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At least 379 records · Page 21Linked to original sources
PubMed1995

Stability of cisapride in a liquid dosage form at two temperatures.

OBJECTIVE: To determine the stability of cisapride in a liquid dosage form stored in plastic bottles at 2 temperatures. DESIGN: Cisapride tablets were used to prepare a suspension in equal volumes of methylcellulose 1% and simple syrup to yield a concentration of 1 mg/mL. The cisapride suspension was stored in 10 amber plastic prescription bottles. Five bottles were stored at room temperature (25 +/- 0.1 degrees C) and 5 under refrigeration (4 degrees C). Samples were drawn from each bottle immediately after mixing (day 0), and at 7, 14, 28, 42, 56, 70, and 91 days of storage at each temperature. All samples were analyzed in duplicate on each day of analysis. Cisapride was measured by a stability-indicating HPLC method. RESULTS: The mean concentration of cisapride exceeded 90% of its initial concentration throughout the 91-day study period at 4 degrees C, but only during the first 28 days at 25 degrees C. No significant change in pH was observed during the study period. CONCLUSIONS: Cisapride was stable in a suspension for 91 days at 4 degrees C and 28 days at 25 degrees C in amber plastic prescription bottles.

Chromatography, High Pressure Liquid↗
PubMed1993

High-performance liquid chromatographic method for the determination of norfloxacin glutamate and glucuronate in solid and liquid dosage forms and its application to stability testing.

A simple, precise, stability-indicating reversed-phase high-performance liquid chromatographic method for norfloxacin glutamate and norfloxacin glucuronate in liquid and solid dosage forms is described. Chloronitrodiazepine was used as the internal standard. The eluent used with a C18 bonded phase column was methanol-water-diethylamine (50:50:0.4, v/v/v) (pH* 5.5). The effects of the eluent pH*, the ratio of methanol to water, and the quantity of diethylamine on the retention times of the sample and internal standard were investigated. The method showed good linearity in the range 1-45 micrograms ml-1 for norfloxacin. Solid samples were ground, dissolved in the eluent, filtered, and then determined by this method. Liquid samples were dissolved in the same solvent. The average recoveries of norfloxacin glutamate and norfloxacin glucuronate in their simulated preparations were 99.5% for solid products and 99.8% for liquid products. The method was applied to the study of the thermal stability of the drugs by following the degradation of norfloxacin glutamate and glucuronate in the four products in accelerated tests at 37-80 degrees C for up to 3 months. Shelf-lives at 25 degrees C of the four products were predicted from the results assuming zero- and first-order kinetics of decomposition, and were at least 1.5 years for liquid products and 2 years for solid products.

Chemistry, Pharmaceutical↗
PubMed1985

The in vitro development of extended-release solid oral dosage forms.

A system is described for developing extended-release products, based upon predicting or simulating the entire plasma level-time curve to be expected from the administration of a controlled-release oral dosage form. Termed "biorelevant dissolution," it employs the product's in vitro dissolution behavior and the drug's pharmacokinetic parameters in conjunction with a classical pharmacokinetic model. The basic system is described along with some pertinent examples.

Administration, Oral↗
PubMed2005

Assessment of NIR spectroscopy for nondestructive analysis of physical and chemical attributes of sulfamethazine bolus dosage forms.

The goal of this study was to assess the utility of near infrared (NIR) spectroscopy for the determination of content uniformity, tablet crushing strength (tablet hardness), and dissolution rate in sulfamethazine veterinary bolus dosage forms. A formulation containing sulfamethazine, corn starch, and magnesium stearate was employed. The formulations were wet granulated with a 10% (wt/vol) starch paste in a high shear granulator and dried at 60 degrees C in a convection tray dryer. The tablets were compressed on a Stokes B2 rotary tablet press running at 30 rpm. Each sample was scanned in reflectance mode in the wavelengths of the NIR region. Principal component analysis (PCA) of the NIR tablet spectra and the neat raw materials indicated that the scores of the first 2 principal components were highly correlated with the chemical and physical attributes. Based on the PCA model, the significant wavelengths for sulfamethazine are 1514, (1660-1694), 2000, 2050, 2150, 2175, 2225, and 2275 nm; for corn starch are 1974, 2100, and 2325 nm; and for magnesium stearate are 2325 and 2375 nm. In addition, the loadings show large negative peaks around the water band regions ( approximately 1420 and 1940 nm), indicating that the partial least squares (PLS) models could be affected by product water content. A simple linear regression model was able to predict content uniformity with a correlation coefficient of 0.986 at 1656 nm; the use of a PLS regression model, with 3 factors, had an r (2) of 0.9496 and a standard error of calibration of 0.0316. The PLS validation set had an r (2) of 0.9662 and a standard error of 0.0354. PLS calibration models, based on tablet absorbance data, could successfully predict tablet crushing strength and dissolution in spite of varying active pharmaceutical ingredient (API) levels. Prediction plots based on these PLS models yielded correlation coefficients of 0.84 and 0.92 on independent validation sets for crushing strength and Q(120) (percentage dissolved in 120 minutes), respectively.

