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At least 955 records · Page 53Linked to original sources
PubMed1980

Acetazolamide dosage forms in the treatment of glaucoma.

Patients with chronic glaucoma had a carefully scheduled series of intraocular pressure measurements before and after taking acetazolamide for one week at the following dosages: none, 500 mg of sustained-release capsules once a day, 500 mg of capsules twice a day, and 250 mg of tablets four times a day. A capsule taken once a day, which is better tolerated than one taken twice a day by some patients, offers a substantial pressure-lowering effect that lasts at least 23 hours, although the magnitude of the pressure lowering is less than with higher dosages. One capsule twice a day appears to be as effective in the regulation of IOP as one tablet four times a day. The 45% reduction in outflow pressure is achieved with an acetazolamide serum concentration in the range of 15 to 20 micrograms/mL.

Acetazolamide↗
PubMed1979

High-pressure liquid chromatographic evaluation of aqueous vehicles for preparation of prednisolone and prednisone liquid dosage forms.

A high-pressure liquid chromatographic method was developed that separates prednisolone from prednisone, prednisone from methylprednisolone succinate sodium, and hydrocortisone from hydrocortisone acetate or cortisone acetate. The common liquid dosage preservatives methylparaben, propylparaben, and sodium benzoate do not interfere with quantitative prednisolone, prednisone, and hydrocortisone determinations. The method was used to study prednisolone and prednisone stability in five aqueous vehicles (water, citrate buffer USP, 50% glycerin, 50% sorbitol, and 50% sucrose) containing 10% (v/v) ethanol. Prednisone crystallized out in all vehicles except glycerin, in which it appeared to be stable for at least 92 days. Prednisolone did not crystallize in any vehicle but decomposed quickly in citrate buffer. Sorbitol and glycerin appeared to be the best vehicles for prednisolone. The developed method was applied successfully to the quantitative determinations of prednisolone, prednisone, and hydrocortisone in commercial tablets.

Chromatography, High Pressure Liquid↗
PubMed1989

Pharmacokinetics of buflomedil after various dosage forms.

The pharmacokinetic disposition of buflomedil was compared in humans after oral administration of solution, tablets and film tablets. Six healthy male volunteers received a single oral dose of the three different dosage formulations. Blood and urine samples were taken before dosing and at selected times over 24 h and 72 h, resp., after dosing. The concentration of the drug in samples was measured by gas-chromatography with nitrogen detector. The absorption of buflomedil was faster after solution administration, while other plasma parameters did not show any major differences. Also the amount of drug excreted in urines was higher with solution dosing.

Adult↗
PubMed1990

Pharmacokinetic evaluation of conventional and controlled release dosage form of propranolol.

A comparative pharmacokinetic study of a new controlled release multiple unit propranolol formulation and a conventional propranolol tablet was carried out in twelve healthy human volunteers in a randomized balanced crossover design. Under a single dosage regimen, subjects were administered either a single capsule containing controlled release propranolol equivalent to 160 mg of the drug or 80 mg of conventional propranolol tablet, twelve hourly. Peak plasma propranolol concentrations were low which occurred later after controlled release administration than after the administration of the conventional tablet. Analysis of the area under the plasma concentration-time curve (AUC) for the two formulations indicate no significant difference of bioavailability despite a prolonged absorption time and maintenance of effective plasma concentration for the controlled release preparation.

Adult↗
PubMed1990

Sustained-release dosage forms.

Transdermal drug delivery provides an effective and advantageous alternative to the oral delivery of therapeutic agents. Currently, many other drugs are being evaluated for transdermal delivery including testosterone, fentanyl, nicotine and timolol. They offer the promise of simplified dosage regimens, enhanced compliance, reduced side effects and improved therapy of disease.

Administration, Cutaneous↗
PubMedDate not supplied

[The efficacy of different oral dosage forms of furazolidone for E. coli infections in carrier pigeons].

The clinical efficiacy of furazolidon for treatment of E. coli-induced gastro-intestinal infections in racing pigeons was investigated. 36 adult pigeons were treated with 2 different oral modes of application (capsule/drinking water) with a daily therapeutic dosage of 12.5 mg furazolidon/pigeon. The pigeons used for this study (Columba livia f. domestica) originated from conventional breeders and were housed in 3 different groups (control-, capsule- and powder-group) in different stables. After infection with an E. coli-strain (O150:H8) that proved to be pathogenic for pigeons, the animals developed clinical signs of disease within 2 days. After onset of disease the treatment with furazolidon for 5 days started. This phase was followed by an adspectory phase for 6 days. The negative identification of the E. coli O150:H8 was determined as main parameter for the clinical efficiacy of the treatment with furazolidon. This parameter showed a highly significant (p = 0.0001) difference between both groups treated with furazolidon and the control group. In both groups treated with furazolidon the E. coli strain could not be isolated after the end of the treatment. An improvement of clinical signs was seen 24 hours after treatment via capsule and 48 hours after treatment via drinking water formulation. The time difference might be caused by the high concentration of furazolidon in the capsules due to the single daily application. Considering the inaccurate dosing via drinking water that results from the varying drinking water intake in pigeons, the application by capsule should be prefered. Both furazolidon preparations proved to be effective in treating gastro-intestinal E. coli-infections in racing pigeons in a dosage of 12.5 mg/pigeon for 5 days, however, best results were obtained by application via capsule.

