Formation Of Ion-pair Complex Research Articles

Evaluation of the on–off fluorescence method for facile measurement of vilazodone in pharmaceutical dosage form; Application to content uniformity testing and greenness evaluation

Vilazodone is a recently approved antidepressant medicine used for treating major depressive disorder. A simple, extremely sensitive, accurate and green spectrofluorimetric method was constructed for its determination through formation of ion-pair complex with erythrosine B. The formation of ion-pair complex lowers the dye’s native fluorescence emission measured at 552 nm (λ ex = 530 nm). In terms of analysis, the system’s parameters for producing the vilazodone-erythrosine B complex have been optimized. The reaction was carried out in Teorell-Stenhagen buffering solution (pH 4.6). The fluorescence emission intensity of the dye decreased linearly in the range of 20 – 600 ng mL−1 and the correlation coefficient was 0.9999. The quantitation and detection limit values were 18.5 and 6.1 ng mL−1, respectively. The proposed strategy has been validated according to the ICH criteria. The proposed technique was thoroughly employed for evaluating vilazodone in raw material and pharmaceutical tablet dosage form. Furthermore, it was also successfully used for content uniformity testing. Lastly, using four advanced tools namely the Eco-Scale, the National Environmental Method Index (NEMI), the Green Analytical Procedure Index (GAPI), and the Analytical Greenness metric approach (AGREE), the greenness of the established technique was evaluated.

Determination of Methdilazine by Extractive Colorimetric Method from Pharmaceutical Dosage Form

Simple sensitive and accurate ion pair complex formation, extractive spectrophotometric methods have developed for the estimation of methdilazine hydrochloride in pharmaceutical dosage form. The methods are based on the formation of ion paired coloured complexes by the drug with reactive dyes like Congo red, picric acid and methyl orange in acidic medium. The ion associated complexes were formed and quantitatively extracted under the experimental condition in chloroform. The absorbance values were measured at 490 nm, 400 nm, and 430 nm respectively. The proposed methods were validated statistically. Recoveries of methods were carried out by standard addition method. The linearity was found to be 1-10 μg/ml, 2-12 μg/ml, and 1-14 μg/ml for methods respectively. The low values of standard deviation and percentage RSD indicate high precision of methods. Hence these methods are useful for routine estimation of methdilazine hydrochloride in pharmaceutical dosages.

Thermodynamic studies on the formation of ion-pair cobalt complexes in acetone–water mixtures

Dicarboxylic acids are stronoger acids than moncraboxylic acids and more soluble in water due to the presence of two carboxylic (–COOH) groups which are industrially important in producing polyester, polyamides, and polyols and as a pioneer to pharmaceutical additives. Succinic acid is one of the most prosperous chemicals that can be generated from renewable resources which can be used in the industries of antiseptics, cosmetics, sutures, drugs, solvents, detergents, herbicides, fungicides, synthetic resins, and inks. The ion–pair formation is very important in diferent applications, used widely for inorganic analysis by liquid chromatography and used for the heavy metal removal from waste water, so studing the ion-pair association constant (KA) formed between chloropentamminecobalt(III) cation [CpX2+] and a different ligands of dicarboxylate anions (AC2-), have been determined by EMF technique in different compositions of acetone aqueous media (0–44.20 wt% acetone) for succinic acid and for the other dicarboxylic acids (Maleic, Malonic and Malic) in the same solvent composition (40 wt% acetone) with in temperature range (30 – 60 °C). The thermodynamic association properties (ΔGA°, ΔHA° and ΔSA°) have been estimated and discussed. Extra thermodynamic correlations like ΔHA°- ΔSA° and ΔGA°- ΔGI(orII)° (where I and II are mentioned for the first and second dissociation constant of the dicarboxylic acids) in different compositions of acetone aqueous media for succinic acid and in fixed solvent composition for the other dicarboxylic acids were examined in order to give more information about the behavior of solvent molecules and its effect on formation of the ion-pair molecules. In addition, The Gibbs free energy of transfer for the association process ΔGA°(t) from water to acetone mixed solvents were calculated for succinic acid in order to indicate the spontaneous nature and the stabilization of the ion-pair by increasing the acetone weight percent in the mixed acetone – aqueous media. The linear correlation between pKD values and the relative permittivity of acetone aqueous medium is in accordance to Born’s equation.

Two green and sensitive spectrofluorimetric approaches for determination of Ambroxol and guaifenesin in their single and combined pharmaceutical formulations.

