Search

The physically-chemically bounded water is an important parameter directly related to the gain of mechanical strength during the hydration of cements. In this work, quantitative determinations of the physically - chemically bounded water of two types of belite cements, called FABC-2-W and FABC-2-N, were carried out by means of thermogravimetry analyses during a period of 180 days of hydration. The hydrated products were characterized by X-ray diffraction and BET surface area. Important direct quantitative correlations were obtained between the combined water and technological characteristics of cements such as the compressive mechanical strength or the BET surface area. TG measurements for hydrated FABC-2-W and FABC-2-N cements were carried out in flowing nitrogen on a TGA/SDTA 851 (Mettler) in the temperature range from 25 to 1100°C with heating rate of 10 °C min-1 and nitrogen flow rate of 25 mL min-1. BET surface area was measured using nitrogen adsorption at 77 K, on an ASAP 2010 (Micromeritics).

The present research work compares the effect of microsphere preparation technique on micromeritics and release behaviors of theophylline microspheres. Microspheres were prepared by oil-in oil (O(1)/O(2)) emulsion solvent evaporation method (ESE) using different ratios of anhydrous theophylline to cellulose acetate butyrate (CAB). Cyclohexane was used as non-solvent to modify the ESE technique (MESE method) and the effect of non-solvent volume on properties of microspheres was investigated. The obtained microspheres were analyzed in terms of drug content, particle size and encapsulation efficiency. The morphology of microsphere was studied using scanning electron microscope. The solid state of microspheres, theophylline and CAB were investigated using X-ray, FT-IR and DSC. The drug content of microspheres prepared by MESE method was significantly lower (15.54% +/- 0.46) than microspheres prepared by ESE method (41.08 +/- 0.40%). The results showed that as the amount of cyclohexane was increased from 2 mL to 6 mL the drug content of microspheres was increased from 15.54% to 28.71%. Higher encapsulation efficiencies were obtained for microspheres prepared by ESE method (95.87%) in comparison with MESE method (64.71%). Mean particle size of microsphere prepared by ESE method was not remarkably affected by drug to polymer ratio, whereas in MSES method when the volume of cyclohexane was increased the mean particle size of microsphere was significantly decreased. The ratio of drug to polymer significantly changed the rate of drug release from microspheres and the highest drug release was obtained for the microsphere with high drug to polymer ratio. The amount of cyclohexane did not significantly change the drug release. Although, x-ray showed a small change in crystallinity of theophylline in microspheres, DSC results proved that theophylline in microspheres is in amorphous state. No major chemical interaction between the drug and polymer was reported during the encapsulation process.

In this paper, ketoprofen and ketoprofen lysinate were used as model drugs in order to investigate release profiles of poorly soluble and very soluble drug from sodium alginate beads manufactured by prilling. The effect of polymer concentration, viscosity, and drug/polymer ratio on bead micromeritics and drug release rate was studied. Ketoprofen and ketoprofen lysinate loaded alginate beads were obtained in a very narrow dimensional range when the Cross model was used to set prilling operative conditions. Size distribution of alginate beads in the hydrated state was strongly dependent on viscosity of drug/polymer solutions and frequency of the vibration. The release kinetics of the drugs showed that drug release rate was related with alginate concentration and solubility of the drug. Alginate solutions with concentration higher than 0.50% (w/w) were suitable to prepare ketoprofen gastro-resistant formulation, while for ketoprofen lysinate alginate, concentration should be increased to 1.50% (w/w) in order to retain the drug in gastric environment. Differential scanning calorimetry thermograms and Fourier transform infrared analyses of drug-loaded alginate beads indicated complex chemical interactions between carboxyl groups of the drug and polymer matrix in drug-loaded beads that contribute to the differences in release profile between ketoprofen and ketoprofen lysinate. Total release of the drugs in intestinal medium was dependent on the solubility of the drug and was achieved between 4 and 6 h.

Geopolymers are a new class of ceramic materials which are best understood as rigid inorganic, aluminosilicate, hydrated gels, charge-balanced by cations such as Na+1, K+1, or Cs+1. The ease and versatility of forming, together with the tailorability of their properties (e.g. nano-porosity) qualify geopolymers as promising candidates for a variety of applications such as filters, catalyst supports, light weight, thermal shock resistant refractory composites, thermal/environmental barrier coatings, as well as smart composites. The PIs group, supported by AFOSR (Grant no. FA 9550-06-1-0221) is working on tailoring the nano- and meso-porosity, and the microstructure of geopolymers and their composites. This grant was used to procure equipment to synthesize and characterize the nano- and meso-porous geopolymers, and study their evolution upon curing and conversion to ceramic phase. The instruments purchased included (a) Micromeritics ASAP 2020 equipped with chemisorption option and mass spectrometer, (b) TestEquity 1007H Temperature/Humidity Chamber, is deemed essential, (c) Union Process Model 01HD Attritor mill, and (d) Thinky Mixer ARE 250.

