A stability-indicating HPLC method for the determination of glucosamine in pharmaceutical formulations

A stability-indicating high performance liquid chromatographic (HPLC) method was developed for the assay of glucosamine in bulk forms and solid dosage formulations. The HPLC separation was achieved on a Phenomenex Luna amino column (150 mm x 4.6 mm, i.d., 5 microm particle size) using a mobile phase of acetonitrile-phosphate buffer (75:25, v/v, pH 7.50) at a flow rate of 1.5 ml min(-1) and UV detection at 195 nm. The method was validated for specificity, linearity, solution stability, accuracy, precision, limit of detection, and limit of quantitation. The detector response for glucosamine hydrochloride was linear over the selected concentration range from 1.88 to 5.62 mg ml(-1) with a correlation coefficient 0.9998. The accuracy was between 98.9 and 100.5%. The precision (R.S.D.) amongst six sample preparations was 1.1%. The limit of detection and the limit of quantitation are 0.037 and 0.149 mg ml(-1), respectively. The sample and standard solutions were stable for 1 week. The method was successfully used for analysis of active-excipient compatibility samples used for development of a solid dosage formulation in our laboratory and subsequent stability studies. The method was also used for the analysis of glucosamine in several commercially available solid dosage forms.     

Development and validation of an assay for citric acid/citrate and phosphate in pharmaceutical dosage forms using ion chromatography with suppressed conductivity detection

The paper describes the development and validation of a simple, rapid, accurate, and sensitive ion chromatographic procedure to assay total citrate (citric acid/citrate) and phosphate in nine dosage forms. The dosage forms chosen represent all dosage forms in USP27-NF22 for which the respective monographs require an assay for either citric acid/citrate or citric acid/citrate and phosphate. Citrate and phosphate were separated in <10min by a hydroxide-selective column using anion-exchange chromatography with a 20mM potassium hydroxide eluent and detected by suppressed conductivity. The method showed linear responses over the concentration ranges 0.2-100microg ml(-1) (r(2) > 0.9990) for citrate and 0.2-60microg ml(-1) (r(2) = 0.9999) for phosphate, with limits of quantitation (signal-to-noise (S/N) = 10) of 0.2microg ml(-1) for both analytes. The accuracy of the procedure, determined by spiked recovery measurements, was within 95-105%. The intraday and the interday precision were demonstrated by the relative standard deviations (R.S.D.) of <1 and <2%, respectively, for both analytes. The ruggedness was determined by a full factorial design using analyst, equipment, column lot, and eluent preparation procedure as variables. The results show an overall R.S.D. of <3% and that an electrolytically generated 20mM KOH eluent produces assay results equivalent to a manually prepared 20mM NaOH eluent.     

Simultaneous determinations of paeonol and palmatine hydrochloride in Shangshi Aerosols by HPLC method

A simple and rapid HPLC method was described for the simultaneous determination of paeonol and palmatine hydrochloride in Shangshi Aerosols. The optimum separation for these analytes was achieved using the mixture of 0.025 M sodium dihydrogen phosphate-acetonitrile-diethylamine (64:35:1, v/v/v) as the mobile phase and a Nova-Pak((R)) C8 column. The linear ranges of paeonol and palmatine hydrochloride were 0.2-80 and 0.06-60 microg/ml with the regression equations being Y=11716.4+2.96 x 10(6)X (R=0.99969), Y=-6388.8+1.89 x 10(5)X (R=0.99976), and limit of quantifications (LOQ) for paeonol and palmatine hydrochloride were 0.2 and 0.06 microg/ml, respectively (n=6). Other validation parameters: intra-day precision (R.S.D.: 0.71-1.65%) and inter-day precision (R.S.D.: 0.89-2.11%), and reproducibility (recoveries values: 94.6-98.2% for paeonol, 94.85-97.58% for palmatine hydrochloride) were found to be satisfactory. The proposed HPLC method had been applied for the determination of paeonol and palmatine hydrochloride in Shangshi Aerosols; R.S.D. values were 1.45 and 1.13%, respectively. In short, this method was rapid and convenient, which could be used for the routine control of paeonol and palmatine hydrochloride in Shangshi Aerosols.     

