Commercial Pharmaceuticals Research Articles

A new ion selective electrode method for determination of oseltamivir phosphate (Tamiflu) and its pharmaceutical applications

Oseltamivir phosphate (OP) is an antiviral drug that is used in the treatment and prophylaxis of both influenza A and influenza B. It is effective against all known influenza viruses that can infect humans, including pandemic influenza viruses and may be the most appropriate antiviral option against avian influenza caused by H5N1 virus. Tamiflu, the registered trademark used under exclusive license by Roche laboratories with OP as active pharmaceutical ingredient, is considered the best treatment for the bird flu disease.The construction and electrochemical response characteristics of poly vinyl chloride (PVC) membrane sensors for the determination of (OP) were described. The sensors are based on the use of the ion association complexes of (OP) cation with sodium tetraphenylborate–oseltamivir phosphate (NaTPB–OP), tungestosilisate–oseltamivir phosphate (TS–OP), phosphomolbdate–oseltamivir phosphate (PM–OP) and phosphotungestate–oseltamivir phosphate (PT–OP) as ion exchange sites in the PVC matrix. The performance characteristics of these sensors, which were evaluated according to IUPAC recommendations, reveal a fast, stable and linear response for (OP) over the concentration range from 10−5 to 10−2molL−1 with cationic slopes of 51.5±0.3, 50±0.5, 55±0.2 and 50±0.4mV per decade across an extended OP concentration range from 1.0×10−6 to 1.0×10−2molL−1 for NaTPB–OP, TS–OP, PM–OP and PT–OP, respectively. The direct potentiometric determination of (OP) using the proposed sensors gave average recoveries of 99.9, 99.8, 99.9 and 99.7 for NaTPB–OP, TS–OP, PM–OP and PT–OP, respectively. The sensors are used for determination of (OP) in tablets. The method was successfully applied to commercial pharmaceuticals, Tamiflu. Validation of the method shows suitability of the proposed sensors for use in the quality control assessment of (OP). The developed method was found to be simple, accurate and precise when compared with a reported HPLC method.

Bi-enzyme l-arginine-selective amperometric biosensor based on ammonium-sensing polyaniline-modified electrode

A novel l-arginine-selective amperometric bi-enzyme biosensor based on recombinant human arginase I isolated from the gene-engineered strain of methylotrophic yeast Hansenula polymorpha and commercial urease is described. The biosensing layer was placed onto a polyaniline–Nafion composite platinum electrode and covered with a calcium alginate gel. The developed sensor revealed a good selectivity to l-arginine. The sensitivity of the biosensor was 110±1.3nA/(mMmm2) with the apparent Michaelis–Menten constant (KMapp) derived from an l-arginine (l-Arg) calibration curve of 1.27±0.29mM. A linear concentration range was observed from 0.07 to 0.6mM, a limit of detection being 0.038mM and a response time — 10s. The developed biosensor demonstrated good storage stability. A laboratory prototype of the proposed amperometric biosensor was applied to the samples of three commercial pharmaceuticals (“Tivortin”, “Cytrarginine”, “Aminoplazmal 10% E”) for l-Arg testing. The obtained l-Arg-content values correlated well with those declared by producers.

Novel and validated titrimetric method for determination of selected angiotensin-II-receptor antagonists in pharmaceutical preparations and its comparison with UV spectrophotometric determination

