Amount Of Excipients Research Articles

Effect of Crospovidone on the Physical Properties of Acetaminophen Tablets

AbstractAcetaminophen tablets containing minimum amount of excipients and varying amounts of cross linked polyvinyl pyrrolidone were prepared under accurately controlled conditions of compression speed and pressure. The disintegration time, dissolution rate, crushing force, friability as well as effect of temperature and humidity on these parameters during storage were determined. Increasing proportions of the cross linked polymer (1-10%) did not influence crushing force or friability but significantly decreased disintegration and dissolution time. Satishctory tablets with desired properties were obtained by incorporation of optimum quantity of crospovidone. Storage of acetaminophen tablets at room temperature and humidity for a period of 4 weeks did not alter any of the physical properties tested weekly. However the combined effect of elevated temperature and humidity on tablet properties, especially on the dissolution time was significant. The influence of incorporation of equal amounts of crospovidone ...

Shrinking and swelling properties of pellets containing microcrystalline cellulose and low substituted hydroxypropylcellulose: I. Shrinking properties

From a previous study it is known that pellets obtained from extrusion/spheronization containing microcrystalline cellulose (MCC) and/or low-substituted hydroxypropylcellulose (L-HPC) are able to shrink during drying. This phenomenon has important consequences for pellet properties. The pellet size is reduced while the shape remains constant. Densification during shrinking leads to a lower porosity. In the actual study, shrinking and swelling phenomena were analysed quantitatively. This paper (part I) describes the manufacturing of the pellets and their shrinking properties together with their porosities, friabilities and liquid saturations. The accompanying article (part II) investigates the swelling and dissolution properties of the resulting pellets. Drying methods are of great importance for the properties of resulting pellets. Parts of the same formulations were dried alternatively by fluid-bed, oven or freeze-drying techniques and analysed with the aid of image analysis. Additionally, image analysis of the wet pellets was performed before drying. Freeze-drying almost suppressed shrinking of pellets. The size distributions of freeze-dried pellets are comparable to those of wet (undried) pellets and their porosities are very high. Fluid-bed and oven drying led to identical shrinking phenomena. The influence of the presence of L-HPC in the formulation on the shrinking process was studied. The extent of shrinking is influenced by the amount of excipients which are able to absorb water, the water content of the extrudate and the manner of drying. Freeze-drying prevents shrinking.

Powdered solution technology: principles and mechanism.

The concept of powdered solutions can be used to formulate liquid medications in dry, nonadherent, free-flowing, and readily compressible powders. The technique is based on simple admixture of drug solution or liquid drug with selected carrier and coating materials. Improved drug release profiles are exhibited by such delivery systems even for poorly water-soluble drugs. Previous work using this method has rendered its industrial application impractical because of the unsatisfactory flow properties of the powder admixtures. This article presents a theoretical model based on the principles and mechanism of powdered solutions and introduces a new physical property of powders termed the flowable liquid-retention potential (phi value). Mathematical expressions are derived that can be used to calculate the optimum amount of excipients required to yield powder admixtures with acceptable flowability. The validity and applicability of these expressions have been verified experimentally using clofibrate and prednisolone as test materials. The proposed model is shown to be superior to previously reported studies in optimizing the amount of excipients needed to prepare powdered solutions with acceptable flow properties.

Preparation of directly compressible powders of a physical mixture and a complex of theophylline-phenobarbital using spray-drying

A directly compressible powder of the physical mixture and the complex of theophylline and phenobarbital was prepared directly from droplets using a spray-drying technique. Aqueous or ammonium hydroxide slurries of theophylline and phenobarbital, with colloidal silica or methylcellulose, were atomized by a centrifugal wheel atomizer into a drying chamber held at various temperatures. The products prepared from the aqueous slurry were physical mixtures of theophylline and phenobarbital with a small amount of the molecular complex. From the ammonium hydroxide slurry, the molecular complex containing a small amount of theophylline or phenobarbital was prepared. The parameters affecting the amount of the molecular complex contained in the resultant products were the amounts of excipients, i.e. colloidal silica or methylcellulose, and the composition ratio of theophylline to phenobarbital in the formulation used for spray-drying. Drying temperature also affected the amount of the molecular complex in the products

Evaluation of cyclodextrin polymer as an additive for furosemide tablet.

The effectiveness of cyclodextrin polymer as a disintegrating agent for directly compressed tablets containing furosemide, cyclodextrin polymer and microcrystalline cellulose was investigated. Regression analysis based on statistically designed experiments made it possible to determine how various tablet characteristics are affected by the amount of excipients. As a result of computer optimization an optimum formulation was obtained exhibiting high dissolution rate, sufficient dissolution stability, fast disintegration, high hardness immediately after preparation and adequate hardness after ageing.