Simultaneous high-performance liquid chromatographic assay of furosemide and propranolol HCL and its application in a pharmacokinetic study

A practical, sensitive, selective and efficient reversed-phase high-performance liquid chromatographic (HPLC) method is reported for the determination of two commonly used antihypertensive drugs, furosemide and propranolol hydrochloride. The drugs were eluted through a Nucleosil C(18) column with a mobile phase composed of 0.02 M potassium dihydrogen phosphate and acetonitrile (80:20, v/v) adjusted to pH 4.5 and the effluent from the column was monitored at 235 nm. The present method enabled simple and isocratic HPLC with UV detection of these drugs in raw materials and in pharmaceutical formulations. These procedures were also applied for the assay of furosemide in rabbits' plasma, using propranolol hydrochloride as an internal standard. The linear concentration range of the assay was 0.1-200 and 5-200 microg ml(-1) for furosemide and propranolol hydrochloride, respectively. The inter and intra-day assay precision and accuracy showed reproducibility and good linearity (r(2)>0.99). The method retained its accuracy and precision when applying the standard addition technique. The results obtained by applying the proposed method was statistically analysed and compared with those obtained by the reported methods.     

Determination of phillyrin in rat plasma by high-performance liquid chromatography and its application to pharmacokinetic studies

A simple high-performance liquid chromatographic method was developed to study the pharmacokinetics of phillyrin in rat after intravenous administration. Plasma was extracted with ethyl acetate after addition of the internal standard, arctiin. Separation was achieved on a reversed-phase C18 column with UV detection at 228 nm. The calibration curves were linear ranging from 0.052 to 26.670 microg/ml. The intra- and inter-day precisions were no more than 9.83% and 12.31%, respectively. The average recovery of phillyrin was 95.44% from plasma. And the limit of quantification (LOQ) was estimated as 0.026 microg/ml with an intra-day relative standard deviation (R.S.D.)相似文献   

An optimized reverse-phase high performance liquid chromatographic method for evaluating percutaneous absorption of glucosamine hydrochloride

A relatively simple, selective, precise and accurate high performance liquid chromatography (HPLC) method based on a reaction of phenylisothiocyanate (PITC) with glucosamine (GL) in alkaline media was developed and validated to determine glucosamine hydrochloride permeating through human skin in vitro. It is usually problematic to develop an accurate assay for chemicals traversing skin because the excellent barrier properties of the tissue ensure that only low amounts of the material pass through the membrane and skin components may leach out of the tissue to interfere with the analysis. In addition, in the case of glucosamine hydrochloride, chemical instability adds further complexity to assay development. The assay, utilising the PITC-GL reaction was refined by optimizing the reaction temperature, reaction time and PITC concentration. The reaction produces a phenylthiocarbamyl-glucosamine (PTC-GL) adduct which was separated on a reverse-phase (RP) column packed with 5 microm ODS (C18) Hypersil particles using a diode array detector (DAD) at 245 nm. The mobile phase was methanol-water-glacial acetic acid (10:89.96:0.04 v/v/v, pH 3.5) delivered to the column at 1 ml min-1 and the column temperature was maintained at 30 degrees C. Galactosamine hydrochloride (Gal-HCl) was used as an internal standard. Using a saturated aqueous solution of glucosamine hydrochloride, in vitro permeation studies were performed at 32+/-1 degrees C over 48 h using human epidermal membranes prepared by a heat separation method and mounted in Franz-type diffusion cells with a diffusional area 2.15+/-0.1 cm2. The optimum derivatisation reaction conditions for reaction temperature, reaction time and PITC concentration were found to be 80 degrees C, 30 min and 1% v/v, respectively. PTC-Gal and GL adducts eluted at 8.9 and 9.7 min, respectively. The detector response was found to be linear in the concentration range 0-1000 microg ml-1. The assay was robust with intra- and inter-day precisions (described as a percentage of relative standard deviation, %R.S.D.) <12. Intra- and inter-day accuracy (as a percentage of the relative error, %RE) was 相似文献   

Simultaneous determination of benazepril hydrochloride and hydrochlorothiazide in tablets by second-order derivative spectrophotometry

