Renewed Looks at the Distribution of a Sum of Independent or Dependent Discrete Random Variables and Related Problems

Methodology and Computing in Applied Probability - Butler and Stephens (2017) have investigated the exact and approximate distributions of a sum S of independent binomial random variables with...     

Ensuring robustness in the quality of antibiotic susceptibility test discs for four novel antibiotics

Antibiotic susceptibility test (AST) discs are used as an in-vitro diagnostic tool to select the appropriate antibiotic to treat an infection. Generally, the concentration of the drug loaded on to the AST discs is measured by studying its activity against quality control organisms. This methodology has several limitations—it is time consuming, requires trained manpower, has a wider acceptance criteria of zone of inhibitions—causing ambiguity in judging smaller variations in drug concentration. To overcome these issues, we have developed and validated high-performance liquid chromatographic (HPLC) methods for the determination of strength of AST discs for in-house researched antibiotics, namely Levonadifloxacin/WCK 771, Nafithromycin/WCK 4873, Cefepime-Tazobactam/WCK 4282, and Cefepime-Zidebactam/WCK 5222. The drugs were extracted from the AST discs using an appropriate solvent. The developed methods are simple, accurate, precise, reproducible, rugged, and robust. They are efficient in terms of time, and can be easily conducted in a quality control laboratory during release as well as stability evaluation of AST disc. Application of HPLC methods for the determination of strength of AST discs ensures flawless quality and, consequently, a better selection of drugs to treat bacterial infections in clinics.     

Investigation on Impurity Profiling and Degradation Behavior of WCK 771

Chromatographia - WCK 771 is a novel antibacterial drug recently launched in India for the treatment of acute bacterial skin and skin structure infections (ABSSSI). This report describes...     

Rationalisation of extractive protocol by high-performance thin-layer chromatographic–densitometric quantification of berberine in multiple hydroalcoholic extract of Tinospora cordifolia stem

JPC – Journal of Planar Chromatography – Modern TLC - Drug development from medicinal plants by using various hydroalcoholic solvents has been an emerging trend in the last few decades....     

Studies on Curcumin Loaded Poly(N-isopropylacrylamide) Silver Nanocomposite Hydrogels for Antibacterial and Drug Releasing Applications

Design of silver nanoparticles containing poly(N-isopropylarclamide) (PNIPAAm) hydrogels were prepared by free-radical polymerization of N-isopropylarclamide as an environmentally sensitive monomer and MBA as a crosslinker in an aqueous medium. The embedded silver nanocomposite hydrogels (AgNCH) structure were characterized by, UV-Vis, FTIR, DLS, TEM and X-ray analysis. Curcumin loading and release characteristics were performed for PNIPAAm hydrogel, silver ions loaded hydrogels as well as silver nanocomposite hydrogels. These curcumin loaded silver nanocomposite hydrogels exhibit excellent antibacterial action on Escherichia coli (E. coli). Therefore, the present study clearly provides novel antimicrobial hydrogels which are potentially useful in biomedical applications.     

Synthesis and Characterization of Four-Arm Star Poly(ϵ-caprolactone)-Block-Poly(cyclic-carbonate methacrylate) Copolymers by Combining Ring-Opening Polymerization With Atom Transfer Radical Polymerization

Well-defined four-arm star poly(?-caprolactone)-block-poly(cyclic carbonate methacrylate) (PCL-b-PCCMA) copolymers were synthesized by combining ring-opening polymerization (ROP) with atom transfer radical polymerization (ATRP). First, a four-arm poly(?-caprolactone) (PCL) macroinitiator [(PCL-Br)₄] was prepared by the ROP of ?-CL catalyzed by stannous octoate at 110°C in the presence of pentaerythritol as the tetrafunctional initiator followed by esterification with 2-bromoisobutyryl bromide. The sequential ATRP of CCMA monomer was carried out by using the (PCL-Br)₄ tetrafunctional macroinitiator (MI) and in the presence of CuBr/2, 2′-bipyridyl system in DMF at 80°C with [(MI)]:[CuBr]:[bipyridyl] = 1:1:3 to yield block polymers with controlled molecular weights (M_n (NMR) = 10700 to 27300 g/mol) by varying block lengths and with moderately narrow polydispersities (M_w/M_n = 1.2–1.4). Block copolymers with different PCL: PCCMA copolymer composition such as 50:50, 70:30 and 74:26 were prepared with good yields (48-74%). All these block copolymers were well characterized by NMR, FTIR and GPC and tested their thermal properties by DSC and TGA.     

Rapid Biosynthesis of Silver Nanoparticles Using Areca Nut (Areca catechu) Extract Under Microwave-Assistance

In this research paper, we report on the rapid synthesis of silver nanoparticles using dried areca nut (Areca catechu). The microwave exposed aqueous areca nut powder when treated with the aqueous silver salt solution yielded irregular shaped silver nanoparticles. The formation and morphology of the nanoparticles are studied using UV–visible spectroscopy, field emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy. The X-ray diffraction studies and energy dispersive X-ray analysis indicate that the particles are crystalline in nature. The understanding of capping of biological moiety is derived from Fourier transform infrared spectroscopy and the thermogravimetric analysis. The green chemistry approach for the synthesis of silver nanoparticles is modest, amenable for large scale commercial production. Further the biologically synthesized silver nanoparticles are known for their potential antibacterial activity.     

Cyclizations of Some Terminally Substituted a,c-Biladienes

Several examples of 1′,8′-disubstituted a,c-biladiene salt cyclizations, using copper(II) or iodine/bromine in hot o-dichlorobenzene, to give meso-substituted porphyrins are described.