A novel and simple titrimetric method for determination of commonly used angiotensin-II-receptor antagonists (ARA-IIs) is developed and validated. The direct acid base titration of four ARA-IIs, namely eprosartan mesylate, irbesartan, telmisartan and valsartan, was carried out in the mixture of ethanol:water (1:1) as solvent using standardized sodium hydroxide aqueous solution as titrant, either visually using phenolphthalein as an indicator or potentiometrically using combined pH electrode. The method was found to be accurate and precise, having relative standard deviation of less than 2% for all ARA-IIs studied. Also, it was shown that the method could be successfully applied to the assay of commercial pharmaceuticals containing the above-mentioned ARA-IIs. The validity of the method was tested by the recovery studies of standard addition to pharmaceuticals and the results were found to be satisfactory. Results obtained by this method were found to be in good agreement with those obtained by UV spectrophotometric method. For UV spectrophotometric analysis ethanol was used as a solvent and wavelength of 233nm, 246nm, 296nm, and 250nm was selected for determination of eprosartan mesylate, irbesartan, telmisartan, and valsartan respectively. The proposed titrimetric method is simple, rapid, convenient and sufficiently precise for quality control purposes.

Assessing the Chronic Aquatic Toxicity of Phthalate Ester Plasticizers

ABSTRACT Phthalic acid esters (PAE) are a class of chemicals varying greatly in terms of uses, properties, and toxicity. C1 to C4 PAE are used in non-vinyl commercial products and pharmaceuticals. C8 to C10 PAE are additives imparting flexibility to vinyl resins. The purpose of the present study is to assess chronic effects of PAE on aquatic organisms. Studies show that populations of fish and invertebrates may be adversely affected by exposure to C1 to C4 PAE, but are not adversely affected by exposure to C8 or higher PAE. Secondary endpoints, including molecular, biochemical, and/or histological responses to chemical exposure, do not appear to predict effects related to primary endpoints of survival, growth and development, or reproductive fitness. A previously published risk assessment for C1 to C4 PAE demonstrated low risks in North American and Western European surface waters. Risk assessments conducted by authorities in Europe with di-2-ethylhexyl-, di-isononyl-, and di-isodecyl phthalates have concluded no risks to aquatic organisms due to aqueous solubility constraints, low expected surface water concentrations, and metabolic biotransformation capabilities of aquatic organisms. The present review of chronic aquatic toxicity data, which includes data from studies performed subsequent to the risk assessments, confirms these earlier conclusions.

Identifying New Persistent and Bioaccumulative Organics Among Chemicals in Commerce II: Pharmaceuticals

The goal of this study was to identify commercial pharmaceuticals that might be persistent and bioaccumulative (P&B) and that were not being considered in current wastewater and aquatic environmental measurement programs. We developed a database of 3193 pharmaceuticals from two U.S. Food and Drug Administration (FDA) databases and some lists of top ranked or selling drugs. Of the 3193 pharmaceuticals, 275 pharmaceuticals have been found in the environment and 399 pharmaceuticals were, based upon production volumes, designated as high production volume (HPV) pharmaceuticals. All pharmaceuticals that had reported chemical structures were evaluated for potential bioaccumulation (B) or persistence (P) using quantitative structure property relationships (QSPR) or scientific judgment. Of the 275 drugs detected in the environment, 92 were rated as potentially bioaccumulative, 121 were rated as potentially persistent, and 99 were HPV pharmaceuticals. After removing the 275 pharmaceuticals previously detected in the environment, 58 HPV compounds were identified that were both P&B and 48 were identified as P only. Of the non-HPV compounds, 364 pharmaceuticals were identified that were P&B. This study has yielded some interesting and probable P&B pharmaceuticals that should be considered for further study.

Simultaneous diffuse reflectance infrared determination of clavulanic acid and amoxicillin using multivariate calibration techniques

A method for simultaneous determination of clavulanic acid (CA) and amoxicillin (AMO) in commercial tablets was developed using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and multivariate calibration. Twenty-five samples (10 commercial and 15 synthetic) were used as a calibration set and 15 samples (10 commercial and 5 synthetic) were used for a prediction set. Calibration models were developed using partial least squares (PLS), interval PLS (iPLS), and synergy interval PLS (siPLS) algorithms. The best algorithm for CA determination was siPLS model with spectra divided in 30 intervals and combinations of 2 intervals. This model showed a root mean square error of prediction (RMSEP) of 5.1 mg g(-1). For AMO determination, the best siPLS model was obtained with spectra divided in 10 intervals and combinations of 4 intervals. This model showed a RMSEP of 22.3 mg g(-1). The proposed method was considered as a suitable for the simultaneous determination of CA and AMO in commercial pharmaceuticals products.