The wet granulation process still finds large applicability close to the modern pharmaceutical industry for the production of tablets, because it eliminates some of the main attributed problems of the direct compression: the segregation tendency and the low flow properties of the powders during the process. The present work evaluates and it compares through micromeritical studies and statistical analysis the flow characteristics of granulates destined to the development of tablets of hydrochlorothiazide 50 mg. Three binders were tested (paste of starch and the aqueous dispersions, prepared to cold, of pregelatinized starch and povidone). It was still evaluated the compatibility between the drug and the employed excipients, through termoanalytical studies (DSC), and the influence of the extra granular addition of the "superdisintegrant" crospovidone in the values of dissolution efficiency (%DE) of the obtained tablets. The obtained granulates presented good flow and compressibility properties, characterized by: values of compressibility index between 5 and 15; Hausner ratio less than 1,25 and angle of repose between 30 and 35º. The crospovidone addition did not increase the values of %ED of the developed formulations, in the experimental conditions employed, although it has reduced, in way a low significance, the disintegration times of the formulations. O processo de granulação úmida ainda encontra larga aplicabilidade junto à moderna indústria farmacêutica para a produção de comprimidos, pois elimina alguns dos principais problemas atribuídos à compressão direta: a tendência de segregação e as baixas propriedades de fluxo dos pós durante o processo. O presente trabalho avalia e compara através de estudos micromeríticos e análise estatística as características de fluxo de granulados destinados ao desenvolvimento de comprimidos de hidroclorotiazida 50 mg. Foram testados três aglutinantes (pasta de amido e as dispersões aquosas, preparadas a frio, de amido pré-gelatinizado e povidone). Avaliou-se ainda a compatibilidade entre o fármaco e os excipientes empregados, através de estudos termoanalíticos (DSC), e a influência da adição extragranular do superdesintegrante crospovidone nos valores de eficiência de dissolução (%ED) dos comprimidos obtidos. Os granulados obtidos apresentaram propriedades de fluxo e compressibilidade boas a excelentes, caracterizadas por: valores de índice de compressibilidade situados entre 5 e 15; proporções de Hausner inferiores a 1,25 e ângulos de repouso entre 30 e 35º. A adição de crospovidone não incrementou os valores de %ED das formulações desenvolvidas, nas condições experimentais empregadas, ainda que tenha reduzido, de forma pouco significativa, os tempos de desintegração das formulações.

The present commentary aims to review the modern and innovative strategies in particle engineering by the supercritical fluid technologies and it is principally concerned with the aspects of solid-state chemistry. Supercritical fluids based processes for particle production have been proved suitable for controlling solid-state, morphology and particle size of pharmaceuticals, in some cases on an industrial scale. Supercritical fluids should be considered in a prominent position in the development processes of drug products for the 21st century. In this respect, this innovative technology will help in meeting the more and more stringent requirements of regulatory authorities in terms of solid-state characterisation and purity, and environmental acceptability.

