Stability-indicating High-performance Liquid Chromatographic Assay Research Articles

A stability-indicating high-performance liquid chromatographic assay for the determination of some pharmaceutically important nitrocompounds

A simple, rapid and precise stability-indicating high performance liquid chromatographic assay for the determination of furazolidone (I), nitrofurazone (II), nitrofurantoin (III), niridazole (IV) and nifuroxime (V) in pure form and in pharmaceutical preparations has been devloped. Reversed phase chromatography was conducted using a Lichrosorb R.P. 18 column (250×4 mm), with methanol-water-buffer pH3 (40∶55∶5) eluent and detection at 365, 375, 367, 368 and 340 nm respectively. Calibration graphs were linear over the concentration ranges 3–18, 1–10, 1–10, 3–18 and 3–18 μm·ml−1. Reoveries from bulk drugs were 99.94–100.00 with a relative standard deviation of 1.02–1.61. Sunlight degradation of most of the studied drugs to 5-nitrofuraldehyde was observed. Accelerated stability studies have been carried out on each drug by exposure to sunlight for different time periods. Graphs of log of the remaining concentration (Log. C) against time indicated that photodecomposition of the nitrocompounds is a first order reaction. The proposed method was applied to some representative dosage forms and the results obtained were in good agreement with those obtained by the official methods.

Stability of ranitidine hydrochloride at dilute concentration in intravenous infusion fluids at room temperature

The stability of ranitidine at low concentration (0.05 mg/mL) in five intravenous infusion solutions (0.9% sodium chloride, 5% dextrose, 10% dextrose, 5% dextrose with 0.45% sodium chloride, and 5% dextrose with lactated Ringer's injections) was studied. Admixtures were stored for seven days at room temperature in 150-mL and 1-L polyvinyl chloride infusion bags. Ranitidine stability in 0.9% sodium chloride injection and in 5% dextrose injection was also examined for up to 28 days, and these data were compared with data obtained at higher ranitidine concentrations (0.5-2.0 mg/mL). At intervals during the storage periods, color, clarity, and solution pH were examined and ranitidine content was determined by a stability-indicating high-performance liquid chromatographic assay. Ranitidine content remained greater than 90% of the initial concentration for more than 48 hours in all infusion fluids except 5% dextrose with lactated Ringer's injection. No visual changes or appreciable changes in pH were observed for any of the solutions. At the dilute concentration, ranitidine was markedly more stable after eight hours in 0.9% sodium chloride injection than in 5% dextrose injection. In 0.9% sodium chloride injection, ranitidine concentrations remained above 95% for up to 28 days, but drug concentrations in 5% dextrose injection fell below 90% after seven days. Stability in 5% dextrose injection improved as ranitidine concentrations increased from 0.05 to 2.0 mg/mL. Ranitidine (0.05 mg/mL) is stable for at least 48 hours at room temperature in all infusion fluids tested except 5% dextrose with lactated Ringer's injection.

Compatibility of cisplatin and fluorouracil in 0.9% sodium chloride injection

The effect of drug concentration and light on the compatibility and stability of cisplatin and fluorouracil in i.v. admixtures was studied. Two sets of admixtures were prepared in 0.9% sodium chloride injection in polyvinyl chloride bags--(1) cisplatin 200 micrograms/mL and fluorouracil 1,000 micrograms/mL and (2) cisplatin 500 micrograms/mL and fluorouracil 10,000 micrograms/mL. Half of the admixtures were protected from light. All admixtures were stored at room temperature (24-26 degrees C), and those admixtures not protected from light were stored under room fluorescent light. After visual inspection, the pH of each admixture was determined, and an aliquot was assayed for drug concentration using a stability-indicating high-performance liquid chromatographic assay. Over a four-hour period, no visual changes were observed and the pH changes observed were negligible. In admixtures containing the lower concentrations of cisplatin and fluorouracil, it took approximately 1.5 hours for the concentration of cisplatin to reach 90% of the initial concentration. By four hours (lower concentration range) and three hours (higher concentration range) after the admixtures were prepared, less than 75% of the initial cisplatin concentration remained. There was less than a 5% decrease measured in the fluorouracil concentrations over the observation time. Admixtures of cisplatin and fluorouracil in 0.9% sodium chloride injection at the concentrations evaluated in this study must be used within one hour of preparation, whether or not they are protected from light. Intravenous administration of fluorouracil and cisplatin by continuous infusion will require alternative approaches to mixing the two drugs in the same container.