Ambroxol hydrochloride (AMX) and guaifenesin (GFN) are approved drugs utilized to treat coughs through their potent mucolytic and expectorant properties. Due to their massive, combined administration in many illnesses, there is a persistent need for their concurrent estimation in different pharmaceutical formulations. Two sensitive, environmentally friendly spectrofluorimetric methods were developed. AMX was determined using the first method (I) without interference from GFN. This method depends on the quenching of Erythrosine B (EB) native fluorescence at 552 nm after excitation at 527 nm due to the formation of a non-fluorescent AMX-EB ion-pair complex in Britton-Robinson buffer (BRB) solution pH (3.5). The concentration plot is linear over the 0.25-5.0μg/mL range, with a mean percent found value of 99.74%. Method (II) depends on measuring the native fluorescence of aqueous GFN solution at two analytical wavelengths, either 300 or 600 nm, after excitation at 274 nm. Relative fluorescence intensity (RFI)-concentration plots are linear over the ranges of 0.02-0.5 and 0.1-2.0μg/ml, with mean percent found at 99.96% and 99.91% at dual wavelengths, respectively. The proposed methods were successfully applied to assay both drugs in raw materials and different single and combined pharmaceutical formulations. These methods have been thoroughly validated following International Committee on Harmonisation (ICH) guidelines. National Environmental Methods Index, Analytical Eco-Scale, and Green Analytical Procedure Index were used to prove greenness, thereby enhancing their applicability. The proposed techniques provide straightforward, precise, and cost-effective solutions for routine formulation analysis in quality control laboratories.

Spectrophotometric quantification of amitriptyline hydrochloride in pharmaceutical tablets: method development and validation

AbstractThe development and validation of two uncomplicated, selective, and non-extraction-based visible spectrophotometric methods was carried out for the quantification of a tricyclic antidepressant amitriptyline hydrochloride as pharmaceutical tablets as well as in its pure form. The methods rely on the formation of ion pair complexes between amitriptyline base and two acidic dyes, bromothymol blue and bromocresol purple, which were subsequently measured at 410 and 400 nm, respectively. The developed methods included numerous reaction variables that were examined and improved. Beer's law is applicable under optimal conditions for the bromothymol blue and bromocresol purple methods, respectively, over concentrations from 0.5 to 12.5 μg mL−1 and from 0.5 to 10.0 μg mL−1 amitriptyline hydrochloride. The computed values of molar absorptivity were 1.79 × 104 and 2.32 × 104 L.mol−1.cm−1 for bromothymol blue and bromocresol purple methods, respectively, with Sandell’s sensitivity values of 0.0155 and 0.0119 μg cm−2. Both detection limits and quantification limits were computed and determined to be 0.55 and 1.67 μg mL−1 for bromothymol blue method, and 0.49 and 1.49 μg mL−1 for bromocresol purple method, respectively. The developed methods were successfully applied to estimate the concentration of amitriptyline hydrochloride in bulk form and commercial pills. Therefore, these methods demonstrate promising potential for testing this drug in labs for quality control. Graphical abstract Spectrophotometric quantification of amitriptyline hydrochloride in pharmaceutical tablets: method development and validation

Validation of Molnupiravir by Application of Reactive Dyes from Pharmaceutical Dosages

Simple sensitive and accurate ion pair complex formation with reactive dyes, extractive spectrophotometric methods have developed for the estimation of molnupiravir in pharmaceutical dosage form. The methods are based on the formation of ion paired coloured complexes by the drug with reactive dyes like Congo red, eriochrome black T and methyl orange in acidic medium. The ion associated complexes were formed and quantitatively extracted under the experimental condition in chloroform. The absorbance values were measured at 490nm, 500nm, and 430nm respectively. The proposed methods were validated statistically. Recoveries of methods were carried out by standard addition method. The linearity was found to be 4.0-24.0μg/ml, 2-12μg/ml, and 2-16μg/ml for methods respectively. The low values of standard deviation and percentage RSD indicate high precision of methods. Hence these methods are useful for routine estimation of molnupiravir in pharmaceutical dosages.

Synthesis of (R)-(6-Methoxyquinolin-4-yl)[(1S,2S,4S,5R)-5-vinylquinuclidin-2-yl]methanol Tetraphenylborate Ion-Pair Complex: Characterization, Antimicrobial, and Computational Study.