Fast-disintegration technologies have encountered increased interest from industries in the past decades. In order to orientate the formulators to the choice of the best disintegrating agent, the most common disintegrants were selected and their ability to quickly disintegrate direct compressed tablets was evaluated. For this study, a central composite design was used. The main factors included were the concentration of disintegrant (X1) and the compression force (X2). These factors were studied for tablets containing either Zeparox or Pearlitol 200 as soluble diluents and six different disintegrants: L-HPC LH11 and LH31, Lycatab PGS, Vivasol, Kollidon CL, and Explotab. Their micromeritics properties were previously determined. The response variables were disintegration time (Y1), tensile strength (Y2), and porosity (Y3). Whatever the diluent, the longest disintegration time is obtained with Vivasol as the disintegrant, while Kollidon CL leads to the shortest disintegration times. Exception for Lycatab PGS and L-HPC LH11, formulations with Pearlitol 200 disintegrate faster. Almost the same results are obtained with porosity: no relevant effect of disintegrant concentration is observed, since porosity is mainly correlated to the compression force. In particular, highest values are obtained with Zeparox as the diluent when compared to Pearlitol 200 and, as the type of disintegrant is concerned, no difference is observed. Tensile strength models have been all statistically validated and are all highly dependent on the compression force. Lycatab PGS concentration does not affect disintegration time, mainly increased by the increase of compression pressure. When Pearlitol 200 is used with Vivasol, disintegration time is more influenced by the disintegrant concentration than by the compression pressure, an increase in concentration leading to a significant and relevant increase of the disintegration time. With Zeparox, the interaction between the two controlled variables is more complex: there is no effect of compression force on the disintegration time for a small amount of disintegrant, but a significant increase for higher concentrations. With Kollidon CL, the main factor influencing the disintegration time is the compression force, rather than the disintegrant concentration. Increasing both the compression force and the disintegrant concentration leads to an increase of the disintegration time. For lower Kollidon CL percentages, the compression pressure increases dramatically the tablet disintegration. With the Explotab, whatever the increase of compression force, the disintegrant concentration leads to an increase of the disintegration time. According to Student's t-test, only the compression force significantly and strongly influences the disintegration time when Pearlitol 200 is used. A slight interaction and some trends nevertheless appear: above 150 MPa, increasing the disintegrant concentration leads to a shortened disintegration time, below this limit the opposite effect is observed.

Esse trabalho teve por objetivo estudar o efeito de uma eteramina sobre o potencial zeta dos minerais hematita e quartzo. As amostras utilizadas possuíam alto grau de pureza, com granulometria na faixa de 53 a 44m. O reagente utilizado foi um acetato de eteramina a 50% de grau de neutralização. Foi utilizada a célula eletroforética, Zeta potencial - Model 1202, fabricada pela Micromeritcs. Em uma primeira fase, determinou-se a curva de potencial zeta da hematita e do quartzo, condicionados somente com água destilada. O IEP da hematita ocorreu em valores de pH entre 6 e 8. Os valores de potencial zeta do quartzo foram negativos para todos os valores de pH (6 a 12). Nos ensaios utilizando soluções de amina, observou- se que o potencial zeta dos dois minerais tornou-se menos negativo em relação aos ensaios na ausência desse reagente e que essa diminuição, no caso do quartzo, foi bem mais acentuada que a da hematita. Observou-se a mudança de sinal de negativo para positivo do potencial zeta do quartzo entre o pH 9 e 10 para a dosagem de amina a 3,54x10-4M. The objective of this paper was to study the influence of eteramine on the zeta potential of hematite and quartz. Minerals with high purity degree, between 53 and 44 mm size distribution, and a 50% neutralization degree eteramine acetate were used. The tests were carried out on an eletroforetic cell, Zeta potential- model 1202 of Micromeritics. The pulp used had 12 % w/w solid. Initially, the zeta potential of both minerals were determined in distilled water (pH from 6 to 12). The hematite IEP occurred at pH values between 6 and 8 and the zp of quartz was negative for all pH studied. It was observed that the zeta potential of quartz became less negative in the presence of amine. At 3,54x10-4M eteramine concentration, it was observed that the zeta potential of quartz changes from a negative to a positive value at pH values between 9 and 10.

The present investigation described the influence of viscosity and drug: Polymer ratio on Hydrochlorothiazide release. Floating microspheres loaded with hydrochlorothiazide were prepared by Emulsion solvent evaporation method. The prepared microspheres were evaluated by micromeritics properties, in vitro drug release, floating ability and drug entrapment efficiency.

In this study UiO-66 and UiO-66-NH2 were synthesized by solvothermal method. The effect of preparation conditions on the quality of UiO-66-NH2 was studied. The obtained material has been characterized by x-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimatric analysis (TGA), scanning electron microscopy (SEM) and nitrogen physisorption measurements (BET). The CO2 and CH4 physisorption measurements were carried out using a high pressure volumetric analyzer (Micromeritics HPVA—100). The results showed that the UiO-66-NH2 of ball shape crystalline had been obtained and characterized by high surface area (BET) up to 876 m2 g−1, specific volume 0.379 cm3 g−1, pore radius 9.5 A and thermal stability up to 673 K, respectively. The experiments indicated that in comparison with UiO-66 the addition of NH2 is able to increase the CO2 and CH4 storage capacity at 1 bar and 303 K twice from 28.43 cm3 g−1 up to 52 cm3 g−1 and from 6.68 cm3 g−1 to 11.1 cm3 g−1, respectively.

