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1.
Acta Chim Slov ; 61(4): 681-7, 2014.
Article in English | MEDLINE | ID: mdl-25551706

ABSTRACT

The solubilization and partitioning study of five newly synthesized organic compounds (Cyclohexenone Carboxylates) with ionic surfactants, sodium dodecylsulphate (SDS) and cetyltrimethylammonium bromide (CTAB) was studied using ultraviolet-visible absorption spectroscopy technique. The differential spectroscopic technique was employed to study the partition coefficient (K(x)) of organic molecules between bulk water phase and the miceller phase. The values of partitioning coefficient were in the range 29.714 × 10(3) to 5.46 × 10(6). The standard free energy of partitioning (ΔG(op)) was also determined, which was found out in the range of -25 to -38 kJ /mole and shows the stability of the system. The results show that the cyclohexenone carboxylate compounds have great interactions with CTAB as compared to SDS.


Subject(s)
Cyclohexenes/chemistry , Micelles , Surface-Active Agents/chemistry , Cetrimonium , Cetrimonium Compounds/chemistry , Electrons , Ions , Magnetic Resonance Spectroscopy , Models, Chemical , Sodium Dodecyl Sulfate/chemistry , Spectrophotometry , Spectrophotometry, Ultraviolet , Spectroscopy, Fourier Transform Infrared , Static Electricity , Thermodynamics , Water/chemistry
2.
RSC Adv ; 14(27): 19539-19549, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38895531

ABSTRACT

Ascorbic acid plays a pivotal role in the human body. It maintains the robustness, enlargement, and elasticity of the collagen triple helix. However, the abnormal concentration of ascorbic acid causes various diseases, such as scurvy, cardiovascular diseases, gingival bleeding, urinary stones, diarrhea, stomach convulsions, etc. In the present work, an iron-doped hydroxyapatite (HAp@Fe2O3)-based biosensor was developed for the colorimetric detection of ascorbic acid based on a low-cost, biocompatible, and ubiquitous material. Due to the catalytic nature of HAp owing to the acidic and basic moieties within the structure, it was used as a template for HAp@Fe2O3 synthesis. This approach provides an active as well as large surface area for the sensing of ascorbic acid. The synthesized platform was characterized by various techniques, such as UV-Vis, FTIR, SEM, XRD, TGA, EDX, etc. The HAp@Fe2O3 demonstrated inherent peroxidase-like activity in the presence of 3,3',5,5'-tetramethylbenzidine (TMB) oxidized with the assistance of H2O2. It resulted in the color changing to blue-green, and after the addition of ascorbic acid, the color changed to colorless, resulting in the reduction of TMB. To achieve optimal sensing parameters, experimental conditions were optimized. The quantity of HAp@Fe2O3, H2O2, pH, TMB, time, and the concentration of ascorbic acid were fine-tuned. The linear range for the proposed sensor was 0.6-56 µM, along with a limit of detection of 0.16 µM and a limit of quantification of 0.53 µM. The proposed sensor detects ascorbic acid within 75 seconds at room temperature. The proposed platform was also applied to quantitatively check the concentration of ascorbic acid in a physiological solution.

