			Home About us Contact

Pharmaceutical Formulations (pharmaceutical + formulations)

Distribution by Scientific Domains

Chemistry	78%

Selected Abstracts

Electroanalytical Determination of Promethazine Hydrochloride in Pharmaceutical Formulations on Highly Boron-Doped Diamond Electrodes Using Square-Wave Adsorptive Voltammetry

ELECTROANALYSIS, Issue 18 2008
Francisco, Wirley
Abstract The electrochemical oxidation of promethazine hydrochloride was made on highly boron-doped diamond electrodes. Cyclic voltammetry experiments showed that the oxidation mechanisms involved the formation of an adsorbed product that is more readily oxidized, producing a new peak with lower potential values whose intensity can be increased by applying the accumulation potential for given times. The parameters were optimized and the highest current intensities were obtained by applying +0.78,V for 30 seconds. The square-wave adsorptive voltammetry results obtained in BR buffer showed two well-defined peaks, dependent on the pH and on the voltammetric parameters. The best responses were obtained at pH,4.0, frequency of 50,s,1, step of 2,mV, and amplitude of 50,mV. Under these conditions, linear responses were obtained for concentrations from 5.96×10,7 to 4.76×10,6,mol L,1, and calculated detection limits of 2.66×10,8,mol L,1 (8.51,,g L,1) for peak 1 and of 4.61×10,8,mol L,1 (14.77,,g L,1) for peak 2. The precision and accuracy were evaluated by repeatability and reproducibility experiments, which yielded values of less than 5.00% for both voltammetric peaks. The applicability of this procedure was tested on commercial formulations of promethazine hydrochloride by observing the stability, specificity, recovery and precision of the procedure in complex samples. All results obtained were compared to recommended procedure by British Pharmacopeia. The voltammetric results indicate that the proposed procedure is stable and sensitive, with good reproducibility even when the accumulation steps involve short times. It is therefore very suitable for the development of the electroanalytical procedure, providing adequate sensitivity and a reliable method. [source]

Development of a Novel Automatic Potentiometric System for Determination of Selenium and Its Application in Pharmaceutical Formulations and Anodic Slime

ELECTROANALYSIS, Issue 9 2008
Ayman
Abstract Poly(vinyl chloride) polymeric membrane sensors containing Sn(IV) phthalocyanine dichloride (SnPC) and Co(II) phthalocyanine (CoPC) as novel electroactive materials dispersed in o -nitrophenyl octylether (o -NPOE) as a plasticizer are examined potentiometrically with respect to their response toward selenite (SeO32,) ions. Fast Nernstian response for SeO32, ions over the concentration ranges 7.0×10,6,1.0×10,3 and 8.0×10,6,1.0×10,3 mol L,l at pH,3.5,8.5 with lower detection limit of 5.0×10,6 and 8.0×10,6 mol L,1 and calibration slopes of ,25.4 and ,29.7,mV decade,1 are obtained with SnPC and CoPC based membrane sensors, respectively. The proposed sensors reveals by the modified separate solution method (MSSM) a good selectivity over different anions which differ significantly from the classical Hofmeister series. A segmented sandwich membrane method is used to determine complex formation constants of the ionophores in situe in the solvent polymeric sensing membranes. Membrane incorporating CoPC in a tubular flow detector is used in a two channels flow injection set up for continuous monitoring of selenite at a frequency of ca. 50 samples h,1. Direct determination of selenium in pharmaceutical formulations and anodic slime gives results in good agreement with data obtained using standard ICP method. [source]

Simultaneous determination of metronidazole and spiramycin in bulk powder and in tablets using different spectrophotometric techniques

