Glutaraldehyde Volume Research Articles

Evaluation of Ulcer Protective Activity of Morus alba L. Extract-Loaded Chitosan Microspheres in Ethanol-Induced Ulcer in Rat Model.

Due to an unhealthy lifestyle, gastric ulcers have become a very common disease these days. Moreover, the side effects linked with the prolonged use of conventional treatments have shifted the paradigm towards herbal therapies. The leaves of Morus alba L. (Family-Moraceae) have been traditionally used for a large number of metabolic diseases. In the present research, we focused on the development of chitosan microspheres using extracts of leaves of Morus alba L. and their evaluation for gastroprotective efficacy against ethanol-induced ulcers in experimental rats. The process of development of M. alba extract microsphere (MEM) is also optimized using the Box-Behnken design. The formulation was prepared at optimized conditions (chitosan concentration (1.66% w/w), volume of glutaraldehyde (4.69 mL), and stirrer rotation per minute, RPM, 854.8), and the percentage yield (Y1) of the resulted microspheres is ∼95% with an encapsulation efficiency (EE) of (Y2(rutin)) ∼86%, Y2(quercetin)) ∼85%, and particle size (Y3) of ∼40 µm. The MEM prepared at optimized conditions can also be characterized for various parameters to ensure the uniformity of parameters. Also, the drug release studies indicated that the percentage release of rutin and quercetin from MEM was enhanced as compared to M. alba extract (ME) alone. Furthermore, in vivo analysis of the antiulcer potential of pretreatment with ME and MEM (500 mg/kg p.o.) in rats indicated that mucosal lesions, gastric juice volume, and total acidity were significantly altered as compared to ethanol-treated animals. Histopathology of tissue sections also confirmed the protection of gastric mucosa on pretreatment with MEM at 500 mg/kg p.o. On the basis of these findings, we can conclude that prepared microspheres can be used to develop a sustained release formulation of extract for the management of gastric ulcers. However, additional research is needed to establish the specific mechanisms of M. alba's antiulcer efficacy.

The impact of glutaraldehyde on the characteristics of bovine hydroxyapatite-gelatin based bone scaffold as gentamicin delivery system.

Biomaterials are widely used as drug delivery systems targeting bone tissue, such as to treat bone infectious disease. However, the addition of drugs to biomaterials weakens their mechanical properties. Crosslinkers are compounds that improve the mechanical properties of biomaterials. This study aims to determine the effect of glutaraldehyde (GTA) as a crosslinker on the characteristics of bovine hydroxyapatite-gelatin-based bone scaffold with gentamicin as antibiotics (BHA-GEL-GEN-GTA). BHA-GEL-GEN-GTA scaffold with GTA solid content ranging from 0.1 to 1.4wt% was made by direct compression. The compressive strength test was carried out using autograph. Scaffold degradation test was carried out by dissolving the scaffolds in PBS. Scaffold toxicity was performed by MTT assay using BHK-21 fibroblast cells. There was a significant difference in the scaffolds' compressive strength due to differences in GTA volume. Scaffold crosslinked using GTA with solid content 0.1 and 0.2wt% in 2mL solution had higher compressive strength than those in 1mL solution. Furthermore, GTA with solid content 0.6, 1, 1.2, and 1.4wt% showed higher compressive strength than those without GTA. Degradation test results showed that GTA increased the percentage of weight loss and swelling of the scaffold. The scaffold exhibited a nontoxic profile in MTT assay. GTA with optimum solid content shows great compressive strength, stable swelling profile with low percentage of scaffold's weight loss, and is considered as nontoxic.

Effects of shell-thickness on the powder morphology, magnetic behavior and stability of the chitosan-coated Fe3O4 nanoparticles

Chitosan-coated Fe3O4 nanoparticles were prepared by coprecipitation followed by reaction with chitosan and different volumes of glutaraldehyde. Coating was modified by varying the volume of glutaraldehyde and reaction time. XRD pattern shows maxima compatible Fe3O4 structure. FTIR spectroscopía confirms the presence of chitosan, more evident in samples with higher chitosan content, as denoted by TGA. TEM images of samples with low glutaraldehyde content reveal particles coated with a homogeneous chitosan shell. Meanwhile, those prepared with high glutaraldehyde volume show nanoparticles dispersed in an organic matrix. Samples present almost superparamagnetic behavior with magnetization saturation values that are reduced as the content of organic matter increases. Regarding the stability of these samples in solution, the presence of a homogeneous coating improves the initial suspension, although it does not prevent its subsequent aggregation over time. However, this aggregation process is reduced for sample synthesized with 1mL of glutaraldehyde after 6h of reaction.