A second-order derivative spectrophotometric method for the simultaneous determination of benazepril hydrochloride and hydrochlorothiazide in pharmaceutical dosage forms is described. The determination of benazepril hydrochloride in the presence of hydrochlorothiazide was achieved by measuring the second-order derivative signals at 253.6 and 282.6 nm, while the second-order derivative signal at 282.6 nm was measured for the determination of hydrochlorothiazide. The linear dynamic ranges were 14.80-33.80 microg ml(-1) for benazepril hydrochloride and 18.50-42.20 microg ml(-1) for hydrochlorothiazide, the correlation coefficient for the calibration graphs were better than 0.9998, n = 5, the precision (%RSD) was better than 1.43% and the accuracy was satisfactory (Er < 0.99%). The detection limits were found to be 2.46 and 1.57 microg ml(-1) for benazepril hydrochloride and hydrochlorothiazide, respectively. The method was applied in the quality control of commercial tablets and proved to be suitable for rapid and reliable quality control.     

Ion-pair complex-based solvent extraction combined with chemiluminescence determination of chlorpromazine hydrochloride with luminol in reverse micelles

A new chemiluminescence (CL) method is proposed for the determination of chlorpromazine hydrochloride, which is based on the dichloromethane solvent extraction of ion-pair complex of tetrachloroaurate(III) with chlorpromazine hydrochloride and luminol chemiluminescence detection in a reversed micellar medium formed by the cation surfactant cetyltrimethylammonium bromide in a dichloromethane-cyclohexane (1:1 V/V)-water (0.3 mol/L Na2CO3 buffer solution with the pH of 11.5). The ion-pair complex of tetrachloroaurate(III) with chlorpromazine hydrochloride produced an analytical chemiluminescence signal when it entered the reversed micellar water pool. In the optimum conditions, CL intensities are proportional to concentrations of the studied drug over the range 0.05 approximately 10 microg/mL with a detection limit (DL) of 6 ng/mL. The relative standard deviation (R.S.D.) is 2.6% for 1.25 microg/mL chlorpromazine hydrochloride (n = 11). R.S.D. (precision) of inter-day and intra-day is less than 6%, and accuracy of inter-day and intra-day is satisfactory. The method has been applied to the determination of studied drug in pharmaceutical preparations and biological fluids with satisfactory results.     

Spectrophotometric determination of fluoxetine and sertraline using chloranil, 2, 3 dichloro-5, 6 dicyano benzoquinone and iodine

Spectrophotometric procedures are presented for the determination of two commonly used antidepressant drugs, fluoxetine (I) and sertraline hydrochloride (II). The methods are based mainly on charge transfer complexation reaction of these drugs with either pi acceptors chloranil and 2, 3 dichloro-5, 6-dicyanoquinone (DDQ) or sigma acceptor iodine. The colored products are quantified spectrophotometrically at 550, 450 and 263 nm for fluoxetine and at 450, 455 and 290 nm for sertraline in chloranil, DDQ and iodine methods, respectively. The molar combining ratio and the optimum assay conditions were studied. The methods determine the cited drugs in concentration ranges of 8-640, 16-112 and 7.5-60 microg/ml with mean percentage recoveries of 99.83, 99.76 and 100.00% and R.S.D. of 1.24, 0.95 and 1.13% in fluoxetine and ranges of 16-160, 15-105 and 6-48 microg/ml with mean percentage recoveries of 100.39, 99.78 and 99.69% and R.S.D. of 1.02, 0.81 and 0.57% in sertraline for chloranil, DDQ and iodine methods, respectively. A more detailed investigation of the complex formed was made with respect to its composition, association constant K(AD)c, molar absorptivity xiAD(A) and free energy change deltaG. The proposed methods were applied successfully to the determination of the cited drugs either in pure or dosage forms with good accuracy and precision. The results were compared statistically with those given by the reported methods.     

A capillary zone electrophoresis method for the assay and quality control of mesembrine in Sceletium tablets