3.
Front Bioeng Biotechnol ; 12: 1338920, 2024.
Article in English | MEDLINE | ID: mdl-38390362

ABSTRACT

Hydrogen peroxide (H2O2) is one of the main byproducts of most enzymatic reactions, and its detection is very important in disease conditions. Due to its essential role in healthcare, the food industry, and environmental research, accurate H2O2 determination is a prerequisite. In the present work, Morus nigra sawdust deposited zinc oxide (ZnO) nanoparticles (NPs) were synthesized by the use of Trigonella foenum extract via a hydrothermal process. The synthesized platform was characterized by various techniques, including UV-Vis, FTIR, XRD, SEM, EDX, etc. FTIR confirmed the presence of a Zn‒O characteristic peak, and XRD showed the hexagonal phase of ZnO NPs with a 35 nm particle size. The EDX analysis confirmed the presence of Zn and O. SEM images showed that the as-prepared nanoparticles are distributed uniformly on the surface of sawdust. The proposed platform (acetic acid-capped ZnO NPs deposited sawdust) functions as a mimic enzyme for the detection of H2O2 in the presence of 3,3',5,5'-tetramethylbenzidine (TMB) colorimetrically. To get the best results, many key parameters, such as the amount of sawdust-deposited nanoparticles, TMB concentration, pH, and incubation time were optimized. With a linear range of 0.001-0.360 µM and an R2 value of 0.999, the proposed biosensor's 0.81 nM limit of quantification (LOQ) and 0.24 nM limit of detection (LOD) were predicted, respectively. The best response for the proposed biosensor was observed at pH 7, room temperature, and 5 min of incubation time. The acetic acid-capped sawdust deposited ZnO NPs biosensor was also used to detect H2O2 in blood serum samples of diabetic patients and suggest a suitable candidate for in vitro diagnostics and commercial purposes.

4.
RSC Adv ; 14(10): 7022-7030, 2024 Feb 21.
Article in English | MEDLINE | ID: mdl-38414991

ABSTRACT

Uric acid (UA) is a significant indicator of human health because it is linked to several diseases, including renal failure, kidney stones, arthritis, and gout. Uric acid buildup in the joints is the source of chronic and painful diseases. When UA is present in large quantities, it causes tissue injury in the joints that are afflicted. In this research, silver oxide-doped activated carbon nanoparticles were synthesized and then functionalized with an ionic liquid. The synthesized nanomaterial assembly was employed as a colorimetric sensing platform for uric acid. Activated carbon offers a large internal surface area that acts as a good carrier for catalytic reactions. A salt-melting approach was used to synthesize the silver oxide-doped activated carbon nanocomposite. The synthesis was confirmed through various techniques, such as UV-vis spectrophotometer, FTIR, XRD, SEM, and EDX. The colorimetric change from blue-green to colorless was observed with the naked eye and confirmed by UV-vis spectroscopy. To obtain the best colorimetric change, several parameters, such as pH, capped NP loading, TMB concentration, hydrogen peroxide concentration, and time, were optimized. The optimized experimental conditions for the proposed sensor were pH 4 with 35 µL of NPs, a 40 mM TMB concentration, and a 4 minutes incubation time. The sensor linear range is 0.001-0.36 µM, with an R2 value of 0.999. The suggested sensor limits of detection and quantification are 0.207 and 0.69 nM, respectively. Potential interferers, such as ethanol, methanol, urea, Ca2+, K+, and dopamine, did not affect the detection of uric acid.

5.
Front Bioeng Biotechnol ; 12: 1364700, 2024.
Article in English | MEDLINE | ID: mdl-38694624

ABSTRACT

Dopamine is one of the most important neurotransmitters and plays a crucial role in various neurological, renal, and cardiovascular systems. However, the abnormal levels of dopamine mainly point to Parkinson's, Alzheimer's, cardiovascular diseases, etc. Hydroxyapatite (HAp), owing to its catalytic nature, nanoporous structure, easy synthesis, and biocompatibility, is a promising matrix material. These characteristics make HAp a material of choice for doping metals such as cobalt. The synthesized cobalt-doped hydroxyapatite (Co-HAp) was used as a colorimetric sensing platform for dopamine. The successful synthesis of the platform was confirmed by characterization with FTIR, SEM, EDX, XRD, TGA, etc. The platform demonstrated intrinsic peroxidase-like activity in the presence of H2O2, resulting in the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). The proposed sensor detected dopamine in a linear range of 0.9-35 µM, a limit of detection of 0.51 µM, limit of quantification of 1.7 µM, and an R2 of 0.993. The optimization of the proposed sensor was done with different parameters, such as the amount of mimic enzyme, H2O2, pH, TMB concentration, and time. The proposed sensor showed the best response at 5 mg of the mimic enzyme, pH 5, 12 mM TMB, and 8 mM H2O2, with a short response time of only 2 min. The fabricated platform was successfully applied to detect dopamine in physiological solutions.

