THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

Polysaccharides-based nanoparticles as drug delivery systems

The zeta potential (ZP) of colloidal systems and nano-medicines, as well as their particle size exert a major effect on the various properties of nano-drug delivery systems. Not only the stability of dosage forms and their release rate are affected but also their circulation in the blood stream and absorption into body membranes are dramatically altered by ZP. In this paper the effect of ZP on the various properties of nano-medicines are reviewed. Furthermore, the ability of employing zeta potential to target drug delivery systems to, and drug release at specific sites of the body are discussed.

/pdf/effect-of-zeta-potential-on-the-properties-of-nano-drug-405o0h1ibp.pdf

Effect of Zeta Potential on the Properties of Nano-Drug Delivery Systems - A Review (Part 2)

Use of natural biopolymers for diversified applications in life sciences has several advantages, such as availability from replenishable agricultural or marine food resources, biocompatibility, biodegradability, therefore leading to ecological safety and the possibility of preparing a variety of chemically or enzymatically modified derivatives for specific end uses. Polysaccharides, as a class of natural macromolecules, have the tendency to be extremely bioactive, and are generally derived from agricultural feedstock or crustacean shell wastes. Cellulose, starch, pectin, etc. are the biopolymers derived from the former while chitin and chitosan are obtained from the latter. In terms of availability, chitin is next to cellulose, available to the extent of over 10 gigatons annually. The application potential of chitosan, a deacetylated derivative of chitin, is multidimensional, such as in food and nutrition, biotechnology, material science, drugs and pharmaceuticals, agriculture and environmental protection, and recently in gene therapy too. The net cationicity as well as the presence of multiple reactive functional groups in the molecule make chitosan a sought-after biomolecule. The latter offers scope for manipulation for preparing a broad spectrum of derivatives for specific end use applications in diversified areas. The biomedical and therapeutic significance of chitin/chitosan derivatives is a subject of significant concern to many all over the world. An attempt is made in this overview to consolidate some of the recent findings on the biorelated application potential of chitosan and its derivatives.

Chitin/chitosan: modifications and their unlimited application potential—an overview

Chitosan-starch composite film: preparation and characterization.

Chitosan-reinforced calcium pectinate (ChCP) gel beads were prepared by ionotropic gelation method. Theswelling of ChCP gel beads and release behavior of indomethacin from the beads were investigated and comparedwith conventional calcium pectinate (CP) gel beads. The factors, such as molecular weight of chitosan,concentration of chitosan, and release medium, which can have a significant effect on the swelling and releasebehaviors from the beads, were discussed in this study. The mechanical test showed that the ChCP beads haveslightly higher strength than that of CP beads. The swelling index of the ChCP beads in acidic medium was muchlower than that in neutral medium. The release of indomethacin from ChCP beads under conditions mimickingintestinal transit were evaluated in pH 7.4 Tris buffer. The acid pretreatment caused a faster drug release fromChCP beads. The less swelling in acidic medium and faster drug release of acid-pretreated ChCP beads may bedue to the dissolution of chitosan from the beads in acidic medium, as no fluorescence signal was seen at the shellof the beads. The results suggested that the acid, which essentially found in stomach, influenced the swelling andrelease behaviors of ChCP beads. Key Words: Chitosan; Pectin; Calcium pectinate; Beads; Drug release; Acid pretreatment

Effect of Acidic Medium on Swelling and Release Behaviors of Chitosan-Reinforced Calcium Pectinate Gel Beads

This work aimed at studying factors affecting preparations of chitosan microcapsules for colonic drug delivery. Chitosan microcores (CS, 45kDa, 87% degree of deacetylation) containing diclofenac sodium (DS) coated with Eudragit®S100 (ED) were prepared by a desolvation technique. Sodium sulfate was used as a desolvating agent and the drying process was freeze-drying. Factors affecting morphology, particle size and zeta potential of microcapsules were evaluated, i.e. weight ratio of DS:CS:ED, surfactant (polysorbate 80), anti-adherent (silicon dioxide), and the use of sonication or homogenization in preparation processes. The weight ratio of DS:CS:ED at 1:2:6 provided the smallest microcapsules of about 82.37±1.61 micrometer in diameter and they were in aggregated forms. Zeta potential of the microcapsules was around -25.74 +4.78 mV which indicated that the core particles of CS and DS with zeta potential of 42.14±1.74 mV were encapsulated by ED. Increasing the amount of CS and ED, the size of microcapsules was increased but the zeta potential was not affected. Adding of polysorbate 80 could not reduce the size of microcapsules, but silicon dioxide could reduce the size and aggregation of microcapsules. Finally, the use of sonication and homogenization were effective in reducing of the size of microcapsules to 53.45 +0.63 and 58.72+1.28 micrometers, respectively.

/pdf/factors-affecting-preparations-of-chitosan-microcapsules-for-3sfntg2318.pdf

Factors affecting preparations of chitosan microcapsules for colonic drug delivery

The aim of this study was to manufacture the ternary solid dispersions composed of nifedipine, Eudragit® E and adsorbent. Dissolution enhancement of nifedipine was also investigated. The inert solid carriers were added in the mixtures of nifedipine and Eudragit® E at varying ratios. The physicochemical properties of ternary systems, compared to physical mixtures, were analyzed using powder x-ray diffraction (PXRD) and differential scanning calorimetry (DSC). The dissolution of nifedipine from ternary systems was compared to the drug alone. The influence of drug:polymer: adsorbent ratio and type of adsorbent on the dissolution rate of the drug was also evaluated. The PXRD and DSC results of the systems with high amount of polymer showed that the drug was present in an amorphous form. On the other hand, the diffraction patterns and DSC thermograms of the physical mixtures revealed that to some extent the drug was present in a crystalline form. The results from this study demonstrated that an improvement in dissolution rate of nifedipine with Eudragit® E and adsorbents was obtained.

Manufacture of Ternary Solid Dispersions Composed of Nifedipine, Eudragit ® E and Adsorbent

The purpose of this research was to determine surface free energy and contact angle of hydrolyzed shellac by using sessile drop technique. It is a method for determination of contact angle by placing a drop of liquid on a substrate and the surface free energy is then calculated by using the Wus equation. The substrate in this study was the hydrolyzed shellac prepared by hydrolysis of the native shellac at various times; 0, 15, 30 and 45 min using 2.0 %w/w sodium hydroxide. Water, formamide and ethylene glycol were liquids used for the investigation of the contact angle and surface free energy. The effect of hydrolysis time tended to reduce the contact angle and increase in the total surface free energy and polar force of hydrolyzed shellac. The result could be due to the breaking of the ester bonds of shellac during the hydrolysis process causing the higher free carboxyl group giving the higher polar group indicating by higher polar force and surface free energy. Therefore, the contact angle and surface free energy detected by sessile drop technique could be of benefit for the determination of hydrolysis process.

Jurairat Nunthanid

Papers

Effect of Acidic Medium on Swelling and Release Behaviors of Chitosan-Reinforced Calcium Pectinate Gel Beads

Factors affecting preparations of chitosan microcapsules for colonic drug delivery

Manufacture of Ternary Solid Dispersions Composed of Nifedipine, Eudragit ® E and Adsorbent

Determination of Surface Free Energy and Contact Angle for Hydrolyzed Shellac

Factors affecting on the enhancement of mechanical properties of composite edible film based on shellac and gelatin.