Rapid screening of active ingredients in drugs by mass spectrometry with low-temperature plasma probe

A high-throughput method for rapid screening of active ingredients in drugs has been developed with mass spectrometry coupled to a low-temperature plasma (LTP) probe ion source. Without sample preparation or pretreatment, the active ingredients of 11 types of commercial pharmaceuticals, including hormones, antipyretic analgesics, cardiovascular, digestant, neuro-psychotherapeutic, diuretic, antithyroid, sulfa anti-inflammatory, antiparastic, sedative-hypnotics, and antibacterial, were directly desorbed/ionized and detected by a linear ion trap mass spectrometry (MS). The structures of these ingredients were elucidated by tandem MS. The analysis of 18 methyltestosterone tablets could be accomplished within 1.9 min, which allows fast detection with a speed of approximate 600 samples within 1 h. This work demonstrated that LTP probe ion source combined with MS is a high-throughput method for screening of pharmaceuticals and potentially applied to on-line quality control in pharmaceutical industry.

The Rule of Five Revisited: Applying Log D in Place of Log P in Drug-Likeness Filters

The much publicized "Rule of 5" has been widely adopted among the pharmaceutical industry. It is used as a first step filter to perform virtual screening of compound libraries, in an effort to quickly eliminate lead candidates that have poor physicochemical properties for oral bioavailabilty. One of the key parameters used therein is log P, which is a useful descriptor, but one that fails to take into account variation in the lipophilicity of a drug with respect to the ionic states present at key biological pH values. Given that the majority of commercial pharmaceuticals contain an ionizable moiety, we propose that log D is a better descriptor for lipophilicity in the context of the Rule of 5. It gives more physiologically relevant results, thereby reducing the number of potential false-negatives incorrectly eliminated in screening. Using a series of commercial compound libraries, this study showed that the adapted Rule of 5 using log D instead of log P provides notable improvement in pass rate for compounds that have the desired lipophilicity at a relevant physiological pH.

Development and validation of a rapid HPLC method for the determination of oseltamivir phosphate in Tamiflu ® and generic versions

Oseltamivir phosphate (OP) is an antiviral drug that is used in the treatment and prophylaxis of both influenza A and influenza B. It is effective against all known influenza viruses than can infect humans, including pandemic influenza viruses and may be the most appropriate antiviral option against avian influenza caused by H5N1 virus. Tamiflu ®, the registered trademark used under exclusive license by Roche laboratories with OP as active pharmaceutical ingredient, is considered the best treatment for the bird flu disease. A simple, selective, linear, accurate and precise HPLC method was developed and validated for rapid assay of OP aimed to the quality control of Tamiflu ® capsules and generic versions. Isocratic elution at a flow rate of 1.2 mL/min was employed on a Zorbax CN column (150 mm × 4.6 mm; 5 μm) at ambient temperature. The mobile phase consisted of methanol and 0.04 M formic acid pH 3.0 (50:50, v/v). The UV detection wavelength was 226 nm and 20 μL of sample was injected. Sotalol hydrochloride was used as the internal standard (IS). The retention times for OP and IS were 3.40 and 2.25 min, respectively. The method was successfully applied to commercial pharmaceuticals, Tamiflu ® and generic versions. The proposed method could be applicable for routine analysis of OP and monitoring of the quality of marketed drugs as possibly counterfeit Tamiflu ®.

