Buffer Medium Research Articles

Characteristics and Release Profile : Formula of Insulin Nanoparticles using Medium Molecular Weight Chitosan and Pectin Polymers

Insulin is a macromolecular polypeptide hormone with low drug stability and permeability along the digestive tract. The nanoparticle delivery system has been proven to be able to increase the bioavailability of per-oral insulin. However, the formulation of insulin nanoparticles using chitosan and pectin polymers has not been widely studied. The purpose of this research is to figure out the physical characteristics and profile of insulin release from nanoparticle formulas made with ionic gelation techniques using chitosan and pectin polymers. The 0.1% insulin nanoparticle formula is made with variations of 2 levels of medium molecular chitosan and pectin concentrations to obtain 4 formulas, i.e. F1 (0.01%; 0.1%), F2 (0.03%; 0.1%), F3 (0.01%; 0.2%), and F4 (0.03%; 0.2%). The optimum formula is determined by the factorial design method contained in the Design Expert program using response characteristics in the form of percentage of the entrapment efficiency and zeta potential value. The selected formula is then tested for particle size and shape, and insulin release profile in vitro. The particle size and morphology are observed with TEM (Transmission Electron Microscope), while the insulin release profile is determined on HCl buffer media pH 1.2 and PBS pH 6.8. The optimization results of the formula show that F1 is the optimum formula with a desirability value of 0.786. The selected formula shows that the entrapment efficiency is 57.66%, the zeta potential is 12.0 mV, the shape of particles is spherical, and the size is <500 nm. In vitro studies show the profile of insulin release from the matrix following the Weibull kinetics model on HCl and Korsmeyer-Peppas media on PBS media, using the Fickian diffusion method. Overall, the insulin nanoparticles obtained have met the expected characteristic of the nanoparticles.

Novel intein-based self-cleaving affinity tag for recombinant protein production in Escherichia coli

We evaluated several intein-based self-cleaving affinity tags for expression and single-step affinity chromatography purification of recombinant proteins produced in Escherichia coli. We used human growth hormone (hGH) as target protein that contains two internal disulfide bridges and an N-terminal phenylalanine. Use of N-terminal thiol-induced Sce VMA1 intein affinity tag resulted in purified hGH deficient in disulfide bonds. Inteins with self-cleavage inducible by pH and/or temperature shift were analyzed. N-terminal Ssp DnaX intein affinity tag resulted in a completely cleaved cytosolic protein, whereas N-terminal Ssp DnaB intein affinity tag resulted in a cytosolic fusion protein incapable of releasing hGH. Periplasmic expression of target protein was analyzed using an N-terminal signal peptide and C-terminal Ssp DnaX pH-inducible self-cleaving affinity tag. The fusion protein was properly expressed in pH 8 buffered culture medium. Fusion of a periplasmic signal peptide to the N-terminus of the POI allowed secretion to the periplasmic region and presence of the natural N-terminal amino acid of the POI following cleavage. Periplasmic expression of hGH fused to this novel C-terminal DnaX intein-based self-cleaving affinity tag made possible expression and purification of hGH protein containing disulfide bonds and free of extra amino acids.

Preparation of pellets containing a standardized Artemisia annua L. extract by extrusion-spheronization

Artemisinin, the major substance with antimalarial activity of Artemisia annua L., is a poorly water-soluble drug. The development of pellets containing a standardized hydroethanolic extract of A. annua may overcome these drawbacks while offer an intermediate product with good technological properties for subsequent tablet manufacture. This work aimed to obtain and characterize A. annua pellets using the extrusion-spheronization technique. The extract was prepared by percolation and artemisinin content was determined using a validated HPLC method. The standardized extract was then used as a liquid binder in the preparation of pellets with different liquid: solid ratio. The formulation PF5 containing microcrystalline cellulose: A. annua extract (40:58) resulted in pellets with 1.49 ± 0.02 % (w/w) artemisinin, average size of approximately 500 µm and sphericity of 0.82 ± 0.08. These pellets were encapsulated in hard gelatin capsules and the percentage released was higher than 80% in 10 min using 0.1N HCl and phosphate buffer media. These data allow to suggest that the pelletizing strategy used made it possible to achieve the desired artemisinin dissolution and generates perspectives for the potential further use of the A. annua pellets as a solid dosage form for malaria treatment.

