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Fulltext pH responsive N-succinyl chitosan/Poly (acrylamide-co-acrylic acid) hydrogels and in vitro release of 5-fluorouracil

Bashir S, Teo YY, Naeem S, Ramesh S, Ramesh K

PLoS One, 2017;12(7):e0179250.
PMID: 28678803 DOI: 10.1371/journal.pone.0179250

There has been significant progress in the last few decades in addressing the biomedical applications of polymer hydrogels. Particularly, stimuli responsive hydrogels have been inspected as elegant drug delivery systems capable to deliver at the appropriate site of action within the specific time. The present work describes the synthesis of pH responsive semi-interpenetrating network (semi-IPN) hydrogels of N-succinyl-chitosan (NSC) via Schiff base mechanism using glutaraldehyde as a crosslinking agent and Poly (acrylamide-co-acrylic acid)(Poly (AAm-co-AA)) was embedded within the N-succinyl chitosan network. The physico-chemical interactions were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and field emission scanning electron microscope (FESEM). The synthesized hydrogels constitute porous structure. The swelling ability was analyzed in physiological mediums of pH 7.4 and pH 1.2 at 37°C. Swelling properties of formulations with various amounts of NSC/ Poly (AAm-co-AA) and crosslinking agent at pH 7.4 and pH 1.2 were investigated. Hydrogels showed higher swelling ratios at pH 7.4 while lower at pH 1.2. Swelling kinetics and diffusion parameters were also determined. Drug loading, encapsulation efficiency, and in vitro release of 5-fluorouracil (5-FU) from the synthesized hydrogels were observed. In vitro release profile revealed the significant influence of pH, amount of NSC, Poly (AAm-co-AA), and crosslinking agent on the release of 5-FU. Accordingly, rapid and large release of drug was observed at pH 7.4 than at pH 1.2. The maximum encapsulation efficiency and release of 5-FU from SP2 were found to be 72.45% and 85.99%, respectively. Kinetics of drug release suggested controlled release mechanism of 5-FU is according to trend of non-Fickian. From the above results, it can be concluded that the synthesized hydrogels have capability to adapt their potential exploitation as targeted oral drug delivery carriers.

Matched MeSH terms: Chemistry, Pharmaceutical/methods
Vaginal drug delivery: strategies and concerns in polymeric nanoparticle development

Wong TW, Dhanawat M, Rathbone MJ

Expert Opin Drug Deliv, 2014 Sep;11(9):1419-34.
PMID: 24960192 DOI: 10.1517/17425247.2014.924499

Vaginal infection is widespread and > 80% of females encounter such infections during their lives. Topical treatment and prevention of vaginal infection allows direct therapeutic action, reduced drug doses and adverse effects, convenient administration and improved compliance. The advent of nanotechnology results in the use of nanoparticulate vehicle to control drug release, to enhance dosage form mucoadhesive properties and vaginal retention, and to promote mucus and epithelium permeation for both extracellular and intracellular drug delivery.

Matched MeSH terms: Chemistry, Pharmaceutical/methods
Use of microwave in processing of drug delivery systems

Wong TW

Curr Drug Deliv, 2008 Apr;5(2):77-84.
PMID: 18393808

Microwave has received a widespread application in pharmaceuticals and food processing, microbial sterilization, biomedical therapy, scientific and biomedical analysis, as well as, drug synthesis. This paper reviews the basis of application of microwave to prepare pharmaceutical dosage forms such as agglomerates, gel beads, microspheres, nanomatrix, solid dispersion, tablets and film coat. The microwave could induce drying, polymeric crosslinkages as well as drug-polymer interaction, and modify the structure of drug crystallites via its effects of heating and/or electromagnetic field on the dosage forms. The use of microwave opens a new approach to control the physicochemical properties and drug delivery profiles of pharmaceutical dosage forms without the need for excessive heat, lengthy process or toxic reactants. Alternatively, the microwave can be utilized to process excipients prior to their use in the formulation of drug delivery systems. The intended release characteristics of drugs in dosage forms can be met through modifying the physicochemical properties of excipients using the microwave.