Stability of Imipenem and Cilastatin Sodium in Total Parenteral Nutrient Solution

The chemical stability and compatibility of imipenem-cilastatin sodium (Primaxin) in two different total parenteral nutrient (TPN) solutions was determined. TPN solutions consisted of 4.25% and 5% amino acids with 25% and 35% dextrose, respectively. Imipenem-cilastatin sodium was constituted with 10 ml of sterile water and admixed with 90 ml of TPN solution for a final concentration of 5 mg/ml of each drug. The final solutions were assayed at times 0 (immediately after admixture), 15 min, 30 min, 1, 4, 8, and 24 hr by a stability-indicating high-performance liquid chromatographic assay. Concurrently, test TPN solutions were monitored for pH changes, color changes, and precipitate formation. The potential effect of imipenem-cilastatin sodium on the stability of amino acids and other TPN additives was not evaluated. Imipenem and cilastatin sodium was stable (greater than or equal to 90% recovered) in each TPN solution at 15 min. A significant (greater than or equal to 10%) and steady decrease of imipenem recovery occurred at subsequent sampling times. Cilastatin appeared more stable than imipenem in both TPN solutions. A physical color change from colorless to dark orange appeared in each TPN solution over the 24-hr study period. Imipenem-cilastatin sodium is stable for 15 min in the TPN solutions studied; however, until the stability of the amino acids can be determined, the antibiotic should be administered through a separate line or Y-site while the TPN infusion is interrupted.

Simultaneous determination of physostigmine and tetrahydroaminoacridine in a transdermal permeation study by high-performance liquid chromatography

A selective and stability-indicating high-performance liquid chromatographic assay with diazepam as the internal standard was developed for simultaneously analyzing physostigmine and tetrahydroaminoacridine in skin samples, permeation diffusates and dosage form. Baseline resolution was achieved with an octadecyl column for physostigmine, its two degradation products and tetrahydroaminoacridine. Peak homogeneity of physostigmine and tetrahydroaminoacridine was confirmed. The calibration curves for both drugs in skin samples were established at 1-50 μg per 200 mg skin. Those for diffusate samples were at 10-50 ng per 50 μl for physostigmine and 30-150 ng per 50 μl for tetrahydroaminoacridine. The assay was reproducible with within-day and between-day variations of 5-6 and 4-10%, respectively. Application of the assay for in vitro transdermal permeation study was demonstrated.

Kinetics of the acid-catalyzed hydrolysis of famotidine

The kinetics of hydrolysis of famotidine were studied in 0.01–0.10 M hydrochloric acid solutions of 2 mg/ml using a stability-indicating high-performance liquid Chromatographic assay with ultraviolet detection. The hydrolysis followed pseudo-first order kinetics with respect to famotidine concentration. The observed rate constant was found to depend on hydrogen ion concentration and was not influenced by the ionic strength. The specific hydrogen ion catalytic rate constant was calculated to be 3.427 M −1· h −1 at 37° C. The temperature dependence of famotidine hydrolysis was investigated in 0.1 M hydrochloric acid solutions having an ionic strength of 0.2 in the temperature range 37–55° C. The activation energy was determined to be 63.7 kJ/mol. The impact of the acid-catalyzed hydrolysis on the stability of famotidine in the stomach was discussed. It was estimated that in the gastric pH 1–2 and with a gastric emptying half-life of 50 min in normal young adults about 5.3–35.8% of an oral dose of famotidme would undergo degradation in the stomach. This percentage might be even increased to 12.0–57.8% in the elderly.

Stability-indicating high-performance liquid chromatographic assay for the determination of metoclopramide hydrochloride in pharmaceutical dosage forms.

