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PubMed2000

[Suppression of graft versus host reaction by depositing a magnet-controlled adriamycin dosage form in bone marrow allotransplantation in animal experiments].

The main causes of failures during allogenous bone marrow transplantation is the development of graft versus host reactions. The methods of its prevention and treatment are the use of large doses of human toxic cytostatics and immunosuppressants aimed against donor immunocompetent cells. A way of preventing the adverse effects of cytostatics are targeted transport of long-acting cytostatic dosage forms to an organ or target cell through carriers, such as liposomes, microcapsules, microspheres and their conjugates with monoclonal antibodies. For this purpose, the study used gelatin and gum arabic microspheres containing the immunosuppressive cytostatic adriamycin. To enhance the efficiency of cytostatic depositing at the site of transplantation, the procedure of intraosseous transplantation of allogenous bone marrow transplantation with long-acting adriamycin depositing was developed. With this approach, the authors could not only deposit the agent, but could substantially increase the proportion of donor cells kept at the site of grafting as compared to the intravenous and intraosseous infusion of donor cells. The main advantage of the new technique of allogenous bone marrow transplantation in combination with a long-acting cytostatic dosage form is that acute and chronic graft versus host reactions can be inhibited long by using adriamycin in subtherapeutic dosages.

Animals↗

PubMed2003

Differential pulse anodic voltammetric determination of pantoprazole in pharmaceutical dosage forms and human plasma using glassy carbon electrode.

Pantoprazole is used as an anti-ulcer drug through inhibition of H(+), K(+)-adenosine 5(')-triphosphatase in gastric parietal cells. It reduces the gastric acid secretion regardless of the nature of stimulation. The use of differential pulse voltammetry for the determination of pantoprazole in pharmaceutical dosage forms and human plasma using a glassy carbon electrode has been examined. The best voltammetric response was reached for a glassy carbon electrode in Britton-Robinson buffer solution of pH 5.0 submitted to a scan rate of 20.0 mVs(-1) and a pulse amplitude of 50.0 mV. This electroanalytical procedure was able to determine pantoprazole in the concentration range 6.0 x 10(-6)-8.0 x 10(-4)M. Precision and accuracy of the developed method was checked with recovery studies. The limit of detection and limit of quantitation were found to be 4.0 x 10(-7) and 9.0 x 10(-7)M, respectively. Rapidity, precision, and good selectivity were also found for the determination of pantoprazole in pharmaceutical dosage forms and human plasma. For comparative purposes high-performance liquid chromatography with a diode array and UV/VIS detection at 290.0 nm determination also was developed.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2000

Oral and intravenous dosage forms of pantoprazole are equivalent in their ability to suppress gastric acid secretion in patients with gastroesophageal reflux disease.

OBJECTIVE: The aim of this study was to assess the ability of pantoprazole to maintain gastric acid suppression in patients with gastroesophageal reflux disease who are switched from an oral (p.o.) to an intravenous (i.v.) dosage form. METHODS: A total of 65 patients with gastroesophageal reflux disease were administered either 40 or 20 mg of p.o. pantoprazole daily for 10 days, then were switched to either a matching dose of i.v. pantoprazole or to placebo for 7 days. Acid output (basal and maximal) was measured at the end of the p.o. treatment period and on the first and last days of i.v. therapy. In the primary efficacy analysis, the acid output values at the end of the p.o. pantoprazole treatment were compared with those at the end of the i.v. treatment. Safety was monitored by periodic vital sign measurements, clinical laboratory evaluations, ophthalmic examinations, electrocardiograms, and reports of adverse events. The data were tested by an analysis of covariance and by Wilcoxon signed rank and t tests. RESULTS: Maximal acid output (mean +/- SD) in the 40 mg and 20 mg pantoprazole group after p.o. treatment was 6.5 +/- 5.6 mEq/h and 14.5 +/- 15.5 mEq/h, respectively; whereas, at the end of the i.v. treatment period, the values were 6.6 +/- 6.3 mEq/h and 11.1 +/- 10.2 mEq/h, respectively. In patients given i.v. placebo, acid output was significantly (p < 0.05) increased to 29.2 +/- 13.0 mEq/h by day 7. Both p.o. and i.v. pantoprazole dosage forms had similar favorable safety and tolerability profiles. CONCLUSIONS: The p.o. and i.v. formulations of pantoprazole (40 and 20 mg) are equivalent in their ability to suppress gastric acid output. The i.v. form of pantoprazole offers an alternative for gastroesophageal reflux disease patients who are unable to take the p.o. formulation.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed1990

[Interaction between polyethylene films and brombexine HCl in solid dosage form. II. Effects of moisture property on the sorption of the drug].