Compressive Strength↗
PubMed1992

Comparison of isotachophoresis, capillary zone electrophoresis and high-performance liquid chromatography for the determination of salbutamol, terbutaline sulphate and fenoterol hydrobromide in pharmaceutical dosage forms.

Reversed-phase high-performance liquid chromatography (RP-HPLC), isotachophoresis (ITP) and capillary zone electrophoresis (CZE) were applied to the determination of salbutamol, terbutaline sulphate and fenoterol hydrobromide in commercially available pharmaceutical dosage forms. The comparison showed that especially with the use of ITP, high concentrations of other charged sample components can disturb the separation process. If special attention is paid to ensure a complete separation, all methods give comparable results. For the regression lines of the calibration graphs, regression coefficients of at least ca. 0.999 and nearly zero intercepts are obtained with relative standard deviations of ca. 1-2% for peak area or zone lengths. By applying the different techniques, often different components of the sample matrix can be detected, i.e., a more complete impression of the sample composition can be obtained by using all the three techniques.

Albuterol↗
PubMed1976

Gastric acid inactivation of erythromycin stearate in solid dosage forms.

The effect of hydrochloric acid at pH 1.2-3.2 ON ERYTHROMYCIN STEARATE AND COMMERCIAL DOSAGE FORMS OF ERYTHROMYCIN STEARATE WAS STUDIED. Under all conditions examined, erythromycin was readily dissolved from the stearate as hydrochloride, and rapidly lost its biological activity in solution. The inclusion of pepsin in the test systems did not affect the results. Although formulation differences somewhat affected the rate of destruction, acid lability was exhibited by all products examined, except enteric-coated tablets. Amounts of acid considered to be normal in the fasting stomach contents of adults during the time likely for a dose to remain in the stomach caused 70-90% destruction within 15 min after the shells started to rupture. Amounts of hydrochloric acid appreciably less than 1 mEq, representing abnormally small quantities even in the fasting state, caused destruction ranging from 30 to 70% of the doses in 15 min. These results are not reconcilable with published statements that the sensitivity of erythromycin to gastric acid is overcome by providing the antibiotic in the form of stearate salt.

Capsules↗
PubMed1999

Spectrophotometric methods for the determination of benazepril hydrochloride in its single and multi-component dosage forms.

Three sensitive and accurate methods are presented for the determination of benazepril in its dosage forms. The first method uses derivative spectrophotometry to resolve the interference due to formulation matrix. The second method depends on the color formed by the reaction of the drug with bromocresol green (BCG). The third one utilizes the reaction of benazepril, after alkaline hydrolysis, with 3-methylbenzothialozone (MBTH) hydrazone where the produced color is measured at 593 nm. The latter method was extended to develop a stability-indicating method for this drug. Moreover, the derivative method was applied for the determination of benazepril in its combination with hydrochlorothiazide. The proposed methods were applied for the analysis of benazepril in the pure form and in tablets. The coefficient of variation was less than 2%.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Efficacy on supragingival plaque control of cetylpyridinium chloride in a slow-release dosage form.

To evaluate the relative efficacy of a non-degradable osmotic slow-release dosage form containing 6.6 mg cetylpyridinium chloride (MOTS [Mucosal Oral Therapeutic System] CPC) to inhibit new plaque formation and gingivitis, a single-blind, randomised, parallel group pilot study was set up. 52 healthy volunteers were assigned to receive one of the following treatments for 18 days of non-brushing: holding 1 MOTS CPC 2 x daily for 2 h intra-orally, or rinsing 30 s with 15 ml Peridex 2 x daily, or dissolve Cepacol (each 1.6 mg CPC) lozenges 2 x daily unsupervised. Before the test period, the subjects received a thorough tooth cleaning followed by tooth polishing 1 x a week for 3 weeks to achieve clinical gingival health. After the start of therapy, the subjects were examined at day 4, 7 (+/- 2), 14 (+/- 2) and 18 (2 +/-). Relative efficacy was assessed by the modified Navy plaque index, the Quigley and Hein index, the planimetric plaque index, as well as the papillary marginal gingival index. There was an increase in both plaque formation and gingivitis over the 18 +/- 2 day period of nonbrushing for all subjects in the study. Peridex was the most effective in inhibiting plaque and gingivitis formation over that period of time. There was no difference between MOTS CPC and Cepacol at any time point in plaque accumulation and gingivitis intensity. Peridex was considered more convenient than MOTS CPC. Cepacol resulted in more staining at 18 days than MOTS CPC and Peridex.