The (R)-(6-Methoxyquinolin-4-yl)[(1S,2S,4S,5R)-5-vinylquinuclidin-2-yl]methanol (quinine)-tetraphenylborate complex was synthesized by reacting sodium tetraphenyl borate with quinine in deionized water at room temperature through an ion-pair reaction (green chemistry) at room temperature. The solid complex was characterized by several physicochemical methods. The formation of ion-pair complex between bio-active molecules and/or organic molecules is crucial to comprehending the relationships between bioactive molecules and receptor interactions. The complex under study was examined for antimicrobial activity. All theoretical calculations were carried out in vacuum and water using the B3LYP level 6-311G(d,p) levels of theory. The theoretical computation allowed for the prediction and visualization of ionic interactions, which explained the complex's stability. The results of energy optimization showed that the Q-TPB complex is stable with a negative complexation energy. The obtained geometries showed that the boron (B-) and nitrogen (N+) in piperidine of the two molecules tetraphenylborate and quinine are close to each other, which makes it possible for ions to interact. The modest energy gap between HOMO and LUMO showed that the compound was stable. The computation of the electron transitions of the two models by density functional theory (TD-DFT) in the solvent at the theoretical level B3LYP/6-311G(d,p) allowed for the detection of three UV/visible absorption bands for both models and the discovery of a charge transfer between the host and the guest. The UV absorption, infrared, and H NMR are comparable with the experimental part.

EXTRACTIVE SPECTROPHOTOMETRIC METHODS FOR THE ASSAY OF OSELTAMIVIR PHOSPHATE, FAMCICLOVIR AND ACYCLOVIR IN PURE AND DOSAGE FORMS

For the determination of oseltamivir phosphate (OSP), acyclovir (ACL), and famciclovir (FMV) medicines in pure form and their formulations, quick, accurate, and simple spectrophotometric procedures have been established. The procedures were relied on the formation of ion-pair complexes between the drugs and anionic dyes (OSP with bromothymol blue (BTB), ACL with methyl red (MTR) and FMV with methyl orange (MTO)) in an acidic medium, separately. The yellow OSP-bromothymol blue complex, orange ACL-methyl red complex and orange-yellow FMV-methyl orange complex formed were quantitatively extracted with chloroform and their absorbance measured at 416, 416 and 488 nm wavelengths, respectively. The limits of detection and quantification were found to be 0.5, 1.5, 1.0 µg mL-1 and 1.7, 5.0 and 3.3 µg mL-1 for the OSP, ACL and FMV, respectively. The linearity was established from 1-5, 2-12 and 5-14 µg mL-1 for OSP, ACL and FMV, respectively. R2 (regression coefficient) values were above 0.996 for all the three drugs. Recovery (accuracy) results were found within 98.0 % to 102 %. The developed methods comply with the ICH guidelines. The developed methods were successfully used to measure OSP, ACL and FMV in both their pure and in formulation forms.

Acriflavine: an efficient green fluorescent probe for sensitive analysis of aceclofenac in pharmaceutical formulations

Acriflavine is a multipurpose drug that shows antibacterial, antiviral, antimalarial, and antifungal activities. The remarkable native fluorescence of acriflavine is exploited in analytical chemistry field as an efficient probe for analysis of pharmaceutical and biological compounds. The fluorescent probe action of acriflavine is based on the remarkable fluorescence turning-off via formation of ion-pair complexes with acidic drugs at a specific pH. Herein, the acidic drug aceclofenac is analysed for the first time using acriflavine as a fluorescent probe. Aceclofenac can form an ion-pair complex with acriflavine at pH 8.5, and hence it partially turns off the fluorescence intensity of acriflavine over a concentration range of 1–20 µg/mL. The fluorescence quenching was monitored at 502 nm following an excitation at 265 or 451 nm. The reaction stoichiometry between acriflavine and aceclofenac was found to be 1:1 using limiting logarithmic method. The type of quenching was confirmed to be static using Stern–Volmer plot. The method showed low values of quantitation limit (0.89 µg/mL) and detection limit (0.29 µg/mL). Moreover, the method was linear (r = 0.9999), accurate, precise (RSD < 1.7%), robust, and specific. The proposed method was successfully employed to analyse aceclofenac in its dosage forms with high %recovery (98–101%). Additionally, GAPI and AGREE approaches were used to guarantee the suggested techniques' greenness, and the findings showed an excellent level of greenness.