The Sceletium plant has been reported to contain psychoactive alkaloids, specifically mesembrine, mesembrenone, mesembrenol and other related alkaloids. Sceletium is marketed through health shops and on the internet as dried plant powder and as pharmaceutical dosage forms. The objectives of this research was to develop and validate a capillary zone electrophoresis (CZE) method to identify five alkaloids and quantitatively determine the content of the important alkaloid, mesembrine in Sceletium tablets. Since reference standards of the relevant alkaloids are not commercially available for use in quality control of Sceletium products, it was necessary to isolate and characterize an appropriate analytical marker for use in the assay and additional markers for fingerprinting by CZE. The separation of the relevant alkaloids was carried out by CZE on a 50cm effective length, fused silica capillary tubing (50microm i.d.x360microm o.d.) using 50mM of sodium dihydrogen orthophosphate dihydrate at pH 1.5 as the background electrolyte and monitored at a UV wavelength of 228nm. All the marker alkaloids were found to be well resolved and were identified in the plant material and in commercially available Sceletium tablets based on the relative migration times (MTs) with respect to quinine hydrochloride that was used as an internal standard. The method was validated and used to assay the mesembrine content in Sceletium tablets. Calibration curves were found to be linear over the entire concentration range of 2.5-80microg/ml with correlation coefficients >0.995. The accuracy was found to be 92.5 and 104.5% (R.S.D.<3.5%) and the R.S.D.'s of the inter-day precision at low, medium and high tablet masses were better than 0.9, 2.2 and 2.7%, respectively. The recoveries were all within the range of 91.8 and 105.8% (R.S.D.<8.5%) and the limit of quantitation (LOQ) and limit of detection (LOD) values were found to be 2.5 and 1.5microg/ml, respectively.     

Validation of a levofloxacin HPLC assay in plasma and dialysate for pharmacokinetic studies

An HPLC method with fluorescence detection suitable for routine determination of levofloxacin in plasma and dialysate has been validated. Sample preparation was assured by one-step protein precipitation for plasma or direct injection of the dialysate solution, respectively. Separation occurred on an YMC Pro C18 RP column (150 mm x 2 mm) with an acidic binary gradient mobile phase and detection at excitation and emission wavelengths of 296 and 504 nm. The assay was linear between 0.1 and 6 microg/ml for plasma and 0.1 and 5 microg/ml for dialysate with intra- and inter-day precision and accuracy lower than 10%. No degradation of levofloxacin was observed under the applied conditions for both matrices. The method was successfully applied to an in vitro pharmacokinetic study and patient samples as well.     

LC method for the analysis of cefetamet pivoxil hydrochloride in drug substance and powder for oral suspension

A high-performance liquid chromatography isocratic procedure was developed for the assay of cefetamet pivoxil hydrochloride in drug substance and powder for oral suspension. The method validation yielded good results and included the range, linearity, precision intra- inter-day, accuracy, specificity, LOD and LOQ values. The chromatographic system consisted of a C(18) absorbosphere column (150 x 4.6 mm i.d., 5 microm particle size), a mobile phase composed of water-acetonitrile-methanol-phosphate buffer, pH 3.5 (50:35:10:5, v/v), flow rate of 1.5 ml min(-1) and UV detection at 254 nm. The relative standard deviation varied between 0.03 and 1.76%, and accuracy of 100.09% was found. Calibration curve was linear from 30.0-80.0 microg ml(-1); its correlation coefficient was 0.99989.     

Rapid quantitative analysis of oxiracetam in human plasma by liquid chromatography/electrospray tandem mass spectrometry

A rapid and accurate reversed-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the quantitative determination of oxiracetam in human plasma. Oxiracetam, a highly polar compound, was successfully retained by Atlantis dC18 reversed-phase column and detected with triple-quadrupole tandem mass spectrometry. After addition of internal standard (piracetam) to human plasma, plasma was simply precipitated with two volume of acetonitrile, evaporated and dissolved in 0.1% acetic acid. This method for the determination of oxiracetam was accurate and reproducible, with a limit of quantitation of 0.2microg/ml in human plasma. The standard calibration curve for oxiracetam was linear (r(2) = 0.999) over the concentration range 0.2-40.0microg/ml in human plasma. The intra- and inter-day precision over the concentration range of oxiracetam was lower than 8.3% (relative standard deviation, %R.S.D.), and accuracy was between 92.5 and 106.4%.     

