Carrier Erythrocytes Research Articles

Co-encapsulation of a Drug with a Protein in Erythrocytes for Improved Drug Loading and Release: Phenytoin and Bovine Serum Albumin (BSA)

The aim of the present study was to use a novel protein co-encapsulation method to prepare phenytoin-loaded human erythrocytes with improved loading parameters and release profiles. Carrier erythrocytes were prepared using the hypotonic pre-swelling method. A series of in vitro characterization tests were carried out on the carrier cells, including loading parameters, drug and hemoglobin release, hematological indices, particle size analysis, osmotic fragility, turbulence fragility, and scanning electron microscopy (SEM). Co-encapsulation with bovine serum albumin (BSA) resulted in about 8-times higher drug loading in erythrocytes, with biphasic release trend instead of triphasic in the case of drug alone loading. In comparison to the normal unloaded cells, MCH and MCHC indices were decreased in the case of both drug and drug/protein loading, apparent cell sizes were unchanged, cell shapes were changed to spherical rather than biconcave discoid, and the osmotic as well as turbulence fragilities were higher in the case of drug/protein but were unchanged in the case of drug alone loading. The most profound finding of this study was the possibility of achieving remarkably higher drug loading and more controllable drug release profile in the case of drug/protein loading, with no unwanted in vitro characteristics change.

Characterization of Human Erythrocytes as Potential Carrier for Pravastatin: An In Vitro Study

Drug delivery systems including chemical, physical and biological agents that enhance the bioavailability, improve pharmacokinetics and reduce toxicities of the drugs. Carrier erythrocytes are one of the most promising biological drug delivery systems investigated in recent decades. The bioavailability of statin drugs is low due the effects of P-glycoprotein in the gastro-intestinal tract as well as the first-pass metabolism. Therefore in this work we study the effect of time, temperature as well as concentration on the loading of pravastatin in human erythrocytes to be using them as systemic sustained release delivery system for this drug. After the loading process is performed the carriers' erythrocytes were physically and cellulary characterized. Also, the in vitro release of pravastatin from carrier erythrocytes was studied over time interval. Our results revealed that, human erythrocytes have been successfully loaded with pravastatin using endocytosis method either at 25(o)C or at 37(o)C. The loaded amount at 10 mg/ml is 0.32 mg/0.1 ml and 0.69 mg/0.1 ml. Entrapment efficiency is 34% and 94% at 25(o)C and 37(o)C respectively at drug concentration 4 mg/ml. Moreover the percent of cells recovery is 87-93%. Hematological parameters and osmotic fragility behavior of pravastatin loaded erythrocytes were similar that of native erythrocytes. Scanning electron microscopy demonstrated that the pravastatin loaded cells has no change in the morphology. Pravastatin releasing from carrier cell was 83% after 23 hours in phosphate buffer saline and decreased to 72% by treatment of carrier cells with glutaraldehyde. The releasing pattern of the drug from loaded erythrocytes obeyed first order kinetics. It concluded that pravastatin is successfully entrapped into erythrocytes with acceptable loading parameters and moderate morphological changes, this suggesting that erythrocytes can be used as prolonged release for pravastatin.

Preparation and in-vitro characterization of tramadol-loaded carrier erythrocytes for long-term intravenous delivery

The hypo-osmotic dialysis method was used for preparation of tramadol-loaded human intact erythrocytes. In response to rapid drug escape from the erythrocytes, a membrane cross-linker, glutaraldehyde, was used successfully. The resulting carrier cells were validated in terms of the accuracy and precision of the whole drug loading procedure. The average loaded amount, entrapment efficiency and cell recovery were 1.9041 mg, 95.98% and 85.13%, respectively. The effects of different drug concentrations on loading parameters were studied with the concentration of 10 mg/ml selected as optimal. A series of in-vitro characteristics of carrier erythrocytes, including tramadol release behaviour, haematological indices, particle size distribution, scanning electron microscopy, and osmotic/turbulence fragilities were determined compared with the sham-entrapped and unloaded cells. The results of these in-vitro tests indicated that the erythrocytes did not undergo remarkable irreversible size and shape/topology changes, but the fragility of the membranes of the processed cells were increased. The collective results of this study showed that the optimized method of entrapment was suitable for the encapsulation of tramadol in erythrocytes with the final carrier cells ready to enter the in-vivo animal studies as a promising long-circulating carrier for tramadol.