Administration, Oral↗
PubMedDate not supplied

Effect of meals and dosage-form modification on theophylline bioavailability from a 24-hour sustained-release delivery system.

The bioavailability of theophylline from an extended-release formulation (Uni-Dur) intended for once-daily administration was assessed in a randomized, single-dose, five-way crossover study to determine the effects of food and breaking the tablet, and the bioequivalence of two dosage strengths. The five treatments given at 1-week intervals were (1) immediate-release theophylline (Slo-Phyllin) 5 x 100 mg to fasting subjects as a reference treatment; (2) sustained-release Uni-Dur 600-mg theophylline tablet to fasting subjects; (3) Uni-Dur 600-mg tablet after a high-fat meal; (4) Uni-Dur 600-mg dose administered as two half tablets to fasting subjects; and (5) Uni-Dur 400-mg tablet to fasting subjects. Serial blood samples were collected immediately before and for 57 hours after dosing. The mean relative extents of absorption for the four Uni-Dur treatments were not significantly different from Slo-Phyllin treatment or from each other (84.30 +/- 23.6%, 600 mg, fasting; 88.73 +/- 18.63%, 600 mg, fed; 93.65 +/- 19.67%, half tablet; and 92.87 +/- 19.5%, 400 mg, fasting). The maximum theophylline serum concentrations with Uni-Dur were significantly lower and the times to reach peak concentrations were significantly longer than with Slo-Phyllin. Differences noted among the four Uni-Dur treatments were as follows: the time to peak theophylline concentration was significantly longer in the fed state (17.09 hours) as were the times to 50% (11.73 hours) and 80% (18.46 hours) absorption compared with fasting (13.57 hours, 8.57 hours, and 14.07 hours, respectively). The Uni-Dur 400-mg treatment resulted in a significantly higher maximum theophylline serum concentration (6.64 mu g/mL) compared with the Uni-Dur 600-mg fasting treatment (5.33 mu g/mL); however, the correlation between in vivo and in vitro data supports the bioequivalence of the two strengths. This study shows that theophylline is slowly and consistently absorbed from the Uni-Dur 24-hour sustained-release form, and food or breaking the tablet does not alter the extent of absorption. Thus Uni-Dur potentially provides greater ease of administration and convenience for patients while maintaining therapeutic theophylline serum levels over the 24-hour dosing interval.

Adult↗
PubMed1985

[The increase in the liberation rate of propyphenazone from preoral solid dosage forms].

The authors report on the influence of the granulation and tabletting applying macromolecular agents (polyvinylpolypyrrolidone Heweten 40, polyethylenglycol 6000, polyvinylpyrrolidone K25, polyvinylpyrrolidone K90 and potato starch) on the liberation rate of propyphenazone which exhibits by its hydrophobicity unfavourable dissolution parameters. A significant increase of the liberation rate of propyphenazone (re-crystallized from various media) has been realized by direct pressing of polyvinylpolypyrrolidone and Heweten 40 as well as by gelatine solution granulation, with which the last method exhibits the advantage of an increased accuracy of dosage and a decreased friability. The gelatine granulation of the drug itself as well as the starch granulate addition resulted in an increased dissolution rate. The addition of other agents (polyvinylpyrrolidone K25, K90 and polyethylenglycol 6000) as well as the pressing of a propyphenazone produced by re-crystallization of an aqueous tenside solution, which distinguishes by an extreme dissolution rate, were not at all suitable for the tabletting. The tablet disintegration caused by hydrophile disintegration media, is the condition granting the liberation of the hydrophobic drug. The wettability and thus the dissolution rate of the drug are increased by the liberation.

Antipyrine↗
PubMed2006

A validated chiral HPLC method for the determination of mebeverine HCl enantiomers in pharmaceutical dosage forms and spiked rat plasma.