6.
Pharm Biol ; 51(6): 722-7, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23570516

ABSTRACT

CONTEXT: A steroidal alkaloid, 4-acetoxy-plakinamine B (4APB), is a recently discovered marine natural product with inhibitory effect against acetylcholinesterase (AChE), but its mechanism of interaction with the enzyme remains to be elucidated. OBJECTIVE: The main objective was to study molecular binding mode of the compound, its interactions with catalytic subsites and molecular mechanism behind its significant inhibitory effect. MATERIALS AND METHODS: All possible interactions of ligands in the binding sites were analyzed using FRED 2.1 and the OMEGA pre-generated multi-conformer library. RESULTS: Dipole-dipole interactions were observed between the secondary amino group of 4APB and Ser200 at a distance of 3.91 Å and also with Gly117 and Gly118. A further dipole-dipole interaction was between Arg289 and the heterocyclic nitrogen. Hydrogen bonding interactions were observed between Tyr130 and secondary amino and C-4 acetyl groups as well as between heterocyclic nitrogen and Phe288 at a distance of 3.04 Å. Hydrophobic interactions were evident between rings C/D of 4APB and with Phe288, Phe330 and Phe331. The computational studies revealed 4APB's critical molecular interaction with amino acids of peripheral active (PAS) and anionic (AS) subsites. DISCUSSION: Our data provided molecular evidence for the mixed competitive inhibitory effect of 4APB. For lead optimization, structural insights revealed the N-methyl group of 4APB could be replaced by NH2 moiety to generate a more favorable hydrogen bonding with Glu199. A polar group insertion such as NH2 or OH at certain sites of the 4APB skeleton is also recommended. CONCLUSION: These computational insights explained the mixed-competitive enzyme kinetic behavior of 4APB. This study outlines a strategy for designing novel derivatives of 4APB with potentially better AChE inhibitory activities through interaction at the PAS and AS sites.


Subject(s)
Acetylcholinesterase/drug effects , Alkaloids/pharmacology , Cholinesterase Inhibitors/pharmacology , Drug Design , Steroids/pharmacology , Acetylcholinesterase/chemistry , Acetylcholinesterase/metabolism , Binding Sites , Computer Simulation , Hydrogen Bonding , Hydrophobic and Hydrophilic Interactions , Molecular Docking Simulation
7.
Pak J Pharm Sci ; 26(1): 131-5, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23261738

ABSTRACT

This piece of research work present the toxicological impact of varied concentrations of palladium nitrate [Pd (NO3)2] by changing the chemical status of glutathione and the way how glutathione plays its role in detoxification and conjugation processes of [Pd (NO(3))(2))] in whole blood components (plasma and cytosolic fraction). The impact of different concentration of [Pd (NO3)2] on reduced glutathione level in whole blood component (plasma and cytosolic fraction) were measured spectrophotometrically following Standard Ellman's method. Compared with control sample, significant decrease in the GSH content in whole blood components (plasma and cytosolic fraction) was obtained with various concentrations (100µM-1000µM) of palladium nitrate. Depleted GSH level was more pronounced with time incubation period (0-90) minutes. These finding shows that changes in the GSH status produced by palladium nitrate could either be due to palladium nitrate and glutathione( Pd-SG) complex formation or by conversion of reduce glutathione (2GSH + Pd(+2) - GSSG). This change in the GSH metabolic status provides information regarding the mechanism of palladium, in blood components.