Analysis of the iron state in ferric and ferrous iron containing pharmaceutical products by Mössbauer spectroscopy

An analysis of the iron state in commercial pharmaceuticals containing ferric and ferrous iron compounds, which are used for treatment of iron deficiency, was made by Mossbauer spectroscopy. Small variations of the FeOOH cores of injectable iron-dextran complexes were observed. The presence of ferrous impurity in iron-dextran complexes was found. Characterization of the iron state in vitamins and dietary supplements containing ferrous compounds was made. The presence of ferrous and ferric impurities and iron compounds that were in disagreement with compounds announced by the manufacturer was detected by Mossbauer spectroscopy.

Development and Validation of a Rapid HPLC Method for the Direct Determination of Colchicine in Pharmaceuticals and Biological Fluids

A reversed‐phase high performance liquid chromatographic (RP‐HPLC) method is developed and validated for the determination of the colchicine, an anti‐gout alkaloid. The analytical column, an Inertsil ODS‐2, 5 µm, 250×4 mm, was operated at ambient temperature. Isocratic elution with A: 48% CH3COONH4 0.05 M and B: 52% CH3OH, was used at a flow rate of 1.0 mL/min. Inlet pressure was 270 kg/cm2. UV detection was performed at 245 nm. The Limit of Detection was 0.5 ng, per 20 µL injection volume, while linearity held up to 2.5 ng/µL. Codeine was used as Internal Standard at a concentration level of 10 ng/µL. The statistical evaluation of the method was performed in terms of intra‐day (n=8) and inter‐day calibration (n=8) and was found to be satisfactory, with high accuracy and precision results. The method was successfully applied to commercial pharmaceuticals and biological fluids. Blood serum samples, after deproteinization with acetonitrile, yielded high recovery rates from 97.2 to 104.6%, while direct analysis of urine after a 10‐fold dilution provided recovery rates ranging from 89.5 to 104.0%.

Determination of Salbutamol in Pharmaceuticals by Capillary Electrophoresis

A capillary electrophoresis (CE) method for the separation and determination of salbutamol (SAL) in commercial pharmaceuticals was developed. Several parameters affecting the separations were studied including type and concentration of the carrier ion, counter ion, and the pH of the buffer. A hydrodynamically closed CE separation mode employing a 300 mum I.D. capillary, dynamically coated by polymeric buffer additive, provided good performance parameters (precision, accuracy, sensitivity). The obtained results suggest that the proposed method is suitable for routine assay of SAL in pharmaceutical preparations and can be used as an alternative to the conventional open CE mode for this application.

Micellar electrokinetic chromatography for simultaneous determination of six corticosteroids in commercial pharmaceuticals

We have developed a micellar electrokinetic chromatography (MEKC) method using bile salts for the simultaneous determination of six corticosteroids, including betamethasone, cortisone, prednisolone, 6alpha-methylprednisolone, triamcinolone, and prednisone. The separation was performed using borate buffer containing sodium cholate and sodium deoxycholate. Several parameters were studied, including bile salt concentrations, concentrations and pH of borate buffer, and analytical voltages. In method validation, calibration curves were linear over a range of 10-100 microM for each corticosteroid. The RSD (relative standard deviation) and RE (relative error) were all less than 5% for intra- and interday assays. The limit of detection of each analyte was 5 microM. The recoveries were greater than 95%. Application of this method for quality control of commercial tablets also proved to be feasible. All analytical values fall within the labeled amount of 90-110% for betamethasone and prednisolone, and of the labeled amount of 92.5-107.5% for 6alpha-methylprednisolone, as required by the United State Pharmacopeia 25 (USP 25).

Determination of Fexofenadine in Tablets by Capillary Electrophoresis in Free Solution and in Solution with Cyclodextrins as Analyte Carriers

ABSTRACTCapillary electrophoresis (CE) methods for the determination of fexofenadine (FEX) in commercial pharmaceuticals were developed. It was demonstrated that FEX could be effectively analyzed in free solution cationic CE at low pH. Another analytical approach studied was based on cyclodextrin (CD) modified CE where highly charged CD derivatives served as analyte carriers. In this way, the separation range was spread to physiological pH region and a CE analysis of FEX, present actually in its zwitterionic form, could be accomplished. Several parameters affecting the separations were studied, including the type and concentration of carrier ion, counterion, analyte carrier, and pH of the buffer. The methods based on the free solution CE and CD-modified CE were compared each other, validated, and applied for the determination of FEX in tablets.