New Spectrophotometric Gliclazide Determination in Tablets Formulations by Charge Transfer Complexation

Rapid useful and easy spectrophotometric method for quantitative analysis of Gliclazide(GLZ)in raw material and tablets pharmaceutical formulation has been described. This method is based on the formation of yellow ion-pair complex between (GLZ) and Bromocresol purple (BCP) in Toluene medium. Different parameters affecting the reaction such as: effect of solvents, time, reagent concentration, correlation ratio, etc. were optimized. The absorbance of the formed complex GLZ-BCP was measured by visible spectrum at absorption maximum 415 nm. The range of linearity was(4.85 – 113.19) µg/mL,regression analysis had a good correlation coefficient R2 = 0.9999. The limit of detection (LOD)and limit of quantification (LOQ)were to be 0.47µg/mL and 1.44µg/mL respectively. The average percent recovery of (GLZ) was found to be (99.73 – 100.41)%. The method was successfully applied for the determination of (GLZ) in tablets pharmaceutical formulations in Syrian pharmaceutical products: UNICRON. The proposed method is simple, direct, and sensitiveand does not require any pre-extractionprocess. Thus, the method could be ready to apply in routine analysis and quality control.

Synthesis of 4-Amino-N-[2 (diethylamino)Ethyl]Benzamide Tetraphenylborate Ion-Associate Complex: Characterization, Antibacterial and Computational Study

The 4-amino-N-[2 (diethylamino) ethyl] benzamide (procainamide)-tetraphenylborate complex was synthesized by reacting sodium tetraphenyl borate with 4-amino-N-[2 (diethylamino) ethyl] benzamide, chloride salt, and procainamide in deionized water at room temperature through an ion-associate reaction (green chemistry) at room temperature, and characterized by several physicochemical methods. The formation of ion-associate complex between bio-active molecules and/or organic molecules is crucial to comprehending the relationships between bioactive molecules and receptor interactions. The solid complex was characterized by infrared spectra, NMR, elemental analysis, and mass spectrometry, indicating the formation of ion-associate or ion-pair complex. The complex under study was examined for antibacterial activity. The ground state electronic characteristics of the S1 and S2 complex configurations were computed using the density functional theory (DFT) approach, using B3LYP level 6-311 G(d,p) basis sets. R2 = 0.9765 and 0.9556, respectively, indicate a strong correlation between the observed and theoretical 1H-NMR, and the relative error of vibrational frequencies for both configurations was acceptable, as well. HOMO and LUMO frontier molecular orbitals and molecular electrostatics using the optimized were used to obtain a potential map of the chemical. The n → π* UV absorption peak of the UV cutoff edge was detected for both configurations of the complex. Spectroscopic methods were structures used to characterize the structure (FT-IR and 1HNMR). In the ground state, DFT/B3LYP/6-311G(d,p) basis sets were used to determine the electrical and geometric properties of the S1 and S2 configurations of the title complex. Comparing the observed and calculated values for the S1 and S2 forms, the HOMO-LUMO energy gap of compounds was 3182 and 3231 eV, respectively. The small energy gap between HOMO and LUMO indicated that the compound was stable. In addition, the MEP reveals that positive potential sites were around the PR molecule, whereas negative potential sites were surrounding the TPB site of atoms. The UV absorption of both arrangements is comparable to the experimental UV spectrum.

Assay of Tretinoin using Safranine-O as a Chromogenic Reagent in Bulk and Dosage Forms

A new, economical and accurate analytical technique was developed for the assay of tretinoin (TTN) in bulk and formulations. While developing the method, it was found that the reaction was carried out due to the formation of ion-pair association complex involving the carboxyl group in the side chain of the TTN with safranine-O. The colored species formined was stable up to 60 minutes. The optical density of color species was measured at 520 nm. All the variables were optimized. The linearity range lies for the developed method within the concentration ranges of 2-10 μg mL-1.The linear correlation coefficient (r) and molar absorptivity (ϵmax)values were found as 0.9999 and 1.66 x 104 L mol–1cm–1. Percentage recoveries were found from 99.2 ± 1.8 to 100.2 ± 0.7.The method was validated as per ICH guidelines.

Application of reactive dyes in Validation of favipiravir from pharmaceutical dosages

Simple sensitive and accurate ion pair complex formation with reactive dyes, extractive spectrophotometric methods have developed for the estimation of favipiravir in pharmaceutical dosage form. The methods are based on the formation of ion paired coloured complexes by the drug with reactive dyes like Congo red, eriochrome black T and methyl orange in acidic medium. The ion associated complexes were formed and quantitatively extracted under the experimental condition in chloroform. The absorbance values were measured at 490 nm, 500 nm, and 430 nm respectively. The proposed methods were validated statistically. Recoveries of methods were carried out by standard addition method. The linearity was found to be 5.0-30.0 μg/ml, 5 -12 μg/ml, and 2-20 μg/ml for methods respectively. The low values of standard deviation and percentage RSD indicate high precision of methods. Hence these methods are useful for routine estimation of favipiravir in pharmaceutical dosages.