A new, precise, simple and accurate HPLC method was developed for the first time to separate and determine mebeverine enantiomers. Enantiomeric resolution was achieved on a cellulose Tris (3,5-dimethylphenyl carbamate) column known as Chiralcel OD, with UV detection at 263 nm. The mobile phase consisted of n-hexane, isopropyl alcohol and triethylamine (90:9.9:0.1 v/v/v). Sample run time was 18 min. On using the chromatographic conditions described, mebeverine enantiomers were well resolved with mean retention times of about 11 and 14 min. A linear response (r>0.999) was observed over the concentration range 0.5-20 microg/mL racemic mebeverine. Precision, accuracy and stability were studied according to ICH guidelines. The limit of detection was found to be 0.05 microg/mL for each enantiomer of mebeverine. The proposed method was applied for analysis of mebeverine in commercially available tablets dosage formulations. Examples of application to biological samples are also given. Reanalysis of samples several weeks after the initial analysis showed no degradation of mebeverine.

Animals↗
PubMed2007

Enteric-coated solid dosage forms containing sodium bicarbonate as a drug substance: an exception from the rule?

Sodium bicarbonate (sodium hydrogen carbonate) is used as an oral medication in disorders such as mild metabolic acidosis and chronic kidney disease. The two commercial products on the German market, bicaNorm and Nephrotrans, and also newly developed multiple-unit pellet formulations, have been characterized in these investigations by in-vitro methods like disintegration and dissolution testing. Both marketed products containing sodium bicarbonate are of sufficient pharmaceutical quality according to the European Pharmacopoeia. However, they and the novel pellet preparations showed different drug release at moderately elevated pH values. Early drug release may cause dose dumping in the stomach and adverse drug effects from the developed carbon dioxide. The soft capsule preparation (Nephrotrans) released the smallest amount of sodium bicarbonate at pH 1 and 4.5 of all formulations tested. It appeared that oral dosage formulations of sodium bicarbonate were an exception to the rule: the monolithic soft capsule seemed to be superior to an enteric-coated tablet as well as to multiple-unit pellet formulations from the biopharmaceutical point of view. Our results correspond with individual reports on adverse effects from patients treated with the sodium bicarbonate products.

Capsules↗
PubMed1996

The relative bioavailability of two marketed controlled release diltiazem dosage forms at steady state in healthy volunteers.

This study was conducted to determine the relative bioavailability of Dilacor XR capsules compared to Cardizem CD capsules at both low (180 mg d-1) and high (540 mg d-1) dose levels. Trough and serial plasma samples were obtained and pharmacokinetic parameters were calculated from the steady state concentration-time profiles. Mean steady state plasma diltiazem concentrations (AUCss(0-24)) of Dilacor XR were 19% and 26% lower than those of Cardizem CD for the 180 mg d-1 and 540 mg d-1 dose levels, respectively. In addition, Dilacor XR had lower mean Cmax,ss, Tmax,ss, Cmin,ss, and trough values than Cardizem CD with percentage differences ranging from 17% to 29%. The variability (%CV) in the data from the Dilacor XR treatments was higher for each calculated pharmacokinetic parameter compared to the Cardizem CD treatments. The %CV for Dilacor XR ranged from 34% to 104% while the %CV for Cardizem CD ranged from 21% to 49%. From these results, it may be concluded that Dilacor XR is not bioequivalent to Cardizem CD at steady state doses of 180 mg d-1 and 540 mg d-1.

Adult↗
PubMedDate not supplied

Comparative bioavailability and pharmacokinetics of hydrochlorothiazide from oral tablet dosage forms, determined by plasma level and urinary excretion methods.

The bioavailability and pharmacokinetics of two hydrochlorothiazide products were compared following single 50 mg oral doses to 20 healthy male volunteers. Plasma and urine were assayed for hydrochlorothiazide by a specific and sensitive HPLC method. Plasma profiles of hydrochlorothiazide were adequately described by a triexponential function. The bioavailability of hydrochlorothiazide from the two brands did not differ significantly as judged by the values of Cmax, tmax, AUC0 leads to infinity, mean residence time, variance of residence time, and urinary excretion of unchanged drug. Close similarity was observed between urinary excretion rates and concentrations of drug in plasma.

Adult↗
PubMedDate not supplied

Human platelet response to three salicylate dosage forms.

Acetylsalicylic acid (ASA) inhibition of platelet aggregation as evaluated by collagen-induced 14C-serotonin release, has been measured in 12 healthy male subjects. Each subject received a single oral dose (650 mg) of enteric-coated ASA (ecASA) and compressed ASA tablets (cASA), or ecASA and sodium salicylate (578 mg) separated by a minimum of 5 weeks. The platelet response was related to plasma ASA and salicyclic acid determined by high-pressure liquid chromatography. Both ecASA and cASA inhibited 14C-serotonin release; no significant difference was observed in the maximum effect between these two products (p less than 0.05). No relationship was found between the maximum observed plasma ASA level and the maximum effect. Further, no correlation was found between the maximum inhibition of 14C-serotonin release in vivo and the release predicted from in vitro experiments wherein the effect was measured after incubating plasma containing specified ASA concentrations.

Adult↗