A simple, reliable and selective high-performance liquid chromatographic method for the determination of metoclopramide hydrochloride in pharmaceutical dosage forms has been developed and evaluated. The drug and the internal standard (phenobarbitone) were eluted from a 5-micron C8 reversed-phase column at ambient temperature with a mobile phase consisting of phosphate buffer (10 mM)-methanol-acetonitrile (50 + 28 + 22) adjusted to pH 4.8 with orthophosphoric acid. The mobile phase was pumped at a flow-rate of 1.5 ml min-1 and the effluent was monitored spectrophotometrically at 214 nm. The retention times of the internal standard and metoclopramide hydrochloride were 3.0 and 7.5 min, respectively. Quantification was achieved by measuring the peak-height ratio of the drug to the internal standard. A linear relationship was found over the range 1-10 micrograms ml-1. Within-day coefficients of variation (CVs) ranged from 0.50 to 1.70% and between-day CVs from 0.68 to 4.07% at three different concentrations. The developed procedure was compared with the current BP method for the assay of metoclopramide hydrochloride in tablets. The proposed method was also used to study the stability of metoclopramide hydrochloride.

In vitro diffusion cell design and validation. I. A stability-indicating high-performance liquid chromatographic assay for betamethasone 17-valerate in purified isopropyl myristate receptor phase.

The development of a reliable in vitro permeation system necessitates the use of a precise and accurate method of quantifying tb~ amount of permeant partitioning from the membrane into the cell receptor phase. Aqueous donor and receptor chamber fluids have ~en used in the majority of reported investigations, which makes quantitative permeant analysis relatively facile. Alternatively, radiolabelled diffusants have been used and flux rates monitored by scintillation counting, obviating the need for chromatographic separation of the receptor-phase components. However, this technique is not applicable when nonlabelled compounds or commercial dosage forms are to be evaluated by a cell system. Furthermore, several studies indicate that aqueous receptor phases may not present an optimal partitioning environment for certain lipophilic permeants (1~), thereby impairing accurate flux monitoring due to limited diffusant solubility. Several attempts have thetefore been made to improve the partitioning environment within these systems, by the addition of surfactants for example (4). A lipophilic receptor environment appears beneficial for corticosteroid partitioning, and thus, the use of isopropyl myristate has been investigated because of its bipolar properties that tend to mimic the biochemical composition of the skin (5,6). Betamethasone 17-valerate and its 21-valerate degradation product are highly soluble in isopropyl myristate and this nonaqueous solvent willnot augmentC-17-to-C-21ester degradation reactions. The UV absorbance of the receptor-phase solutions has been measured directly by spectrophotometry without prior chromat9graphic'separation (7-10). However, compounds other than the diffusant of interest may permeate from the donor compartment, or may leach fromthe membrane, and may contribute to this measured absorbance. Therefore,

Stability-indicating high-performance liquid chromatography assay for the anticancer drug bryostatin 1

Stability-indicating high-performance liquid chromatography assay for the anticancer drug bryostatin 1

Stability-indicating high-performance liquid chromatography assay for bepridil hydrochloride drug substance and drug products

Stability-indicating high-performance liquid chromatography assay for bepridil hydrochloride drug substance and drug products

Preformulation study of etoposide: identification of physicochemical characteristics responsible for the low and erratic oral bioavailability of etoposide.

Preformulation studies of etoposide, including pH-solubility profile, partition coefficient, pH-stability profile, and in vitro dissolution kinetics, were conducted to identify the responsible factor(s) for the low and erratic oral bioavailability of etoposide. A stability-indicating high-performance liquid chromatographic (HPLC) assay was used for drug monitoring. The equilibrium aqueous solubility of etoposide at 37 degrees C was low, 148.5-167.25 micrograms/ml, and did not vary over the pH range of 2 to 6. The pH-stability profile indicated rapid degradation of etoposide at pH 1.3 and 10, with degradation half-lives of 2.88 and 3.83 hr, respectively, at 25 degrees C. The half-life at pH 7.30 was 27.72 days. Maximum stability at 25 degrees C was reached at pH 5 to 6.15, with half-lives of 63 and 49.5 days, respectively. The intrinsic dissolution rate, determined on a Wood's apparatus, was slow, 0.0094 mg/min/cm2, while the etoposide partition coefficient between n-octanol and water was 9.94. Therefore, etoposide absorption appears to be dissolution rate limited rather than permeation rate limited. The low equilibrium aqueous solubility, slow intrinsic dissolution rate, and chemical instability at pH 1.3 could account for the low oral bioavailability.