Determination of Lansoprazole and Simvastatin via area under curve and ion pair methods

A two simple, sensitive, and economic methods were developed for the determination of lansoprazole and simvastatin in their pure and pharmaceutical dosages forms . first method based on measurement of area under curve (AUC) for zero order spectrum and the second method based on formation of ion pair complex between each of both drugs and Bromo phenol blue dye. Beer's law obeyed in concentrations ranges of (4-70 μg.ml-1) and (4-50 μg.ml-1) in the first method and (1-70 μg.ml-1) and (1-60 μg.ml-1) in the second method for lansoprazole (LNZ) and simvastatin (SMV) respectively . Average recovery percentage were (99.43%) and (99.36%) in the first method , and (99.71%) and (100.18%) in the second method for LNZ and SMV respectively. The RSD% values were (0.0044-0.0172%) and (0.1041-0.4129%) for LNZ in first and second methods, and (0.0097-0.0311%) and (0.1358-0.5165%) for SMV in the two methods mentioned above. Limit of detection of LNZ in the first method were (0.185×10-3 μg.ml-1) and (0.268×10-3 μg.ml-1) in the second method . While limit of quantification were (0.227×10-3 μg.ml-1) and (0.204×10-3 μg.ml-1) in the first method and (0.894×10-3 μg.ml-1) and (0.68×10-3 μg.ml-1) in the second method for LNZ and SMV respectively. The two methods were successfully applied for the determination of both drugs in pure and pharmaceutical dosages forms .

SENSITIVE SPECTROPHOTOMETRIC DETERMINATION OF TRIPROLIDINE HYDROCHLORIDE DRUG IN THE CAPSULES VIA ION PAIR COMPLEX FORMATION

The objective of this study was to develop two simple and selective visible spectrophotometric methods for the determination of antihistamine drug triprolidine hydrochloride (TRH) in the capsules. The methods were based on the formation of ion-pair complexes between TRH and two dyes, namely, bromocresol green (BCG) and bromophenol blue (BPB). The produced ion-pair complexes were measured at 415 and 410 nm for BCG and BPB methods, respectively. Beer’s law was applicable in the concentration ranges of 2.50-15.0 µg mL-1 TRH for both methods. The molar absorptivity values were found to be 2.12 × 104 and 2.07 × 104 L mol-1 cm-1 for the BCG method and BPB method, respectively, and the Sandell’s sensitivity values were 0.0149 and 0.0152 µg cm-2. The limits of detection and quantification were calculated and found to be 0.29 and 0.86 µg mL-1 for the BCG method and 0.31 and 0.95 µg mL-1 for the BPB method. The methods were applied successfully for TRH determination in bulk drug and in the capsules.

Studies on nano crystalline copper doped Nickel Zinc ferrites for optoelectronic applications

Investigation of optical and dielectric properties of nanocrystalline Ni0.65Zn0.35 Cu x Fe(2-2x/3) O4 (for x = 0.00–0.05 in steps of 0.01) ferrites synthesized using hydrothermal route is successfully carried out. Two distinct analytical spectroscopic methods with Dichloro – 5,6-Dicyano – 1,4-Benzo quinone (DDQ) and Bromo Phenol Blue (BPB) are adopted to observe the UV–visible absorption spectroscopy in the dispersed solutions of all samples. The formation of ion pair complex in the presence of BPB results in two distinct absorption edges in the visible region, around 440 nm and 580 nm in the present ferrite samples. Application of Tauc's formalism gives rise to two optical band gap values Eg1 and Eg2 in the range of 2.12–2.40 eV and 3.583–3.674 eV, respectively. The formation of charge transfer complex with all sample solutions in presence of DDQ reagent results in sharp absorption edges in the UV-region around 306 nm wavelength. An initial rise followed by continuous drop in band gap values ranging from 3.814 to 3.824 eV is observed from Tauc's plots. The optimum refractive index (n) values calculated for the three types of band gap values using empirical relations display the optical absorption potentiality of Ni–Cu–Zn nano ferrites in both Visible and UV – regions. Variation of band gap values is ascribed to the lattice strain effect, quantum confinement and narrowing band gap effects. Real part of dielectric constant (ε′), dielectric loss factor (tanδ) and ac-conductivity(σac) are studied for all samples at room temperature with in the frequency range of 42 Hz to 5 MHz. The values of ε′ and tanδ are observed to decrease with increase in frequency, while that of σac are found to increase with increase in frequency. Improved dielectric properties, existence of optical band-gap values observed in the present Ni–Cu–Zn ferrites promote these materials for their utility in optoelectronic devices and high frequency applications.

