using photodiode array detector in the stressed sample chromatograms, which demonstrated the specificity of the method for the estimation in presence of degradants. The described method showed excellent linearity over a range of 10-300 µg/ml for prasugrel. The correlation coefficient is 0.999. The relative standard deviation of peak area for six measurements is always less than 2%. Overall, the proposed method was found to be suitable and accurate for quantitative determination and stability study of prasugrel in pharmaceutical dosage form.

A comprehensive platform for quality control of botanical drugs (PhytomicsQC): a case study of Huangqin Tang (HQT) and PHY906.

BACKGROUND: Establishing botanical extracts as globally-accepted polychemical medicines and a new paradigm for disease treatment, requires the development of high-level quality control metrics. Based on comprehensive chemical and biological fingerprints correlated with pharmacology, we propose a general approach called PhytomicsQC to botanical quality control. METHODS: Incorporating the state-of-the-art analytical methodologies, PhytomicsQC was employed in this study and included the use of liquid chromatography/mass spectrometry (LC/MS) for chemical characterization and chemical fingerprinting, differential cellular gene expression for bioresponse fingerprinting and animal pharmacology for in vivo validation. A statistical pattern comparison method, Phytomics Similarity Index (PSI), based on intensities and intensity ratios, was used to determine the similarity of the chemical and bioresponse fingerprints among different manufactured batches. RESULTS: Eighteen batch samples of Huangqin Tang (HQT) and its pharmaceutical grade version (PHY906) were analyzed using the PhytomicsQC platform analysis. Comparative analysis of the batch samples with a clinically tested standardized batch obtained values of PSI similarity between 0.67 and 0.99. CONCLUSION: With rigorous quality control using analytically sensitive and comprehensive chemical and biological fingerprinting, botanical formulations manufactured under standardized manufacturing protocols can produce highly consistent batches of products.

Induced ER chaperones regulate a receptor-like kinase to mediate antiviral innate immune response in plants.

Mounting an effective innate immune response against pathogens requires the rapid and global reprogramming of host cellular processes. Here we employed complementary proteomic methods to identify differentially regulated proteins early during a plant's defense response. Besides defense-related proteins, constituents of the largest category of upregulated proteins were cytoplasmic- and ER-residing molecular chaperones. Investigating the significance of upregulated ER chaperones, we find that silencing of ER-resident protein disulfide isomerases NbERp57 and NbP5 and the calreticulins NbCRT2 and NbCRT3 led to partial loss of N immune receptor-mediated defense against Tobacco mosaic virus (TMV). Furthermore, NbCRT2 and NbCRT3 were required for the expression of a previously uncharacterized induced receptor-like kinase (IRK). IRK is a plasma membrane-localized protein required for N-mediated hypersensitive response, programmed cell death, and resistance to TMV. These data support a model in which ER-resident chaperones are required for the accumulation of membrane-bound or secreted proteins during plant innate immunity.

Study of Arabidopsis thaliana resistome in response to cucumber mosaic virus infection using whole genome microarray.

The plant innate immune response is mediated by resistance (R) genes and involves hypersensitive response (HR) cell death. During resistance responses, the host undergoes net changes in the transcriptome. To understand these changes, we generated a whole genome transcript profile for RCY1-mediated resistance to cucumber mosaic virus strain Y (CMV-Y) in Arabidopsis. Using a very stringent selection criterion, we identified 444 putative factors belonging to nine different functional classes that show significant transcript regulation during Arabidopsis-CMV-Y interaction. Genes with unknown function formed the largest class. Other functional classes represented in the resistome include kinases and phosphatases, protein degradation machinery/proteases, transcriptional regulators, and others. Interestingly, several of the unknown function genes possess well characterized domains and secondly many genes encode small peptides with less than 100 amino acids. Analysis of 1.1 kb promoter regions of the 444 genes revealed that 9 out of the 12 known cis-binding elements are significantly associated with pathogen responsive cluster. Location and distribution of five prominent binding elements for select group of disease resistance related and unknown function genes is presented. The analysis also revealed 80 defense-responsive genes that might participate in R gene-mediated defense against both viral and bacterial pathogens. In addition, chromosome distribution of genes that respond to bacterial and viral pathogens suggests that they are located in small gene clusters and may be transcriptionally co-regulated. Exploring the precise function of the new genes identified in this analysis will offer new insights into plant defense.