Subject(s)
Glutathione/blood , Palladium/toxicity , Cytosol/metabolism , Dose-Response Relationship, Drug , Humans , Palladium/blood , Spectrophotometry , Time Factors
8.
J Ayub Med Coll Abbottabad ; 35(2): 285-287, 2023.
Article in English | MEDLINE | ID: mdl-37422822

ABSTRACT

BACKGROUND: Blood transfusion is a lifesaving method in clinical emergencies. Despite various preventive measures, the spread of Hepatitis B, C and HIV remains a big issue in Pakistan. This study was done to describe transfusion transmitted diseases using NAT and CLIA techniques, on exposure to these viruses. METHODS: This study was conducted from 1st April to 25th August 2022. A descriptive study was done along with univariate analysis. The data was obtained from the regional blood centre in Abbottabad and it consists of reactive and non-reactive cases of NAT and CLIA in the sample size of 6233 donors. Data was collected from donors, and selected according to predefined criteria. RESULTS: In 6233 samples, 53 were reactive for either Hepatitis B, C or HIV. Forty-seven were reactive with both CLIA and NAT. 6 were reactive with NAT only and 6107 were non-reactive. CONCLUSIONS: NAT yield detected in this study is 0.096%. (1:1039 donations). It implies that NAT should be the preferred method for screening in blood banks.


Subject(s)
HIV Infections , Hepatitis B , Humans , Blood Donors , Hepatitis B/diagnosis , Hepatitis B/epidemiology , Hepatitis B Surface Antigens , Pakistan/epidemiology , HIV Infections/diagnosis , HIV Infections/epidemiology , Hepatitis B virus
9.
J Ayub Med Coll Abbottabad ; 35(4): 654-657, 2023.
Article in English | MEDLINE | ID: mdl-38406955

ABSTRACT

BACKGROUND: A sensitive and specific donor screening strategy is essential for the prevention of transfusion-transmitted infections (TTI). The study was conducted to ascertain the comparative efficacy of ICT, CLIA and NAT methods. METHODS: This cross-sectional analytical study was conducted in Regional Blood Center Abbottabad, Pakistan from 1st April to 25 August 2022. 6233 donors were screened for Hep B, C, and HIV by testing simultaneously with ICT, CLIA and NAT. RESULTS: Active Hep B, C and HIV Infection was present in 0.51%, 0.28% and 0.00048% donors respectively. The sensitivity was found to be higher for HBV and HIV with CLIA as compared to ICT but was equal for HCV with both. whereas specificity was the same with both CLIA and ICT for all three viruses. PPV was higher with ICT for HBV and HCV, but for HIV it was found higher by CLIA. NPV was higher for all three viruses by CLIA as compared to ICT. CONCLUSIONS: In case rapid testing devices are used for the initial screening of blood in countries with limited resources, positive cases must be confirmed by CLIA and if possible, then by NAT because of missing cases in the window period and false positive cases.


Subject(s)
HIV Infections , Hepatitis B , Hepatitis C , Humans , Hepatitis B virus , Blood Donors , HIV Infections/diagnosis , HIV Infections/epidemiology , Cross-Sectional Studies , Mass Screening/methods , Hepatitis B/diagnosis , Hepatitis B/epidemiology , Hepatitis C/diagnosis , Hepatitis C/epidemiology , Hepacivirus
10.
ACS Omega ; 8(47): 44931-44941, 2023 Nov 28.
Article in English | MEDLINE | ID: mdl-38046308

ABSTRACT

Ascorbic acid is a vital biomolecule for human beings. When the body's level of ascorbic acid is abnormal, it can lead to a number of illnesses. Its appropriate concentration is necessary for the oxidation of prostaglandins and cyclic adenosine monophosphate, the production of dopamine, norepinephrine, epinephrine, and carnitine, and the expansion and durability of the collagen triple helix in humans. In the present work, silver nanoparticle synthesis was performed through a paracetamol-mediated approach. Different characterization techniques, such as X-ray diffractometry (XRD), energy dispersive X-ray (EDX), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM), were used to confirm the prepared nanoparticles. Subsequently, the prepared Ag NPs functionalized with an ionic liquid were used as a sensing platform for ascorbic acid in blood serum samples. To achieve the best possible results, the proposed biosensor was optimized with different parameters such as TMB concentration, time, amount of capped nanoparticles (NPs), and pH. The proposed biosensor offers a sensitive and straightforward method for ascorbic acid with a linear range from 2 × 10-9 to 3.22 × 10-7 M, an LOD of 1.3 × 10-8 M, an LOQ of 4.3 × 10-8 M, and an R2 of 0.9996, Moreover, applications of the proposed biosensor were successfully used for the detection of ascorbic acid in samples of human plasma, suggesting that Ag NPs with high peroxidase-like activity, high stability, and facile synthesis exhibited promising applications in biomedical fields.

