Showing papers in "Pharmazeutische Industrie in 1993"

Anwendung der automatischen Bildanalyse zur Charakterisierung von Pellets

Abstract: Automatic image analysis is an appropriate tool for simultaneous characterization of size and shape of pellets. Reproducable results can only be obtained using a standardized measurement procedure. An analysis instruction is developed for the rapid analysis of 500 to 600 pellets. To limit the possible error caused by wrong detection the magnification of the lens is adjusted for a mean size of 50-60 pixels per particle. Length, width and area of the pellets are measured as direct parameters while aspect ratio, mean feret and equivalent diameter are calculated Due to the technology of measurement an error is made for some of the parameters. Eight Feret diameters are measured by the system

Schnellzerfallende Tabletten mit gesteuerter Wirkstoffabgabe

Abstract: Small particles as crystals, granules and pellets of a particle size in the range of 0.3-1.2 mm were coated with aqueous dispersions of methacrylic acid and methacrylic ester copolymers (Eudragit RL 30 D, RS 30 D, L 30 D and NE 30 D) for taste masking, resistance to gastric fluid and diffusion controlled sutained release properties and compressed into fast disintegrating tablets

Aqueous coating of pellets to sustained-release dosage forms in a fluid-bed coater : influence of product temperature and polymer concentration on in vitro release

Abstract: In order to investigate the influence of product temperature and polymer concentration on in vitro release, theophylline pellets were coated with an aqueous ethyl cellulose dispersion and a latex polymer dispersion consisting of a copolymerisate from acrylic and methacrylic acid ester in a Kugelcoater at different product temperatures and at different levels of dispersion polymer concentration. The results of the experiments showed that the optimal product temperature lies approx. 10-20 o C above the minimum film formation temperature

Determination of the surface hydrophobicity of colloidal dispersions by mini-hydrophobic interaction chromatography

Abstract: Hydrophobic interaction chromatography (HIC) was used as a method which allows the determination of the surface hydrophobicity of colloidal particles in their original dispersion medium (water). A miniaturized version (Mini-HIC) was established as a more rapid and less costly screening assay. By reducing the bed volume from at least 8 ml to 1 ml the analysis time could be reduced from hours to minutes. Surface-modified polystyrene particles were used as model dispersions and analyzed with both methods with regard to surface hydrophobicity and the presence of subpopulations differing in their surface properties

Use of laser light diffraction in determining the size distributions of different shaped particles

Abstract: Laser light diffraction (LLD) is rapid and highly repeatable method in determining the particle size distributions of pharmaceutical powders. The materials used in this study were narrow sieve fractions of spherical pellets, cubic sodium chloride and acicular anhydrous theophylline. The size distribution determinations were made by Malvern 2600c droplet and particle sizer as dry dispersions. An interactive image analysis (IA) system (Kontron Vidas + ) was used as an absolute control method. The results showed that in all determinations the LLD method broadened the size distributions compared to the IA method. Furthermore, the LLD method overestimated the particle size of spherical particles even by 40%

Comparative measurements of nanoparticle degradation velocity using an accelerated hydrolysis test

Abstract: The degredation velocities of polyester particles in relation to each other were determined using an accelerated hydrolysis test. Degradation of particles suspended in water was monitored by absorption measurements at 400 nm. The particles were degraded at increased pH (10.5 to 13.0) and increased temperature (60 o C). This accelerated the degradation to be completed within 8 h compared to the in vivo hydrolysis lasting from a few weeks to several months

Expert systems in solid dosage development

Abstract: This article introduces and reviews the use of expert systems in solid dosage development (tablets and film coating). The applications, experience and benefits to the pharmaceutical industry are discussed. Expert systems, where introduced and implemented, have generated significant benefits in terms of knowledge protection, cost reduction, training, consistency and improved communication

Comparative effectiveness of super disintegrants on the characteristics of directly compressed triamterene hydrochlorothiazide tablets

Abstract: The effectiveness of Ac-Di-Sol®, Explotab®, and Crospovidone N. F. was investigated in a directly compressible triamterene (TRM)/hydrochlorothiazide (HCT) tablets based on Avicel®/Emcompress® as the diluents. A high shear mixer (Processall® Model-HV) was used to mix the powder blend. The 3 distintegrants were used at concentrations of 1% w/w to 5% w/w. The tablets were compressed at a compression force of 800 lbs (3.558 kN) under standardized conditions