Spectrophotometric and Spectrofluorimetric Determination of Terazosin in Tablets by Eosin Y

Simple, sensitive and accurate two methods were described for the determination of terazosin. The spectrophotometric method (A) is based on measuring the spectral absorption of the ion-pair complex formed between terazosin with eosin Y in the acetate buffer medium pH 3 at 545 nm. Method (B) is based on the quantitative quenching effect of terazosin on the native fluorescence of Eosin Y at the pH 3. The quenching of the fluorescence of Eosin Y was measured at 556 nm after excitation at 345 nm. The two methods obeyed Beer’s law over the concentration ranges of 0.1-8 and 0.05-7 µg/mL for method A and B respectively. Both methods succeeded in the determination of terazosin in its tablets

Preparation, optimization, characterization and in vitro release of baicalein-solubilizing glycyrrhizic acid nano-micelles

Glycyrrhizic acid is an amphiphilic molecule, which can form host-guest complexes by self-assembly, thereby encapsulating the guest molecule and increasing its solubility. The complexes can also achieve a controlled release effect for encapsulated drugs, so they have potential as drug delivery-systems. Baicalein is a flavonoid, with many pharmacological activities, but its oral bioavailability is limited by its poor solubility. In this study, glycyrrhizic acid-baicalein nano-micelles were prepared by an ultrasonic-film hydration method. The baicalein-loaded nano-micelles were evaluated by encapsulation efficiency, baicalein loading, particle size, polydispersity index and ζ-potential. A Box-Behnken statistical design was applied to obtain the optimal formulation (glycyrrhizic acid: 90 mg, baicalein: 8 mg, water bath shaking time: 12 h, ultrasonication time: 10 min). Nano-micelles prepared with the optimal formulation improved the solubility of baicalein in water by more than 4500 times and were characterized by differential scanning calorimetry and Fourier-transform infrared spectroscopy. An in vitro drug release study determined the cumulative drug release of baicalein in pH 6.8 and pH 8.3 buffer medium, after 6 h to be 18.20% and 47.96%, respectively, which indicates that the nano-micelles have a sustained-release effect on baicalein and that the release rate can be modulated by changing the pH.

Comparative evaluation study of polycomplex carriers based on Eudragit® EPO/S100 copolymers prepared in different media

AbstractInterpolymer complexes (IPC) Eudragit® EPO/S100 were prepared in different media (water pH of 7.0 and ethanol). According to the elemental analysis, FTIR spectroscopy, and thermal analysis data, IPC prepared in aqueous media (denoted as interpolyelectrolyte complexes—IPECs) is stabilized predominantly by ionic intermacromolecular bonds and has a composition close to equimolar. However, polycomplexes formed in nonaqueous (ethanol) media (denoted as IPC) are stabilized by both hydrogen and ionic bonds and characterized by an almost twofold excess of Eudragit® S100. All samples do not include free copolymer domains. IPECs and IPCs have different behavior in the buffer media mimicking the gastrointestinal tract. Matrices of IPECs are characterized by the surface erosion and pH‐independent swelling profiles with low values of a swelling degree. Matrices of the IPCs swell significantly in the buffer media with pH 1.2, 5.8, and 6.8 with subsequent decrease in the swelling degree due to the surface erosion. According to the assessment of release of the model active pharmaceutical ingredient (API), IPECs are prospective carriers for sustained delivery of II class Biopharmaceutical Classification System (BCS) drug (diclofenac sodium). At the same time, IPCs provide sustained release of the II class BCS and prolonged release of the I class BCS drug (theophylline).

Egg White Protein Carrier-Assisted Development of Solid Dispersion for Improved Aqueous Solubility and Permeability of Poorly Water Soluble Hydrochlorothiazide.

