China Science » Health Sciences

Fluid bed drying of guarana ( Paullinia cupana HBK) extract: Effect of process factors on caffeine content

admin — Mon, 02 Feb 2009 14:26:52 +0000

The aim of this study was to study the convective drying of the hydroalcoholic extracts obtained from powdered guarana seeds in a spouted bed dryer. The influence of process variables, such as the convective airflow rate, extract feed rate,; air inlet temperature, on the quality of the dry extract was determined using the caffeine; moisture content for the process evaluation. The caffeine content in the alcoholic; dried extracts was determined by capillary gas chromatography. The experiments were performed following a 3[3] factorial design; the data analyzed by response surface. The analysis of dry extract showed that the air; extract feed rates did not significantly affect (25% level) the caffeine content, but that drying temperature is a major factor to consider when the extract is submitted to fluid bed drying. Caffeine losses were significant (1% level) for drying temperatures above 120�C, while moisture content was lower than 3% for temperatures above 120�C. The data showed that there is an optimum temperature for the drying of guarana extracts in spouted beds,; under the conditions used in this study it was 120�C.

Renata S. Pagliarussi1?Jairo K. Bastos1?Luis A. P. Freitas1Email:lapdfrei@usp.br
[1] Faculdade de Ci�ncias Farmac�uticas de Ribeiro Preto, Universidade de So Paulo, Via do Caf� s/n, 14040-903 Ribeiro Preto, So Paulo, Brazil

A mucoadhesive in situ gel delivery system for paclitaxel

admin — Mon, 02 Feb 2009 14:25:46 +0000

MUC1 gene encodes a transmembrane mucin glycoprotein that is overexpressed in human breast cancer; colon cancer. The objective of this study was to develop an in situ gel delivery system containing paclitaxel (PTX); mucoadhesives for sustained; targeted delivery of anticancer drugs. The delivery system consisted of chitosan; glyceryl monooleate (GMO) in 0.33M citric acid containing PTX. The in vitro release of PTX from the gel was performed in presence; absence of Tween 80 at drug loads of 0.18%, 0.30%,; 0.54% (wt/wt), in Sorensen�s phosphate buffer (pH 7.4) at 37�C. Different mucin-producing cell lines (Calu-3

Saurabh Jauhari1?Alekha K. Dash1Email:adash@creighton.edu
[1] School of Pharmacy & Health Professions, Creighton University Medical Center, 2500 California Plaza, Omaha, NE

Dissolution improvement of high drug-loaded solid dispersion

admin — Mon, 02 Feb 2009 14:24:16 +0000

This study focused on an investigation of a high drug-loaded solid dispersion system consisting of drug, carrier,; surfactant. Solid dispersions of a water-insoluble ofloxacin (OFX) with polyethylene glycol (PEG) of different molecular weights, namely binary solid dispersion systems, were prepared at drug to carrier not less than 5?5. Polysorbate 80, a nonionic surfactant, was incorporated into the binary solid dispersion systems as the third component to obtain the ternary solid dispersion systems. The powder x-ray diffraction; differential scanning calorimetric studies indicated that crystalline OFX existed in the solid dispersions with high drug loading. However, a decreased crystallinity of the solid dispersions obtained revealed that a portion of OFX was in an amorphous state. The results indicated a remarkably improved dissolution of drug from the ternary solid dispersion systems when compared with the binary solid dispersion systems. This was because of polysorbate 80, which improved wettability; solubilized the non-molecularly dispersed or crystalline fraction of OFX.

Siriporn Okonogi1Email:sirioko@chiangmai.ac.th?Satit Puttipipatkhachorn2
[1] Faculty of Pharmacy, Dept. of Pharmaceutical Sciences, Chiang Mai University, 50200 Chiang Mai, Thailand ;[2] Faculty of Pharmacy, Dept. of Manufacturing Pharmacy, Mahidol University, 10400 Bangkok, Thailand

Studies on effect of pH on cross-linking of chitosan with sodium tripolyphosphate: A technical note

admin — Mon, 02 Feb 2009 13:11:06 +0000

Conclusions The ionotropic gelation method for formation of crosslinked chitosan particles can be easily modified from ionic cross-linking to deprotonation by adjusting the pH of TPP. Chitosan was cross-linked ionically with TPP at lower pH; by deprotonation mechanism at higher pH. The swelling behavior of cross-linked chitosan appeared to depend on the pH of TPP. The ionically cross-linked chitosan showed higher swelling ability. Thus the nature of crosslinked chitosan can be tailor made to obtain the desired properties in terms of cross-linking density, crystallinity,; hydrophilicity.