Stability of Nizatidine in Commonly Used Intravenous Fluids and Containers

The stability of nizatidine in commonly used i.v. fluids stored in glass and plastic containers was studied. Stock solutions of nizatidine 0.75, 1.5, and 3.0 mg/mL in 15 i.v. fluids were prepared using nizatidine injection 25 mg/mL. Six 50-mL aliquots of each solution were transferred to separate glass infusion bottles and stored at room temperature or under refrigeration. Twenty-one 40-mL aliquots of additional stock solutions of nizatidine 0.75 and 3.0 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection were transferred to polyvinyl chloride (PVC) bags and stored at room or refrigerated temperature; some of these solutions were frozen, thawed, and refrigerated before analysis. Samples of each admixture were analyzed after 0.5, 1, 2, 3, and 7 days of storage for nizatidine concentration using a stability-indicating high-performance liquid chromatographic assay and also for visible changes and pH. The concentration of nizatidine in each admixture remained within 92%-106% of actual initial storage concentration throughout the study period, with the exception of nizatidine 3.0 mg/mL in 8.5% amino acid injection. The stability of nizatidine in admixtures stored in polyvinyl chloride bags was similar to that of admixtures stored in glass bottles. In the i.v. fluids, concentrations, and containers studied, nizatidine admixtures are stable for at least 7 days at either room or refrigerated temperature and 30 days when stored frozen in polyvinyl chloride bags. Admixtures of nizatidine 3.0 mg/mL in 8.5% amino acid injection should not be stored at room temperature for longer than four days.

Stability of papaverine hydrochloride and phentolamine mesylate in injectable mixtures

The stability of papaverine hydrochloride and phentolamine mesylate combined in a single vial was studied. Injectable mixtures (10 mL) of papaverine hydrochloride 300 mg and phentolamine mesylate 5 mg (from two sources) were prepared by adding the contents of one vial of lyophilized phentolamine mesylate to the contents of one vial of papaverine hydrochloride injection. The vials were stored at 5 degrees C and 25 degrees C. Duplicate aliquots of the mixtures were obtained, and the concentrations of papaverine hydrochloride and phentolamine mesylate remaining at time 0 and after 1, 2, 5, 10, 20, and 30 days were determined in triplicate by a stability-indicating high-performance liquid chromatographic assay. The concentration of papaverine hydrochloride stored in the vials remained constant (less than 1% loss) over the 30-day period at both 5 degrees C and 25 degrees C. Phentolamine mesylate was less stable than papaverine but still retained more than 97% of its original concentration after 30 days at 5 degrees C and more than 95% of its original concentration at 25 degrees C. Papaverine hydrochloride and phentolamine mesylate are stable in injectable mixtures when stored for up to 30 days at 5 degrees C or 25 degrees C.

Stability of cefazolin sodium in various artificial tear solutions and aqueous vehicles