Development and validation of a capillary electrophoresis method for the determination of codeine, diphenhydramine, ephedrine and noscapine in pharmaceuticals

The present work describes a simple, accurate and rapid method for the separation and simultaneous determination of codeine, diphenhydramine, ephedrine and noscapine present in cough–cold syrup formulations by capillary zone electrophoresis. Factors affecting the separation were the buffer pH and concentration, applied voltage, and presence of additives. Separations were carried out in less than 10 min with a 20 mM sodium tetraborate buffer, pH 8.50. The carrier electrolyte gave baseline separation with good resolution, great reproducibility and accuracy. Calibration plots were linear over at least three orders of magnitude of analyte concentrations, the lower limits of detection being within the range 0.42–1.33 μg ml –1. Detection was performed by UV absorbance at wavelengths of 205 and 250 nm. Quantification of the components in actual syrup formulations was calculated against the responses of freshly prepared external standard solutions. The method was validated and met all analysis requirements of quality assurance and quality control. The procedure was fast and reliable and commercial pharmaceuticals could be analyzed without prior sample clean-up procedure.

Development of a validated HPLC method for the determination of iodotyrosines and iodothyronines in pharmaceuticals and biological samples using solid phase extraction

Identification, separation and quantitation of iodoaminoacids, is essential for the biological research and the clinical diagnosis of thyroid gland disease. Under this aspect a reversed-phase high-performance liquid chromatographic method was developed for the determination of thyroid gland hormones and some of their primary metabolites, 3,3′,5,5′-tetra-iodo- l-thyronine ( l-thyroxine), 3,3′,5-tri-iodo- l-thyronine, 3,5-di-iodo- l-thyronine, l-thyronine, 3,5-di-iodo- l-tyrosine, 3-iodo- l-tyrosine and l-tyrosine. Analysis was performed on an Inertsil C 18 column with photodiode-array detection, using a 25 min gradient scale program of a binary mobile phase consisted of 0.1% aqueous solution of trifluoroacetic acid at pH 3 as solvent A and acetonitrile as solvent B, at a flow rate of 1 mL/min. Quantitation was performed using were obtained using theophylline as internal standard. The method was applied to commercial pharmaceuticals and biological samples (serum, urine and tissue). Drug-free urine and serum samples were spiked with known concentrations of the analytes standards and pretreated by solid phase extraction to remove matrix interferences. C 18 cartridges were used, yielding recoveries ranging from 87.1% to 107.6% for serum samples and from 92.1% to 98.7% for urine samples. With regard to total-T 4 concentrations in serum samples, results are cross-validated with RIA and found to agree well.

The use of a monolithic column to improve the simultaneous determination of four cephalosporin antibiotics in pharmaceuticals and body fluids by HPLC after solid phase extraction—a comparison with a conventional reversed-phase silica-based column

The use of a monolithic column (Chromolith ®, SpeedROD RP-18e, by Merck) was studied on the determination of cephalosporin antibiotics. Results were compared with those from a previously developed analytical method using conventional silica-based analytical column. A rapid, accurate and sensitive method has been developed and validated for the quantitative simultaneous determination of four cephalosporins: Cephalexine and Cephadroxil (first generation), Cefaclor (second generation) and Cefotaxim (third generation) in pharmaceuticals as well as in human blood serum and urine. Hydroflumethiazide (HFM) (3,4-dihydro-6(trifluoromethyl)-2H-1,2,4-benzothiadiazine-7-sulfonamide-1,1-dioxide) was used as an internal standard at a concentration of 1.5 ng/μL. A rectilinear relationship was observed up to 5 ng/μL for the four compounds. Analysis time was less than 4 min. The statistical evaluation of the method was examined by means of within-day repeatability ( n = 8) and day-to-day precision ( n = 8) and was found to be satisfactory with high accuracy and precision results. The method was applied to the determination of the cephalosporins in commercial pharmaceuticals and in biological fluids: human blood serum after solid phase extraction and urine simply after filtration and dilution. Recovery of analytes in spiked serum samples was in the range from 88.7 to 107.8%, while for urine samples recovery was from 98.0 to 105.6%. By comparing the figures of merit for the monolithic column and the silica-based one, regarding the determination of the four cephalosporins investigated in the present study, the outstanding efficiency of the monolithic column can be noticed.

