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At least 397 records · Page 22Linked to original sources
PubMed2006

Continuous release of Rh-interferon (alpha-2a from triglyceride implants: storage stability of the dosage forms.

Tristearin implants containing polyethylene glycol 6000 (PEG) were shown to be a promising platform for the delivery of pharmaceutical proteins for periods up to 1 month. The objective of this study was to investigate the storage stability of the lipid devices, as long-term storage stability ensuring acceptable shelf-life can be considered the most important parameter for commercially viable sustained-release dosage forms. Rh-Interferon alpha-2a was stabilized by a lyophilization process using either trehalose or hydroxypropyl-beta-cyclodextrin as stabilizer. Tristearin implants containing the lyophilized protein material and 10% PEG were stored over 3 months and 6 months, both at 4 degrees C and room temperature, before release studies were initiated. Data from stored implants demonstrated trehalose not to be effective to provide full protein stabilization during long-term storage of the lipid matrices, this was apparent from both the reduced total drug level liberated and the release of aggregated specimen compared to the situation immediately after implant manufacture. In contrast, hydroxypropyl-beta-cyclodextrin (HP-beta-CD) exhibited a high potential for protein stabilization within the matrices during both storage and release. Generally, 95% of the incorporated protein was delivered continuously within 1 month in monomeric form, even after 6 months' storage of the implants at room temperature.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1979

GLC determination of trihexyphenidyl hydrochloride dosage forms.

A rapid, sensitive, and specific GLC method for the quantitation of trihexyphenidyl hydrochloride in various pharmaceutical dosage forms is described. The procedure involves chloroform extraction of the active ingredient from a weakly acidic solution, followed by GLC determination using a 3% methyl silicone column. The specificity of the system in relation to several compendial drug analogs also is reported.

Capsules↗
PubMed2006

Influence of plasticizer level on the drug release from sustained release film coated and hot-melt extruded dosage forms.

In the current study, the influence of plasticizer level on drug release was investigated for solid dosage forms prepared by hot-melt extrusion and film coating. The properties of two highly water-soluble compounds, diltiazem hydrochloride (DTZ) and chlorpheniramine maleate (CPM), and a poorly water-soluble drug, indomethacin (IDM), were investigated in the melt extrudates containing either Eudragit RSPO or Eudragit RD 100 and triethyl citrate (TEC) as the plasticizer. In addition, pellets containing DTZ were film coated with Eudragit RS 30D and varying levels of TEC using a fluidized bed coating unit. Differential scanning calorimetry (DSC) demonstrated that both CPM and IDM exhibited a plasticization effect on the acrylic polymers, whereas no plasticizing effect by DTZ on Eudragit RSPO was observed. Thermogravimetric analysis (TGA) was used to investigate the thermal stability of the DTZ, Eudragit RSPO and TEC at 140 degrees C, the maximum temperature used in the hot-melt extrusion process. The chemical stability of DTZ and IDM in the extrudate following hot-melt processing was determined by high pressure liquid chromatography (HPLC). Drug release rates of both DTZ and CPM from hot-melt extrudates increased with an increase in the TEC level in the formulations, while the release rate of DTZ from the Eudragit RS 30D-coated pellets decreased with an increase in TEC in the coating dispersion. This phenomenon was due to the formation of a reservoir polymeric structure as a result of the thermal stress and shear stress involved in the hot-melt extrusion process regardless of the TEC level. In contrast, coalescence of the polymer particles in the film coating process was enhanced with higher levels of TEC, as demonstrated by scanning electron microscopy (SEM). The addition of TEC (0% to 8%) in the IDM hot-melt extrudate formulation had no influence on the drug release rate as the drug release rate was controlled by drug diffusion through the inside of the polymeric materials rather than between the polymer particles.

Calorimetry, Differential Scanning↗
PubMed2002

Development and validation of a HPLC method for the determination of cetirizine in pharmaceutical dosage forms.

A rapid, simple and accurate HPLC method is described for the assay of cetirizine in commercial dosage forms. Methanol was found to be a suitable extraction solvent for tablets and for preparing solutions from drops and oral liquids. The samples were chromatographed on a Nova-Pak C18 column and UV detected at 227 nm. The elution was achieved isocratically with a mobile phase of 0.067 M phosphate buffer pH 3.40/acetonitrile (1:1, v/v). Ketotifen was applied as an internal standard. The method was validated for linearity, precision, accuracy and limit of detection. The recovery (mean +/- SD) for tablets was 100.88% +/- 0.8967, for drops 100.35% +/- 0.4062 and for solutions 101.20% +/- 1.1698.

Anti-Allergic Agents↗
PubMedDate not supplied

Liquid chromatographic determination of chlorpropamide in tablet dosage forms: collaborative study.