DRUG TESTING AND ANALYSIS, Issue 1 2010
Fatma I. Khattab
Abstract Metronidazole (MZ) is an anti-infective drug used in the treatment of anaerobic bacterial and protozoa infections in humans. It is also used as a vetinary antiparasitic drug. Spiramycin (SP) is a medium-spectrum antibiotic with high effectiveness against Gram-positive bacteria. Three simple, sensitive, selective and precise spectrophotometric methods were developed and validated for the simultaneous determination of MZ and SP in their pure form and in pharmaceutical formulations. In methods A and B, MZ was determined by the application of direct spectrophotometry and by measuring its zero-order (D0) absorption spectra at its ,max = 311 nm. In method A, SP was determined by the application of first derivative spectrophotometry (D1) and by measuring the amplitude at 218.3 nm. In method B, the first derivative of the ratio spectra (DD1) was applied, and SP was determined by measuring the peak amplitude at 245.6 nm. Method C entailed mean centring of the ratio spectra (MCR), which allows the determination of both MZ and SP. The methods developed were used for the determination of MZ and SP over a concentration range of 5,25 µg ml,1. The proposed methods were used to determine both drugs in their pure, powdered forms with mean percentage recoveries of 100.16 ± 0.73 for MZ in methods A and B, 101.10 ± 0.90 in method C, 100.09 ± 0.70, 100.02 ± 0.88 and 100.49 ± 1.26 for SP in methods A, B and C, respectively. The proposed methods were proved using laboratory-prepared mixtures of the two drugs and were successfully applied to the analysis of MZ and SP in tablet formulation without any interference from each other or from the excipients. The results obtained by applying the proposed methods were compared statistically with a reported HPLC method and no significant difference was observed between these methods regarding both accuracy and precision. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Determination of Diazepam, Temazepam and Oxazepam at the Lead Film Electrode by Adsorptive Cathodic Stripping Voltammetry

ELECTROANALYSIS, Issue 17-18 2010
Katarzyna Tyszczuk
Abstract The determination of psychoactive 1,4-benzodiazepine drugs is of relevant interest in clinical, biomedical areas. Therefore a highly sensitive and simple voltammetric method for the determination of temazepam, diazepam and oxazepam at an in situ plated lead film electrode was developed. The method was successfully applied to the determination of diazepam and temazepam in pharmaceutical formulations with minimum sample manipulation and oxazepam in human urine samples without any separation steps. The determinations of oxazepam in human urine samples were performed in a flow system. Therefore a previous extraction procedure was not necessary to separate the active compound before its determination. [source]

Alkanethiols Modified Gold Electrodes for Selective Detection of Molecules with Different Polarity and Molecular Size.

ELECTROANALYSIS, Issue 3-5 2009
Application to Vitamin B2 Analysis
Abstract The cyclic voltammetry behavior of several molecules with different polarity and molecular size on gold electrodes modified with nonfunctionalized alkanethiols of different chain length, usually employed as chromatographic stationary phases, are studied. The redox systems hexacyanoferrate(II/III), ferrocene/ferrocine and hydroquinone/quinone are chosen as template molecules. As modifiers, ethanethiol, 1-octanethiol and di- n -octadecyldisulfide are selected. We can conclude that polar molecules can reach the electrode surface through channels created by the modifiers. However, when nonpolar compounds are analyzed, the nonpolar interactions between the analyte and the terminal group of the modifier lead to retention of the compound, retarding its arrival to the electrode surface. A molecule with polar and nonpolar part was used for the application of this conclusion. If the gold electrode is modified with di- n -octadecyldisulfide, the electrochemical behavior of vitamin B2 becomes simpler than that observed on a bare one. This result allows a sensitive and selective procedure to be developed for direct determination of vitamin B2 in pharmaceutical formulations. [source]

Development of a Novel Automatic Potentiometric System for Determination of Selenium and Its Application in Pharmaceutical Formulations and Anodic Slime

Electrochemical Evaluation of Nucleoside Analogue Lamivudine in Pharmaceutical Dosage Forms and Human Serum

ELECTROANALYSIS, Issue 20 2005
Burcu Dogan
Abstract Lamivudine (LAM) is a synthetic nucleoside analogue with activity against human immunodeficiency virus-type 1 (HIV-1) and Hepatitis B virus (HBV). The aim of this study was to determine LAM levels in serum and pharmaceutical formulations, by means of electrochemical methods using hanging mercury drop electrode (HMDE). On this electrode, LAM undergoes irreversible reduction at the peak potential near Ep,1.26,V (vs. Ag/AgCl/3,M KCl). Reduction LAM signals were measured by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and square-wave voltammetry (OSW). DPV and OSW techniques for the determination of LAM in acetate buffer at pH,4.5, which allows quantitation over the 4×10,6 to 1×10,4,M range in supporting electrolyte for both methods, were proposed. The linear response was obtained in acetate buffer in the ranges of 2×10,6 to 2×10,4,M for spiked serum samples at pH,4.5 for both techniques. The repeatability and reproducibility of the methods for all media were determined. The standard addition method was used in serum. Precision and accuracy were also checked in all media. No electroactive interferences from the endogenous substances were found in serum. With respect to side effects of high doses and short half-life of LAM, a fast and simple detection method is described in this study. [source]