Adolescent↗
PubMed2004

[Clinical efficacy of clarithromycin delayed release dosage form in the treatment of community-acquired pneumonia].

The efficacy of clarithromycin retarded release dosage form in the treatment of patients with community-acquired pneumonia was estimated in a open prospective comparative study. The drug was administered in a dose of 500 mg once a day (29 patients) and in a dose of 500 mg twice a day (28 patients). The clinical efficacy in the compared regimens amounted to 90.6 and 93.3% of the patients respectively and the bacteriological efficacy was 93.3 and 84.6% respectively. The adverse reactions were observed in 15.6 and 30.0% of the cases respectively.

Adolescent↗
PubMed2000

Use of mixed anhydrides for the determination of terfenadine in dosage forms and spiked human plasma.

Terfenadine reacts with mixed anhydrides (malonic and acetic anhydrides) producing a yellow-coloured product with intense fluorescence. Based on this fact, a spectrophotometric method was developed for the determination of terfenadine in dosage forms. The relation between the absorbance at 395 nm and the concentration is rectilinear over the range 0.5-5 microg ml(-1) (molar absorptivity is 1.405 x 10(5) l mol(-1) cm (-1)). The reaction product was also measured spectrofluorimetrically at 435 nm after excitation at 395 nm. The fluorescence intensity was directly proportional to the concentration over the range 0.5-4 ng ml(-1) with minimum detectability (S/N = 2) of 0.07 microg ml(-1) (approximately 1.5 x 10(-10) M). The different parameters affecting the development and stability of the reaction product were carefully studied and incorporated into the procedure. The proposed spectrophotometric method was successfully applied to the determination of terfenadine in tablets and suspensions; the percentage recoveries were 99.83 +/- 0.75 and 99.65 +/- 0.83, respectively. The proposed spectrofluorimetric method was applied to the determination of terfenadine in spiked human plasma. The percentage recovery was 99.35 +/- 2.19. The method is highly sensitive and specific. No interference was noticed from co-formulated drugs, such as pseudoephedrine and ibuprofen.

Anhydrides↗
PubMed2003

Determination of imipramine in presence of iminodibenzyl and in pharmaceutical dosage form.

Two spectrophotometric methods for the determination of imipramine in presence of iminodibenzyl as an impurity are described. The first method is a ratio-spectra first derivative spectrophotometry, the signals were measured at 240.2 nm for imipramine. Calibration graph was found linear in the range 5-30 microg ml(-1). The second method is based on the reaction of imipramine base, being an electron donor, with p-chloranilic acid, being pi acceptor, to form a purple colored charge transfer complex. The absorbance was measured at 520.5 nm without interference with iminodibenzyl. Both methods are rapid, simple and do not require any preliminary separation or treatment of the samples. Furthermore, the two methods were applied to pharmaceutical dosage form.

Benzylamines↗
PubMed1982

Mathematical model for in vitro drug release from controlled release dosage forms applied to propoxyphene hydrochloride pellets.

The in vitro release of drugs from controlled-release dosage forms has been studied in terms of a diffusion model. The model has been applied to a pellet formulation containing propoxyphene hydrochloride. It is demonstrated that the model may be used to predict the drug release profile adequately, when the pellet size is changed and when the thickness of the coating is varied. The size distribution of pellets in an experiment may be too broad to justify a simulation with just one average pellet size. Therefore, the results for pellets of the same size are generalized to any size distribution of pellets in an experiment. This is only trivial if sink condition exists in the extraction medium, since under that condition, the release from each pellet type is independent of the releases from other pellet types. In that case, the total release may therefore be found as the sum of the individual releases. In the general case considered here, the releases are coupled.