Hydrochlorothiazide (HTZ) is a first-line drug used in the treatment of hypertension suffered from low oral bioavailability due to poor aqueous solubility and permeability. Hence, lyophilized egg white protein-based solid dispersion (HTZ-EWP SD) was developed to explore its feasibility as a solid dispersion carrier for enhanced aqueous solubility and permeability of HTZ. The HTZ-EWP SD was prepared using the kneading method. HTZ-EWP SD was characterized using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transforms infrared spectroscopy (FT-IR), powder X-ray diffractometer (PXRD), solubility, in vitro dissolution, and ex vivo permeation studies. The physico-chemical evaluation suggested the formation of the solid dispersion. Optimized HTZ-EWP SD4 drastically enhanced (~32-fold) aqueous solubility (~16.12 ± 0.08 mg/mL) over to pure HTZ (~ 0.51 ± 0.03 mg/mL). The dissolution study in phosphate buffer media (pH 6.8) revealed that HTZ-EWP SD4 significantly enhanced the release rate of HTZ (~ 87 %) over to HTZ (~ 25 %). The permeation rate of HTZ from optimized HTZ-EWP SD4 was enhanced significantly (~ 84 %) compared to pure HTZ (~ 24 %). Optimized HTZ-EWP-SD4 enhanced the rate of HTZ dissolution (~ 86 %) in FeSSIF (fed state simulated intestinal fluid), compared to a low dissolution rate (~ 72 %) in FaSSIF (fasted state simulated intestinal fluid) state after 2-h study. Obtained results conclude that lyophilized egg white protein can be utilized as an alternative solid dispersion carrier for enhancing the solubility and permeability of HTZ.

Preanalytical Issues and Cycle Threshold Values in SARS-CoV-2 Real-Time RT-PCR Testing: Should Test Results Include These?

Since the emergence of SARS-CoV-2 pandemic, clinical laboratories worldwide are overwhelmed with SARS-CoV-2 testing using the current gold standard: real-time reverse-transcription polymerase chain reaction (RT-PCR) assays. The large numbers of suspected cases led to shortages in numerous reagents such as specimen transport and RNA extraction buffers. We try to provide some answers on how strongly preanalytical issues affect RT-PCR results by reviewing the utility of different transport buffer media and virus inactivation procedures and comparing the literature data with our own recent findings. We show that various viral inactivation procedures and transport buffers are available and are less of a bottleneck for PCR-based methods. However, efficient alternative lysis buffers remain more difficult to find, and several fast RT-PCR assays are not compatible with guanidine-containing media, making this aspect more of a challenge in the current crisis. Furthermore, the availability of different SARS-CoV-2-specific RT-PCR kits with different sensitivities makes the definition of a general cutoff level for the cycle threshold (Ct) value challenging. Only a few studies have considered how Ct values relate to viral infectivity and how preanalytical issues might affect viral infectivity and RNA detection. We review the current data on the correlation between Ct values and viral infectivity. The presence of the SARS-CoV-2 viral genome in its own is not sufficient proof of infectivity and caution is needed in evaluation of the infectivity of samples. The correlation between Ct values and viral infectivity revealed an RT-PCR cutoff value of 34 cycles for SARS-CoV-2 infectivity using a laboratory-developed RT-PCR assay targeting the RdRp gene. While ideally each clinical laboratory should perform its own correlation, we believe this perspective article could be a reference point for others, in particular medical doctors and researchers interested in COVID-19 diagnostics, and a first step toward harmonization.

A kinetic study of the oxidation of the tetrakisoxalatouranate(IV) ion by the hexacyanoferrate(III) ion in an oxalate buffer medium

A kinetic study of the oxidation of the tetrakisoxalatouranate(IV) ion by the hexacyanoferrate(III) ion in an oxalate buffer medium

Sequence-function relationship within water-soluble Peptoid Chelators for Cu2+

Chelation of Cu2+ by synthetic molecules is an emerging therapeutic approach for treating several illnesses in human body such as Wilson disease, cancer and more. Among synthetic metal chelators, those based on peptoids – N-substituted glycine oligomers – are advantageous due to their structural similarity to peptides, ease of synthesis on solid support and versatile controlled sequences. Tuning peptoid sequences, via systematically changing at least one side chain, can facilitate and control their function. Along these lines, this work aims to explore the role of the non-coordinating side chain within peptoid chelators in order to understand the factors that control the selectivity of these chelators to Cu2+ in water medium. To this aim, a set of peptoid trimers having a pyridine group at the acetylated N-terminal, a 2,2′-bipyridine group at the second position and a non-coordinating group at the C-terminus, where the latter is systematically varied between aromatic, aliphatic, chiral or non-chiral, were investigated as selective chelators for Cu2+. The effect of the position of the non-coordinating group on the selectivity of the peptoid to Cu2+ was also tested. Based on extensive spectroscopic data, we found that the choice of the non-coordinating group along with its position dramatically influences the selectivity of the peptoids to Cu2+. We showed that peptoids having bulky chiral groups at the C-terminus enable high selectivity to Cu2+. We further demonstrated the ability of one of the selective chelators to remove Cu2+ from the natural copper binding protein metallothionein in HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) buffer medium.