Devika R. Bhumkar1?Varsha B. Pokharkar1Email:vbpokharkar@yahoo.co.in
[1] Department of Pharmaceutics, Poona College of Pharmacy, Bharati Vidyapeeth Deemed University, Erandwane, 411038 Pune, Maharashtra State, India

Commerical reference shape standards use in the study of particle shape effect on laser diffraction particle size analysis

admin — Mon, 02 Feb 2009 13:10:01 +0000

The purpose of this paper is to describe the use of LGC Promochem AEA 1001 to AEA 1003 monosized fiberanalog shape standards in the study of the effect of particle shape on laser diffraction (LD) particle size analysis (psa). The psa of the AEA standards was conducted using LD psa systems from Beckman Coulter, Horiba,; Malvern Instruments. Flow speed settings, sample refractive index values,; sample cell types were varied to examine the extent to which the shape effect on LD psa results is modified by these variables. The volume; number probability plots resulting from these measurements were each characterized by a spread in the particle size distribution that roughly extended from the breadth to the longest dimension of the particles. For most of the selected sample refractive index values, the volume probability plots were characterized by apparent bimodal distributions. The results, therefore, provide experimental verification of the conclusions from theoretical studies of LD psa system response to monosized elliptical particles in which this apparent bimodality was the predicted result in the case of flow-oriented particles. The data support the findings from previous studies conducted over the past 10 years that have called into question the verity of the tenets of,; therefore the value of the application of, the equivalent spherical volume diameter theory; the random particle orientation model to the interpretation of LD psa results from measurements made on nonspherical particles.

Richard N. Kelly2Email:RKelly@prdus.jnj.com?Jacqueline Kazanjian1
[1] Yves Rocher North America Inc, Exton, PA ;[2] Johnson & Johnson Pharmaceutical Research & Development, LLC, Room P-1029 McKean & Welsh Roads, 19477-0776 Spring House, PA

Spherical agglomeration of mefenamic acid; nabumetone to improve micromeritics; solubility: A technical note

admin — Mon, 02 Feb 2009 13:09:11 +0000

Conclusions Spherical agglomeration techniques were developed for improving the flow; compressibility characteristics of microcrystalline mefenamic acid; nabumetone. The process involved agglomerating microcrystals using agglomerating solvents. Temperature; speed of agitation were optimized to obtain spherical agglomerates in a desired range, which was found to be essential to enhance compressibility. Incorporation of polymer HPMC during agglomeration significantly enhanced the dissolution rate of mefenamic acid while incorporation of solubilizing agent lecithin improved the solubility of nabumetone. Thus, spherical agglomeration is an important technique for improving direct compressibility of pharmaceutical powders; is especially useful when the drug dosage is high.

Chelakara L. Viswanathan1Email:chelakara_viswanathan@yahoo.com?Sushrut K. Kulkarni1?Dhanashri R. Kolwankar1
[1] Bombay College of Pharmacy, Kalina, Santacruz ;[East], 400 098 Mumbai, India

Mathematical modeling of an aqueous film coating process in a Bohle Lab-Coater: Part 2: Application of the model

admin — Mon, 02 Feb 2009 13:06:42 +0000

For the prediction of the air; product temperatures, the product moisture,; the air humidity during a coating process in a Bohle Lab-Coater, a model was developed. The purpose of this work was to determine the limit moisture, the critical moisture,; the constant for the exchange rate between both zones; to use these values for other sets of experiments to test the model. The adaptation of the 3 parameters (limit moisture, critical moisture,; exchange rate constant), was done by calculation of the product temperature in both zones for several sets of parameters in order to minimize the sum of square deviation between the calculated; the measured product temperatures. This set of parameters was used to test the validity of the model. By applying the model, the product temperature could be predicted based on the product, process,; equipment-related parameters. Hence, the model can be used to theoretically investigate the influence of different process paramaters. The mean difference between the predicted,; measured product temperatures in the steady state is ?2 up to 3 K using the determined parameter set for the limit moisture, the critical moisture,; the exchange rate constant. The model is useful for the prediction of the air; product temperatures, the product moisture,; air humidity during a coating process in the Bohle Lab-Coater using round, biconvex tablets.