Virus-induced gene silencing.

In the postgenomic era, large-scale functional genomic approaches are necessary for converting sequence information into functional information. A para-genetic approach, called virus-induced gene silencing (VIGS), offers a rapid means of gaining insight into gene function in plants. VIGS system could be used to suppress endogenous gene expression by infecting plants with a recombinant virus vector (VIGS vector) carrying host-derived sequence. Here, we describe the use of tobacco rattle virus (TRV)-based VIGS technique to study gene function in Nicotiana benthamiana and tomato.

Plant defense: one post, multiple guards?!

Arabidopsis RIN4 is a key bacterial virulence target that is guarded by the resistance (R) protein RPM1. Two recent studies suggest that another R protein, RPS2, also guards RIN4. Bacterial avirulence (Avr) effectors AvrB, AvrRpm1, and AvrRpt2 alter this key protein. R proteins RPM1 and RPS2 recognize the altered status and initiate a defense-signaling response. The guard hypothesis is in!

Tobacco Rar1, EDS1 and NPR1/NIM1 like genes are required for N-mediated resistance to tobacco mosaic virus.

The tobacco N gene confers resistance to tobacco mosaic virus (TMV) and encodes a Toll-interleukin-1 receptor/nucleotide binding site/leucine-rich repeat (TIR-NBS-LRR) class protein. We have developed and used a tobacco rattle virus (TRV) based virus induced gene silencing (VIGS) system to investigate the role of tobacco candidate genes in the N-mediated signalling pathway. To accomplish this we generated transgenic Nicotiana benthamiana containing the tobacco N gene. The transgenic lines exhibit hypersensitive response (HR) to TMV and restrict virus spread to the inoculated site. This demonstrates that the tobacco N gene can confer resistance to TMV in heterologous N. benthamiana. We have used this line to study the role of tobacco Rar1-, EDS1-, and NPR1/NIM1- like genes in N-mediated resistance to TMV using a TRV based VIGS approach. Our VIGS analysis suggests that these genes are required for N function. EDS1-like gene requirement for the N function suggests that EDS1 could be a common component of bacterial, fungal and viral resistance signalling mediated by the TIR-NBS-LRR class of resistance proteins. Requirement of Rar1- like gene for N-mediated resistance to TMV and some powdery mildew resistance genes in barley provide the first example of converging points in the disease resistance signalling pathways mediated by TIR-NBS-LRR and CC-NBS-LRR proteins. The TRV based VIGS approach as described here to study N-mediated resistance signalling will be useful for the analysis of not only disease resistance signalling pathways but also of other signalling pathways in genetically intractable plant systems.

The tobacco mosaic virus resistance gene, N.

Summary In this mini review we discuss recent advances in the understanding of the N gene-mediated resistance to tobacco mosaic virus (TMV). The tobacco N gene belongs to toll-interleukin-1 receptor homology/nucleotide binding/leucine rich repeat (TIR-NB-LRR) class of resistance genes. It encodes two transcripts, N(S) and N(L), by alternative splicing, both of which are required to confer resistance to TMV. The structure-function analysis of the N gene indicates that the TIR, NB and LRR domains are indispensable for its function. The N gene response is elicited by the C-terminal helicase domain of the 126 kDa TMV replicase protein. Tobacco N gene can also confer resistance to TMV in heterologous plants like tomato and Nicotiana benthamiana. Recent studies on N-mediated signalling suggest that EDS1, Rar1 and NPR1 genes play an important role in TMV resistance. Finally, we discuss current status of the N-mediated signal transduction and speculate directions for future work to understand N-TMV interaction.