The interaction between bromhexine HCl and polyethylene containers was studied in solutions and in tablet packaging systems. Various bromhexine HCl aqueous solutions of different pHs were stored in polyethylene containers at 25 degrees C. The remaining amount of bromhexine HCl was determined by high performance liquid chromatography. It was observed that the transition of bromhexine HCl to polyethylene was inhibited by the addition of some surfactants into the solution, and by lowering the solution pH. In the solid dosage forms, influences of the additives were also studied. It was observed that the decrease of the content of bromhexine HCl in the solid dosage form was inhibited by the addition of acids (citric acid, tartaric acid) and surfactant (sodium dodecyl sulfate) and accelerated by the addition of sodium bicarbonate, similarly to those in solutions. The results indicated that the transition to polyethylene films was influenced by the molecular state of bromhexine HCl.

Adsorption↗

PubMed1999

Colon-specific delivery of budesonide with azopolymer-coated pellets: therapeutic effects of budesonide with a novel dosage form against 2,4,6-trinitrobenzenesulphonic acid-induced colitis in rats.

The objective of this study was to achieve colon-specific delivery of budesonide using azopolymer-coated pellets and to accelerate healing of 2,4,6-trinitrobenzenesulphonic acid sodium salt (TNBS)-induced colitis in rats. After oral administration of azopolymer-coated pellets containing budesonide, a significant increase was observed in the therapeutic effects of the drug accompanied by a decrease in its systemic adverse effects when compared with oral administration in saline or rectal administration by enema. In addition, with the use of the colon-specific oral dosage form the dose of budesonide could be reduced. These results suggested that azopolymer-coated pellets may be a useful dosage form for the colon-specific delivery of budesonide as an anti-inflammatory steroid drug to bring about the healing of TNBS-induced colitis in rats.

Administration, Oral↗

PubMed2002

Preparation of extruded carbamazepine and PEG 4000 as a potential rapid release dosage form.

The aim of this research was to use a ram extruder to prepare directly a fast release dosage form with uniform shape and density, containing carbamazepine (C) as a water-insoluble drug and polyethylene glycol 4000 (PEG) as a low melting binder. The potential inclusion of lactose (L) as a hydrophilic filler was also considered. The temperature suitable to ensure a successful extrusion process of several formulations containing PEG in different percentages was found to be below the melting point of the PEG. The influence of composition on the extrusion process of different ram speeds was checked by measuring the pressure at the steady state, the apparent shear rate and the apparent shear stress of a range of mixtures of drug, lactose and PEG. The physical-mechanical properties of extrudates, including tensile strength and Young's modulus, prepared with different ram velocities were also determined. The solid-state physical structure by differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD) was established. The dissolution of the extrudates and their corresponding physical mixtures were compared. The mixtures were found to be shear thinning when extruded; the tensile strength of extrudates was dependent on the composition but not the extrusion rate, while the value of Young's modulus was strongly influenced by the rate of extrusion, but less affected by the composition of the extrudates. The results of DSC and XRD indicated that the solid structure of the extrudates corresponded to that of a physical mixture of the components, hence there had been no change in the physical form of the drug induced by extrusion. In terms of dissolution, the rate of the extrusion process did not influence the performance of the products, whereas the composition did. The extruded mixtures of an equivalent composition exhibited a more rapid release than a simple physical mixture. The addition of lactose reduced the dissolution rate.

Anticonvulsants↗

PubMed2006

Application of reverse-flow micellar electrokinetic chromatography for the simultaneous determination of flavonols and terpene trilactones in Ginkgo biloba dosage forms.