Filmüberzüge auf Basis wässriger Polymethacrylat-Dispersionen mit verzögertem Zerfall im Darmbereich

Abstract: Spray-dried powders of methacrylic acid copolymers described in the USP/NF monograph as Types A, B contain 30-50% methacrylic acid units and can be redispersed in water by partial neutralisation to latexes up to 15 mol%. If 50% of plasticizer as triethyl citrate are added, the minimum film forming temperature is below 70 o C. Enteric coating of tablets, pellets and granules can be done under usual spraying conditions. The coated cores show excellent resistance to simulated gastric fluid and less than 5% of drug are released up to pH 6.8 if type B is applied with 30% methacrylic acid units and a dissolution pH of 7

Gezieltes Entwickeln und Optimieren von Kapselformulierungen mit einer instrumentierten Dosierröhrchen-Kapselabfüllmaschine. I: Instrumentierung und Einfluss der Füllgut- und Maschinenparameter

Abstract: On a capsule filing machine Zanasi LZ 64 with intermittent operation the dosator was instrumental with strain gauges and the influence on the quality of the formulation and machine parameters was examined. As model formulations served Avicel PH 101 as visco-elastic material and Lactose anhydrous as brittle material as well as mixtures of various sieve fractions of Lactose. It was shown that for unproblematic filling with uniform fill weights the good compressibility by reaction of volume as well as strength of binding is important

Interaction of carbamazepine with cyclodextrins

Abstract: The potentiality of interaction of carbamazepine with cyclodextrins, viz, α-cyclodextrin (α-CD), β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HPBCD) has been investigated in aqueous and solid state through differential ultraviolet spectroscopy, solubility method, differential scanning calorimetry (DSC) and dissolution studies. Differential UV-spectroscopy revealed a marked effect of cyclodextrins on the spectral pattern of the drug

Gezieltes Entwickeln und Optimieren von Kapselformulierungen mit einer instrumentierten Dosierröhrchen-Kapselfüllmaschine. II: Grundlagen der Optimierungsstrategie

Abstract: On an instrumented capsule filling machine (Zanasi LZ 64) with intermittent operation, the influence of the excipient- and machine parameters on the filling of the capsules and the dissolution rate using coffeine as model substance was determined. It was found that a sufficient lubrication of the capsule mixture, measurable by low ejection forces, is critical for a uniform fill weight: Adding too much lubrificant, however, prevents the compact from forming and the standard deviation of the fill weight increases. Magnesium stearate and Precirol are more effective lubricants than stearic dispersion

Comparison of two microcrystalline cellulose brands for the direct compression of hydrochlorothiazide tablets

Abstract: The effect of storage on tablets formulated with two different brands of coarse microcrystalline cellulose (MCC). MCC-1 and MCC-2, was studied. To compare the two, 25 mg hydrochlorothiazide tablets were prepared by direct compression, using a 50:50 blend of MCC and anhydrous lactose, incorporating crosslinked PVP, croscarmellose, or sodium starch glycolate and magnesium steorate. Tablets (150 mg) were compressed on a rotary tablet press and were evaluated for weight, thickness, hardness, friability, disintegration time, and dissolution (U.S.P) initially, and after 9 months storage at room temperature

Interaction of mebeverine hydrochloride and carbopol

Abstract: The interaction of mebeverine hydrochloride and Carbopol 934 in aqueous medium was studied using a dialysis technique. The effect of pH, drug and polymer concentration and electrolytes on such interaction were studied. The results revealed that the interaction of the drug and the polymer (Carbopol 934) was inversely proportional to the initial concentration of the drug and directly proportional to the polymer concentration. The drug-polymer interaction was found to be pH-dependent. The presence of electrolyte decreased the interaction between the drug and the polymer

Phenylpropanolamine controlled-release tablets : in vitro availability

Abstract: Cellulosic and Eudragit polymers as well as polycarbophil were used to prepare phenylpropanolamine tablets either by direct compression, or compression after wet granulation or coprecipitation, in an attempt to obtain satisfactory release characteristics for the drug over a prolonged time: The release rate was studied both in 0.1 mol/l HCl and phosphate buffer (Ph 7.4). In general, release was more rapid in acid medium. Directly compressed tablets made of polycarbophil gave a rather slow release