Matched MeSH terms: Chemistry, Pharmaceutical/methods
Use of artificial neural networks to predict drug dissolution profiles and evaluation of network performance using similarity factor

Peh KK, Lim CP, Quek SS, Khoh KH

Pharm Res, 2000 Nov;17(11):1384-8.
PMID: 11205731

PURPOSE: To use artificial neural networks for predicting dissolution profiles of matrix-controlled release theophylline pellet preparation, and to evaluate the network performance by comparing the predicted dissolution profiles with those obtained from physical experiments using similarity factor.
METHODS: The Multi-Layered Perceptron (MLP) neural network was used to predict the dissolution profiles of theophylline pellets containing different ratios of microcrystalline cellulose (MCC) and glyceryl monostearate (GMS). The concepts of leave-one-out as well as a time-point by time-point estimation basis were used to predict the rate of drug release for each matrix ratio. All the data were used for training, except for one set which was selected to compare with the predicted output. The closeness between the predicted and the reference dissolution profiles was investigated using similarity factor (f2).
RESULTS: The f2 values were all above 60, indicating that the predicted dissolution profiles were closely similar to the dissolution profiles obtained from physical experiments.
CONCLUSION: The MLP network could be used as a model for predicting the dissolution profiles of matrix-controlled release theophylline pellet preparation in product development.

Matched MeSH terms: Chemistry, Pharmaceutical/methods*
Tumor regression and modulation of gene expression via tumor-targeted tocotrienol niosomes

Tan DM, Fu JY, Wong FS, Er HM, Chen YS, Nesaretnam K

Nanomedicine (Lond), 2017 Oct;12(20):2487-2502.
PMID: 28972460 DOI: 10.2217/nnm-2017-0182

AIM: To develop 6-O-palmitoyl-ascorbic acid-based niosomes targeted to transferrin receptor for intravenous administration of tocotrienols (T3) in breast cancer.
MATERIALS & METHODS: Niosomes were prepared using film hydration and ultrasonication methods. Transferrin was coupled to the surface of niosomes via chemical linker. Nanovesicles were characterized for size, zeta potential, morphology, stability and biological efficacy.
RESULTS: When evaluated in MDA-MB-231 cells, entrapment of T3 in niosomes caused 1.5-fold reduction in IC50 value compared with nonformulated T3. In vivo, the average tumor volume of mice treated with tumor-targeted niosomes was 12-fold lower than that of untreated group, accompanied by marked downregulation of three genes involved in metastasis.
CONCLUSION: Findings suggested that tumor-targeted niosomes served as promising delivery system for T3 in cancer therapy.

Matched MeSH terms: Chemistry, Pharmaceutical/methods
Fulltext Topical Lyogel Containing Corticosteroid Decreases IgE Expression and Enhances the Therapeutic Efficacy Against Atopic Eczema

Ng SF, Anuwi NA, Tengku-Ahmad TN

AAPS PharmSciTech, 2015 Jun;16(3):656-63.
PMID: 25511806 DOI: 10.1208/s12249-014-0248-y

Hydrocortisone cream intended for atopic eczema often produces unwanted side effects after long-term use. These side effects are essentially due to repeated percutaneous administration of the medication for skin dermatitis, as atopic eczema is a relapsing disorder. Hence, there is a need to develop a new hydrocortisone formulation that will deliver the drug more effectively and require a reduced dosing frequency; therefore, the side effects could be minimized. In this study, a hydroxypropyl methylcellulose (HPMC) lyogel system based on 80% organic and 20% aqueous solvents containing 1% hydrocortisone was formulated. The hydrocortisone lyogel physicochemical characteristics, rheological properties, stability profile, and in vitro Franz cell drug release properties, as well as the in vivo therapeutic efficacies and dermal irritancy in Balb/c mice were investigated. The HPMC lyogel appeared clear and soft and was easy to rub on the skin. The lyogel also showed a higher drug release profile compared with commercial hydrocortisone cream. Similar to the cream, HPMC lyogels exhibited pseudoplastic behavior. From the mouse model, the hydrocortisone lyogel showed higher inflammatory suppressive effects than the cream. However, it did not reduce the transepidermal water loss as effectively as the control did. The dermal irritancy testing revealed that the hydrocortisone lyogel caused minimal irritation. In conclusion, HPMC lyogel is a promising vehicle to deliver hydrocortisone topically, as it showed a higher drug release in vitro as well as enhanced therapeutic efficacy in resolving eczematous inflammatory reaction compared with commercial cream.