Preparation of Hydrogel Based on Pineapple Leaf Cellulose Microcrystalline (Ananas Comosus L. Merr) with Variation in Glutaraldehyde Volume

Serat alami daun nanas mengandung lignin, hemiselulosa, dan selulosa. Kandungan selulosa daun nanas sekitar 69,5% -71,5%.Mikrokristal turunan selulosadapat digunakan di bidang farmasi sebagai pengikat dalam formulasi pembuatan tablet.Tujuan penelitian untuk mengetahui daun nanas dapat menghasilkan mikrokristal,mikrokristaldapat digunakan pada pembuatan hidrogel dan untuk mengetahui variasi voume glutaraldehid yang dapat mempengaruhi hidrogel. Metode:Penelitian ekperimetal dimulai dengan didelignifikasi dengan NaOH 4%, direndam 1 jam dan dipanaskan, dicuci dengan akuades sampai pH netral dan dibleachingdengan NaOH 2,7%, asam asetat 7,9 %, NaOCl sampai putih, dipanaskan, diambil residu dan ditiriskan, direndam dengan HCl 1 N, kembali dipanaskan 2 jam, reesidudioven dan diblender sampai halus. Hidrogel selulosa dilarutkandalam NaOH 8,5% danditambahan glutaraldehid bebrbagai variasi volume. Mikrokiristal selulosa dan hidrogel dikarakterisasi visual, uji rasio swelling, FTIR, SEM dan XRD. Rendemen mikrokristal selulosa22 %, berwana putih, homogeny. Mikrokristal selulosa dan hidrogel mengandung gugus O-H (3800-2700 cm-1), C-H(3000-2850 cm-1) dan C-O (1300-800 cm-1).Mikrokristal selulosa dapat dibuat dari daun nanas, pembentukan hidrogel dipengaruhi variasi volume glutaradehid dan rasio swellingtertinggi dan terendah masing-masing 400% dan 12,5%

Nasal Mucoadhesive Microspheres of Lercanidipine with Improved Systemic Bioavailability and Antihypertensive Activity

The current study entails the design, development, and optimization of nasal mucoadhesive microspheres of lercanidipine with improved systemic bioavailability for the management of hypertension. Mucoadhesive microspheres of lercanidipine were prepared by solvent evaporation and polymerization method using bovine serum albumin (BSA) as the carrier and glutaraldehyde as the chelating agent. For screening the material and process variables, Taguchi design revealed the major influence of BSA concentration and glutaraldehyde volume as the critical factors for the preparation of microspheres. These factors were systematically optimized using Central Composite design to evaluate the particle size, entrapment efficiency, and in vitro drug release from the microspheres as the response variables. The optimized microspheres were prepared using 4.4% BSA and 0.25-mL glutaraldehyde, and stirring speed at 1500 rpm, which exhibited particle size of 34 μm, entrapment efficiency of 88.6%, Q6h of 94.67%, T60% of 3.2 h, and bioadhesion efficiency of 93.2%. In vivo pharmacokinetics in rabbits showed remarkable superiority of the optimized nasal microspheres (p < 0.001) with nearly eightfold improvement in the drug absorption parameters vis-a-vis the pure drug lercanidipine. Accelerated stability studies for 6 months demonstrated nearly similar drug release profiles at different time intervals, indicating the robustness of the optimized formulation. In a nutshell, the present studies resulted in the successful development of optimized lercanidipine microspheres for nasal delivery.

Characterization of Chitosan-Gelatin Blend Scaffolds

Vacuum freeze-drying was used to prepare chitosan-gelatin (CG) scaffolds from hydrogels, with glutaraldehyde (GA) used as a crosslinker. The effects of the changes in volume ratios of the 2 wt% CG and GA solutions on scaffold performance were studied. The ratio of chitosan to gelatin solution volumes, vr(C/G), was adjusted to 1/2 or 1/1, with the 0.25 wt% GA volume at 3, 6, or 8% of the CG/GA volume. Six groups of CG scaffolds were fabricated and the scaffolds performance compared. After the cells were incubated for 4 days, hematoxylin eosin (HE) staining was used to observe the spreading of human skin keratinocyte (HaCaT) cells on these scaffolds, with the MTT method also used to detect the cells proliferation. The inhibition zone method was used on cells cultures to determine the antibacterial properties of the scaffolds against S. aureus and E. coli. Scaffolds were also examined for degradation in lysozyme and their compression properties were tested after degradation. The results showed that the HaCaT cells grew well on these scaffolds and proliferated significantly, indicating that these scaffolds possessed good cytocompatibility. With increased chitosan volume, the antibacterial properties of the scaffolds against S. aureus increased, however, there was no significant change in the antibacterial properties toward E. coli. Increased volumes of chitosan and GA decreased the scaffolds degradation rates and improved the elastic compressive moduli of the scaffolds after degradation. The scaffolds in the vr(C/G) = 1/1, 8% GA group have potential application prospects in the field of skin regeneration.

