Publications by authors named "Rakesh Kumar Mahajan"

Background: Migraine is one of the primary headaches having a global prevalence of 15%. It is characterized by neurovascular dysfunction and recurrent episodes of headache. The hyperexcitability of the cerebral cortex has been recognized as an important factor in the pathogenesis of migraine, and magnesium (Mg) being a regulator of neuronal excitability is thought to participate in migraine pathogenesis.

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Pluronic (PEO-PPO-PEO) block copolymers can form nano-sized micelles with a structure composed of a hydrophobic PPO core and hydrophilic PEO shell layer. Pluronics are U.S.

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Human sparganosis is a rare but important food borne zoonosis and could be attributed to increased consumption of raw meat of fish, frogs, snakes etc. Sparganosis may involve varied organ systems but subcutaneous sparganosis remains the one of the commonly reported clinical condition. Rarity of this problem reinforces the necessity of sensitising the treating physicians of the differential possibility of this infection in patients with history of practice of consuming raw meat.

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 As a consequence of growth and advancement in health care, production of health care waste has seen an exponential upward trend. Waste from individual health care facilities can vary based on the nature and scope of health care services they provide.  To analyze the amount of biomedical waste generated by a tertiary care hospital.

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The nature of counter-ions governs the micellar and structural characteristics of surface-active ionic liquids (SAILs). Especially, the introduction of aromatic counter-ions significantly increases their surface adsorption and induces the formation of various types of aggregates like prolate ellipsoidal micelles, rodlike micelles, vesicles, lamellars, etc. The present study reports the role of charge delocalization of two different aromatic counter-ions in the micellization behavior of their respective SAILs in aqueous medium.

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Pluronics (tri-block copolymers) have a significant role in the pharmaceutical industry and are being used to enhance the solubility and delivery of hydrophobic drugs in different marketed formulations. However, instability and unsatisfactory drug-loading capacity are the major weak spots of these pluronic micelles. The present research work is designed to solve the existing issues by the solubilization study of hydrophobic drugs in different pluronic micelles at variable temperatures.

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Chikungunya (CHIK) has re-emerged as a potential neurotropic virus, with outbreaks recently being reported from many parts of India. The present study was conducted to study the spectrum and outcome of neurological complications in patients of CHIK during the 2016 outbreak in Delhi. A total of 42 cases seropositive for IgM CHIK antibodies by MAC-ELISA and developing neurological complications were enrolled.

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In this report, the solubilization behaviour of a hydrophobic drug Clozapine (CLZ) in micellar suspensions of pluronics having different hydrophilic lipophilic balance (HLB) ratios viz. P84, F127 and F108 in the absence and presence of bile salt sodium deoxycholate (SDC) has been studied. UV-Vis spectroscopy has been exploited to determine the solubilization capacity of the investigated micellar systems in terms of drug loading efficiency, average number of drug molecules solubilized per micelle (n), partition coefficient (P) and standard free energy of solubilization (∆G).

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A simple and cost effective unsymmetrical azine based Schiff base, 5-diethylamino-2-[(2-hydroxy-benzylidene)hydrazonomethyl]-phenol (1) was synthesized which selectively detect Cu ions in the presence of other competitive ions through "naked eye" in physiological conditions (EtOH-buffer (1:1, v/v, HEPES 10mM, pH=7.4)). The presence of Cu induce color change from light yellow green to yellow with the appearance of a new band at 450nm in UV-Vis spectra of Schiff base 1.

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Gemini surfactants have been the subject of intensive scrutiny by virtue of their unique combination of physical and chemical properties and being used in ordinary household objects to multifarious industrial processes. In this review, we summarize the recent developments of gemini surfactants, highlighting the classification of gemini surfactants based on the variation in headgroup polarity, flexibility/rigidity of spacer, hydrophobic alkyl chain and counterion along with potential applications of gemini surfactants, depicting the truly remarkable journey of gemini surfactants that has just come of age. We have focused on those objectives which will act as suitable candidates to take the field forward.