Matched MeSH terms: Chemistry, Pharmaceutical/methods
Thermal sintering: a novel technique used in the design, optimization and biopharmaceutical evaluation of propranolol HCl gastric floating tablets

Venkata Srikanth M, Songa AS, Nali SR, Battu JR, Kolapalli VR

Drug Dev Ind Pharm, 2014 Jan;40(1):33-45.
PMID: 23317339 DOI: 10.3109/03639045.2012.744416

The objective of the present investigation was to study the applicability of thermal sintering technique for the development of gastric floating tablets of propranolol HCl. Formulations were prepared using four independent variables, namely (i) polymer quantity, (ii) sodium bicarbonate concentration, (iii) sintering temperature and (iv) sintering time. Floating lag time and t95 were taken as dependent variables. Tablets were prepared by the direct compression method and were evaluated for physicochemical properties, in vitro buoyancy and dissolution studies. From the drug release studies, it was observed that drug retarding property mainly depends upon the sintering temperature and time of exposure. The statistically optimized formulation (PTSso) was characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry studies, and no significant chemical interaction between drug and polymer was observed. Optimized formulation was stable at accelerated conditions for a period of six months. PTSso was evaluated for in vivo buoyancy studies in humans for both fed and fasted states and found that gastric residence time of the floating tablets were enhanced by fed stage but not in fasted state. Optimized formulation PTSso and commercial formulation Ciplar LA 80 were subjected to bioavailability studies in healthy human volunteers by estimating pharmacokinetic parameters such as Cmax, Tmax, area under curve (AUC), elimination rate constant (Kel), biological half-life (t1/2) and mean residence time (MRT). There was a significant increase in the bioavailability of the propranolol HCl from PTSso formulation, which was evident from increased AUC levels and larger MRT values than Ciplar LA 80.

Matched MeSH terms: Chemistry, Pharmaceutical/methods
Thermal sintering: a novel technique in the design of gastroretentive floating tablets of propranolol HCl and its evaluation

Meka VS, Songa AS, Nali SR, Battu JR, Kukati L, Kolapalli VR

Invest Clin, 2012 Sep;53(3):223-36.
PMID: 23248967

The aim of the present investigation was to formulate thermally sintered floating tablets of propranolol HCl, and to study the effect of sintering conditions on drug release, as well as their in vitro buoyancy properties. A hydrophilic polymer, polyethylene oxide, was selected as a sintered polymer to retard the drug release. The formulations were prepared by a direct compression method and were evaluated by in vitro dissolution studies. The results showed that sintering temperature and time of exposure greatly influenced the buoyancy, as well as the dissolution properties. As the sintering temperature and time of exposure increased, floating lag time was found to be decreased, total floating time was increased and drug release was retarded. An optimized sintered formulation (sintering temperature 50 degrees C and time of exposure 4 h) was selected, based on their drug retarding properties. The optimized formulation was characterized with FTIR and DSC studies and no interaction was found between the drug and the polymer used.

Matched MeSH terms: Chemistry, Pharmaceutical/methods*
Fulltext The use of umbelliferone in the synthesis of new heterocyclic compounds

Al-Amiery AA, Musa AY, Kadhum AA, Mohamad AB

Molecules, 2011 Aug 10;16(8):6833-43.
PMID: 21832973 DOI: 10.3390/molecules16086833

New coumarin derivatives, namely 7-[(5-amino-1,3,4-thiadiazol-2-yl)methoxy]-2H-chromen-2-one, 5-[(2-oxo-2H-chromen-7-yloxy)methyl]-1,3,4-thiadiazol-2(3H)-one, 2-[2-(2-oxo-2H-chromen-7-yloxy)acetyl]-N-phenylhydrazinecarbothioamide, 7-[(5-(phenylamino)-1,3,4-thiadiazol-2-yl)methoxy]-2H-chromen-2-one and 7-[(5-mercapto-4-phenyl-4H-1,2,4-triazol-3-yl)methoxy]-2H-chromen-2-one were prepared starting from the natural compound umbelliferone. The newly synthesized compounds were characterized by elemental analysis and spectral studies (IR, ¹H-NMR and ¹³C-NMR).