Voltammetric Assay of Naproxen in Pharmaceutical Formulations Using Boron-Doped Diamond Electrode

ELECTROANALYSIS, Issue 11 2005
V. Suryanarayanan
Abstract The electrooxidation of naproxen was studied, for the first time, using boron-doped diamond (BDD) electrode by cyclic and differential pulse voltammetry (CV and DPV) in nonaqueous solvent supporting electrolyte system. The results were also compared with glassy carbon electrode (GC) under the same conditions. Naproxen undergoes one electron transfer resulting in the formation of cation radical for the first electrooxidation step, which follows other chemical and electrochemical steps such as deprotonation, removal of another electron and the attack of nucleophile (ECEC mechanism). BDD electrode provided higher signal to background ratio, well resolved and highly reproducible cyclic voltammograms than the GC electrode. With a scan rate of 50,mV s,1 and pulse height of 50,ms, respectively, the DPV technique was able to determine the naproxen concentrations in the range of 0.5 to 50,,M with a detection limit of 30,nM. The influence of interference compounds namely 2-acetyl-6-methoxy naphthalene (AMN) on naproxen oxidation can also be followed successfully. Moreover, the percentage of AMN present in the standard chemical form of a mixture containing naproxen can be found accurately. Rapidity, precise and good selectivity were also found for the determination of naproxen in pharmaceutical formulations. [source]

Enantioselective determination of thyroxine enantiomers by ligand-exchange CE with UV absorbance and ICP-MS detection

ELECTROPHORESIS, Issue 10 2009
Jianzhen Kang
Abstract A simple CE method has been developed for the separation and determination of thyroxine (T4) enantiomers in pharmaceutical formulations. The method was based on ligand-exchange mechanism using a Cu(II)/L -proline complex as chiral selector. The effects of different parameters affecting separation such as chiral selector concentration, organic additive, buffer pH and temperature were investigated. A baseline separation of the two enantiomers was obtained at a Cu(II)/L -proline ratio of 1:8 in a borate buffer (15,mmol/L, pH 9.6) containing 10%,v/v acetonitrile. Under the optimized conditions, precision linearity range and detection limits of the developed enantioselective CE method were evaluated and compared using two different detection systems: conventional UV detection at 226,nm and iodine (127I)specific detection ("chiral speciation") with ICP-MS. Both methodologies show adequate analytical performance characteristics with detection limits around 0.30,,g/mL for each enantiomer of T4. Finally, a levothroid pharmaceutical formulation sample was successfully analyzed using both developed methods CE-UV and CE-ICP-MS. [source]

Determination of amino acids by micellar EKC: Recent advances in method development and novel applications to different matrices

ELECTROPHORESIS, Issue 1 2008
Paolo Iadarola Professor
Abstract The extensive use of CE for the analysis of amino acids has been well documented in a series of research articles and reviews. Aim of this report is to address the attention of the reader on the recent advances of micellar electrokinetic chromatography for the separation and determination of these analytes. Enhancements in selectivity of this technique through the use of pseudostationary phases containing mixed micelles, polymers, and chiral selectors are presented. Selected applications concerning separation and quantitation of even minute amounts of amino acids in: (i) biological fluids; (ii) microdialysates; (iii) plant cells; (iv) food stuff; and (v) pharmaceutical formulations have also been covered. Advantages of MEKC over other techniques for the amino acid analysis have been underlined. [source]

Fast quantitative determination of diuretic drugs in tablets and human urine by microchip electrophoresis with native fluorescence detection

ELECTROPHORESIS, Issue 16 2007
Kamal Tolba
Abstract Microchip electrophoresis (MCE) with native fluorescence detection has been applied for the fast quantitative analysis of pharmaceutical formulations. For this purpose, methods for fast separation and sensitive detection of the unlabeled diuretic drugs, amiloride, triamterene, bendroflumethiazide (BFMTZ), and bumetanide were developed. An epifluorescence setup was used enabling the coupling of different lasers into a commercial fluorescence microscope. The detection sensitivity of different excitation light sources was compared utilizing either a HeCd laser (,exc,=,325,nm), a frequency quadrupled Nd:YAG laser (,exc,=,266,nm), or a mercury lamp (,exc,=,330,380,nm). At optimal conditions using the HeCd laser, the drugs were separated within 15,s with LODs less than 1,,g/mL for the four compounds. A linear relationship between concentration and peak area was obtained in the concentration range of 0.05,20,,g/mL with a mean correlation coefficient of around 0.996 for all analytes. The method was successfully applied to the analysis of the respective drugs in commercial formulations and in human urine without interference from other constituents. These data show that MCE has a great potential for reliable drug analysis. [source]