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Here, we present how replacing the usual inorganic counter ion with a pharmaceutically active aromatic one can greatly affect the interfacial as well as bulk properties of ionic liquids (ILs). We have synthesized a series of novel drug-based ILs, namely, 1-alkyl-3-methylimidazolium diclofenate ([C mim][DF]; = 6, 8, 10, 12, and 14) abbreviated as DF-ILs, wherein DF is a well-recognized analgesic and nonsteroidal anti-inflammatory drug. We show strong synergistic interactions between C mim and aromatic DF attributed to reduced electrostatic repulsions and increased hydrophobicity from their incorporation, reflecting a 300-fold smaller critical aggregation concentration than that of their Cl analogue [C mim][Cl].

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The aim of this article is to study the interactions between flavonoids and surfactants with attention of finding the probable location of flavonoids in micellar media that can be used for controlling their antioxidant behavior. In present study, the micellar and interfacial behavior of twin tailed anionic surfactants viz. sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and sodium bis(2-ethylhexyl)phosphate (NaDEHP) in the presence of two flavonoids, namely quercetin (QUE) and kaempferol (KFL) have been studied by surface tension measurements.

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Catanionic surfactant-hydrotrope mixtures have proven to be a striking alternative to tune microstructures over a wide range of compositions and also to minimize precipitation that is normally observed in catanionic mixtures at an equimolar ratio. These mixtures are supposed to be of great relevance in biological systems when a hydrotrope is a "drug". Keeping this in view, here we report composition- and dilution-induced structural changes in a catanionic mixture comprising ionic liquids (ILs), such as 1-dodecyl-3-methylimidazolium bromide (C12mimBr)/1-tetradecyl-3-methylimidazolium bromide (C14mimBr), and a drug, diclofenac sodium (DFNa), in aqueous solution.

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Keeping in view the role of neurotransmitters (NTs) in central nervous system diseases and in controlling various physiological processes, present study is aimed to study the binding of neurotransmitters (NTs) such as norepinephrine hydrochloride (NE) and serotonin hydrochloride (5-HT) with twin tailed surfactant sodium bis(2-ethylhexyl)sulfosuccinate (AOT). Spectroscopic and electrochemical measurements combined with microcalorimetric measurements were used to characterize the interactions between AOT and NTs. Meteoric modifications to emission profile and absorption spectra of NTs upon addition of AOT are indicative of the binding of NTs with AOT.

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The interactions of an anionic redox-active dye Alizarin Red S (ARS) with novel N-hydroxyethyl-3-alkyloxypyridinium surfactants 1-(2-hydroxyethyl)-3-(tetradecyloxy)pyridinium bromide, [HEC14OPyBr], and 1-(2-hydroxyethyl)-3-(hexadecyloxy)pyridinium bromide, [HEC16OPyBr], were investigated in an aqueous solution for the first time with an attempt to obtain comprehensive knowledge of oppositely charged dye-surfactant mixed systems. Different state-of-the-art techniques viz. conductivity, surface tension (ST), UV-visible spectroscopy, cyclic voltammetry (CV), linear sweep voltammetry (LSV), potentiometry, dynamic light scattering (DLS) and (1)H-NMR analysis have been employed.

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The present study aims to develop an understanding of the interactions between an anionic polyelectrolyte, poly sodium 4-styrene sulphonate (NaPSS), and cationic surface active imidazolium based ionic liquids (SAILs), [Cnmim][Cl] (n = 10, 12, 14) using a multi-technique approach. Various physicochemical and electrochemical techniques such as surface tension, conductivity, fluorescence, isothermal titration calorimetry (ITC), dynamic light scattering (DLS), turbidity, potentiometry, cyclic voltammetry (CV), and differential pulse voltammetry (DPV) are employed to obtain comprehensive information about NaPSS-SAIL interactions. Different stages of interaction, corresponding to the critical aggregation concentration (cac), critical saturation concentration (Cs) and critical micelle concentration (cmc) have been observed owing to the strong electrostatic and hydrophobic interactions, and the results obtained from different techniques complement each other very well.