A reverse-flow micellar electrokinetic chromatographic (RF-MEKC) method was developed for the simultaneous qualitative determination of 10 components consisting of the flavonol glycosides, rutin and quercitrin, the flavonol aglycones, isorhamnetin, kaempferol and quercetin, the terpene trilactones, ginkgolides A, B, C and J and the sesquiterpene, bilobalide. This method was used to fingerprint Ginkgo biloba solid oral dosage forms and validated for the quantitation of the marker compounds, rutin and quercetin in some commercial products. In addition to the usual variables, the influence of some essential background electrolyte (BGE) components such as sodium dodecyl sulphate (SDS) and -cyclodextrin concentrations were investigated. A polyimide fused-silica square capillary column (75 microm I.D. x 360 microm O.D.) with a total length of 60.0 cm and effective length of 45.0 cm was used for the separation. The final BGE consisted of 20 mM phosphoric acid, 40 mM SDS and 12 mM -cyclodextrin (pH 2.2) using reverse polarity with a voltage of -17.5 kV. Samples were injected electrokinetically at -5 kV for 3 s for the qualitative analysis and hydrodynamically at 20 mbar for 0.6 s for the quantitative assay. The total run time was 22 min and the limits of detection were 3.13 microg/ml and 1.88 microg/ml for rutin and quercetin, respectively. Fingerprint profiles of the solid oral dosage forms and the results of the quantitative analysis indicated that there were major discrepancies in the marker content between products and illustrates the value of this method for use as a procedure to assess product quality of commercially available Ginkgo biloba products.

Chromatography, Micellar Electrokinetic Capillary↗

PubMed1980

High-pressure liquid chromatographic determination of salicylic acid in aspirin powder and pharmaceutical dosage forms.

A sensitive, simple, and rapid method for the quantitation of salicylic acid in aspirin powders and its dosage forms was developed. The method is based on reversed-phase high-pressure liquid chromatography using a mobile phase containing 20% methanol in aqueous phosphate buffer of pH 2.3. Other common ingredients present with aspirin such as acetaminophen, caffeine, codeine phosphate, phenacetin, and salicylamide do not interfere. Salicylic acid quantities as low as 0.1 microgram can be assayed with a relative standard deviation of +/- 2.3%. Sensitivity can be increased by using lower sensitivity settings. The method was tried on numerous commercial products and an old aspirin powder. The results generally were excellent, except that all of the aspirin and salicylic acid could not be extracted from suppositories. The old aspirin powder failed the USP limit test for salicylic acid. The powder apparently absorbed moisture and contained salicylamide as an impurity.

Aspirin↗

PubMed1993

[Combined chemotherapy of patients with tuberculosis - new regimens and dosage forms].

310 patients with pulmonary tuberculosis disseminating bacteria received isoniazid, rifampicin, streptomycin (ethambutol) and pirazinamid in different regimens and dosage forms. The drugs were administered in sequence or simultaneously, in single or divided doses. The best time and number characteristics as regards the discharge negativation were obtained in pirazinamid administration at a single dose daily or each other day irrespective of other drugs intake. 100 patients were given isoniazid, rifampicin and pirazinamid in multicomponent form tricox (Jemis, India). Tricox proved effective under additional administration of isoniazid in the same dose as was fixed in tricox.

Antitubercular Agents↗

PubMed2003

Development and validation of a liquid chromatography-ultraviolet absorbance detection assay using derivatisation for the novel marine anticancer agent ES-285 x HCl [(2S,3R)-2-amino-3-octadecanol hydrochloride] and its pharmaceutical dosage form.

ES-285 x HCl [(2S,3R)-2-amino-3-octadecanol hydrochloride] is a novel investigational anticancer agent, which has shown in vitro and in vivo cytotoxic activity against various tumor cell lines with selectivity for certain solid tumors. The pharmaceutical development of ES-285 x HCl warranted the availability of an assay for the quantification and purity determination of ES-285 x HCl active pharmaceutical ingredient (API) and its pharmaceutical dosage form. A liquid chromatographic method (LC) comprising of derivatisation of ES-285 x HCl with phenylisothiocyanate and UV-detection was developed. The method was found to be linear, precise and accurate. The assay also proved selectivity as determined by analysing ES-285 x HCl in combination with 15 analogues and in combination with hydroxypropyl-beta-cyclodextrin, the excipient used in the lyophilised pharmaceutical dosage form. Stress testing showed that the degradation products were separated from the parent compound, confirming its stability indicating capacity. The method was found robust as determined with design of experiments (DoE), which made it possible to predict system suitability responses in worst case experimental conditions and to define criteria for system suitability testing.