Synthesis of fish gelatin nanoparticles and their application for the drug delivery based on response surface methodology

Fish gelatin nanoparticle is produced using Tilapia fish skin for the first time by the two-step desolvation method. Fish gelatin is chosen for producing gelatin nanoparticles because no experiment have been done in using fish gelatin and to counter the problem associated with the use of mammalian gelatin, such as bovine spongiform encephalopathy disease. The effects of several factors on the particle size such as pH, acetone concentration, glutaraldehyde volume, stirring speed and stirring time are evaluated. Optimum conditions for the formation of gelatin nanoparticles are obtained using response surface method. Fish gelatin nanoparticles with optimum size of can be produced using pH of 2.45, acetone percentage of 16% (vol%), glutaraldehyde , stirring speed of 600 rpm, and stirring time for 6 h. The thermogram and molecular interaction of fish gelatin and fish gelatin nanoparticles are characterized using DSC and FTIR. In vitro drug release kinetic is examined using 5-fluorouracil as the model drug. The entrapment efficiency of 5-fluouracil as model drug is determined to be 40%. Fish gelatin could be used as a good alternative drug carrier for mammalian gelatin.

Chitosan coated tungsten trioxide nanoparticles as a contrast agent for X-ray computed tomography

Recent advances have shown that inorganic nanoparticles (NPs) based on heavy elements are highly appropriate for X-ray computed tomography (CT). In this contribution, tungsten trioxide NPs are prepared by the electrical arc discharge (EAD) method in DI water. The effect of chitosan (CTS) and glutaraldehyde (GTA) as coating and cross-linking agent, respectively, on the hydrodynamic size and zeta potential of prepared tungsten trioxide NPs is investigated. It is found that zeta potential increases by increasing the amounts of CTS. Meanwhile, by increasing the volume of glutaraldehyde (GTA), the final particle size increases whereas the zeta potential deceases. Chitosan coated tungsten trioxide demonstrated no significant cytotoxicity at concentration up to 5mg/mL after 24h. Finally, the X-ray attenuation of prepared chitosan coated tungsten trioxide NPs are higher than Iohexol as the commercially available iodinated contrasting agent at the same concentrations.

Properties of Hydrophilic Chitosan/Polysulfone Nanofibrous Filtration Membrane

Electrospun nanofibrous membranes are useful water filtration materials due to their high interconnected porosity and tunable pore sizes, which cause very high permeability and selectivity. However, poor mechanical properties and easy fouling due to their extremely high surface area limit their applications. Therefore, it is desirable to enhance the mechanical properties and the hydrophilicity of such electrospun nanofibrous membranes. In this paper, electrospun polysulfone (PSF) nanofibrous membranes were treated with plasma. Crosslinked chitosan solution was then employed to pad the membranes. We studied the influence of the chitosan concentration and the volume of glutaraldehyde on the morphology, porosity structure, mechanical properties and hydrophilicity of electrospun polysulfone nanofibrous membranes. The results showed that the average pore size decreased from 4.5 μm to 2.68 μm, the breaking stress increased from 6.01±0.44 MPa to 9.25±0.45 MPa, and the water contact angle decreased from 130.8° to 0° in 30 s when chitosan was applied to the membranes. These changes occurred by padding due to the crosslinked chitosan solution. The results indicate that a significant improvement occurred in the mechanical properties; the highly hydrophobic PSF membrane was changed to a superhydrophilic one and the pore size was reduced. These results encouraged us to propose this material as a water filtration membrane with longer life span, lower fouling and higher rejection efficiency.