Study on warfarin plasma concentration and its correlation with international normalized ratio

A sensitive high-performance liquid chromatographic (HPLC) method was developed for warfarin determination in plasma of patients who undertook cardiac valve replacement and were on anticoagulation with warfarin. The method described proved to be accurate, sensitive, easy to perform, reproducible and specific for plasma warfarin measurement with relative standard deviation (R.S.D.) of <5.27% for inter-day and <6.89% for intra-day. The assay was linear in warfarin concentration ranges of 0.12-3 microg/ml (r=0.9995) with mean recovery of 94.6%. The mean warfarin plasma concentration of 58 patients with heart valve replacement within 1 month of post operation was 567.6+/-122.3 ng/ml. The anticoagulant effect of the drug was monitored by international normalized ratio (INR). The correlation of warfarin dosage and concentration with INR was analysed, and the coefficients were 0.21, 0.1相似文献   

Determination of rifampicin in human plasma and blood spots by high performance liquid chromatography with UV detection: a potential method for therapeutic drug monitoring

A high performance liquid chromatography method has been developed that allows quantification of concentrations of rifampicin in human plasma and blood spots. Rifampicin and papaverine hydrochloride (internal standard) were extracted from plasma using a Strata-X-CW extraction cartridge. These analytes were also extracted into acetonitrile from blood spots dried onto a specimen collection card. The recovery of rifampicin from plasma and blood spots was 84.5% and 65.0%, respectively. Separation was achieved by HPLC on a Kromasil C(18) column with a mobile phase composed of ammonium acetate (20 mM, pH 4.0) and acetonitrile, delivered on a gradient programme. Optimum detection was at 334 nm. The assay was linear over the concentration range of 0.5-20 microg/ml. The limit of quantification was 0.5 microg/ml in plasma; 1.5 microg/ml in blood spots. Both intraday and interday precision data showed reproducibility (R.S.D.< or =8.0, n=9). Stability studies showed rifampicin was stable in plasma for up to 9h after thawing; the samples were also stable for up to 9h after preparation. Five patient samples were analysed using the methods described. A correlation was found between the concentrations of RIF in plasma and blood spots (r(2)=0.92). This method is proposed as a means of therapeutic drug monitoring of rifampicin in patients with tuberculosis.     

Rapid quantitative analysis of oxiracetam in human plasma by liquid chromatography/electrospray tandem mass spectrometry

A rapid and accurate reversed-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the quantitative determination of oxiracetam in human plasma. After addition of internal standard (piracetam) plasma was precipitated with two volumes of acetonitrile and the supernatant was evaporated. The residues were dissolved in 0.1% acetic acid and analyzed by reversed-phase HPLC with the detection of the analyte in the multiple reaction monitoring (MRM) mode. This method for the determination of oxiracetam was accurate and reproducible, with a limit of quantitation of 0.2 microg/ml in human plasma. The standard calibration curve for oxiracetam was linear (r2 = 0.999) over the concentration range 0.2-40.0 microg/ml in human plasma. The intra- and inter-day precision over the concentration range of oxiracetam was lower than 8.3% (relative standard deviation, %R.S.D.), and accuracy was between 92.5-106.4%.     

Simultaneous determination of benazepril hydrochloride and hydrochlorothiazide by micro-bore liquid chromatography

A micro-bore liquid chromatographic method was developed for the simultaneous determination of benazepril hydrochloride and hydrochlorothiazide in pharmaceutical dosage forms. The use of a BDS C-18 micro-bore analytical column, results in substantial reduction in solvent consumption and increased sensitivity. The mobile phase consisted of a mixture of 0.025 M sodium dihydrogen phosphate (pH 4.8) and acetonitrile (55:45, v/v), pumped at a flow rate of 0.40 ml min(-1). Detection was set at 250 nm using an ultraviolet detector. Calibration graphs are linear (r better than 0.9991, n = 5), in concentration range 5.0-20.0 microg ml(-1) for benazepril hydrochloride and 6.2-25.0 microg ml(-1) for hydrochlorothiazide. The intra- and interday R.S.D. values were <1.25% (n = 5), while the relative percentage error (Er) was <0.9% (n = 5). The detection limits attained according to IUPAC definition were 0.88 and 0.58 microg ml(-1) for benazepril hydrochloride and hydrochlorothiazide, respectively. The method was applied in the quality control of commercial tablets and content uniformity test and proved to be suitable for rapid and reliable quality control.     