11.
Drug Dev Ind Pharm ; 38(2): 190-9, 2012 Feb.
Article in English | MEDLINE | ID: mdl-21749268

ABSTRACT

CONTEXT: Controlled release (CR) matrix tablet of Prochlorperazine maleate was developed to improve its patient compliance. METHODS: Tablet formulations F1, F2 and F3 based on different concentrations of Methocel(®) K100 LV-CR Premium, were compacted by direct compression method while tablet formulations F4, F5 and F6, based on distinct blends of Methocel(®) K100 LV-CR Premium and Ethocel(®) Standard 7FP Premium, were compressed by flow-bound dry granulation-slugging method. The prepared powder mixtures, granules and tablets were evaluated for their physicochemical performance. Bioequivalence study of the optimized test tablet versus reference-conventional Stemitil(®) tablet was conducted on rabbits, using HPLC-UV system at λ(max) 254 nm. RESULTS: The test tablet, containing 28% Methocel(®) and 58% Ethocel(®) (F6) exhibited desired zero order kinetics for 24 h and was found stable at accelerated storage conditions for 6 months. In vitro drug release rate decreased as the Ethocel(®) content in the blend was increased, perhaps due to slower penetrability of water. Hydrodynamic conditions and hardness of tablets could not affect drug release kinetics. The tablet displayed significantly (p < 0.05) optimized peak drug concentration-C(max) (45 ± 3.42 vs. 64.5 ± 4.03), extended half life-t(1/2) (16.071 ± 3.97 vs. 5.257 ± 1.314 h) and bioequivalence to the reference tablet taken three times a day (1409 ± 15 ng·h/mL vs. 1346 ± 23 ng h/mL). The tablet showed strong Level A correlation (R(2) = 0.8458) between drug absorbed in vivo and drug released in vitro. CONCLUSIONS: The developed tablet may be adopted by pharmaceutical industry to improve patient compliance of the Prochlorperazine maleate.


Subject(s)
Antipsychotic Agents/pharmacokinetics , Cellulose/analogs & derivatives , Methylcellulose/pharmacology , Prochlorperazine/pharmacokinetics , Animals , Antipsychotic Agents/chemistry , Biological Availability , Cellulose/pharmacology , Chromatography, High Pressure Liquid , Delayed-Action Preparations , Drug Delivery Systems , Humans , Male , Polymers/chemistry , Polymers/pharmacokinetics , Prochlorperazine/chemistry , Rabbits , Tablets , Therapeutic Equivalency
12.
J Pharm Biomed Anal ; 221: 115043, 2022 Nov 30.
Article in English | MEDLINE | ID: mdl-36155483

ABSTRACT

The current work reports the drug-mediated synthesis of silver nanoparticles (AgNPs) and their functionalization with ionic liquid (IL) for acetone determination. The rationale behind the selection of the Augmentin drug was the aromaticity in its structure and the functional groups attached. These properties are not only supposed to work in the synthesis of the nanoparticles but also enhance their electron density. The nanoparticles were further coated with 1-H-3-methylimidazolium acetate IL, having conductivity and aromaticity in their structure. The synthesized nanoparticles have been characterized by different techniques such as FTIR, XRD, SEM, and EDX. Colorimetric determination of acetone was done by using IL capped AgNPs with the assistance of NaCl solution and results were analyzed by UV-Vis spectrophotometry. Low-cost, stable eosin dye works as a substrate and is consumed resulting in a color change from brown to transparent. The IL capped AgNPs act as a reducing agent for the production of reduced radical form of acetone which act on the carboxylate moiety and bubble it out in the form of CO2. Different parameters such as (concentrations, loading of nanoparticles, time and pH, etc.) were optimized to get the best results of the proposed sensor. The sensor shows a wide linear range of (1 ×10-8-2.40 ×10-6 M), low limit of detection 2.66 × 10-9 M, and limit of quantification 8.86 × 10-9 M with an R2 value of 0.997. The proposed sensor has been successfully applied to diabetic patient's urine samples for acetone detection with a visible colorimetric change. It showed good sensitivity and selectivity towards acetone detection.