Spectroscopic strategies for quantitation of varenicline in pharmaceutical preparations and content uniformity testing.

Herein, two new facile methods were examined for varenicline determination using erythrosine. The latter is a food additive that has been recently investigated as a fluorescent dye for the determination of drugs. In the first method, the fluorescence of erythrosine B was quenched quantitatively by increasing the concentration of varenicline through ion-pair complex formation. This linear response was a basis for the spectrofluorimetric method used for varenicline quantitation in pure and dosage forms. The quenching is correlated with the concentration linearly over the range of 0.4–4.0 µg ml−1 at 550 nm after excitation at 528 nm with a correlation coefficient of 0.9993. Different parameters were investigated to reach the optimal conditions with the highest sensitivity and repeatability. The second method is depending on measuring the formed complex by spectrophotometry at 550 nm over the range of 1.0–10.0 µg ml−1 with an excellent correlation coefficient of 0.9999. The suggested methods were validated consistently with ICH guidelines, with acceptable results. The procedures were used to test the uniformity of content of Champix tablets. By comparing with the previous spectroscopic method, there was no significant difference as revealed from the calculated Student t-test and variance ratio F-test values.

Novel approaches of erythrosine B as a food dye-derived spectroscopic probe for assessing trospium chloride in raw material and dosage form.

Two facile spectroscopic methodologies were designed for estimating trospium chloride (TPM) in raw material and tablets with high operational reliability and selectivity. The methods were based on using erythrosine B (EB) as a spectroscopic tool for ion-pair complex formation with the drug. In a mild acidic medium of Britton Robinson buffer (pH4.0), the ionized hydroxyl group in the reagent interacted with the ionized amine in the studied drug. Method I was based on the spectrophotometric measuring of the absorbance of the reaction product at 557 nm. Method II was based on spectrofluorimetric measurement of the quenching effect of TPM on the inherent fluorescence of EB at 550 nm (λex. = 528 nm). The two methods showed linearity through ranges 1.0-10.0 and 0.5-10.0 μg/ml for Methods I and II, respectively. The suggested methods were exploited for analyzing TPM in Trospamexin® tablets and showed good applicability. The designed systems were validated as per International Conference on Harmonization guidelines. Experimental conditions were modulated to obtain the best sensitivities. The quenching mechanism was investigated and the quenching constant was computed relying on the Stern-Volmer equation. Environmental impact was appraised using novel metric green tools, GABI, and AGREE. The suggested systems excelled over other reported methods in terms of greenness, sensitivity, and cost-effectiveness.

A Simple Spectrophotometric Determination of Amoxicillin in Drug Samples

In this study, a fast and simple spectrophotometric method was developed for the determination of amoxicillin in drugs without any extraction steps. The developed method is based on the formation of a colored ion pair complex between bromocresol green and amoxycillin in dimethyl sulfoxide-acetonitrile (50 % v/v) medium. The absorbance of the bluish green complex is measured at a wavelength of 630 nm. The factors that affect the ion pair complex formation, such as time, reagent concentration, etc., have been optimized. Under the optimum conditions, the developed method had an average recovery of 98.16% with a relative standard deviation of 3.62 % and showed a very good linear behavior obeying Lambert-Beer's law in the range 1-18 µg mL-1 of amoxycillin concentration. The developed method has been successfully applied to both tablet and powder forms of pharmaceutical preparations. The standard addition method and statistical parameters were applied to test the accuracy of the proposed method, and the obtained results from the two methods showed good agreement with each other.

Simple spectrophotometric method for the determination of haloperidol from pharmaceutical formulations

A simple, sensitive, rapid, accurate and cost effective spectrophotometric method has been developed and validated for the estimation of haloperidol in bulk drug and for its pharmaceutical formulations. The proposed method is based on the formation of chloroform extractable ion pair complex of haloperidol with bromothymol blue. The absorbance of the coloured extractable ion pair complex is measured at the wavelength of maximum absorbance 420 nm against the reagent blank. Beer’s law is obeyed over a concentration range of 20 to 100 µg/ml of haloperidol, for a linear calibration curve. Results are statistically validated and found to be reproducible.