Advances in the enantioseparation of second-generation antidepressant drugs by electrodriven methods

ELECTROPHORESIS, Issue 1 2006
Roberto Mandrioli
Abstract Stereochemistry is steadily increasing in importance in the development of new drugs, and the availability of pure enantiomer drugs can make therapy safer and more efficacious. In particular, almost all second-generation antidepressant drugs possess one or more chiral centres; however, only some of them are administered as single enantiomers. A fundamental part of the quality control of pharmaceutical formulations is the determination of enantiomeric excess and enantiomeric purity; this is also important for the therapeutic drug monitoring of depressed patients. For this purpose, efficient and reliable analytical methods are needed and electrodriven techniques (most of all CE, CEC and MEKC) are very efficient and inexpensive candidates for the role. In this review, the enantioselective electrodriven methods available for the analysis of second-generation antidepressant are presented and discussed. In particular, the following pharmacological classes of antidepressants will be considered: selective serotonin reuptake inhibitors (fluoxetine, citalopram, paroxetine, sertraline); norepinephrine reuptake inhibitors (reboxetine); serotonin and norepinephrine reuptake inhibitors (venlafaxine, milnacipran, duloxetine); and noradrenergic and specific serotonergic antidepressants (mirtazapine). [source]

Origins and development of biomedical engineering within chemical engineering

AICHE JOURNAL, Issue 3 2004
Nicholas A. Peppas
Abstract Over the past 45 years, the field of biomedical engineering has found a welcome home in academic chemical engineering departments and in companies working with artificial organs, medical devices, and pharmaceutical formulations. The contributions of chemical engineers to the definition and the growth of the field have been important and at times seminal. The development and early contributions in the biomedical field with special emphasis on the contributions of chemical engineers is examined. © 2004 American Institute of Chemical Engineers AIChE J, 50: 536,546, 2004 [source]

Characterization of chitin,metal silicates as binding superdisintegrants

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2009
Iyad Rashid
Abstract When chitin is used in pharmaceutical formulations, processing of chitin with metal silicates is advantageous, from both an industrial and pharmaceutical perspective, compared to processing using silicon dioxide. Unlike the use of acidic and basic reagents for the industrial preparation of chitin,silica particles, coprecipitation of metal silicates is dependent upon a simple replacement reaction between sodium silicate and metal chlorides. When coprecipitated onto chitin particles, aluminum, magnesium, or calcium silicates result in nonhygroscopic, highly compactable/disintegrable compacts. Disintegration and hardness parameters for coprocessed chitin compacts were investigated and found to be independent of the particle size. Capillary action appears to be the major contributor to both water uptake and the driving force for disintegration of compacts. The good compaction and compression properties shown by the chitin,metal silicates were found to be strongly dependent upon the type of metal silicate coprecipitated onto chitin. In addition, the inherent binding and disintegration abilities of chitin,metal silicates are useful in pharmaceutical applications when poorly compressible and/or highly nonpolar drugs need to be formulated. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:4887,4901, 2009 [source]

Analysis of low content drug tablets by transmission near infrared spectroscopy: Selection of calibration ranges according to multivariate detection and quantitation limits of PLS models

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2008
Manel Alcalà
Abstract The content uniformity of low dose products is a major concern in the development of pharmaceutical formulations. Near infrared spectroscopy may be used to support the design and optimization of potent drug manufacturing processes through the analysis of blends and tablets in a relatively short time. A strategy for the selection of concentration ranges in the development of multivariate calibration is presented, evaluating the detection and quantitation limits of the obtained multivariate models. The strategy has been applied to the determination of an active principle in pharmaceutical tablets of low concentration (0,5%, w/w), using Fourier Transform Near Infrared (FT-NIR) transmission spectroscopy. The quantitation and detection limits decreased as the upper concentration level of the calibration models was reduced. The results obtained show that the selection of concentration ranges is a critical aspect during model design. The selection of wide concentration ranges with high levels is not recommended for the determination of analytes at minor levels (<1%, w/w), even when the concentration of interest is within the range of the model. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:5318,5327, 2008 [source]