Characterization of colloidal drug carriers : determination of surface hydrophobicity by hydrophobic interaction chromatography

Abstract: Hydrophobic interaction chromatography (HIC) is presented as a suitable method to determine the surface hydrophobicity of colloidal drug carriers. The experimental design is described in great detail. Results obtained with surface-modified polystyrene particles as model carriers and parenteral fat emulsions are discussed as examples. HIC was able to distinguish between particles chemically modified by the introduction of functional groups. Polystyrene particles of various size were surface-modified by adsorption of the block-polymer Poloxamine 908. HIC distinguished between the hydrophobicities of these adsorption layers

Ketoprofen-Freisetzung aus wässrigen Systemen unter Anwesenheit von hydrophilen β-Cyclodextrin-Derivaten

Abstract: Nonsteroidal antiinflammatory drugs [NSAID] are often characterised by a low water solubility. Possible partners for complexation inducing an increase of the solubility may be cyclodextrins and their derivatives. By using hydrophilic β-cyclodextrin derivatives for inclusion of ketoprofen the solubility is increased by 1500 times. The stability of the drug in these preparations is often higher than in aqueous solution. Only preparations which are physical mixtures of ketoprofen and hydroxypropyl-β-cyclodextrin show a decrease of the drug stability. In case of mechanical separation of the two compartments, drug liberation of cyclodextrin containing systems shows a linear relationship between the amount of liberated drug and the square root of time

Emulsions for intravenous administration. I: Emulsions for nutrition and drug delivery

Abstract: Lecithin stabilized o/w emulsions are used in parenteral nutrition since the fifties, during the last years they attracted increasing attention as colloidal carriers for the intravenous administration of drugs. Emulsion composition, in vivo metabolism, blood clearance and mixed systems (regimes) for total parenteral nutrition (TPN) are briefly discussed. Examples of emulsions as drug carriers are presented, especially considering the reduction of side effects and possibilities for site-specific drug delivery (drug targeting). Part II deals with the stabilising and destabilising mechanisms in emulsion systems

Availability of mebeverine hydrochloride from suppositories

Abstract: Suppositories containing 200 mg of meberine hydrochloride were prepared using different suppositor bases namely: Witepsol E75, E15, H15; Suppocire Am, MC, Novata 75; polyethyleneglycol 4000:6000 mixture in a ratio of 40:60, respectively and cacoa butter. The in vitro release of the drug from these bases in Sorensen's phosphate buffer pH (7.4) using dialysis method, was investigated. The effect of type and concentration of different non-ionic surfactants viz Brif 35, 58; Myrj 51; 53; and Tween 60 and 80 on the rate of drug release form Suppocire AM was studied

Emulsions for intravenous application. II: Destabilisation and stabilisation mechanisms in fat emulsions

Abstract: Preparation of mixed emulsion systems for total parenteral nutrion (TPN) reduces the physical stability of the emulsions. Incorporation of drugs in emulsions can also cause physical instability. Destabilising and stabilising mechanisms in emulsions are discussed, especially with regard to added electrolytes and subssequent reduction of the zeta potential. Stabilising Born hydration and rigidity of the emulsifier film (microviscosity) are also considered

Evaluation of the capability of laser light diffraction to determine the size distributions of spherical particles

Abstract: Comparison of the laser light diffraction and image analysis methods in particle size determination is presented. The test materials were spherical Sephadex and pellet particles. The particles were measured as single distributions, in 1:1 binary mixtures. One trimodal and 1:1:1:1:1 mixture were also studied. The results show that the laser light diffraction method gave quite erroneous results for particles larger 500 μm in diameter. Image analysis was almost an absolute size determination method. It is concluded that laser light diffraction is also usable in particle size determinations, but the method requires proper validation based on some more accurate method

Investigation of new commercial sodium starch glycolate products

Abstract: The availability of 4 experimental sodium starch glycolates (SSG) was investigated. The effects of the molecular structure (degree of substitution) and of the purity (sodium chloride content) on the disintegration efficiency and on the dissolution rate were also studied. A higher degree of substitution and lower sodium chloride content resulted in a shorter disintegration time and faster dissolution. The new experimental SSG products appeared to be excellent disintegrants. They are as good as Primojel® or Explotab®