The stability of cefazolin sodium reconstituted in four artificial tear solutions, two acetate buffer solutions, phosphate buffer solution, and 0.9% sodium chloride injection was studied. Cefazolin was reconstituted in Tearisol, Isopto Tears, Liquifilm Forte, and Liquifilm Tears; acetate buffer solution at pH 4.5 and pH 5.7; phosphate buffer solution at pH 7.5; and 0.9% sodium chloride injection. The solutions were stored at 4 degrees C, 25 degrees C, and 35 degrees C for seven days. All of the solutions were inspected for particulates, turbidity, color, and odor. Five assay determinations on each of three samples of each formulation were performed using a stability-indicating high-performance liquid chromatographic assay. Cefazolin stability was influenced primarily by pH and storage temperature. Reconstitution of cefazolin sodium in the alkaline tear solutions Isopto Tears and Tearisol and in phosphate buffer solution resulted in particulate and color formation at 25 degrees C and 35 degrees C. Turbidity was noted after cefazolin sodium was reconstituted in Isopto Tears. No color or precipitate formation was evident after seven days at 25 degrees C and 35 degrees C in the formulations of acidic pH containing Liquifilm Tears, Liquifilm Forte, 0.9% sodium chloride injection or acetate buffer solution as the vehicles. The extent of degradation of cefazolin was substantially higher in the formulations of alkaline pH than in those of acidic pH at 35 degrees C and 25 degrees C. All of the formulations retained more than 90% of their initial concentration when stored at 4 degrees C. Cefazolin sodium, when reconstituted in artificial tear solutions with an acidic pH, is stable for up to three days at room temperature.

Automated stability-indicating high-performance liquid chromatographic assay for ethinyl estradiol and (levo)norgestrel tablets.

An automated high-performance liquid chromatography (HPLC) assay for ethinyl estradiol and norgestrel or levonorgestrel in oral contraceptive tablets was developed. Tablets were prepared for on-line injection using a solid sampler and segmented continuous flow techniques. The active components were separated from tablet excipients, impurities, and degradation products on reversed-phase C8 and C18 columns by elution with water-acetonitrile-methanol (45:35:15). A UV detector connected in series with a fluorometric detector measured the UV absorbance of levonorgestrel and norgestrel at 240 nm and the fluorescence of ethinyl estradiol at 310 nm (excitation at 210 nm). The method employed computer control of the injection system and solid sampler for synchronization of the chromatographic and segmented flow streams. The method is applicable for content uniformity and stability testing at a rate of eight samples per hour.

Stability-indicating high-performance liquid chromatography of etoposide at various pH conditions using a reversed-phase octyl column

A stability-indicating reversed-phase high-performance liquid chromatographic assay of etoposide is described. Baseline resolution was achieved with an octyl column for etoposide and its four degradation products, including picrolactone. Peak homogeneity of etoposide was confirmed by quantitating etoposide in degraded samples at 230, 254 and 286 nm, respectively. The assay was reproducible with low within-day and between-day variations. Application of the assay for stability kinetic study was demonstrated. Etoposide in 0.1 M hydrochloric acid (pH 1.29) degraded with a half-life of 2.85 h, which may be responsible for the low oral bioavailability of etoposide.

Compatibility of imipenem-cilastatin sodium with commonly used intravenous solutions

The stability of imipenem-cilastatin sodium (Primaxin, Merck Sharp & Dohme) in various intravenous fluids was determined after storage at 4 degrees C or 25 degrees C and after freezing. Samples of imipenem-cilastatin sodium were constituted with 100 mL of each of 17 i.v. fluids to concentrations of 2.5 mg/mL or 5.0 mg/mL of each drug component and stored in glass infusion bottles at constant room temperature (25 degrees C) or constant refrigerated temperature (4 degrees C). The concentration of each solution was determined immediately after constitution by a stability-indicating high-performance liquid chromatographic assay; the concentrations of both drugs were monitored in each i.v. fluid until the time that the concentration of either imipenem or cilastatin decreased to less than 90% of the initial concentration (t90). The exact value of t90 was determined for each solution by linear regression. The solutions were also assessed for changes in pH or color. Cilastatin sodium was more stable in all 17 i.v. fluids than imipenem. The stability of imipenem was dependent on the concentration of that drug in solution; solutions of imipenem 2.5 mg/mL were more stable than solutions of imipenem 5.0 mg/mL. The values of t90 for imipenem in solutions stored at 4 degrees C were greater than the values for solutions stored at 25 degrees C. Imipenem was most stable in 0.9% sodium chloride injection. The pH values of the solutions generally decreased during the study period.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction of aztreonam with nafcillin in intravenous admixtures