A reverse-phase liquid chromatographic method was developed for determining chlorpropamide in tablet dosage forms. Linearity was established over the range 0.2-2.0 micrograms at a wavelength of 240 nm. The Associate Referee obtained a mean recovery for a synthetic tablet mixture of 99.2%, with a relative standard deviation (RSD) of 1.41. For an authentic tablet mixture, collaborators obtained a mean recovery of 99.6% with an RSD of 0.60%. RSDs were 1.24% for 250 mg/tablet commercial product and also for 100 mg/tablet commercial product. The method has been adopted official first action.

Chlorpropamide↗
PubMed1997

Determination of paclitaxel and related taxanes in bulk drug and injectable dosage forms by reversed phase liquid chromatography.

Baseline separation of 15 taxanes including paclitaxel (Taxol) was achieved on pentafluorophenyl (PFP) HPLC columns. Methods using aqueous acetonitrile gradients on each of two commercial PFP columns were developed that are suitable for the determination of potency, content uniformity, and degradation profile of the paclitaxel bulk drug and injectable dosage form. The elution order is apparently related to molecular size, the number of acetylated hydroxyl groups, and the substitution of a xylosyl group at the 7-position. The resolution of several of the taxanes is a sensitive function of the starting eluent composition and the programming rate, which requires optimization of the methods on both columns. Retention of 10 of the taxanes was studied over the temperature range from 30 to 70 degrees C, and enthalpies of transfer, delta H degree, were determined. Conversion of a hydroxy group to an acetyl group, which can interact more strongly with the fluorines on the PFP, has a large effect on the delta H degree, as does the addition of a xylosyl derivative to the 7-hydroxy. The methods developed for the injectable drug form allow good resolution of the taxanes from the excipient Cremophor EL, a polyethoxylated castor oil used with ethanol to solubilize the paclitaxel. The methods for the bulk drug were fully validated in terms of accuracy, precision, specificity including forced degradation, limits of detection and quantitation, and linearity and range.

Antineoplastic Agents, Phytogenic↗
PubMed2005

Pharmaceutical development of a lyophilised dosage form for the investigational anticancer agent Imexon using dimethyl sulfoxide as solubilising and stabilising agent.

Imexon is a member of the class of 2-cyanoaziridine derivatives, which have been of interest as immunomodulators and anticancer agents since the late 1970s. For the scheduled phase I clinical trials a stable, sterile, injectable pharmaceutical dosage form containing 100 mg Imexon was required. Despite adequate solubility, its instability in aqueous media seriously hampered the pharmaceutical development of Imexon. In this study we describe the successful use of the organic solvent dimethyl sulfoxide (DMSO) as a formulation vehicle for Imexon. DMSO is shown to provide the stability required for Imexon during manufacturing and to be a suitable vehicle for lyophilisation, which was employed to gain sufficient shelf-life for the final product. The relatively low vapour pressure of DMSO, which would theoretically result in extremely slow sublimation during lyophilisation, was shown not to limit the successful lyophilisation of Imexon from DMSO at a concentration of 25 mg/mL. The lyophilisation cycle developed for Imexon resulted in residual DMSO contents of 4.6 +/- 0.6% in the lyophilised product, limiting the amount of DMSO administered to the patient to well below the 50 mg/day acceptable in pharmaceutical products as stated in ICH guidelines. Imexon 100 mg/vial lyophilised product was shown stable for at least 12 months of storage at -20 degrees C and +5 +/- 3 degrees C in the dark.

Adsorption↗
PubMed1998

Surface acidity of solid pharmaceutical excipients III. Excipients for solid dosage forms.

The surface acidities of pharmaceutical excipients are detected by color changes of acid-base indicators on the substrate's surface. To quantify the indicator's transition interval on the surface of hydrophilic excipients, as an organic solvent methanol is introduced for the preparation of indicator-excipient mixtures. The influence of the particle size on the determination of the surface acidity is investigated and particle size did not influence the determination within the particle size range investigated. Surface acidities of common excipients used in preparation of solid dosage forms are presented.

Cellulose↗
PubMed1994

Evaluation of 153Sm-diethylenetriaminepentaacetic acid for radiolabelling of pharmaceutical dosage forms by neutron activation.

153Sm-DTPA provides a suitable alternative to 99mTc-DTPA and 111In-DTPA as a water soluble tracer for the evaluation of pharmaceutical preparations. The chelate was handled biologically in a similar way to 99mTc-DTPA and 111In-DTPA. The chelate can be incorporated into the formulation as a non-radioactive excipient and the intact dosage form can then be neutron activated to produce 153Sm.

Administration, Inhalation↗
PubMed2003

Individualising therapy. The right dose, dosage form, frequency and duration.

BACKGROUND: Having chosen which drug to prescribe, the prescription now needs to be individualised for the patient in front of you. OBJECTIVE: This article discusses the factors that have to be considered when individualising drug therapy for each patient. DISCUSSION: Before considering writing a prescription it is important to develop a personalised approach for the individual patient. The prescription should also then be individualised as to the route of administration, dosage, dosage form, frequency, and duration of the medication being prescribed.