Matched MeSH terms: Chemistry, Pharmaceutical/methods*
The transit of dosage forms through the small intestine

Yuen KH

Int J Pharm, 2010 Aug 16;395(1-2):9-16.
PMID: 20478371 DOI: 10.1016/j.ijpharm.2010.04.045

The human small intestine, with its enormous absorptive surface area, is invariably the principal site of drug absorption. Hence, the residence time of a dosage form in this part of the gut can have a great influence on the absorption of the contained drug. Various methods have been employed to monitor the gastrointestinal transit of pharmaceutical dosage forms, but the use of gamma-scintigraphy has superceded all the other methods. However, careful consideration of the time interval for image acquisition and proper analysis of the scintigraphic data are important for obtaining reliable results. Most studies reported the mean small intestinal transit time of various dosage forms to be about 3-4h, being closely similar to that of food and water. The value does not appear to be influenced by their physical state nor the presence of food, but the timing of food intake following administration of the dosage forms can influence the small intestinal transit time. While the mean small intestinal transit time is quite consistent among dosage forms and studies, individual values can vary widely. There are differing opinions regarding the effect of density and size of dosage forms on their small intestinal transit properties. Some common excipients employed in pharmaceutical formulations can affect the small intestinal transit and drug absorption. There is currently a lack of studies regarding the effects of excipients, as well as the timing of food intake on the small intestinal transit of dosage forms and drug absorption.

Matched MeSH terms: Chemistry, Pharmaceutical
Fulltext The influence of operational parameters and feed preparation in a convective batch ribbon powder mixer

Yeow ST, Shahar A, Abdul Aziz N, Anuar MS, Yusof YA, Taip FS

Drug Des Devel Ther, 2011;5:465-9.
PMID: 22162640 DOI: 10.2147/DDDT.S25047

To investigate the effect of feed preparation characteristics and operational parameters on mixing homogeneity in a convective batch ribbon mixer.

Matched MeSH terms: Chemistry, Pharmaceutical
Fulltext The identification of novel Mycobacterium tuberculosis DHFR inhibitors and the investigation of their binding preferences by using molecular modelling

Hong W, Wang Y, Chang Z, Yang Y, Pu J, Sun T, et al.

Sci Rep, 2015;5:15328.
PMID: 26471125 DOI: 10.1038/srep15328

It is an urgent need to develop new drugs for Mycobacterium tuberculosis (Mtb), and the enzyme, dihydrofolate reductase (DHFR) is a recognised drug target. The crystal structures of methotrexate binding to mt- and h-DHFR separately indicate that the glycerol (GOL) binding site is likely to be critical for the function of mt-DHFR selective inhibitors. We have used in silico methods to screen NCI small molecule database and a group of related compounds were obtained that inhibit mt-DHFR activity and showed bactericidal effects against a test Mtb strain. The binding poses were then analysed and the influence of GOL binding site was studied by using molecular modelling. By comparing the chemical structures, 4 compounds that might be able to occupy the GOL binding site were identified. However, these compounds contain large hydrophobic side chains. As the GOL binding site is more hydrophilic, molecular modelling indicated that these compounds were failed to occupy the GOL site. The most potent inhibitor (compound 6) demonstrated limited selectivity for mt-DHFR, but did contain a novel central core (7H-pyrrolo[3,2-f]quinazoline-1,3-diamine), which may significantly expand the chemical space of novel mt-DHFR inhibitors. Collectively, these observations will inform future medicinal chemistry efforts to improve the selectivity of compounds against mt-DHFR.

