Importance of the type of dosage form and saturable acetylation in determining the bioactivity of p-aminosalicylic acid.
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Acetylation↗
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Results for “DOSAGE FORMS”
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[Studies on the bioavailability of beta-aescin following oral administration of various dosage forms. Commentary on the work of Kunz et al. as well as Schrader et al., published in this journal].
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Administration, Oral↗
Spectrophotometric and fluorimetric determination of aztreonam in bulk and dosage forms.
Spectrophotometric and fluorimetric determination of aztreonam were achieved through its reaction with cerium (IV) in acidic medium. The spectrophotometric method involves the quantitation of the amount of ceric equivalent to aztreonam by measuring the absorbance at 317 nm and the corresponding first-derivative value at 284 nm for the blank solution against the reaction solution. Beer's law is obeyed over the concentration ranges of 1.5-4 and 1-4 microg ml(-1), respectively. Meanwhile, in the fluorimetric method, higher sensitivity was achieved by measuring the fluorescence intensity of the formed cerium (III) at lambda(em)=357 nm (lambda(ex)=257 nm) within a concentration range 150-350 ng ml(-1). Study of the reaction conditions and reaction stoichiometry were presented. Interference from L-arginine, which is frequently co-formulated with aztreonam, was tested. The proposed procedures were applied successfully to the determination of aztreonam in pure form and in presence of arginine both in laboratory mixtures and commercial vials. The proposed methods are sensitive, accurate and precise as compared with the official USP 24 HPLC method.
Aztreonam↗
Bioavailability of magnesium ions from solid dosage forms.
The bioavailability of magnesium ions from three formulations: I - the granulate, II - the frothy mixture and III - the tablets was determined. To calculate the cmax, tmax and AUC the computer programs AUC-RPP and KINPAK were used.
Animals↗
HPLC method for the determination of oxytocin in pharmaceutical dosage form and comparison with biological method.
Conditions have been established for the determination of oxytocin by the HPLC method; the method has been validated. The results of HPLC determinations are compared with those obtained by the biological method.
Animals↗
Bioequivalence of topical dermatological dosage forms--methods of evaluation of bioequivalence.
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Administration, Topical↗
[Drug administration and dosage forms in geriatric patients].
The demographic shift demands more and more customized medical supplies and management structures for geriatric patients. The elderly patient with age-related functional restrictions and multi-morbidity is at special risk for an ill-adapted pharmacotherapy. In addition the frail elderly person is dependent on general-practitioner assistance. The prescription of a suitable drug and a safe and workable (galenic) application form is key to therapeutic success. Age-based intake regulations, repeated education, and intake training are crucial tasks for the general-practitioner when caring for a fast growing elderly patient population.
Aged↗
Preparation and evaluation of oral dosage form using acylglycerols. II. Effect of food ingestion on dissolution and absorption of aspirin from the granules prepared by acylglycerols in human subjects.
The dissolution behavior of the aspirin enteric granule prepared using acylglycerols, glyceryl monostearate (GMS) and glyceryl trilaurate (GTL), was investigated in vitro and in human subjects in a fasting or non-fasting state. Aspirin was slowly released from the granule in vitro at pH 1.2. No acceleration of the aspirin dissolution rate in the medium without lipase and cholic acid was observed when the pH level of the medium increased to a neutral region (pH 6.4). However, the dissolution of aspirin was significantly increased by increasing the concentrations of lipase and cholic acid in the medium. Lipase appears to play an essential role in the dissolution process of aspirin granules. In human subjects, the average levels of the cumulative amount of total salicylate excreted in a urine-time curve, and the mean residence time (MRT) obtained after oral administration of a granule in the fasting state were markedly delayed in comparison with the results observed using an aqueous solution and a crystalline form of aspirin. In comparing the fasting condition with the non-fasting condition (after food ingestion), no significant difference was recognized in the total amount of salicylate excreted in urine to an infinite time (Ae(infinity)), whether the MRT was obtained by granule, crystalline form or aqueous solution. It can be concluded that aspirin granule prepared by GMS and GTL has a property of pancreatic lipase-sensitive dissolution, and its bioavailability is unaffected by food intake.
Administration, Oral↗
Simple determination of ranitidine in dosage forms by in-phase selective AC polarography.
A new AC polarographic method for the determination of pharmaceutical forms of ranitidine is proposed, based on the electroactivity of the ranitidine nitro group. Individual and composite assays as well as recovery studies are described. Results show adequate precision and accuracy. Sample preparation is easy and no excipient separation is required.
Dosage Forms↗
1H, 13C, 15N NMR analysis of sildenafil base and citrate (Viagra) in solution, solid state and pharmaceutical dosage forms.
Sildenafil citrate (SC) (Viagra) and sildenafil base in pure form are easily and unequivocally characterized by multinuclear NMR spectroscopy. Analysis of chemical shifts indicates that: (i) N6-H forms intramolecular hydrogen bonds, (ii) N25 is protonated in the salt and (iii) intermolecular OH...N hydrogen bonds involving N2 and N4 are present in the solid sildenafil citrate. 13C CPMAS NMR method has been proposed for the identification and quantitation of Viagra in its pharmaceutical formulations.