Aged↗
PubMedDate not supplied

Reverse phase liquid chromatographic determination of dexamethasone acetate and cortisone acetate in bulk drug substances and dosage forms: method development.

The determination of the steroid acetates was evaluated for ruggedness of the method by using an octyldecylsilane column, 254 nm detection, and acetonitrile-water as mobile phase. Mobile phase pH, oven temperature, and columns from various manufacturers had no dramatic effect on the chromatography. The method was then optimized for dexamethasone acetate and cortisone acetate bulk drug and dosage forms. For dexamethasone acetate, the bulk drug substance should be dried at 105 degrees C before use, and the sample should be dissolved in 50% acetonitrile-buffer pH 6 for stability. Cortisone acetate, on the other hand, was found to be nonhygroscopic and hence could be used as received. For stability, the sample should be stored in 50% acetonitrile-buffer pH 4.

Chromatography, Liquid↗
PubMed2002

Spectrophotometric determination of phenylephrine HCl and orphenadrine citrate in pure and in dosage forms.

A simple and rapid spectrophotometric methods have been estimated for the microdetermination of phenylephrine HCl (I) and orphenadrine citrate (II). The proposed methods are based on the formation of ion-pair complexes between the examined drugs with alizarine (Aliz), alizarine red S (ARS), alizarine yellow G (AYG) or quinalizarine (Qaliz), which can be measured at the optimum lambda(max). The optimization of the reaction conditions is investigated. Beer's law is obeyed in the concentration ranges 2-36 microgram ml(-1), whereas optimum concentration as adopted from Ringbom plots was 3.5-33 microgram ml(-1). The molar absorptivity, Sandell sensitivity, and detection limit are also calculated. The correlation coefficient was >/=0.9988 (n=6) with a relative standard deviation of </=1.7, for six determinations of 20 microgram ml(-1). The proposed methods are successfully applied to the determination of drugs I and II in their dosage forms using the standard addition technique.

Chemistry, Pharmaceutical↗
PubMed1991

Preformulation studies involving moisture uptake in solid dosage forms.

The rates of moisture sorption and the resultant effect on stability of a moisture-sensitive drug blended r formulated with different components are addressed. Total moisture increase was determined by weight gain, and change in mobile water level by water activity measurements. Equilibrium relative humidity is a useful tool in predicting the stability of a moisture-sensitive drug in solid dosage forms. Since immobile water is perceived not to react chemically, the amount of mobile water rather than total water is the critical parameter in degradation reactions involving hydrolysis. Materials that have a high capacity for binding water equilibrate more slowly to higher levels of mobile water and consequently show greater chemical compatibility with a moisture-sensitive drug than materials with lower binding capacities for water.

Chemistry, Pharmaceutical↗
PubMed2005

Development and validation of an LC-UV method for the quantification and purity determination of the novel anticancer agent C1311 and its pharmaceutical dosage form.

C1311 (5-[[2-(diethylamino)ethyl]amino]-8-hydroxyimidazo [4,5,1-de]-acridin-6-one-dihydrochloride trihydrate) is the lead compound from the group of imidazoacridinones, a novel group of rationally designed anticancer agents. The pharmaceutical development of C1311 necessitated the availability of an assay for the quantification and purity determination of C1311 active pharmaceutical ingredient (API) and its pharmaceutical dosage form. A reversed-phase liquid chromatographic method (RP-LC) with ultraviolet (UV) detection was developed, consisting of separation on a C18 column with phosphate buffer (60 mM; pH 3 with 1 M citric acid)-acetonitrile-triethylamine (83:17:0.05, v/v/v) as the mobile phase and UV-detection at 280 nm. The method was found to be linear over a concentration range of 2.50-100 microg/mL, precise and accurate. Accelerated stress testing showed degradation products, which were well separated from the parent compound, confirming its stability-indicating capacity. Moreover, the use of LC-MS and on-line photo diode array detection enabled us to propose structures for four degradation products. Two of these products were also found as impurities in the API and more abundantly in an impure lot of API.

Aminoacridines↗
PubMed2006

[The importance of micronization in the design of dosage forms I. Theoretical and biopharmaceutical aspects].

The role of micronization is growing considering the optimization of the physicochemical characteristics of drug, dissolution enhancement and ensuring appropiate bioavailability. The importance of micronization can be understood on the basis of Noyes-Whitney equation, where the particle characteristics influence the active surface contacting with the dissolution medium, theoretically the solubility, and the boundary layer around the particle under certain hidrodynamic conditions. To adjudge the possibilities and limits of micronization concerning the dosage form design and preparations based on innovative pharmaceutical technology, it is necessary to take the detailed theoretical, physiological and biopharmaceutical aspects into consideration.

Biological Availability↗