Interaction of Rare-Earth Metals and Some Perfluorinated β-Diketones.

In this work, we demonstrate the fundamental relationships between stability constants and periodic, acid-base, and structural parameters for complexes of some 1,3-diketones. The four analogues of hexafluoroacetylacetone-2-thenoyltrifluoroacetone, 2-furoyltrifluoroacetone, benzoyltrifluoroacetone, and 2-naphthyltrifluoroacetone-have been studied as chelating ligands for 16 rare-earth metals (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) in aqueous solutions. Systems have been investigated spectrophotometrically using a multiwave nonlinear least-squares regression algorithm for data processing. Conditional stability constants were obtained for a wide pH region (2.0-5.4) at constant ionic strength (I = 0.5 M, NaCl). To receive the apparent ("true") equilibrium parameters, acid-base and keto-enol characteristics of the studied ligands have been described and revised for specific conditions. Dissociation constants were obtained in citrate-phosphate buffer media and protonation parameters were received in concentrated hydrochloric acid by the Cox-Yates method. The apparent formation constants for monocomplex species were obtained as thermodynamic invariants (depend only on the temperature) for each ligand and lie from 4.2 to 12.7 logarithmic units. Although the studied ligands have similar values of pKa, the stabilities of their complexes vary considerably. Systematic analysis of 64 apparent stability constants demonstrates that the force of interaction between the metals and nonsymmetric β-diketones increases as 2-furoyltrifluoroacetone < 2-thenoyltrifluoroacetone < benzoyltrifluoroacetone < 2-naphthyltrifluoroacetone. The studied ligands display varying degrees of the correlation between the periodic parameters and formation constants. Naphthyltrifluoroacetone and its complexes with heavy lanthanides exhibit a clear trend in properties with increasing ionic potential. In general, the received set of data can be described from purely electrostatic grounds within the framework of the periodic law. Spectral, keto-enol, acid-base, and complexing properties were reproduced using density functional theory modeling and explain some of the regularities discovered.

Highly selective detection of isatin using curcumin analogue and its application in real samples

A novel curcumin analogue bearing indole NH (DP4) unit was synthesized as fluorescent sensor for isatin in biological system with fairly selective over other competitors. The sensor triggered a “turn-off” fluorescence response toward isatin with concurrent decrease with fluorescence intensity in PBS buffer solution at pH 7.4. The detection limit of isatin was calculated as low as 241 nM. It can be employed to detect isatin in biological samples in buffer medium. The hydrogen bonding interaction of probe with isatin was studied using 1H NMR titration and DFT calculation.

Toward In Vivo Transdermal pH Sensing with a Validated Microneedle Membrane Electrode.

We present herein the most complete characterization of microneedle (MN) potentiometric sensors for pH transdermal measurements for the time being. Initial in vitro assessment demonstrated suitable analytical performances (e.g., Nernstian slope, linear range of response from 8.5 to 5.0, and fast response time) in both buffer media and artificial interstitial fluid (ISF). Excellent repeatability and reproducibility together with adequate selectivity and resiliency facilitate the appropriateness of the new pH MN sensor for transdermal ISF analysis in healthcare. The ability to resist skin insertions was evaluated in several ex vivo setups using three different animal skins (i.e., chicken, pork, and rat). The developed pH MN sensor was able to withstand from 5 to 10 repetitive insertions in all the skins considered with a minimal change in the calibration graph (<3% variation in both slope and intercept after the insertions). Ex vivo pH measurements were validated by determining the pH with the MN sensor and a commercial pH electrode in chicken skin portions previously conditioned at several pH values, obtaining excellent results with an accuracy of <1% and a precision of <2% in all cases. Finally, pH MN sensors were applied for the very first time to transdermal measurements in rats together with two innovative validation procedures: (i) measuring subcutaneous pH directly with a commercial pH microelectrode and (ii) collecting ISF using hollow MNs and then the pH measurement of the sample with the pH microelectrode. The pH values obtained with pH MN sensors were statistically more similar to subcutaneous measurements, as inferred by a paired sample t-test at 95% of confidence level. Conveniently, the validation approaches could be translated to other analytes that are transdermally measured with MN sensors.