Study of the factors influencing the encapsulation of zidovudine in rat erythrocytes

Antiretroviral-loaded erythrocytes offer a promising therapy against HIV owing to their potential to deliver this kind of drugs to macrophages and reticulo-endothelial (RES) tissues. The aim of the present work was to develop and optimize a hypotonic dialysis method for the encapsulation of the antiretroviral Zidovudine (AZT) in rat erythrocytes. The influence of several factors in the encapsulation was also evaluated. Variables such as the initial AZT concentration, the dialysis time, and the dialysis bag/buffer volume ratio exhibited statistically significant differences in the encapsulation of the drug in erythrocytes. The amount of drug encapsulated was related to the different values of the variables by multiple linear regression. Osmotic fragility and haematological parameters were estimated as indicators of erythrocyte viability. No statistically significant differences in the osmotic fragility profiles of the control and carrier erythrocytes were observed, and this parameter was also independent of the dialysis concentration of AZT, the hypo-osmotic dialysis time, and the dialysis bag/buffer volume ratio. The in vitro release of AZT from carrier erythrocytes pointed to a fast leakage of the drug; however, around 30% of the drug remained encapsulated for a prolonged period of time. Pre-dialysis diamide treatment did not have a significant effect on the encapsulation and release of AZT in erythrocytes.

Development of novel 5‐fluorouracil carrier erythrocyte with pharmacokinetics and potent antitumor activity in mice bearing malignant ascites

To investigate pharmacokinetics and potency of antitumor activity of a novel 5-fluorouracil carrier erythrocyte (RBC-FU) in mice bearing malignant ascites. RBC-FU was synthesized with a hyperosmotic technique. The entrapment efficiency of targeted carrier erythrocytes was determined by reverse dialysis method with high-performance liquid chromatography (HPLC) for analyzing the quantity of 5-fluorouracil (5-FU). After a H22 hepatocarcinoma malignant ascites model was established in Kunming mice, 5-FU encapsulated by carrier erythrocytes (for Group A) and 5-FU solution (for Group B) at 20 mg per kg were injected into the peritoneal cavity of the mice, respectively. Blood and ascites samples were collected at different times to detect 5-FU quantity by HPLC. Body weight and survival time of mice were recorded in Group A, B and the Control Group in which mice were injected with normal saline only. 5-FU was effectively encapsulated into erythrocytes, with an encapsulating effect as 55 +/- 0.50%. In Group A, the maximum concentration (Cmax) and the area under curve (AUC) in peritoneal exudates were significantly higher than those of Group B (P < 0.05). On the other hand, 5-FU level in serum was significantly lower than that in peritoneal exudates of Group A and B (P < 0.05). High drug levels in the abdominal cavity in Group A were maintained longer than those in Group B. Compared with that in Group B and the control, the quantity of malignant ascites in Group A had significant regression and the survival time was prolonged. The hyperosmotic method described here could be suitable for producing this novel RBC-FU as a liposomal drug of potential value for treating malignant ascites by intraperitoneal administration.

Increasing the selectivity of amikacin in rat peritoneal macrophages using carrier erythrocytes

The selectivity of amikacin in macrophages in vitro and its biodistribution in peritoneal macrophages and other tissues were studied in rats using carrier erythrocytes. Amikacin-loaded erythrocytes were prepared using a hypotonic dialysis method. The in vitro uptake of amikacin by peritoneal macrophages was studied using cell monolayers. The in vivo uptake by macrophages and the tissue distribution of amikacin were studied in two groups of rats that received either amikacin in saline solution, or amikacin-loaded erythrocytes. Pharmacokinetic analyses were performed using model-independent methods. The administration of the antibiotic using carrier erythrocytes elicited a higher accumulation in macrophages, both in vitro and in vivo. The tissue pharmacokinetics of amikacin in vivo using carrier erythrocytes revealed an accumulation of the antibiotic in specific tissues such as the liver and spleen. Minor changes in the pharmacokinetics were observed in organs and tissues such as renal cortex and medulla. According to the partition coefficients obtained, the relative uptake of amikacin when carrier erythrocytes were used was: spleen > peritoneal macrophages > liver > lung > renal cortex > renal medulla. Loaded erythrocytes can be seen to be potentially useful for the delivery of aminoglycoside antibiotics in macrophages.