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Few cases of HIV and neurocysticercosis co-infection have been reported till date. The symptomatic manifestation of cysticercosis may be further reduced by interactions between the 2 disease processes. In patients with HIV, the diagnosis of neurocysticercosis is challenging and management must be individualized depending on the stage and the coexistent opportunistic conditions.

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Salmonella Enteritidis is one of the most important serovars transmitted from animals to humans and a serovar most commonly reported worldwide. Infection with Enteritidis is mainly limited to the intestinal tract, but under certain circumstances may cross the mucosal barrier to disseminate and get established as some localized infectious focus. Although cited as one of the very uncommon causes, Enteritidis may involve the liver and evolve into an overt abscess.

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The voltammetric and potentiometric sensors based on a novel electroactive rhodamine dimer (RD) have been developed for the determination of Fe (III) ions. The RD exhibits two anodic peaks at 0.5 V and 0.

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There has been several reports of an MND like syndrome in HIV-1 infection, however the data is still sparse. Furthermore, HIV-associated amyotrophic lateral sclerosis (ALS) syndrome differs from the classical ALS in some key aspects..

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The interactions of methylene blue (MB), a redox active dye with surface active biamphiphilic ionic liquids (BAILs): 1-butyl-3-methylimidazolium dodecylsulfate, [C4mim][C12OSO3] and 1-hexyl-3-methylimidazolium dodecylsulfate [C6mim][C12OSO3] have been investigated in aqueous medium to explore the candidature of surface active ionic liquids (ILs) in the field of dye-surfactant chemistry. Various thermodynamic, spectroscopic and electrochemical techniques such as conductivity, steady-state fluorescence, UV-visible absorption, and cyclic voltammetry (CV) have been used to obtain comprehensive information about MB-BAIL interactions. The presence of MB is seen to enhance the critical micellar concentration (cmc) of BAILs.

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The surface tension measurements have been employed to characterize the micellar and interfacial behavior of pure and mixed systems of twin-tailed cationic surfactants: dimethylene bis(decyldimethylammonium bromide) (10-2-10), didecydimethylammonium bromide (DDAB), and 1,3-didecyl-2-methylimidazolium chloride (DDIC) with pluronics P84 and F108 in the aqueous solution. The interactions of each surfactant with both pluronics are found to be nonideal and synergistic except for the mixed system of 10-2-10 + F108, for which interactions are antagonistic and every interaction has been studied on the basis of headgroup disparity. Dynamic light scattering (DLS), zeta (ζ) potential, and small angle neutron scattering (SANS) measurements have been used to determine the influence of the mixing ratio on the morphology of the various mixed aggregates that are formed.

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Phenothiazine drugs have been the subject of great interest due to their interesting aggregation properties and ability to interact with surfactants, model lipid bilayers, and biomembranes. Since these drugs show enormous pharmacological actions and deposits on the biomembranes, their pharmacological activities seem to be related to the drug-membrane interactions or to the absorbability on the membrane. Further, the mechanisms for the various biological activities of phenothiazines can be explained by exploring these drug-membrane interactions.

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With an aim to characterize the micellar aggregates of imidazolium based ionic liquids, a new potentiometric PVC sensor based on neutral ion-pair complexes of dodecylmethylimidazolium bromide-sodium dodecylsulfate (C12MeIm(+)DS(-)) has been developed. The electrode exhibited a linear response for the concentration range of 7.9×10(-5)-9.

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Keeping in view the use of surfactants in drug delivery, the interactions of surface active ionic liquids, such as 1-tetradecyl-3-methylimidazolium bromide (C(14)mimBr), with drugs, viz., dopamine hydrochloride (DH) and acetylcholine chloride (AC), have been studied, and the results are further compared with that of the structurally similar conventional cationic surfactant tetradecyltrimethylammonium bromide (TTAB). The micellization and interfacial behavior of C(14)mimBr and TTAB, in the presence of DH and AC, has been investigated from conductivity and surface tension measurements.

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