Matched MeSH terms: Chemistry, Pharmaceutical
The achievement of ligand-functionalized organic/polymeric nanoparticles for treating multidrug resistant cancer

Lee WH, Loo CY, Leong CR, Young PM, Traini D, Rohanizadeh R

Expert Opin Drug Deliv, 2017 08;14(8):937-957.
PMID: 27759437 DOI: 10.1080/17425247.2017.1247804

INTRODUCTION: The effectiveness of conventional cancer chemotherapy is hampered by the occurrence of multidrug resistance (MDR) in tumor cells. Although many studies have reported the development of novel MDR chemotherapeutic agents, clinical success is lacking owing to the high associated toxicity. Nanoparticle-based delivery of chemotherapeutic drugs has emerged as alternative approach to treat MDR cancers via exploitation of leaky vasculature in the tumor microenvironment. Accordingly, functionalization of nanoparticles with target specific ligands can be employed to achieve significant improvements in the treatment of MDR cancer. Areas covered: This review focuses on the recent advances in the functionalization of nanocarriers with specific ligands, including antibodies, transferrin, folate, and peptides to overcome MDR cancer. The limitations of effective ligand-functionalized nanoparticles as well as therapeutic successes in ligand targeting are covered in the review. Expert opinion: Targeting MDR tumors with ligand-functionalized nanoparticles is a promising approach to improve the treatment of cancer. With this approach, higher drug concentrations at targeted sites would be achieved with lower dosage frequencies and reduced side effects in comparison to existing formulations of chemotherapeutic drugs. However, potential toxicities and immunological responses to ligands should be carefully reviewed for viable options in for future MDR cancer treatment.

Matched MeSH terms: Chemistry, Pharmaceutical
Tamoxifen-loaded nanostructured lipid carrier as a drug delivery system: characterization, stability assessment and cytotoxicity

How CW, Rasedee A, Manickam S, Rosli R

Colloids Surf B Biointerfaces, 2013 Dec 1;112:393-9.
PMID: 24036474 DOI: 10.1016/j.colsurfb.2013.08.009

Cancer nanotherapeutics is beginning to overwhelm the global research and viewed to be the revolutionary treatment regime in the medical field. This investigation describes the development of a stable nanostructured lipid carrier (NLC) system as carrier for Tamoxifen (TAM). The TAM-loaded NLC (TAM-NLC) developed with 200mg of TAM showed a spherical particle with the size of 46.6nm, polydispersity index of 0.267, entrapment efficiency of 99.74% and with the zeta potential of -23.78mV. Besides, the equivalent cytotoxicity of TAM and TAM-NLC to human (MCF-7) and mice (4T1) mammary breast cancer cell lines were observed. Incubating the formulation at the physiological pH resulted into reduced Ostwald ripening rate but without any significant change in the absorptivity. When coupled with the measurements of zeta potential and Ostwald ripening rate, the absorbance assay may be used to predict the long-term stability of drug-loaded nanoparticle formulations. The results of the study also suggest that TAM-NLC is a promising drug delivery system for breast cancer therapy. This is the first encouraging report on the in vitro effect of TAM-NLC against human and mouse mammary adenocarcinoma cell lines.

Matched MeSH terms: Chemistry, Pharmaceutical
Fulltext Synthesis, biological evaluation and corrosion inhibition studies of transition metal complexes of Schiff base

Kashyap S, Kumar S, Ramasamy K, Lim SM, Shah SAA, Om H, et al.

Chem Cent J, 2018 Nov 20;12(1):117.
PMID: 30460466 DOI: 10.1186/s13065-018-0487-1

BACKGROUND: The transition metal complexes formed from Schiff base is regarded as leading molecules in medicinal chemistry. Because of the preparative availability and diversity in the structure of central group, the transition metals are important in coordination chemistry. In the present work, we have designed and prepared Schiff base and its metal complexes (MC1-MC4) and screened them for antimicrobial, anticancer and corrosion inhibitory properties.
METHODOLOGY: The synthesized metal complexes were characterized by physicochemical and spectral investigation (UV, IR, 1H and 13C-NMR) and were further evaluated for their antimicrobial (tube dilution) and anticancer (SRB assay) activities. In addition, the corrosion inhibition potential was determined by electrochemical impedance spectroscopy (EIS) technique.
RESULTS AND DISCUSSION: Antimicrobial screening results found complexes (MC1-MC4) to exhibit less antibacterial activity against the tested bacterial species compared to ofloxacin while the complex MC1 exhibited greater antifungal activity than the fluconazole. The anticancer activity results found the synthesized Schiff base and its metal complexes to elicit poor cytotoxic activity than the standard drug (5-fluorouracil) against HCT116 cancer cell line. Metal complex MC2 showed more corrosion inhibition efficiency with high Rct values and low Cdl values.
CONCLUSION: From the results, we can conclude that complexes MC1 and MC2 may be used as potent antimicrobial and anticorrosion agents, respectively.