Carbon Isotopes↗
High pressure liquid chromatographic separation and identification of vitamins D2 and D3 in the presence of fat-soluble vitamins in dosage forms.
A simple and rapid qualitative method is described for determining the presence of vitamin D2 (ergocalciferol) and/or vitamin D3 (cholecalciferol) in various preparations by reverse phase high pressure liquid chromatography (HPLC). When both D2 and D3 are present, this method effectively separates and identifies each vitamin D form by its respective retention time. A significant difference between vitamins D2 and D3 exists in their antirachitic activity in poultry. Preparations can be tested rapidly by this method to ascertain that the correct D vitamin form has been added. Fat-soluble vitamins such as vitamins A, E, K1, and K3 do not interfere. Vitamins D2 and D3 were separated at the baseline in model preparations. As little as 2 ng each of vitamin D2 and vitamin D3 can be separated and identified.
Cholecalciferol↗
Spectrophotometric and spectrofluorimetric methods for the determination of ramipril in its pure and dosage form.
This paper describes three sensitive spectrophotometric and spectrofluorimetric methods for determination of ramipril in its pure form and pharmaceutical tablets. The first method is based on the oxidation of the drug with 1-chlorobenzotriazole reagent (CBT) in strong alkaline medium followed by measuring the absorbance at 350 nm. The method obeys Beer's law over concentration range 15-50 microg ml(-1). For the second and third, both are non-extractive methods based on the formation of ternary complex between copper (II), eosin and ramipril in the presence of methylcellulose as surfactant. Spectrophotometrically, under the optimum condition, the ternary complex showed an absorption maximum at 543 nm. The method obeys Beer's law over concentration range of 20-80 microg ml(-1). A fluorescence quenching method for the determination of ramipril by forming this ternary complex was also investigated for the propose of enhance the sensitivity of the determination. The methods are simple, sensitive, and accurate. The results obtained are reproducible with a coefficient of variation less than 2%. The proposed have been successfully applied to the assay of ramipril in tablets. The results compare favorably with official method.
Dosage Forms↗
Quantitative determinations of phenol and resorcinol in pharmaceutical dosage forms by high-pressure liquid chromatography.
The quantitative determinations of phenol in phenolated calamine lotion USP and of phenol and resorcinol in phenol-resorcinol-boric acid solution by high-pressure liquid chromatography are reported. The procedures are simple, rapid (no special preliminary treatment is required), and accurate. There is no interference from other ingredients of the lotion (bentonite magma, calamine, and zinc oxide) or solution (acetone and boric acid).
Chromatography, High Pressure Liquid↗
Computation of in-house quality control limits for pharmaceutical dosage forms based on product variability.
A method for establishing sampling plans for in-house limits that fix both the producer's and consumer's risks is presented for pharmaceutical systems in which both between-batch and within-batch variations are present. Such plans can always be constructed and require more or less sample assays depending on the variability of the process. The computations involve a numerical approximation to the bivariate normal distribution.
Analysis of Variance↗
New rapid assay for methicillin by spectrofluorimetry in pharmaceutical dosage forms.
A method for the spectrofluorimetric determination of methicillin is proposed (lambda ex = 279 nm, lambda em = 379 nm), for concentrations between 0.030 and 10.0 micrograms ml-1. The method was performed in water, at pH 6.20 provided by addition of phosphate buffer solution. The values obtained for detection and determination limits were 0.0188 and 0.063 micrograms ml-1, respectively. The method was successfully applied to assay a commercial injection containing methicillin sodium monohydrate.
Calibration↗
[Surfactants in dosage forms and biological systems. Part II].
The 2nd parts of publications are summarized the modern drug delivery systems contained surface active agents and the role of surfactants in the formation and stability of drug delivery systems. This paper reviews the structure and stability of multiple emulsions, and the different associates forming from surfactants. The solubilization is characterized and some mathematic functions between surface tension of surfactants and their solubilization capacity are introduced. Surfactants represent as important components of coherent emulsions, different vesicles and liposomes. The tensids have an important biopharmaceutical role. They can influenced the bioavailability by increase of thermodynamic activity of active substance and by change of permeability of cellular membranes.
Dosage Forms↗
Quantitative GLC determination of conjugated estrogens in raw materials and finished dosage forms.
A GLC method is described for the quantitative analysis of conjugated estrogens. The procedure was used for the analysis of various estrogen mixtures obtained from formulations containing estrogen sodium sulfate salts. The method involves slurrying or dissolving a portion of the formulation pH 5.2 buffer, hydrolysis with sulfatase enzyme, extraction with ethylene dichloride, anf finally, GLC separation and quantitation of the corresponding trimethylsilyl ethers on a 2.5% diethylene glycol succinate column.
Animals↗
Validation of a near-infrared transmission spectroscopic procedure. Part B: Application to alternate content uniformity and release assay methods for pharmaceutical solid dosage forms.
NIR analytical methods can be validated to meet the requirement of demonstrating that it is suitable for the analysis of the materials for which it is being used. Applying previously described protocols for NIR methods to the analysis of two types of pharmaceutical products shows that for these products, NIR is suitable as an alternate analytical method for assay and for content uniformity.
Analysis of Variance↗