An interaction between aztreonam and nafcillin sodium in 0.9% sodium chloride injection or 5% dextrose injection stored in glass or plastic containers is reported. During preliminary experiments, admixtures of aztreonam 10 or 20 mg/mL and nafcillin sodium 10 or 20 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection prepared in glass flasks became cloudy and showed evidence of a fine precipitate. Drug concentrations were measured with a stability-indicating high-performance liquid chromatographic (HPLC) assay. Admixtures of aztreonam 20 mg/mL and nafcillin sodium 20 mg/mL in 5% dextrose injection or 0.9% sodium chloride injection were prepared in polyvinyl chloride bags and stored at room temperature (23-25 degrees C) for 48 hours. The admixtures were assayed at 0, 24, and 48 hours with the same HPLC procedure used during the pretesting experiments. The precipitates were isolated, washed, and centrifuged; the supernatant was analyzed by HPLC assay, and the final residue was analyzed by nuclear magnetic resonance (NMR) spectroscopy. The initial recoveries of drug from the pretesting experiments ranged from 99.2 to 102.4%. Analysis of the precipitates indicated that the precipitate was neither a salt nor a complex formed by the physical interaction of aztreonam and nafcillin sodium, but probably a high-molecular-weight polymer formed by the covalent bonding of subunits of the formulation components. Substantial losses of both drugs from the admixtures were evident after 48 hours of storage. The precipitate was observed sooner in the admixtures containing 0.9% sodium chloride injection than in the admixtures prepared in 5% dextrose injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Stability of amiodarone hydrochloride in admixtures with other injectable drugs

The stability of amiodarone hydrochloride in intravenous admixtures was studied. Amiodarone hydrochloride 900 mg was mixed with 500 mL of either 5% dextrose injection or 0.9% sodium chloride injection in polyvinyl chloride or polyolefin containers; identical solutions were also mixed with either potassium chloride 20 meq, lidocaine hydrochloride 2000 mg, quinidine gluconate 500 mg, procainamide hydrochloride 2000 mg, verapamil hydrochloride 25 mg, or furosemide 100 mg. All admixtures were prepared in triplicate and stored for 24 hours at 24 degrees C. Amiodarone concentrations were determined using a stability-indicating high-performance liquid chromatographic assay immediately after admixture and at intervals during storage. Each solution was visually inspected and tested for pH. Amiodarone concentrations decreased less than 10% in all admixtures except those containing quinidine gluconate in polyvinyl chloride containers. The only visual incompatibility observed was in admixtures containing quinidine gluconate and 5% dextrose injection. In most solutions pH either decreased slightly or remained unchanged. Amiodarone hydrochloride is stable when mixed with either 5% dextrose injection or 0.9% sodium chloride injection in polyvinyl chloride or polyolefin containers alone or with potassium chloride, lidocaine, procainamide, verapamil, or furosemide and stored for 24 hours at 24 degrees C. Amiodarone should not be mixed with quinidine gluconate in polyvinyl chloride containers.

Stability of ranitidine admixtures frozen and refrigerated in minibags

The stability of ranitidine hydrochloride stored frozen and refrigerated in polyvinyl chloride minibags was studied. Ranitidine hydrochloride was added to either 5% dextrose injection or 0.9% sodium chloride injection to yield concentrations of 0.5, 1.0, and 2.0 mg/mL. In phase 1 of the study, admixtures containing ranitidine hydrochloride 1 mg/mL were stored at 4 degrees C for 10 days. In phase 2, solutions were frozen for 30 days at -30 degrees C and were later refrigerated for 14 days. Ranitidine concentration was tested using a stability-indicating high-performance liquid chromatographic assay at time zero and at intervals during storage. Sterility tests were performed on some samples, and various admixtures were visually inspected and tested for pH. At least 90% of the initial concentration of ranitidine remained in all solutions at all storage conditions. No visual changes or changes in pH or sterility were observed. Ranitidine hydrochloride in concentrations of 0.5, 1.0, and 2.0 mg/mL in 5% dextrose injection or 0.9% sodium chloride injection may be stored in polyvinyl chloride minibags frozen for 30 days followed by refrigeration for an additional 14 days.