Highly Refined Cellulose (HRC) used in this project was made from fibrous agricultural residues through a patented proprietary process. The structural properties of HRC are of great importance to its applications. The relationships between its structural and functional properties were studied in this research. The lignin, hemicellulose, and cellulose content of HRC were measured using thermogravity analysis. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to identify and characterize the chemical structure of HRC. A Micromeritics ASAP 2000 was used to analyze the morphology of HRC, and crystallinity ratio was obtained through X–ray diffraction. The raw material had hemicellulose content ranging from 25% to 35%, while HRC had less than 2% hemicellulose. Lignin content was reduced from 35% of raw materials to 22.3% of HRC. The DRIFTS of HRC indicated that the resultant HRC materials had a structure typical of cellulose. The water retention capacity (WRC) and oil retention capacity (ORC) of HRC were 23.5–40.0 g water per gram sample and 13.7–20.8 g oil per g sample. These values were greater than those for the raw materials. The Langmuir surface area, BET surface area, and pore diameter of HRC were 7 to 11 times, 4 to 7 times, and 1.2 to 1.5 times values for the raw materials, respectively. The linear correlation coefficients between WRC and BET surface area, and between WRC and Langmuir surface area, were 0.93 and 0.96, respectively. Crystallinity ratio (1.5–2.2) was negatively correlated with both BET surface area and Langmuir surface area. The linear correlation coefficient between crystallinity ratio and pore diameter was 0.84. This study provides basic understanding of the properties of HRC and information that can be used to design and control the manufacturing of HRC products.

Surface and deep-sea core sediments and two sets of standards were measured by three different techniques — Galai Cis-1 laser system, Coulter Counter TA II, and Micromeritics SediGraph 5000D — in order to compare the Galai results with the other two. The differences between the three types of measuring device turned out to be greater in sediments than in standards, and were attributed to the physical properties, shape, density and composition of the particles (complexity of the matrix). Comparison of moment statistics showed that the Galai determines coarser grain sizes than the Coulter and finer than the SediGraph, particularly as regards analysis of surface sediments. The relationships between Galai and SediGraph were estimated using analysis of variation/residuals within individual intervals. The analysis showed a higher variability of residuals for the coarser fractions (8–16 μm and 16–32 μm) with respect to the finer (2–4 μm and 4–8 μm) fractions. The

An evaluation of the sustained release (SR) properties of a polyacrylic acid polymer, Carbopol 971(CP 971) as matrix in the formulation of ciprofloxacin hydrochloride (CH) tablets was carried out. The CP 971 in concentrations of up to 40 % w/w were wet granulated using ethanol 95% v/v and the dried granules were evaluated for packing, densification and flow properties. The tablets were evaluated for hardness, friability, uniformity of weight and content of active ingredient. The formulations dissolution profiles were tested in 0.1 N Hydrochloric acid (0.1 N HCl, pH 1.3), simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.2) without enzymes. Results obtained showed significant retardation (p < 0.05) of ciprofloxacin release as the polymer concentration increased. Drug release was significantly different in the three media used with the release rate being faster in SGF than 0.1 N HCl and SIF. This can be attributed to the high solubility of the drug in acidic media. More than 50% of drug content was released within 4 h. Ciprofloxacin tablets containing 20 % w/w was adjudged the best formulation and drug release from the formulation was diffusion controlled (Fickian).

In this work, nitrofurantoin and amoxicillin trihydrate microcapsules were prepared by complex coacervation at pH 3.5 using carboxymethylcellulose-gelatin at a weight ratio of 3:7. Release rates were studied as a function of core:wall ratios of microcapsules. Dissolution tests of microcapsules and their tabletted microcapsules were studied in artificial gastric and intestinal media without enzyme using the USP XXII basket method. Release rates were examined kinetically and the ideal kinetic models were estimated for drug release. In addition, the micromeritics of these microcapsules were investigated. In order to standardize the drug powder and the microcapsule product for industrial application, the micromeritic properties of microcapsules were studied by determining their bulk volume and weight, tapping volume and weight, fluidity, angle of repose, weight deviation, particle size distribution, density and porosity. Hausner ratio and consolidation index were also calculated to understand flowability rates of microcapsules when tableting or filling into gelatin capsules. The results indicated that the nitrofurantoin microcapsules need appropriate glidant but the amoxicillin trihydrate microcapsules did not. Moreover, it was observed that the microencapsulation changed the micromeritic properties of the drugs significantly.