Simultaneous determination of cloramphenicol, salicylic acid and resorcinol by capillary zone electrophoresis and its application to pharmaceutical dosage forms

This study demonstrates the separation of active ingredients in acne formulations (salicylic acid, cloramphenicol and resorcinol in presence of azulene) by capillary zone electrophoresis. Factors affecting their separations were the buffer pH and concentration, applied voltage, sample preparation, and presence of additives. Optimun results were obtained with a 50 mM sodium tetraborate–50 mM sodium phosphate, pH 9.0. The carrier electrolyte gave baseline separation with good resolution, short migration times (<6 min), great reproducibility and accuracy. Calibration plots were linear over at least three orders of magnitude of analyte concentrations, the lower limits of detection being within the range 0.39–1.25 μg ml −1. The procedure was fast and reliable and commercial pharmaceuticals could be analysed without prior sample clean-up procedure.

Opportunities of Finding Novel Anti-Infective Agents from Plant Cell Cultures

Higher plants have evolved into efficient biochemical defense mechanisms, which comprised of a wide variety of secondary compounds including alkaloids, flavonoids, terpenoids and saponins. Induction of secondary plant metabolism in cells, tissues and organ cultures do provide a potential alternative to the use of the whole plant or total synthesis of the active components. In vitro manipulation of plant secondary products offers biotechnological techniques to exploit cultured plant cell metabolism. In spite of the fact that very few plant cell processes are operating commercially, the most successful commercial pharmaceuticals produced from undifferentiated cell cultures are antibiotic compounds. The naphthoquinone shikonin from Lithospermum erythrorhizon is an anti-inflammatory, the isoquinoline alkaloid berberine from Coptis japonica is an intestinal antiseptic and the oral antimicrobial benzo-phenanthridine alkaloid sanguinarine from Papaver bracteatum are well known examples. Moreover, intensive research studies is currently devoted to produce the anti-leukaemic alkaloids vinblastine and vincristine from Catharanthus roseus, the antimalaria artemisinin from Artemisia annua and the anti-ovarian cancer taxol from Taxus brevifolis. The scope of this review is to analyze the successful in vitro production examples of antimicrobial agents, to give examples of novel chemical structures produced by plant cell cultures and not reported from the corresponding parent plants and to highlight the poten tial of biotransformation, elicitation and transformation techniques for the production of antiinfective agents from plant cell, tissue and organ cultures. Keywords: antimicrobials, biotransformation, elicitation, hairy roots, plant cell culture

Development and validation of chemometrics-assisted spectrophotometry and micellar electrokinetic chromatography for the determination of four-component pharmaceuticals

Two methods were developed for the simultaneous determination of the corticosteroid dexamethasone sodium phosphate (DEX), the Vitamins B6 and B12 and the anti-inflammatory piroxicam (PIR) in pharmaceutical tablets. Chemometrics-assisted spectrophotometry based on partial least-squares (PLS-1) regression of UV-Vis spectra and micellar electrokinetic capillary chromatography (MEKC) were satisfactory applied to synthetic samples and to several commercial pharmaceuticals. Both described methodologies avoid preliminary sample separation steps. The results were statistically comparable to the reference high performance liquid chromatography method (HPLC).