Matched MeSH terms: Chemistry, Pharmaceutical
Stability indicating HPLC-UV method for detection of curcumin in Curcuma longa extract and emulsion formulation

Syed HK, Liew KB, Loh GO, Peh KK

Food Chem, 2015 Mar 1;170:321-6.
PMID: 25306352 DOI: 10.1016/j.foodchem.2014.08.066

A stability-indicating HPLC-UV method for the determination of curcumin in Curcuma longa extract and emulsion was developed. The system suitability parameters, theoretical plates (N), tailing factor (T), capacity factor (K'), height equivalent of a theoretical plate (H) and resolution (Rs) were calculated. Stress degradation studies (acid, base, oxidation, heat and UV light) of curcumin were performed in emulsion. It was found that N>6500, T<1.1, K' was 2.68-3.75, HETP about 37 and Rs was 1.8. The method was linear from 2 to 200 μg/mL with a correlation coefficient of 0.9998. The intra-day precision and accuracy for curcumin were ⩽0.87% and ⩽2.0%, while the inter-day precision and accuracy values were ⩽2.1% and ⩽-1.92. Curcumin degraded in emulsion under acid, alkali and UV light. In conclusion, the stability-indicating method could be employed to determine curcumin in bulk and emulsions.

Matched MeSH terms: Chemistry, Pharmaceutical
Smart nanocrystals of artemether: fabrication, characterization, and comparative in vitro and in vivo antimalarial evaluation

Shah SM, Ullah F, Khan S, Shah SM, de Matas M, Hussain Z, et al.

Drug Des Devel Ther, 2016;10:3837-3850.
PMID: 27920499

Artemether (ARTM) is a very effective antimalarial drug with poor solubility and consequently low bioavailability. Smart nanocrystals of ARTM with particle size of 161±1.5 nm and polydispersity index of 0.172±0.01 were produced in <1 hour using a wet milling technology, Dena(®) DM-100. The crystallinity of the processed ARTM was confirmed using differential scanning calorimetry and powder X-ray diffraction. The saturation solubility of the ARTM nanocrystals was substantially increased to 900 µg/mL compared to the raw ARTM in water (145.0±2.3 µg/mL) and stabilizer solution (300.0±2.0 µg/mL). The physical stability studies conducted for 90 days demonstrated that nanocrystals stored at 2°C-8°C and 25°C were very stable compared to the samples stored at 40°C. The nanocrystals were also shown to be stable when processed at acidic pH (2.0). The solubility and dissolution rate of ARTM nanocrystals were significantly increased (P<0.05) compared to those of its bulk powder form. The results of in vitro studies showed significant antimalarial effect (P<0.05) against Plasmodium falciparum and Plasmodium vivax. The IC50 (median lethal oral dose) value of ARTM nanocrystals was 28- and 54-fold lower than the IC50 value of unprocessed drug and 13- and 21-fold lower than the IC50 value of the marketed tablets, respectively. In addition, ARTM nanocrystals at the same dose (2 mg/kg) showed significantly (P<0.05) higher reduction in percent parasitemia (89%) against P. vivax compared to the unprocessed (27%), marketed tablets (45%), and microsuspension (60%). The acute toxicity study demonstrated that the LD50 value of ARTM nanocrystals is between 1,500 mg/kg and 2,000 mg/kg when given orally. This study demonstrated that the wet milling technology (Dena(®) DM-100) can produce smart nanocrystals of ARTM with enhanced antimalarial activities.