Susanne Page1?Karl-Heinrich Baumann2?Peter Kleinebudde3Email:Kleinebudde@uni-duesseldorf.de
[1] Institute of Pharmaceutics; Biopharmaceutics, Martin-Luther-University Halle-Wittenberg, Wolfgang-Langenbeck-Str 4, D-06120 Halle, Germany ;[2] Department of Engineering, Martin-Luther-University Halle-Wittenberg, Geusaer Str 132, D-06217 Merseburg, Germany ;[3] Institute of Pharmaceutics; Biopharmaceutics, Heinrich-Heine-University Duesseldorf, Universitaetsstr 1, 40627 D�sseldorf, Germany ;[4] Present address: F. Hoffmann-La Roche Ltd, Basel, Switzerland

Mathematical modeling of an aqueous film coating process in a Bohle Lab-Coater, Part 1: Development of the model

admin — Mon, 02 Feb 2009 13:05:48 +0000

The purpose of this study was to develop a model to predict (1) air; product temperatures, (2) product moisture,; (3) air humidity during an aqueous coating process using a Bohle Lab-Coater. Because of the geometrical properties; the airflow, the drum of the Bohle Lab-Coater can in principle be divided into 2 zones of equal size�the drying; the spraying zones. For each zone, 4 balance equations could be set up describing the change of the air humidity, the product moisture, the enthalpy of the air,; the enthalpy of the product in each zone. For this purpose, knowledge regarding heat; mass transfer; also the motion of the tablets in drums was used. Based on the considerations of the heat; mass transfer, a set of first-order coupled ordinary differential equations (ODEs) was developed. This set of ODEs can be solved numerically. In this part, the development of the model is described in detail, whereas the application of the model can be found in part 2.

Characterization of 5-fluorouracil microspheres for colonic delivery

admin — Mon, 02 Feb 2009 13:04:53 +0000

The purpose of this investigation was to prepare; evaluate the colon-specific microspheres of 5-fluorouracil for the treatment of colon cancer. Core microspheres of alginate were prepared by the modified emulsification method in liquid paraffin; by cross-linking with calcium chloride. The core microspheres were coated with Eudragit S-100 by the solvent evaporation technique to prevent drug release in the stomach; small intestine. The microspheres were characterized by shape, size, surface morphology, size distribution, incorporation efficiency,; in vitro drug release studies. The outer surfaces of the core; coated microspheres, which were spherical in shape, were rough; smooth, respectively. The size of the core microspheres ranged from 22 to 55 ?m,; the size of the coated microspheres ranged from 103 to 185 ?m. The core microspheres sustained the drug release for 10 hours. The release studies of coated microspheres were performed in a pH progression medium mimicking the conditions of the gastrointestinal tract. Release was sustained for up to 20 hours in formulations with core microspheres to a Eudragit S-100 coat ratio of 1?7,; there were no changes in the size, shape, drug content, differential scanning calorimetry thermogram,; in vitro drug release after storage at 40�C/75% relative humidity for 6 months.

Ziyaur Rahman1Email:ziyaur_rahman2@rediffmail.com?Kanchan Kohli1?Roop K. Khar1?Mushir Ali1?Naseem A. Charoo1?Areeg A. A. Shamsher1
[1] Department of Pharmaceutics, F/O Pharmacy, Hamdard University, 110063 New Delhi, India ;[2] D-615. Gali No 1, Chauhan Bangar, 110053 Delhi, India

Preparation; in vitro evaluation of polystyrene-coated diltiazem-resin complex by oil-in-water emulsion solvent evaporation method

admin — Mon, 02 Feb 2009 13:04:04 +0000

The purpose of this study was to examine the suitability of polystyrene-coated (PS-coated) microcapsules of drug-resin complex for achieving prolonged release of diltiazem-HCl, a highly water-soluble drug, in simulated gastric; intestinal fluid. The drug was bound to Indion 254, a cation-exchange resin,; the resulting resinate was microencapsulated with PS using an oil-in-water emulsion-solvent evaporation method. The effect of various formulation parameters on the characteristics of the microcapsules was studied. Mean diameter; encapsulation efficiency of the microcapsules rose with an increase in the concentration of emulsion stabilizer; the coat/core ratio, while the same characteristics tended to decrease with an increase in the volume of the organic disperse phase. The desorption of drug from the uncoated resinate was quite rapid; independent of the pH of the dissolution media. On the other hand, the drug release from the microcapsules was prolonged for different periods of time depending on the formulation parameters; was also found to be independent of the pH of the dissolution media. Both the encapsulation efficiency; the retardation of drug release were found to be dependent on the uniformity of coating, which in turn was influenced by the formulation parameters. Kinetic studies revealed that the desorption of drug from the resinate obeyed the typical particle diffusion process, whereas the drug release from the microencapsulated resinate followed the diffusion-controlled model in accordance with the Higuchi equation. PS appeared to be a suitable polymer to provide prolonged release of diltiazem independent of the pH of the dissolution media.

Arindam Halder1?Biswanath Sa1Email:biswanathsa2003@yahoo.com
[1] Centre for Advanced Research in Pharmaceutical Sciences, Department of Pharmaceutical Technology, Jadavpur University, 700 032 Kolkata, India