Alkanes↗

PubMed1994

Chromatographic analysis of selected tetracyclines from dosage forms and bulk drug substance using polymeric columns with acidic mobile phases.

The LC analysis of selected tetracyclines from dosage forms and bulk drug substance using polymeric columns has been studied. Mobile phases containing acetonitrile-0.02 M sodium perchlorate (pH 2.0) were used. The tetracyclines were detected by their absorbance at 280 nm. The columns included: a polystyrene-divinylbenzene (PS-DVB) column and a polymethacrylate column with octadecyl ligands (PM-C18). Performance of the two columns was compared and applicability of the described methods for compendial use has been evaluated. The tetracyclines investigated include: minocycline, oxytetracycline, tetracycline, demeclocycline, chlortetracycline, methacycline, doxycycline and meclocycline.

Acetonitriles↗

PubMed2002

Application of pressurized liquid extraction technology to pharmaceutical solid dosage form analysis.

The technique of pressurized liquid extraction has been evaluated for the extraction of active ingredients from pharmaceutical dosage forms using montelukast sodium oral chewable tablets as a model. The extraction method was optimized for the number of extraction cycles, extraction time, extraction solvent composition and temperature. Samples were extracted using two cycles of water for 2 min with a cell temperature of 40 degrees C and a pressure of 1.0 x 10(4) kPa, to disintegrate the tablet, followed by three cycles of methanol for 3 min at 70 degrees C and 1.0 x 10(4) kPa, to solubilize montelukast sodium. The method demonstrated an extraction efficiency of 98.2% of label claim and an RSD of 1.3% (n=10), as compared to 97.6% and an RSD of 0.9% obtained using a validated mechanical extraction method.

Chromatography, Liquid↗

PubMedDate not supplied

Pharmacokinetic evaluation of novel sustained-release dosage forms of valproic acid in humans.

Five new sustained-release dosage forms of valproic acid (VPA) were developed. The new sustained-release formulations were administered to six healthy subjects for comparison with a standard tablet and an i.v. preparation of the drug. Three of the formulations exhibited a more prolonged and uniform absorption rate and yielded more sustained serum levels after ingestion. These three formulations maintained serum therapeutic levels of VPA for 24 h after a single oral administration of 1 g, and were bioequivalent to a marketed standard tablet of VPA. The absorption profile of the various oral formulations was analysed pharmacokinetically, using the Loo-Riegelman procedure.

Administration, Oral↗

PubMed1993

In vitro/in vivo correlation of prolonged release dosage forms containing diltiazem HCI.

Six preparations were considered: three multiple unit dosage forms (micropellets in capsules) (D, E and G) and one matrix tablet (B) were experimental prolonged release formulations, two non-disintegrating tablets (A and C) were commercial products. The in vitro dissolution behaviour of the differing formulations was investigated using the USP XXII paddle apparatus. The in vivo study was effected on a panel of 12 healthy volunteers. The two commercial tablets (A and C) showed mean dissolution time (MDT) of 1.34 and 1.44 h and td of 91 and 92 min, respectively; for prolonged release formulations (B, E, D, and G) MDT ranged between 2.28 and 4.23 h and td between 149 and 291 min. The mean residence time (MRT) was 8.68 and 6.47 h for tablets A and C, respectively; it ranged between 9.62 and 10.24 h for the multiple unit formulations E, D, and G and was 11.27 h for matrix B. Formulation B also showed the higher apparent elimination half-life t1/2 (7.12 h), while apparent t1/2 for all the other formulations were very similar, ranging between 5.04 and 5.28 h. High variability between the various formulations was found for Cmax and AUC values, and no relationships could be established with the type of formulation. An in vitro/in vivo correlation was found for all the formulations examined on the basis of analogous parameters (MDT and MRT); (r = 0.83, p < 0.05). In a few cases the Wagner-Nelson deconvolution method was applied to individual plasma level versus time curves and the corresponding absorption curves were obtained. In these cases the in vitro/in vivo correlation was tested on the basis of the comparison of the in vivo absorption curves with the in vitro dissolution profiles. This was accomplished using the 'Levy's plot' (per cent released versus per cent absorbed) approach and provided further support for the correlation found.