Preparation and evaluation of chitosan microspheres containing nicorandil

Objectives:The objective of present study was to develop chitosan-based sustained release nicorandil microspheres to reduce the dosing frequency.Materials and Methods:The nicorandil-loaded chitosan microspheres were formulated by emulsion crosslinking method. A 32 factorial design was employed to study the influence of drug: Polymer ratio and volume of glutaraldehyde (GA) on percentage entrapment efficiency, particle size, and % drug release at 8 h.Results:The entrapment efficiency was found to be 41.67 ± 1.43-77.33 ± 1.97% and particle size range 65.67 ± 2.08-146.67 ± 2.18 μm. The batch CH5 showed 79.11 ± 2.23 and 96.21 ± 2.41% drug release at 8 and 12 h, respectively.Conclusions:Drug: Polymer ratio and volume of GA had significant effect on % entrapment efficiency, particle size, and % drug release. From the scanning electron microscopy (SEM) study observed that microspheres were spherical and fairly smooth surface. Fickian diffusion was the mode of drug release from nicorandil-loaded chitosan microspheres formulations.

Preparation of berbamine loaded chitosan-agarose microspheres and in vitro release study

Berbamine loaded chitosan-agarose microspheres were prepared using a water-in-oil emulsion technique. Optimum preparing parameters were determined by orthogonal experiments as follows: ratio of berbamine to chitosan (w/w) is 1:10; percentage of emulsifier (span 80, v/v) is 6%; volume of glutaraldehyde is 2 mL; and reaction temperature is 70 oC. Under these optimal conditions, the encapsulation efficiency and loading capacity of microspheres are 84.57% and 8.44%, respectively. The swelling tests showed that the microspheres possessed higher swelling ratio at pH 7.4 than at pH 1.2. FTIR indicated that berbamine had been successfully loaded in the chitosan-agarose microspheres by physical entrapment. In vitro release studies showed that berbamine was released from microspheres in a significantly sustained fashion.

Design and development of gliclazide-loaded chitosan microparticles for oral sustained drug delivery: in-vitro/in-vivo evaluation

The objective of this study was to prepare gliclazide-chitosan microparticles with tripolyphosphate by ionic crosslinking. Chitosan microparticles were produced by emulsification and ionotropic gelation. The effects of process variables including chitosan concentration, pH of tripolyphosphate solution, glutaraldehyde volume and release modifier agent such as pectin added to the tripolyphosphate crosslinking solution were evaluated. The microparticles were examined with scanning electron microscopy, infrared spectroscopy and differential scanning colorimetry. The serum glucose lowering effect of gliclazide microparticles was studied in streptozotocin-diabetic rabbits compared with the effect of pure gliclazide powder and gliclazide commercial tablets. The particle sizes of tripolyphosphate-chitosan microparticles were over the range 675-887 µm and the loading efficiency of drug was greater than 94.0%. In-vivo testing of the gliclazide-chitosan microparticles in diabetic rabbits demonstrated a significant antidiabetic effect of gliclazide-chitosan microparticles after 8 h that lasted for 18 h compared with gliclazide powder, which produced a maximum hypoglycaemic effect after 4 h. The results suggests that gliclazide-chitosan microparticles are a valuable system for the sustained delivery of gliclazide.

Chitosan microspheres as a delivery system for nasal insufflation

The aim of the present study was to develop and characterize chitosan mucoadhesive microspheres for nasal delivery. The microspheres were prepared by emulsification-crosslinking method and evaluated for morphology, particle size, swelling index, in vitro mucoadhesion and delivery properties from Miat(®) nasal insufflator. The results showed that the microspheres were spherical in shape with smooth surfaces. The particle size of microspheres was found to be dependent on the concentration of the chitosan. The mean particle size was significantly increased when high concentration of chitosan was used. Aqueous to oil phase ratio, stirring rate and dioctyl sodium sulfosuccinate (DOSS) concentration also influenced the particle size distribution of the microspheres. It was found that, as stirring rate was increased, the size of the microspheres was decreased. The volume of glutaraldehyde and crosslinking time had very slight effect on particle size distribution. The % equilibrium water uptake of the microspheres was ranged from 124% to 232% and the mucoadhesive strength from 70.64±2.14 to 86.32±3.96%. The results of powder delivery from the device showed that, almost entire amount was delivered after three puffs. The images of the delivery sequences of microsphere powder clouds demonstrated that microspheres were delivered forming an elongated puff. The core of the clouds was homogeneous which can be expected to provide effective distribution pattern.