Subject(s)
Ionic Liquids , Metal Nanoparticles , Acetone , Amoxicillin-Potassium Clavulanate Combination , Carbon Dioxide , Colorimetry/methods , Eosine Yellowish-(YS) , Humans , Metal Nanoparticles/chemistry , Reducing Agents , Silver/chemistry , Sodium Chloride
13.
J Enzyme Inhib Med Chem ; 26(4): 468-71, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21054146

ABSTRACT

Antibacterial and antifungal activities of the two isolated compounds from Conyza canadensis have been reported in the current study. The two isolated compounds i.e. Conyzolide (1) and Conyzoflavone (2) were tested against six bacterial and five fungal strains, employing hole diffusion and macrodilution methods. Both the compounds showed significant activities against the tested pathogens with special reference to E. coli, P. aeruginosa, S. aureus, Trichophytom longifusus, C. albicans, and C. glaberata. Conyzolide revealed comparatively better antibacterial activity against E. coli (minimum inhibitory concentration (MIC): 25 µg/mL) in comparison to Conyzoflavone. However, in case of antifungal activities, Conyzoflavone exhibited superior antifungal activity against C. albicans (MIC: 10 µg/mL) as compared to Conyzolide.


Subject(s)
Anti-Bacterial Agents/pharmacology , Antifungal Agents/pharmacology , Bacteria/drug effects , Conyza/chemistry , Diterpenes/pharmacology , Flavanones/pharmacology , Fungi/drug effects , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Antifungal Agents/chemistry , Antifungal Agents/isolation & purification , Diterpenes/chemistry , Diterpenes/isolation & purification , Dose-Response Relationship, Drug , Flavanones/chemistry , Flavanones/isolation & purification , Microbial Sensitivity Tests , Molecular Structure , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Plant Extracts/pharmacology , Structure-Activity Relationship
14.
AAPS PharmSciTech ; 12(2): 525-33, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21494924

ABSTRACT

Controlled-release (CR) matrix tablet of 4 mg risperidone was developed using flow bound dry granulation-slugging method to improve its safety profile and compliance. Model formulations F1, F2, and F3, consisting of distinct blends of Methocel® K100 LV-CR and Ethocel® standard 7FP premium, were slugged. Each batch of granules (250-1,000 µm), obtained by crushing the slugs, was divided into three portions after lubrication and then compressed to 9-, 12-, and 15-kg hard tablets. In vitro drug release studies were carried out in 0.1 N HCl (pH 1.2) and phosphate buffer (pH 6.8) using a paddle dissolution apparatus run at 50 rpm. The CR test tablet, containing 30% Methocel® and 60% Ethocel® (F3) with 12-kg hardness, exhibited pH-independent zero-order release kinetics for 24 h. The drug release rate was inversely proportional to the content of Ethocel®, while the gel layer formed of Methocel® helped in maintaining the integrity of the matrix. Changes in the hardness of tablet did not affect the release kinetics. The tablets were reproducible and stable for 6 months at 40 ± 2°C/75 ± 5% relative humidity. Risperidone and its active metabolite, 9-hydroxyrisperidone, present in the pooled rabbit's serum, were analyzed with HPLC-UV at λ(max) 280 nm. The CR test tablet exhibited bioequivalence to reference conventional tablet in addition to the significantly (p < 0.05) optimized peak concentration, C(max), and extended peak time, T (max), of the active moiety. There was a good association between drug absorption in vivo and drug release in vitro (R(2) = 0.7293). The successfully developed CR test tablet may be used for better therapeutic outcomes of risperidone.