Slow release properties and liver‐targeting characteristics of methotrexate erythrocyte carriers

To study the releasing properties and tissue-targeting characteristics of methotrexate-loaded red blood cells (MTX-RBCs), pharmacokinetics and tissue distributions of intravenous injected MTX-RBCs and free MTX were compared. MTX-RBCs were made from rat erythrocytes using a hypertonic method. After i.v. injection of MTX-RBCs or free MTX to rats, both plasma and tissue homogenate samples at each time-point were collected and analyzed by RP-HPLC. From this data, pharmacokinetic parameters and tissue distributions of MTX were obtained. MTX-RBCs were successfully produced by the hypertonic method. After i.v. injection, MTX-RBCs displayed more than three times longer half-life and MRT than free MTX, and the velocity of MTX clearance from plasma was much slower. The ratio of area under the concentration time curve (AUC)(tissue) to AUC(plasma) in the liver was clearly higher than that for other organs after MTX-RBCs administration; MRT in the liver was also longer. This study has demonstrated that the hypertonic method for making MTX-RBCs has led to a preparation with slow release properties as well as liver-targeting characteristics in rats. This approach offers considerable potential for the treatment of tumors in liver, which would merit further investigation.

EXPERIMENTAL BASIS OF CELL CARRIERS USING FOR DIRECTED TRANSPORT OF ANTIBIOTICS AND FLUOROQUINOLONE IN NON-OBSTRUCTIVE PYELONEPHRITIS

It was shown in investigations on rats that introduction of aminoglycoside antibiotics or fluoroquinolone, included into erythrocyte or leukocyte carriers in pyelonephritis, decreased amount of leukocyte accumulation centers in kidneys increased or normalized the level of enzymes in the organ, excretory function of kidneys, impaired immunometabolic parameters.

Thermo-fluidic devices and materials inspired from mass and energy transport phenomena in biological system

Mass and energy transport consists of one of the most significant physiological processes in nature, which guarantees many amazing biological phenomena and activities. Borrowing such idea, many state-of-the-art thermofluidic devices and materials such as artificial kidneys, carrier erythrocyte, blood substitutes and so on have been successfully invented. Besides, new emerging technologies are still being developed. This paper is dedicated to presenting a relatively complete review of the typical devices and materials in clinical use inspired by biological mass and energy transport mechanisms. Particularly, these artificial thermo-fluidic devices and materials will be categorized into organ transplantation, drug delivery, nutrient transport, micro operation, and power supply. Potential approaches for innovating conventional technologies were discussed, corresponding biological phenomena and physical mechanisms were interpreted, future promising mass-and-energytransport-based bionic devices were suggested, and prospects along this directionwere pointed out. It is expected that many artificial devices based on biological mass and energy transport principle will appear to better improve various fields related to human life in the near future.

In vitro studies of amikacin-loaded human carrier erythrocytes

Erythrocyte-encapsulated antibiotics have the potential to provide an effective therapy against intracellular pathogens. The advantages over the administration of free antibiotics include a lower systemic dose, decreased toxicity, a sustained delivery of the antibiotic at higher concentrations to the intracellular site of pathogen replication, and increased efficacy. In this study, the encapsulation of amikacin by human carrier erythrocytes prepared using a hypo-osmotic dialysis was investigated. The effects of the initial amikacin dialysis concentration and hypo-osmotic dialysis time on the encapsulation efficiency of amikacin were determined, and the osmotic fragility and hematologic parameters of amikacin-loaded carrier erythrocytes were measured. The efficiency of amikacin entrapment by carrier erythrocytes was dependent on the initial dialysis concentration of the drug. Statistically significant differences in the osmotic fragility profiles between control and carrier erythrocytes were observed, which were dependent on the hypo-osmotic dialysis time and on the dialysis concentration of amikacin. Mean hematologic parameters were evaluated and compared with unloaded, native erythrocytes; the mean corpuscular volume (MCV) of amikacin-loaded carrier erythrocytes was statistically significant smaller. Amikacin demonstrated a sustained release from loaded erythrocytes over a 48-h period, which suggests a potential use of the erythrocyte as a slow systemic-release system for antibiotics.