Adult↗

PubMedDate not supplied

Dissolution evaluation of marketed tetracyclines solid oral dosage forms.

Tetracyclines are produced by several pharmaceutical industries, mainly as capsule dosage form. This paper aimed to evaluate quality performance of commercially available tetracycline and oxytetracycline hydrochloride capsules and doxycycline hydrochloride enteric-coated tablets by means of in vitro dissolution test. 36 samples from 12 different producers containing 500 mg of tetracycline and oxytetracycline and 100 mg of doxycycline were analyzed using the USP XXIII procedures. Thirty four samples (94.4%) were approved and the remaining two samples (5.6%) were rejected. Although only one of the producers had some samples rejected, this fact must be seriously taken into account, considering the need of a highly qualified industrial production of medicines.

Capsules↗

PubMed1977

Effect of food on absorption of indoprofen administered orally to man in two dosage forms.

The influence of food on the bioavailability of two oral dosage forms (100-mg capsules and 200-mg tablets) of indoprofen, a new propionic acid derivative with marked anti-inflammatory and analgesic properties, has been investigated. Plasma levels and urinary excretion of indoprofen were determined both in the fasting state and after a standard meal in healthy volunteers after administration of two 100-mg capsules (4 subjects) and of one 200-mg tablet (6 subjects). Indoprofen in biological fluids was determined by gas-liquid chromatography. The extent of absorption from tablets was not affected by food as indicated from the values of the total area under plasma level curves and urinary excretion of the drug. The rate of absorption was faster after meal than in the fasting state. The opposite was found for capsules, which showed a slightly delayed absorption after food. The results suggest that food may differently influence the absorption pattern of different pharmaceutical forms of the same drug.

Administration, Oral↗

PubMed1985

[The pharmacokinetics and bioequivalence of various dosage forms of ambroxol].

An intraindividual comparative single-dose study was carried out under carefully controlled conditions on 12 healthy volunteers in order to establish the bioavailability of trans-4-(2-amino-3,5-dibromobenzyl)-amino-cyclohexanol (ambroxol) the active principle of newly developed tablets and drops, in comparison to a commercial i.v. preparation. In an additional single-dose, cross-over study on 12 healthy volunteers the bioequivalence of ambroxol was investigated after administration of a newly developed vs. a commercial dose-equivalent, sustained-release dosage form. Following off-line derivatisation using formaldehyde to the corresponding tetrahydroquinazoline compound, ambroxol was assayed from plasma by high-performance liquid chromatography. A 2-compartment model was taken as a basis for the calculation of the plasma concentration curves and the pharmacokinetic parameters following intravenous injection of the drug. After i.v. administration, the terminal elimination half-life, the apparent volume of distribution and the total plasma clearance were determined to be 3.72 h, 1.52 l/kg and 565 ml/min, respectively. From the tablet and drop formulations the systemic availabilities were calculated to 73 and 81%, respectively; the mean transit times were determined to be 6.8 and 5.4 h, respectively. Both sustained-release dosage forms investigated are bioequivalent.

Adult↗

PubMed1994

Evaluation of the performance of controlled release dosage forms of ticlopidine using in vitro intestinal permeability and computer simulations.

Prototype controlled release formulations of ticlopidine hydrochloride were developed, but when administered to humans, these formulations significantly reduced the bioavailability of intact drug in plasma. In order to examine the intestinal permeability characteristics and gastrointestinal metabolism of 14C-ticlopidine, we employed an in vitro diffusion cell system to directly measure the permeation of ticlopidine across various segments of monkey and rabbit intestine. High pressure liquid chromatography was used to determine the amount of intact ticlopidine on both the mucosal and serosal sides of the intestinal tissue. Simulations based upon the known pharmacokinetics of ticlopidine were conducted using STELLA, a modeling program, to provide insight as to the nature of the decreased bioavailability of these ticlopidine CR dosage forms. These simulations indicate that the absorption of intact ticlopidine is a non-linear phenomena, with inordinately large increases in absorbed intact drug with increases in dose. Conversely, decreases in drug available for immediate absorption, as with the controlled release dosage forms, lead to non-linear decreases in bioavailability. Such a finding is very consistent with the extensive first-pass metabolism suggested from the tissue permeability studies.

Animals↗