Subject(s)
Cellulose/analogs & derivatives , Chemistry, Pharmaceutical/methods , Methylcellulose/pharmacokinetics , Polymers/pharmacokinetics , Risperidone/pharmacokinetics , Animals , Biological Availability , Cellulose/chemistry , Cellulose/pharmacokinetics , Cellulose/standards , Chemistry, Pharmaceutical/standards , Delayed-Action Preparations/standards , Drug Interactions/physiology , Female , Male , Methylcellulose/chemistry , Methylcellulose/standards , Polymers/chemistry , Polymers/standards , Rabbits , Risperidone/chemistry , Risperidone/standards , Tablets, Enteric-Coated
15.
ACS Omega ; 6(48): 32754-32762, 2021 Dec 07.
Article in English | MEDLINE | ID: mdl-34901624

ABSTRACT

Hydrogen peroxide (H2O2) acts as a signaling molecule to direct different biological processes. However, its excess amount results in oxidative stress, which causes the onset of different types of cancers. TiO2 nanostructure was synthesized by a facile hydrothermal method. The prepared material was characterized by FTIR spectroscopy, XRD, SEM, EDX, TGA, and Raman spectroscopy, which confirmed the formation of nanostructured material. Subsequently, the prepared nanoparticles (NPs) were capped with 1-H-3-methylimidazolium acetate ionic liquid (IL) to achieve its deagglomeration and functionalization. A new colorimetric sensing probe was prepared for the detection of H2O2 based on ionic liquid-capped TiO2 nanoparticles (TiO2/IL) and 3,3',5,5'-tetramethylbenzidine (TMB) dye, which acts as an oxidative chromogenic substrate. H2O2 reacts with TMB, in the presence of ionic liquid-coated TiO2 NPs, to form a blue-green product. The color was visualized with the naked eye, and the colorimetric change was confirmed by a UV-vis spectrophotometer. To obtain the best response of the synthesized sensor, different parameters (time, pH, concentrations, loading of nanomaterials) were optimized. It showed a low limit of detection 8.61 × 10-8 M, a high sensitivity of 2.86 × 10-7 M, and a wide linear range of 1 × 10-9-3.6 × 10-7 M, with a regression coefficient (R 2) value of 0.999. The proposed sensor showed a short incubation time of 4 min. The sensing probe did not show any interference from the coexisting species. The TiO2/IL sensor was effectively used for finding H2O2 in the urine samples of cancer patients.

16.
J Fluoresc ; 20(5): 1049-59, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20446023

ABSTRACT

An approach is demonstrated toward the synthesis of four novel cyclohexenone derivatives (CDs) via a convenient route of Michael addition of ethyl acetoacetate. The molecular structures of CDs were confirmed by means of FT-IR, (1)H NMR, EIMS, UV and also by X-ray single crystal structure analysis. CDs are strongly fluorescent compounds and their fluorescent spectra exhibits intense violet fluorescence. To model the binding to biological membranes the behavior of CDs in micellar solutions of a cationic surfactant, cetyltrimethylammonium bromide (CTAB) and an anionic surfactant, sodium dodecylsulfate (SDS) has also been examined. The characteristics of partition and binding interactions of CDs with CTAB and SDS were investigated by UV-Visible and fluorescence spectroscopic techniques. Higher values of all mentioned interactions in case of CTAB, compared to SDS, indicate that there are greater interactions between the CDs and CTAB than with SDS.