In this study a metal-organic framework (MOF-199) has been synthesized by solvent-thermal method. The conditions of preparation and activation processes have been investigated. The obtained material was characterized by methods of x-ray diffraction (XRD), infrared (IR) spectroscopy, thermogravimatric analysis (TGA) and scanning electron microscopy (SEM). The CO2 adsorption measurements were carried out on a high pressure volumetric analyzer (Micromeritics HPVA − 100). According to experimental results, Cu(NO3)23H2O has been shown to be the best copper(II) precursor for the synthesis of MOF-199 and N,N-dimethylformamide (DMF):C2H5OH:H2O with the ratio of 1:1:1 has been chosen as the most suitable solvent. The appropriate activation condition has been determined as follows: activate at 200 °C for 5 h and use CH3OH as the solvent to remove DMF. At the optimal conditions, an octahedral shape and three-dimensional (3D) structure of crystallite of MOF-199 was obtained. The synthesized MOF-199 expressed a high value of specific surface area (1448 m2 g−1 by Brunauer–Emmet–Teller (BET) method and 2028 m2 g−1 by Langmuir method) with Ta porous size of crystal of 11.8 A and specific volume of 0.693 cm3 g−1; it was still stable up to 332 °C and its CO2 storage capacity reached to 206.59 cm3 (STP) g−1 at 25.76 bar.

We have previously observed and reported a steep BET surface area dependence on adsorbate size for an Argonne Illinois No. 6 coal. During this quarter, the cyclopentane BET surface areas were determined for the entire set of Argonne coals and are presented in Table 1. All surface areas were determined on a Micromeritics stainless steel surface area instrument. The 5-point cyclopentane surface areas were measured at an adsorption temperature of 0{degrees}C, allowing 24 hours equilibration time for the first point and 6 hours equilibration time for each subsequent BET adsorption point.

Now fifteen years ago, Small and co-workers [1, 2], introduced Hydrodynamic Chromatography (HDC) as a simple method for the sizing of submicron particles. The particles are fractionated when flowing through a packed column of uniform impermeable beads and emerge in order of decreasing diameter. Noel et al. [4] and Mullins and Orr [3] reported a variant of the technique using a long open capillary tube which has been called Capillary Hydrodynamic Chromatography (CHDC). Recently Brough et al. [5] were able to expand the size range of CHDC down to particle diameters of 0.07 μm and showed that the technique is also able to achieve fractionation in organic solvents. In an attempt to obtain the same particle size analysis range with CHDC as with the recently commercialised HDC (Micromeritics), we investigated the CHDC performance in very small capillaries (0.1 and 0.15 mm). The emphasis of the study has been led on the nature and the concentration of the eluent composition. Indeed an effective reduction in capillary diameter can be obtained if one uses a commercial block copolymer as eluent material. Adsorption of the block copolymer both on the capillary wall and the particles gives rise to a sterical barrier which reduces further the effective capillary diameter and enhances the resolution of the column towards smaller particle sizes. In our view CHDC represents more possibilities in analysing real particle systems, i. e. dispersions with relatively high polymer or polyelectrolyte concentrations. For such systems classical HDC results mostly in the clogging of the column. A series of dispersions and emulsions in concentrated gelatine have been analysed and the P. S. are compared with the results obtained by LCS.

Recently Davidson and Collins conclusively demonstrated that poly (vinyl chloride) (PVC) latices shrink about 20% in the beam of the transmission electron microscope. Furthermore, they suggested that particles smaller than about 0.05 μm would not be seen at all. Since the measurement of PVC latex particle sizes below 0.2 μm and especially below 0.1 μm still represents a problem, a transmission electron microscope sample preparation technique employing vertical shadowing was developed. In this technique the latex particles are shadowed using gold-palladium at an angle of 90° to the surface of the grid. Even though the particle shrinks in the electron beam, the circular shadow will still represent the original size. Ten PVC latex samples in the range 0.05 to 1.0 μm were examined using this technique and the diameters were found to be in good agreement with those obtained by other methods. The methods chosen for comparison were as follows: fractional creaming, Joyce Loebl Disc Centrifuge, Micromeritics Sedigraph, optical arrays, and Coulter Counter. Care must be taken to recognize the effect of agglomeration if good agreement between various methods is to be obtained.

Samples were prepared usin, 0 the anion exchanger Dowex l-X4 (100-200 mesh) and a Millipore filter (0.45 pm). The chromatographic column was a Partisil 10 SCX column (25 cm x 4.6 mm I.D.) (packed by Reeve Angel, Clifton, N-J., U.S.A.). The HPLC equipment used was a Micromeritics 725 auto-injector, a Spectraphysics 740 pump, a Spectraphysics 8200 filterphotometer at either 254 or 280 nm and a Spectra-Physics system 1 integrator. The eluent was prepared by dissolving potassium citrate in demineralized water, bringin, 0 this solution to the desired pH with H,SO, and subsequently mixing it with methanol.