High performance liquid chromatographic assay of a new fluoroquinolone,LB20304, in the plasma of rats and dogs

High-performance liquid chromatographic method was developed for the determination of LB 20304 (compound 1) in the plasma of rats and dogs. The analyte was deproteinized with 1 volume of methanol and 1/2 volume of 10% zinc sulfate, and the supernatant was injected onto a reversed-phase HPLC column. The mobile phase was a mixture of 24 parts of acetonitrile and 76 parts of 0.1% trifluoroacetic acid. The flow rate was 1 ml/min, and the effluent was monitored by fluorescence detector at an excitation wavelength of 337 nm and an emission wavelength of 460 nm. The retention time of compound 1 was 6.3 min. The assay of compound 1 was linear over the concentration range of 0.2–100 μl/ml in the plasma of rats and dogs. The lower limit of quantification was 0.2 μg/ml using 100 μl of plasma with a 97–99% accuracy and a 12–14% precision. In the 0.5, 5, and 50 μg/ml quality control samples, the intra- and inter-day accuracy were 88–95% and 88–97%, whereas intra- and inter-day precision were 0.5–6.6% and 0.2–9.3%, respectively, in the plasma of rats and dogs. The recoveries were 68–71% independent of concentration and species in the plasma. No interferences from endogenous substances were observed. Taken together, the above HPLC assay method by deproteinization and fluorescence detection was suitable for the determination of compound 1 in the preclinical pharmacokinetics.     

Determination of sitagliptin in human urine and hemodialysate using turbulent flow online extraction and tandem mass spectrometry

High turbulence liquid chromatography (HTLC, or turbulent flow online extraction) and tandem mass spectrometry (MS/MS) methods for the determination of sitagliptin in human urine and hemodialysate were developed and validated to support clinical studies. A narrow bore large particle size reversed-phase column (Cyclone, 50 mm x 1.0 mm, 60 microm) and a BDS Hypersil C18 column (30 mm x 2.1 mm, 3 microm) were used as extraction and analytical columns, respectively. For the urine assay, the LLOQ was 0.1 microg/ml, the linear calibration range was 0.1 to 50 microg/ml, the interday precision (R.S.D.%, n=5) was 2.3-6.5%, and the accuracy was 96.9-106% of the nominal value. For the urine quality control samples (QCs), the intraday precision (R.S.D.%, n=5) and accuracy were 1.8-2.6% and 96.2-106% of the nominal value, respectively. The interday precision (R.S.D.%) for 56 sets of urine QCs over a 6-month period varied from 3.8% to 5.5% and the accuracy from 102% to 105% of the nominal value. For the hemodialysate assay, the LLOQ was 0.01 ng/ml, the linear dynamic range was 0.01-5.0 ng/ml, the interday precision was 1.6-4.1%, and the accuracy was 89.8-104% of the nominal value. For hemodialysate QCs, the intraday precision and accuracy varied from 2.3% to 8.9% and from 99.8% to 111% of the nominal value, respectively. These results demonstrated that both methods are selective, accurate, precise, reproducible, and suitable for quantifying sitagliptin in hemodialysate and human urine samples.     

HPLC determination of aminophylline,methoxyphenamine hydrochloride,noscapine and chlorphenamine maleate in compound dosage forms with an aqueous-organic mobile phase

A high-performance liquid chromatography procedure for the simultaneous determination of aminophylline, methoxyphenamine hydrochloride, noscapine and chlorphenamine maleate in commercially available compound capsule dosage forms has been developed and validated. The separation and quantification were achieved on an Ultrasphere C18 column using a mobile phase of dichloromethane-methanol-0.25% (v/v) diethylamine aqueous solution (20:60:20, v/v/v) at a flow rate of 1 ml min(-1) with detection of all analytes at 264 nm. The separation was achieved within 6 min for each drug mixture. The method showed good linearity for the aminophylline, noscapine, chlorphenamine maleate and methoxyphenamine hydrochloride mixture in the 125-750, 35-210, 10-60 and 62.5-375 microg ml(-1) ranges, respectively. The intra- and inter-day R.S.D.s ranged from 0.4 to 0.5%, 0.4-0.6%, 0.5-0.7% and 0.4-0.6% for aminophylline, noscapine, chlorphenamine maleate and methoxyphenamine hydrochloride, respectively. The recoveries (mean+/-S.D.) of low, middle and high concentrations were 99.9+/-0.9, 100.4+/-1.3 and 99.7+/-0.7% for aminophylline; 99.9+/-1.1, 100.4+/-0.7 and 100.1+/-0.8% for noscapine; 99.8+/-1.1, 99.7+/-1.0 and 100.7+/-0.8% for chlorphenamine maleate; and 99.8+/-0.9, 100.4+/-1.6 and 99.9+/-0.9% for methoxyphenamine hydrochloride, respectively.