Green synthesis of silver nanoparticles using pollen extract: Characterization, assessment of their electrochemical and antioxidant activities

In the present study, a simple, cheaply and environmental friendly method was evaluated for the synthesis of silver nanoparticle via Cupressus sempervirens L. (CSPE) pollen extract as reducing and stabilizing agent. Various parameters such as volume of CSPE, temperature and reaction time on AgNPs formation were investigated spectrophotometrically to optimize reaction conditions. The electrochemical behavior of the biosynthesized AgNPs were investigated by cyclic voltammetry and square wave voltammetry techniques. An electrosensor based on AgNPs modified glassy carbon electrode were constructed and tested on electro reduction of hydrogen peroxide in phosphate buffer medium. The prepared electrosensor could detect the H2O2 in the range of 5.0 μM - 2.5 mM with a detection limit of 0.23 μM. In addition, the antioxidant activity of biosynthesized AgNPs were evaluated against DPPH free radical. Results obtained from the antioxidant study suggested that CSPE mediated AgNPs exhibit a good antioxidant effect.

Active Bromoaniline-Aldehyde Conjugate Systems and Their Complexes as Versatile Sensors of Multiple Cations with Logic Formulation and Efficient DNA/HSA-Binding Efficacy: Combined Experimental and Theoretical Approach.

Two fluorescence active bromoaniline-based Schiff base chemosensors, namely, (E)-4-bromo-2-(((4-bromophenyl)imino)methyl)phenol (HL1) and (E)-2-(((4-bromophenyl)imino)methyl)phenol (HL2), have been employed for the selective and notable detection of Cu2+ and Zn2+ ions, respectively, with the simultaneous formation of two new metal complexes [Cu(L1)2] (1) and [Zn(L2)2] (2). X-ray single crystal analyses indicate that complexes 1 and 2 are tetra-coordinated systems with substantial CH...π/π...π stacking interactions in the solid-state crystal structures. These two complexes are exploited for the next step detection of Al3+ and Hg2+ where complex 2 exhibits impressive results via turn-off fluorescence quenching in (DMSO/H2O) HEPES buffer medium. The sensing phenomena are optimized by UV–vis spectral analyses as well as theoretical calculations (density functional theory and time-dependent density functional theory). The combined detection phenomena of the ligand (HL2) and complex 2 are exclusively utilized for the first time to construct a molecular memory device, intensifying their multisensoric properties. Furthermore, the DNA- and human serum albumin (HSA)-binding efficacies of these two complexes are examined by adopting electronic and fluorometric titration methods. Complex 2 shows a higher DNA-binding ability in comparison with complex 1, whereas in the case of HSA, the reverse situation is observed. Finally, the binding modes of both the complexes with DNA and HSA have been investigated through molecular docking studies, suggesting good agreement with the experimental results.

Exploratory Study on Lercanidipine Hydrochloride Polymorphism: pH-Dependent Solubility Behavior and Simulation of its Impact on Pharmacokinetics

This work describes an exploratory experimental and in silico study of the influence of polymorphism, particle size, and physiology on the pharmacokinetics of lercanidipine hydrochloride (LHC). Equilibrium and kinetic solubility studies were performed on LHC forms I and II, as a function of pH and buffer composition. GastroPlus® was used to evaluate the potential effect of solubility differences due to polymorphism, particle size, and physiological conditions, on the drug pharmacokinetics. The results indicated that solubilities of LHC polymorphs are strongly dependent on the composition and pH of the buffer media. The concentration ratio (CI/CII) is particularly large for chloride buffer (CI/CII = 3.3-3.9) and exhibits a slightly decreasing tendency with the pH increase for all other buffers. Based on solubility alone, a higher bioavailability of form I might be expected. However, exploratory PBPK simulations suggested that (i) under usual fasted (pH 1.3) and fed (pH 4.9) gastric conditions, the two polymorphs have similar bioavailability, regardless of the particle size; (ii) at high gastric pH in the fasted state (e.g., pH 3.0), the bioavailability of form II can be considerably lower than that of form I, unless the particle size is < 20 μm. This study demonstrates the importance of investigating the effect of the buffer nature when evaluating the solubility of ionizable polymorphic substances. It also showcases the benefits of using PBPK simulations, to assess the risk and pharmacokinetic relevance of different solubility and particle size between crystal forms, for diverse physiological conditions.