Formulation and Characterization of Hydralazine Hydrochloride Biodegraded Microspheres for Intramuscular Administration

Objective: To prepare and characterize Albumin microspheres of hydralazine hydrochloride for the treatment of hypertension. Methods: Albumin microspheres of antihypertensive drug hydralazine hydrochloride were prepared by emulsion cross-linking method by using glutaraldehyde as cross-linking agent. Drug and polymer compatibility was determined by Fourier-Transform Infrared spectroscopy. To determine the effect of polymer concentration and amount of glutaraldehyde, formulations were characterized for their entrapment efficiency, particle size, surface morphology and release behavior. In vivo study was carried out on hypertensive wistar rats. Key findings: Maximum percentage entrapment efficiency (%EE) was found to be 68.20±1.03 %. Laser particle size analyzer confirmed mean particle size in the range of 31.7 to 39.6μm. In vitro drug release studies showed a biphasic release pattern for all formulations with an initial burst effect followed by slow release for almost 24 hrs. Conclusion: In vivo study to determine antihypertensive effect of selected formulation strongly correlates with in vitro drug release behavior. The release behavior was significantly regulated by polymer concentration and volume of glutaraldehyde. The study revealed that hydralazine hydrochloride loaded albumin microspheres exhibited prolonged reduction of systolic and diastolic arterial pressure compared to hydralazine hydrochloride solution.

Design and development of gliclazide-loaded chitosan for oral sustained drug delivery: In vitro/in vivo evaluation

Gliclazide (GLZ)/Chitosan microparticles were prepared with tripolyphosphate (TPP) by ionic cross-linking. The particle sizes of TPP–chitosan microparticles were in the range 675–887 µm and the loading efficiencies of drug was more than 94.0%. Chitosan concentration, TPP solution pH and glutaraldehyde volume added to the TPP cross-linking solution had an effect on the drug release characteristics. The microparticles were examined with scanning electron microscopy and infrared spectroscopy. Furthermore, pectin can interact with cationic chitosan on the surface of these TPP/chitosan microparticles to form a polyelectrolyte complex film for the improvement of the drug sustained-release performances. In vivo testing of the GLZ–chitosan microparticles in diabetic albino rabbits demonstrated significant antidiabetic effect of GLZ/chitosan microparticles after 8 h which lasts for 18 h, compared with GLZ powder which produced maximum hypoglycaemic effect after 4 h, suggesting that GLZ/chitosan microparticles are a valuable system for the long-term delivery of GLZ.

Preparation and characterization of chitosan microparticles for oral sustained delivery of gliclazide: in vitro/in vivo evaluation

AbstractChitosan microparticles were prepared with tripolyphosphate (TPP) by ionic cross‐linking with gliclazide (GLZ) as a model drug. The particle sizes of TPP‐chitosan microparticles ranged from 675–887 µm with loading efficiencies of greater than 94%. Chitosan concentration, TPP solution pH, and glutaraldehyde volume solution added to the TPP cross‐linking solution affected drug release characteristics. Pectin interactions with cationic chitosan on the surface of TPP/chitosan microparticles led to the formation of polyelectrolyte complex films that improved drug sustained release performance. In vivo testing of the GLZ‐chitosan microparticles in diabetic albino rabbits demonstrated a significant antidiabetic effect of GLZ/chitosan microparticles after 8 h that lasts for 18 h compared with GLZ powder that produced a maximal hypoglycemic effect at 4 h, suggesting that GLZ/chitosan microparticles represent an improved system for the long‐term delivery of GLZ. Drug Dev Res 72: 235–246, 2011. © 2010 Wiley‐Liss, Inc.

Lacidipine encapsulated gastroretentive microspheres prepared by chemical denaturation for Pylorospasm

The purpose of this research work was to formulate and systematically evaluate in vitro performance of mucoadhesive microspheres of lacidipine for treatment of pylorospasm. Lacidipine microspheres containing chitosan were prepared by chemical denaturation using glutaraldehyde as a cross-linking agent. The microspheres were evaluated for physical characteristics such as particle size, particle shape and surface morphology by scanning electron microscopy, drug entrapment efficiency and in vitro mucoadhesion. Results of preliminary trials indicated that the polymer concentration, cross-linking agent and stirring speed had a noticeable effect on size and surface morphology. A central composite design was employed to study the effect of independent variables, polymer concentration (X1), volume of glutaraldehyde (X2), stirring speed (X3) and cross-linking time (X4) on dependent variables, drug entrapment efficiency and percentage mucoadhesion. The entrapment efficiency varied from 14–40.82% depending upon the polymer concentration, volume of cross-linker and stirring speed. All batches of microspheres exhibited good mucoadhesive property (73–83%) in the in vitro wash-off test. It was observed that polymer concentration and glutaraldehyde volume had a more significant effect on the dependent variables. Maximum entrapment (36.53%) and mucoadhesion (81.33%) was predicted at 3.5% chitosan, 3 ml glutaraldehyde, 3000 rpm stirring speed and 75 min cross-linking time under optimized process condition. The selected formulation showed controlled release for more than 6 h. The release followed Higuchi kinetics via a Fickian diffusion.