N-methylation and N-formylation of a secondary amine drug (varenicline) in an osmotic tablet

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2008
Kenneth C. Waterman
Abstract Significant degradation of the amine-based smoking cessation drug varenicline tartrate in an early development phase osmotic, controlled-release (CR) formulation yields predominantly two products: N-methylvarenicline (NMV) and N-formylvarenicline (NFV). NMV is produced by reaction of the amine moiety with both formaldehyde and formic acid in an Eschweiler-Clarke reaction, while NFV is formed by reaction of formic acid alone with varenicline. This represents the first report of these reactions occurring on storage of solid pharmaceutical formulations. Both formaldehyde and formic acid are formed from oxidative degradation of polyethylene glycol (PEG) used in an osmotic coating through a process heavily dependent on the physical state of the PEG. When the concentration of PEG in the coating is sufficiently low, the PEG remains phase compatible with the other component of the coating (cellulose acetate) such that its degradation (and the resulting drug reactivity) is effectively eliminated. Antioxidants in the coating and oxygen scavengers in the packaging also serve to prevent the PEG degradation, and consequently provide for drug stability. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:1499,1507, 2008 [source]

Evaluation of solution oxygenation requirements for azonitrile-based oxidative forced degradation studies of pharmaceutical compounds

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 7 2006
Eric D. Nelson
Abstract AIBN and ACVA oxidative forced degradation models are examined for two drug molecules whose predominant oxidation chemistries arise from different reaction mechanisms (i.e., free radical vs. nucleophilic). Stress was conducted under a variety of initiator concentrations, and under ambient and pressurized oxygen atmospheres. In each case examined, the azonitrile initiator solutions served as a good predictive model of the major oxidative degradation products observed in pharmaceutical formulations. At low to moderate inititator concentrations, the degradation product distributions and degree of reactivity were similar for samples stored in ambient and pressurized oxygen environments. These results are rationalized with reference to the oxygen consumption kinetics of AIBN and ACVA solutions as a function of initiator concentration. The data suggests that ambient air provides sufficient oxygen to enable chain propagation of peroxy radicals in azonitrile solutions of concentrations appropriate to the forced degradation of pharmaceutical compounds. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95: 1527,1539, 2006 [source]

Effect of polymer size and cosolutes on phase separation of poly(vinylpyrrolidone) (PVP) and dextran in frozen solutions

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2005
Ken-ichi Izutsu
Abstract The aim of this study was to elucidate the effect of the molecular weight of polymers on their miscibility in frozen solutions to model the physical properties of freeze-dried pharmaceutical formulations. Thermal analysis of frozen solutions containing poly(vinylpyrrolidone) (PVP) and dextran of various molecular weights was performed at polymer concentrations below the binodal curve at room temperature. Frozen solutions containing PVP 29,000 and dextran 10,200 showed two thermal transitions (glass transition temperature of maximally freeze-concentrated solution: Tg,) representing two freeze-concentrated amorphous phases, each containing predominantly one of the polymers. A combination of smaller polymers (PVP 10,000 and dextran 1,060) was freeze-concentrated into an amorphous mixture phase across a wide range of concentration ratios. Combinations of intermediate size polymers separated into two freeze-concentrated phases only at certain concentration ratios. Addition of NaCl prevented the phase separation of PVP and dextran in the aqueous and frozen solutions. Higher concentrations of NaCl were required to retain the miscibility of larger polymer combinations in the freeze-concentrate. The molecular weights of the component polymers, polymer concentration ratio, and cosolute composition are the important factors that determine component miscibility in frozen solutions. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:709,717, 2005 [source]

Pharmaceutical applications of mucoadhesion for the non-oral routes

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 1 2005
Katarina Edsman
The adhesion of pharmaceutical formulations to the mucosal tissue offers the possibility of creating an intimate and prolonged contact at the site of administration. This prolonged residence time can result in enhanced absorption and, in combination with a controlled release of the drug, also improved patient compliance by reducing the frequency of administration. During the almost 30 years over which mucoadhesion has been studied, a considerable amount of knowledge has been gained, and much has been learned about the different mechanisms occurring at the formulation-mucus interface and the properties that affect these mechanisms. The in-vivo performance of a dosage form not only depends on the mechanisms occurring at the interface, but also on the properties of the total mucoadhesive complex: the dosage form, the mucosa and the interface between them. A wide variety of methods are used for studying mucoadhesion; some rather similar to the in-vivo situation and some mimicking the interface alone. In this review, the mucus surface, the methods used for the study of mucoadhesion, the different mechanisms involved in mucoadhesion and theories underpinning them have been described. The complexity of mucoadhesion when trying to systemize the subject will also be discussed. The last part of the review describes the buccal, nasal, ocular, vaginal and rectal routes and provides examples of what can be achieved in-vivo when using mucoadhesive formulations. [source]