Chemistry, Pharmaceutical↗
PubMed1989

HPLC determination of tetroxoprim and sulphadiazine in pharmaceutical dosage forms and in biological fluids.

Two HPLC methods for determination of tetroxoprim and sulphadiazine in pharmaceutical dosage forms and in biological fluid are reported. Both methods show good linearity, precision, accuracy and reproducibility. The serum levels and urinary excretion of tetroxoprim and sulphadiazine in man, after oral administration of two different syrup formulations, are reported. Tetroxoprim embonate, an insoluble salt very useful for obtaining a suspension with good palatability, shows a bioavailability not statistically different from that of tetroxoprim base. Sulphadiazine shows the same bioavailability in the two syrups.

Anti-Infective Agents↗
PubMed2004

Oesophageal transport of solid dosage forms depends on body position, swallowing volume and pharyngeal propulsion velocity.

Knowledge about transit of solid dosage forms (SDF) in the gastrointestinal tract is incomplete. Detection of magnetically marked capsules (MMC) via superconducting quantum interference device (SQUID) allows monitoring of oesophageal transport of SDF with high tempospatial resolution. The aim of the study was to investigate the influence of body position, volume at swallowing, and oesophageal motility on orogastric transport of SDF. In 360 measurements we determined tempospatial characteristics of orogastric transit of SDFs by a SQUID device in six volunteers. They swallowed MMCs with various amounts of water in upright and supine position with and without simultaneous oesophageal manometry. Orogastric transit time, oesophageal transport velocity and rate of oesophageal retention of SDF depend on swallowing volume and body position at all experimental conditions. At 50 mL water bolus and in upright position, the retention rate depends on the pharyngeal propulsion velocity, and the transport velocity of MMCs in the oesophageal body are faster than the propulsive oesophageal contractions. Body position, swallowing volume and pharyngeal propulsion velocity markedly influence the oesophageal transport of SDF. They should be taken in upright body position with at least 50 mL of water to minimize entrapment in the oesophagus.

Adult↗
PubMed1989

Application of new silicone gel to sustained release dosage form of antitumor drug.

The object of this study was to develop a sustained release implantable dosage form of a new silicone gel (PHYCON 6600R) which undergoes addition polymerization to produce a solid gel at ordinary temperature. Implantable PHYCON-drug composites were studied as a means of tumor therapy using 3',5'-diesters of 5-fluoro-2'-deoxyuridine (FUdR-Cn) as a model for antitumor drugs. Using an in vitro dissolution test, we found that the release characteristics of drugs from these preparations could be controlled by the addition of powdered L-alanine. In vivo studies of antitumor activity were carried out, using preparations containing the dodecyl ester (FUdR-C12) by measuring the lifespan of lymphoma-inoculated mice. Antitumor activity, reflected in increased lifespan, was shown to be greater following intraperitoneal administration of the PHYCON formulations (drug and L-alanine) than following injections of the drug alone. Our results suggest that sustained release implantable formulations of antitumor drugs in PHYCON might be suitable for tumor chemotherapy.

Animals↗
PubMedDate not supplied

Solubility principles and practices for parenteral drug dosage form development.

Solubilization of poorly water soluble or water insoluble drugs for use in intravenously administered dosage forms is a very formidable task for the parenteral formulation scientist. We have briefly reviewed pertinent literature for parenteral drug solubilization and provided tabular information to assist parenteral formulation scientists in tackling and solving their solubility problems. However, until we can better understand and predict solubility behavior in interactive solvent systems, the why's and how's for parenteral drug solubilization using acceptable (safe and regulatory compliant) approaches will largely remain an empirical effort, leaving great opportunities for scientists to get more involved in this field.

Chemistry, Pharmaceutical↗
PubMed2004

Differential pulse voltammetric determination of carvedilol in tablets dosage form using glassy carbon electrode.

The electrochemical oxidation of antihypertensive drug carvedilol has been studied in pH range 2.0-11.0 at a glassy carbon electrode by cyclic and differential pulse voltammetry. Two oxidation processes were produced in different supporting electrolyte media. Both oxidation processes were irreversible and diffusion-controlled. The first oxidation process was chosen for the analysis of carvedilol. A very resolved voltammetric peak was obtained in Britton-Robinson buffer at pH 8.0 using differential pulse mode. The linear response was obtained in the range of 0.25-10.00 microg ml(-1). The limit of detection was found to be 0.10 microg ml(-1). The developed method was used for the determination of carvedilol in tablet dosage form.

Antihypertensive Agents↗