Formulation and evaluation of ketorolac tromethamine-loaded albumin microspheres for potential intramuscular administration

The objective of this work was to prepare and evaluate ketorolac tromethamine-loaded albumin microspheres using a factorial design. Albumin microspheres were prepared by emulsion cross-linking method. Selected formulations were characterized for their entrapment efficiency, particle size, surface morphology, and release behavior. Analysis of variance (ANOVA) for entrapment efficiency indicated that entrapment efficiency is best fitted to a response surface linear model. From the statistical analysis it was observed that as the drug:polymer (D:P) ratio and volume of glutaraldehyde increased, there was a significant increase in the encapsulation efficiency. Scanning electron microscopy of the microspheres revealed a spherical, nonporous and uniform appearance, with a smooth surface. Based on the entrapment efficiency and physical appearance, 9 formulations were selected for release study. The maximum particle size observed was below 40 microm. The release pattern was biphasic, characterized by an initial burst effect followed by a slow release. All selected microspheres, except those having less polymer proportion (D:P ratio is 1:1), exhibited a prolonged release for almost 24 hours. On comparing r (2) values for Higuchi and Peppas kinetic models, different batches of microspheres showed Fickian, non-Fickian, and diffusion kinetics. The release mechanism was regulated by D:P ratio and amount of cross-linking agent. From the experimental data obtained with respect to particle size and extent of drug release, it could be concluded that the prepared microspheres are useful for once-a-day intramuscular administration of ketorolac tromethamine.

Chapter 79 Enrichment of mRNA Encoding Flagellar Proteins

Publisher Summary In many cases, growth of cilia or flagella is accompanied by large increases in levels of translatable mRNAs encoding flagellar proteins and correspondingly large increases in synthesis of flagellar polypeptides. Thus, the process of cilium/flagellum formation provides the opportunity to study controls over the expression of a specific large set of structurally diverse yet functionally related genes encoding ciliary or flagellar proteins. It also provides an opportunity to isolate mRNA enriched in transcripts encoding flagellar proteins, thus permitting construction of cDNA libraries enriched for these sequences. This chapter discusses a basic protocol for stimulating wild-type Chlamydornonas cells by pH shock, collecting samples of fixed cells for flagellar length measurements, and collecting RNA samples enriched for flagellar mRNAs before and 15, 45, 90, and 120 minutes after stimulation. RNA samples prepared in this manner have been used for cDNA library preparation, Northern, and S1 nuclease protection analysis, and in vitro translation. At the end of this description, variations in the basic method are discussed. As some cells lose their flagella during concentration, allow cells to recover from concentration by gently stirring with a magnetic stirrer under illumination for 120 minutes. After recovery, fix a 100-μl aliquot of cells by pipetting them into a tube containing an equal volume of glutaraldehyde, for the later measurement of flagellar lengths in nonstimulated cells.

Scanning electron microscopy of normal and pathological human erythrocytes.

A few drops of human blood were fixed in a relatively large volume of glutaraldehyde of various concentrations. After dehydration in acetone the blood cells were dried on glass slides in a warm breeze, coated with carbon and gold and observed under the scanning electron microscope.1. The deformations of erythrocytes caused by the osmotic effect of the fixative were examined. Large differences in osmotic resistance were shown among individual cells especially in hypotonic fixation. Glutaraldehyde concentration of 1% (in a 0.1M phosphate buffer) was found to be optimal for the preservation of the natural shape of normal erythrocytes.2. After this fixation the normal erythrocytes were represented by smooth-surfaced biconcave disks occasionally mingled with uniconcave ones. Some erythrocytes showed one or several wart-like elevations in their cell surface. These are believed to correspond to the segresome-like appendage seen in the transmission electron microscopy of sectioned erythrocytes (MIYOSHI and MATSUKURA, 1969).3. As pathological materials, the erythrocytes in elliptocytosis, hereditary spherocytosis and aplastic anemia were observed and their morphological abnormalities were described. Small conic pits were found on the surface of the erythrocytes in spherocytosis.