Matched MeSH terms: Chemistry, Pharmaceutical
Small Molecules for Active Targeting in Cancer

Kue CS, Kamkaew A, Burgess K, Kiew LV, Chung LY, Lee HB

Med Res Rev, 2016 Apr;36(3):494-575.
PMID: 26992114 DOI: 10.1002/med.21387

For the purpose of this review, active targeting in cancer research encompasses strategies wherein a ligand for a cell surface receptor expressed on tumor cells is used to deliver a cytotoxic or imaging cargo. This area of research is more than two decades old, but in those 20 and more years, how many receptors have been studied extensively? What kinds of the ligands are used for active targeting? Are they mostly naturally occurring molecules such as folic acid, or synthetic substances developed in campaigns for medicinal chemistry efforts? This review outlines the most important receptor or ligand combinations that have been used in active targeting to answer these questions, and therefore to address the most important one of all: is research in active targeting affording diminishing returns, or is this an area for which the potential far exceeds progress made so far?

Matched MeSH terms: Chemistry, Pharmaceutical
Simultaneous determination of atenolol and amiloride by capillary electrophoresis with capacitively coupled contactless conductivity detection (C4D)

AL Azzam KM, Aboul-Enein HY

Methods Mol Biol, 2013;919:67-78.
PMID: 22976091 DOI: 10.1007/978-1-62703-029-8_7

Capillary electrophoresis coupled with a capacitively coupled contactless conductivity detector (CE-C(4)D) has been employed for the determination of the β-blocker drugs (atenolol and amiloride) in pharmaceutical formulations. 150 mM acetic acid was used as background electrolyte. The influence of several factors (detector excitation voltage and frequency, buffer concentration, applied voltage, capillary temperature, and injection time) was studied. Non-UV absorbing L-valine was used as an internal standard; the analytes were all separated in less than 7 min. The separation was carried out in normal polarity mode at 28 °C, 25 kV, and using hydrodynamic injection (25 s). The separation was effected in a bare fused-silica capillary 75 μm × 52 cm. The CE-C(4)D method was validated with respect to linearity, limit of detection and quantification, accuracy, precision, and selectivity. Calibration curves were linear over the range 5-250 μg mL(-1) for the studied analytes. The relative standard deviations of intra- and inter-day precisions of migration times and corrected peak areas were less than 6.0%. The method showed good precision and accuracy and was successfully applied to the simultaneous determination of the β-blocker drugs in different pharmaceutical tablets.

Matched MeSH terms: Chemistry, Pharmaceutical
Self-assembled three-dimensional reduced graphene oxide-based hydrogel for highly efficient and facile removal of pharmaceutical compounds from aqueous solution

Umbreen N, Sohni S, Ahmad I, Khattak NU, Gul K

J Colloid Interface Sci, 2018 Oct 01;527:356-367.
PMID: 29843021 DOI: 10.1016/j.jcis.2018.05.010

Herein, self-assembled three-dimensional reduced graphene oxide (RGO)-based hydrogels were synthesized and characterized in detail. A thorough investigation on the uptake of three widely used pharmaceutical drugs, viz. Naproxen (NPX), Ibuprofen (IBP) and Diclofenac (DFC) was carried out from aqueous solutions. To ensure the sustainability of developed hydrogel assembly, practically important parameters such as desorption, recyclability and applicability to real samples were also evaluated. Using the developed 3D hydrogels as adsorptive platforms, excellent decontamination for the above mentioned persistent pharmaceutical drugs was achieved in acidic pH with a removal efficiency in the range of 70-80%. These hydrogels showed fast adsorption kinetics and experimental findings were fitted to different kinetic models, such as pseudo-first order, pseudo-second order, intra-particle and the Elovich models in an attempt to better understand the adsorption kinetics. Furthermore, equilibrium adsorption data was fitted to the Langmuir and Freundlich models, where relatively higher R2 values obtained in case of former one suggested that monolayer adsorption played an important part in drug uptake. Thermodynamic aspects were also studied and negative ΔG0 values obtained indicated the spontaneous nature of adsorption process. The study was also extended to check practical utility of as-prepared hydrogels by spiking real aqueous samples with drug solution, where high % recoveries obtained for NPX, IBP and DFC were of particular importance with regard to prospective application in wastewater treatment systems. We advocate RGO-based hydrogels as environmentally benign, readily recoverable/recyclable material with excellent adsorption capacity for application in wastewater purification.

Matched MeSH terms: Chemistry, Pharmaceutical

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