Subject(s)
Coloring Agents/chemical synthesis , Ions , Micelles , Cetrimonium , Cetrimonium Compounds/chemistry , Coloring Agents/chemistry , Magnetic Resonance Spectroscopy/methods , Sodium Dodecyl Sulfate/chemistry , Spectrometry, Mass, Electrospray Ionization/methods , Spectroscopy, Fourier Transform Infrared/methods , Surface-Active Agents/chemistry , X-Rays
17.
AAPS PharmSciTech ; 11(3): 1397-404, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20824513

ABSTRACT

Controlled-release (CR) tablet formulation of olanzapine was developed using a binary mixture of Methocel® K100 LV-CR and Ethocel® standard 7FP premium by the dry granulation slugging method. Drug release kinetics of CR tablet formulations F1, F2, and F3, each one suitably compressed for 9-, 12-, and 15-kg hardness, were determined in a dissolution media of 0.1 N HCl (pH 1.5) and phosphate buffer (pH 6.8) using type II dissolution apparatus with paddles run at 50 rpm. Ethocel® was found to be distinctly controlling drug release, whereas the hardness of tablets and pH of the dissolution media did not significantly affect release kinetics. The CR test tablets containing 30% Methocel® and 60% Ethocel® (F3) with 12-kg hardness exhibited pH-independent zero-order release kinetics for 24 h. In vivo performance of the CR test tablet and conventional reference tablet were determined in rabbit serum using high-performance liquid chromatography coupled with electrochemical detector. Bioavailability parameters including C(max), T(max), and AUC(0-48 h) of both tablets were compared. The CR test tablets produced optimized C(max) and extended T(max) (P < 0.05). A good correlation of drug absorption in vivo and drug release in vitro (R(2) = 0.9082) was observed. Relative bioavailability of the test tablet was calculated as 94%. The manufacturing process employed was reproducible and the CR test tablets were stable for 6 months at 40 ± 2°C/75 ± 5% relative humidity. It was concluded that the CR test tablet formulation successfully developed may improve tolerability and patient adherence by reducing adverse effects.


Subject(s)
Benzodiazepines/administration & dosage , Benzodiazepines/pharmacokinetics , Cellulose/analogs & derivatives , Delayed-Action Preparations/chemical synthesis , Emulsions/chemistry , Methylcellulose/chemistry , Tablets/chemical synthesis , Animals , Biological Availability , Cellulose/chemistry , Delayed-Action Preparations/pharmacokinetics , Diffusion , Female , Male , Olanzapine , Rabbits , Tablets/pharmacokinetics
18.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 5): o1130, 2010 Apr 21.
Article in English | MEDLINE | ID: mdl-21579179

ABSTRACT

In the title compound, C(7)H(6)N(2)O(3), the planes containing the CNO and ONO atoms subtend dihedral angles of 5.47 (5) and 8.31 (5)°, respectively, with the benzene ring. In the crystal structure, inter-molecular O-H⋯N hydrogen bonds link the mol-ecules into centrosymmetric dimers with an R(2) (2)(6) graph-set motif.

19.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 3): o467, 2009 Feb 06.
Article in English | MEDLINE | ID: mdl-21582138

ABSTRACT

The title compound, C(23)H(23)BrO(4), is an inter-mediate in the synthesis of fused heterocycles. In the title mol-ecule, the cyclo-hexene ring has a distorted half-chair conformation. The bromo-phenyl ring and the mean plane of the cyclo-hexene ring form a dihedral angle of 13.8 (3)°, whereas the benzene and cyclo-hexene rings are approximately perpendicular [88.44 (17)°]. There are only weak C-H⋯O and C-H⋯π inter-molecular inter-actions.

20.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 2): o364, 2009 Jan 23.
Article in English | MEDLINE | ID: mdl-21581962

ABSTRACT

The title compound, C(21)H(16)N(2)O(2), was derived from 1-(2-hydroxy-phen-yl)-3-(-methoxy-phen-yl)propane-1,3-dione. The mol-ecular structure of the title compound is stabilized by an intra-molecular O-H⋯N hydrogen bond. The dihedral angle between the hydroxy-phenyl ring involved in this intra-molecular hydrogen bond and the pyrazole ring is significantly smaller [10.07 (6)°] than the dihedral angle between the pyrazole and the other hydroxy-phenyl ring [36.64 (5)°]. The benzene ring makes a dihedral angle of 54.95 (3)° with the pyrazole ring. The crystal packing is stabilized by O-H⋯O and O-H⋯N hydrogen bonds.

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