Einfluss unterschiedlicher Herstellungsmethoden auf die physikalischen Eigenschaften von Tabletten

Abstract: The quality of tablets, manufactured by using 2 different granulation techniques, the planetary- and the intensive-mixer, and 2 different drying methods, the tray- and the fluidized bed drying, was compared using statistical experimental design. It was found, that equivalent products even by using different production methods can be received when qualified apparatuses and validated unit operations are used, e.g. measurement of power consumption during wet granulation; detection of end point of fluidized bed drying by difference of temperature between fluidized product and wet bulb temperature; control of loss of weighing by strain gauges or floor balance during tray drying

Preparation and in vitro evaluation of some aluminium antacids chewable tablets

Abstract: The in vitro antacid performance of dihydroxyaluminium sodium carbonate (DASC) powder was shown to be superior to that of dihydroxy aluminium aminoacetate (DAA) while aluminium hydroxide gave unsatisfactory results. Magnesium oxide improved the antacid effectiveness in all cases. Different formulations of DASC chewable tablets were prepared using various techniques for the inclusion of the binder. In general, the antacid properties of the tablets were quite good in presence of hydroxypropylmethylcellulose (HPMC) but the onset of action decreased somewhat when this binder was used in the form of a granulating solution. On the other hand, polyvinylpyrrolidone especially the higher molecular weight fraction (PVP K-90) had a detrimental effect on the performance of DASC when used intragranularly particularly as granulating solution

Effect of effervescent salt on the dissolution and bioavailability of drugs from capsules filled on a dosator-type capsule-filling machine

Abstract: The effect of various levels of effervercent salt on the release of fenoprofen calcium and ketoprofen from hard gelatin capsules prepared under three compression forces was studied. The disintegrants, explotab and avicel were also employed to prepare capsules under the same conditions for comparison. In case of effervescent salt, the maximum effectiveness was obtained at low compression pressure. The rate of drug release was markedly increased as the concentration of effeverscent salt increased

Influence of mixers on the characteristics of triamterene/hydrochlorothiazide directly compressed tablets

Abstract: The influence of high speed barrel type, twin shell V-shaped and three dimensional shaking mixers on the characteristics of directly compressible triamterenelhydrochlorothiazide (TRMI HCT) combination tablets was studied. The effect of number of mixer rotations on triamterene and hydrochlorothiazide content uniformity was studied and the properties of the produced tablets were compared. The high speed barrel type mixer was found to be the most favorable for the studied formula as the content uniformity of the drugs was achieved within the minimum time and number of rotations. The tablets produced had the highest crushing strength and the shortest disintegration time when compared to the other 2 mixers

Stabilitätsprüfung von Arzneimitteln : Zuordnung von Ländern zu Klimazonen

Abstract: In this paper is shown, haw a city or a country is classified into the correct climatic zone. In examples the factors to be considered when assigning countries to climatic zones are discussed. Finally tables of the climatic zones of countries for each continent, are listed

Controlled release phenylpropanolamine hydrochloride tablets using ethylcellulose-stearic acid matrix

Abstract: Controlled release phenylpropanolamine hydrochloride (PPA) tablets were prepared using different ratios of ethylcellulose-stearic acid matrix. The matrices were prepared by 3 different techniques. The medicated matrices containing 50% w/w drug, each alone was directly compressed into tablets for the study of drug dissolution from constant surface. Also, the medicated matrices, prepared by the solvent method were mixed with di-calcium phosphate and directly compressed into tablets. The prepared tablets were subjected to physical and release studies

Formulation of stabilized thiamine hydrochloride tablets

Abstract: A study has been carried out to examine the effect of storage conditions on the chemical of thiamine hydrochloride contained in three batches of multivitamin sugar-coated tablets. The study revealed the instability of this vitamin under the influence of storage condition. Prediction of instability was accomplished through an Arrhenius plot; the theoretically calculated values. A shelf life of 12.5 months was found for a brand with labeled shelf-like fo 12.5 months was found for a brand with labeled shelf-life of 3 years. Stabilized formulation of thimaine-containing tablets was suggested