Determination of ibuprofen in pharmaceutical formulations using time-resolved terbium-sensitized luminescence

LUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4 2007
Salma M. Z. Al-Kindy
Abstract A sensitive and specific luminescence method for the determination of ibuprofen (IB) in pharmaceutical formulations in aqueous solution is described. The method is based on the luminescence sensitization of terbium (Tb3+) by formation of ternary complex with IB in the presence of tri- n -octylphosphine oxide (TOPO) and Tween-20 as surfactant. The luminescence signal for Tb,IB,TOPO is monitored at ,ex = 229 nm and ,em = 545 nm. Optimum conditions for the formation of the complex in aqueous system, were 16 mmol/L TRIS buffer, pH 5.7, TOPO 200 µmol/L and 15 µmol/L of Tb3+, which allows for the determination of 9.7 × 10,7 , 9.7 × 10,6 mol/L IB with a detection limit of 1.2 × 10,7 mol/L. The relative standard deviations of the method were <1.4%, indicating excellent reproducibility. The proposed method was successfully applied for the assays of IB in pharmaceutical formulations with average recoveries of 100.3,102.5%. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Enantioselective analysis of primaquine and its impurity quinocide by capillary electrophoresis

BIOMEDICAL CHROMATOGRAPHY, Issue 3 2009
Abdalla A. Elbashir
Abstract A capillary electrophoretic (CE) method for the baseline separation of the enantiomers of primaquine diphosphate (PQ) and quinocide (QC) (a major contaminant) in pharmaceutical formulations is proposed. Both components were separated under the following conditions: 50 mm tris phosphate buffer (pH 3.0) containing 15 mm hydroxypropyl- , -cyclodextrin (HP- , -CD) as background electrolyte; applied voltage, 16 kV; capillary temperature, 25°C; detection wavelength, 254 nm; hydrostatic injection, 10 s. The separations were conducted using a 35 cm length and 50 µm i.d. uncoated fused silica capillary column. Under the optimized conditions, the components were successfully separated in about 5 min. Intraday precision of migration time and corrected peak areas when expressed as relative standard deviation ranged from 0.17 to 0.45 and 2.60 to 3.94%, respectively, while the interday precision ranged from 2.59 to 4.20 and 3.15 to 4.21%, respectively. After the validation exercise, the proposed method was applied for the determination of QC impurity in PQ formulations. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Study on the enantiomeric ratio of the pharmaceutical substances alkannin and shikonin

BIOMEDICAL CHROMATOGRAPHY, Issue 10 2004
A. N. Assimopoulou
Abstract The chiral pair alkannin and shikonin (A/S) are potent pharmaceutical substances with a wide spectrum of biological activity; their enantiomeric ratio does not in,uence the major biological activity studied hitherto. Nevertheless, in pharmaceutical development and approval of chiral drugs from the Health and Regulatory Authorities, full documentation of methods of analysis of enantiomeric drugs, is required in order to evaluate the enantiomeric purity of starting materials and ,nal products and to control the stability of enantiomers in pharmaceutical formulations under several experimental conditions. In the present study, the enantiomeric ratio of A/S was determined in several commercial samples of alkannin and shikonin and also the proportion of A/S derivatives in several Alkanna root samples, which are all used as active ingredients in pharmaceuticals. Light and air proved not to in,uence the enantiomeric ratio of A/S on a shikonin commercial sample, and temperature also did not alter the A/S ratio on shikonin and alkannin commercial samples. Microencapsulation of alkannin and shikonin commercial samples in ethylcellulose microspheres and also molecular inclusion of a shikonin commercial sample in , -hydroxypropyl-cyclodextrin, which are used as drug delivery systems, did not alter the A/S enantiomeric ratio. Copyright © 2004 John Wiley & Sons, Ltd. [source]