This report deals with basic studies concerned with the use of sieving as an accurate means of classifying granular pharmaceutical solids. Attention was focused on the effects of sieve shaker speed, initial load and particle size distribution of the granulation on the rate of particle size reduction and the cumulative per cent of material passing a sieve. The size and concentration of the smaller-than-mesh particles were shown to exert a profound influence on the equilibrium time of a sieve. Using a nest of sieves, an equilibrium time technique was developed to obtain the particle size distribution and permit calculation of various statistical parameters dependent on the observance of the log-normal law. An equilibrium time procedure such as developed here permits the quantitative classification of granular pharmaceutical solids by sieving, with a better assurance that separatio: has been achieved with the minimum of attrition.

Publisher Summary This chapter highlights the cation-exchange high-performance liquid chromatographic analysis of vitamin B 6 . This method is successfully applied to serum, brain, heart, lung, liver, pancreas, stomach, small intestine, kidney, adrenal gland, and bladder. A guard column (4.5 mm × 5 cm) is followed by a 4.6 mm × 30-cm column, both of which are slurry packed with Vydac 401TP-B cation-exchange material using a model 705 column packer from micromeritics. Newly packed columns must be conditioned by running the gradient program about 10 times. As one of the most common contaminants elutes close to pyridoxine, it is prudent to verify the purity of the solvents by occasionally running the gradient with no sample injected. The ultimate goal of the chromatographer is to find a satisfactory isocratic system; the variety of vitamin B 6 compounds combined with the complexity of biological samples makes it unlikely that an isocratic system will be satisfactory when information is needed on all the vitamers. One of the advantages of the complex gradient system considered is that it can easily be adjusted to changes in sample composition, column performance, or the selection of vitamers to be quantitated. The complete gradient for resolving all seven major metabolic forms of vitamin B 6 (pyridoxal, pyridoxal phosphate, pyridoxine, pyridoxine phosphate, pyridoxamine, pyridoxamine phosphate, and pyridoxic acid) is about 35 min.

The deposition of particles from turbulent gas streams due to thermal gradients was predicted using a simplified flow medel. In the medels particle concentration was assumed constant in the turbulent region. The particle deposition velocity was taken to be the radial velocity of thermal - repulsion in the laminar sublayer. Temperature gradients in the laminar sublayer were calculated for constant wall temperature using the Reynoldss analogy. The loss magnilude of suspended particles from loss due to thermal deposition is not generally greats and is most important for submicron particles. (auth)

The aim of this work was to find a drying procedure for moist sucralfate gel capable of producing dried sucralfate gel that retains the original gel properties of bioadhesion, rheology, and micromeritics. Spray-drying and microwave-drying procedures were employed. Mannitol was used as a gel-protective substance during the drying processes. The spray drying of moist sucralfate gel gave rise to a powder whose water suspensions showed significantly reduced viscosity. The bioadhesion of spray-dried sucralfate gel was strongly reduced by drying. When mannitol was used as a gel protector, the spray-dried sucralfate in part maintained the original bioadhesion of moist sucralfate gel. The preparation of a dried sucralfate gel retaining the bioadhesion characteristics, avoiding the use of mannitol, was made possible using the microwave-drying procedure. The microwave-dried product possesses a granular morphology suitable for direct compression because it is a free flowing and strongly coherent granular powder.

An evaluation of techniques for the size analysis of fine-grained sediments revealed that the Malvern Laser Sizer (E3600), Electrozone Particle Counter (Model 112), Micromeritics SediGraph (5000E), and hydrophotometer work well for the analysis of sorted silt. Differences in results may be attributed to the particle property being measured by each instrument. The Malvern Laser Sizer and Electrozone Particle Counter are sizing techniques; the hydrophotometer and SediGraph determine sedimentation diameter through particle settling. There was less agreement among these instruments for unsorted natural sediments containing greater than 15 percent clay by weight. Clay content of less than or equal to 8 percent does not appear to decrease the resolution of silt-sized particles.

Micromeritics. Technology of Fine Particles. J. M. Dalla Valle . 428 + xiv pp. Pitman Publishing Corp., N. Y. City, Chicago, 1943. Price. $8.50. THIS book deals with the measurement of size and the...