In vitro kinetic release study of ketoprofen enantiomers from alginate metal complexes

BackgroundTo explore the release behavior of ketoprofen enantiomers from alginate-metal-complexes. Five mathematical models of drug release kinetics were investigated.ResultsBeads of alginate-metal complexes, loaded with racemic ketoprofen, were prepared by the ionotropic method. Divalent (Ca, Ba, Zn) and trivalent (Fe, Al) metals were used in the preparation of single-metal and mixed-metal alginate complexes. In vitro release experiments were carried out in an aqueous phosphate buffer medium at pH = 7.4. The concentrations of ketoprofen released enantiomers were determined using chiral HPLC technique. The obtained data were used to simulate the release kinetic of ketoprofen enantiomers using various mathematical models. The Korsmeyer-Peppas model was the best fit for Ca, Al, and Fe beads. Moreover, alginate-iron beads tend to release the drug faster than all other cases. In contrast, the drug release for alginate-barium complex was the slowest. The presence of barium in alginate mixed-metal complexes reduced ketoprofen release in the case of Fe and Zn, while it increased the release in the case of Al complex.ConclusionIn all the studied cases, ketoprofen showed very slow release for both enantiomers over a period exceeded 5 h (10 days in some cases). The release rate modification is possible using different multivalent metals, and it is also feasible by using two different metals for congealing either consecutively or simultaneously.

Effects of experimental conditions on solubility measurements for BCS classification in order to improve the biowaiver guidelines

Among the methods described for determining the solubility, shake-flask is suitable to evaluate the equilibrium solubility according to the BCS. Nevertheless, experimental conditions related to the shake-flask method are not well described. Evaluating the effects of experimental conditions on solubility measurements by shake-flask method is important and contributes in biowaiver decision. For this work, propranolol hydrochloride and nimesulide were used as model compound of high and low solubility, respectively. Equilibrium solubility was evaluated at 37 oC, 100 rpm during 48 hours in buffer media. Effects of the rotation speed, temperature, substance in excess and aliquot withdrawn were evaluated. Small variations of temperature caused significant differences in the solubility and then this parameter must be controlled. Excess of raw material influenced the results of the nimesulide, then, little excess is recommended. Rotation speed did not cause differences in the equilibrium solubilities, but at 150 rpm the equilibrium was reached faster. Aliquot did not present significant differences, but excessive withdrawn should be avoided. Therefore, the evaluation of equilibrium solubility using shake-flask method must be performed in physiological pH conditions, 37 ± 1 oC, substance in excess 10% above saturation, 50, 100 or 150 rpm and aliquot withdrawn not more than 10% of the media volume.

Investigation of Electrochemical Behavior of Mordant Dye (C.I. 17135) at Glassy Carbon and Silver Electrodes

In this study, the electrochemical behaviour of Mordant dye (C.I. 17135) was investigated in Britton-Robinson (BR) buffer (pH 2.0-12.0) media by using different voltammetric techniques: square wave voltammetry (SWV), cyclic voltammetry (CV), differential pulse voltammetry (DPV) and direct current voltammetry (DCV). The electrochemical behavior of the dye has been investigated by using a glassy carbon electrode (GCE) and silver electrode (SE). The brode peak of the azo dye occurred at SW and DP voltammograms, is due to its adsorption on the glassy carbon and silver electrode surfaces. Two reduction peaks were observed at pH &lt; 9.5, and one reduction peak was observed at pH &gt; 9.5 for SWV and DPV techniques at a glassy carbon electrode. From the voltammetric data electrochemical reaction mechanism of the azo dye has been suggested at glassy carbon and silver electrodes.

A Novel Potentiometric Ion Selective Electrode Based on Piperine for the Determination of Fe(III) Ions

A new potentiometric sensor highly selective to Fe3+ was prepared using piperine as a neutral ionophore. The electrode exhibits a linear response for Fe3+ ions in the citrate buffer medium over a concentration range from 1 × 10–4 to 1 M (detection limit of 6 × 10–5 M) with a Nernstian slope of 20.5 mV per decade. The electrode can be successfully used in the pH range of 3.15–7.85. It has a fairly good discriminating ability toward Fe3+ ions among some other metal ions such as K+, Ca2+, Mg2+, Cu2+, Ba2+, Co2+, Al3+ and Cr3+ with selectivity coefficients of –2.11, –9.02, –10.38, –8.34, –8.12, –8.79, –8.41 and –3.69, respectively. The electrode can be used for 10 weeks without any considerable divergence in the observed slope. It has been successfully validated using atomic absorption spectrometry and used in the determination of Fe3+ in chewable iron capsules.