Detection of a Thalassemic α-Chain Variant (Hemoglobin Groene Hart) by Reversed-Phase Liquid Chromatography

Hemoglobin (Hb) Groene Hart [alpha119 (H2)Pro-->Ser (alpha1)], also known as Hb Bernalda, is a nondeletional alpha-thalassemic Hb variant that is frequent in southern Italy and North Africa. This variant is not supposed to be produced in the erythrocytes of carriers. The alpha-thalassemic behavior of this variant has been explained as an impaired interaction between the alpha-globin chain and the alpha-Hb-stabilizing protein. To separate globin chains, we developed a modified reversed-phase liquid chromatography (RPLC) procedure that uses acetonitrile-water solvents containing up to 3 mL/L trifluoroacetic acid. After RPLC, we characterized the isolated globin chains by electrospray ionization (ESI) mass spectrometry (MS) and analyzed their tryptic peptides with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS and nano-LC-ESI-MS/MS. RPLC detected an abnormal peak with a retention time substantially greater than that of the wild-type alpha(A)-globin chain. We identified this variant as Hb Groene Hart and found it in the hemolysates of 11 unrelated patients (1 homozygote, 9 heterozygotes, and 1 heterozygote associated with the -alpha(3.7) deletion). These patients possessed abnormal hematologic features suggesting an alpha-thalassemia phenotype. Molecular modeling suggested that the increase in hydrophobicity was due to opening of the GH interhelical segment following replacement of amino acid residue 119 with a nonhelix breaker residue. This method allows the detection of Hb variants at low concentrations, and adjusting the composition of the organic solvents enables the method to identify Hb variants with large changes in hydrophobicity.

Drug Loaded Erythrocytes: As Novel Drug Delivery System

Novel drug delivery systems are one of the widely used delivery systems. In the present scenario, amongst them, "Drug Loaded Erythrocytes" is one of the growing and potential systems for delivery of drugs and enzymes. Erythrocytes are biocompatible, biodegradable, possess long circulation half-life and can be loaded with variety of biologically active substances. Carrier erythrocytes are prepared by collecting blood sample from the organism of interest and separating erythrocytes from plasma. By using various physical and chemical methods the cells are broken and the drug is entrapped into the erythrocytes, finally they are resealed and the resultant carriers are then called "resealed erythrocytes". Surface modification with glutaraldehyde, antibodies, carbohydrates like sialic acid and biotinylation of loaded erythrocytes (biotinylated erythrocytes) is possible to improve their target specificity and to increase their circulation half-life. Upon reinjection the drug loaded erythrocytes serve as slow circulation depots, targets the drug to the reticuloendothelial system (RES), prevents degradation of loaded drug from inactivation by endogenous chemicals, attain steady state concentration of drug and decrease the side-effects of loaded drug. Nowadays, Nanoerythrosomes based drug delivery systems have excellent potential for clinical application.

Pharmacokinetics and biodistribution of amikacin encapsulated in carrier erythrocytes

To study the changes in the pharmacokinetics and tissue distribution of the aminoglycoside amikacin in rats using amikacin carrier erythrocytes as a delivery system. Amikacin-loaded erythrocytes were obtained using a hypotonic dialysis method. The pharmacokinetic and tissue distribution of amikacin were studied in three groups of rats receiving intravenous amikacin in saline solution, amikacin-loaded erythrocytes and amikacin-loaded erythrocytes treated with glutaraldehyde. Pharmacokinetic analysis was accomplished using model-independent methods. Administration of the antibiotic using carrier erythrocytes elicited a sustained release effect, with an increase in the plasma half-life and in the area under the curve of the antibiotic. The tissue pharmacokinetics of amikacin using carrier erythrocytes in comparison with a control group revealed an accumulation of the antibiotic in specific tissues such as the liver and spleen, a similar pharmacokinetics in the lung and moderate changes in the pharmacokinetics in the kidney. Studies of tissue concentrations after the injection of glutaraldehyde-treated loaded erythrocytes demonstrated important changes in organs of the reticulo-endothelial system (RES) in comparison with the results observed for standard carrier erythrocytes, higher levels being observed in the liver whereas spleen levels decreased. The administration of amikacin in loaded erythrocytes in rats leads to significant changes in the pharmacokinetic behaviour of the antibiotic, a greater accumulation being observed in RES organs such as liver and spleen. This shows that loaded erythrocytes are potentially useful for the delivery of antibiotics in phagocytic cells located in the RES.

A 9‐yr evaluation of carrier erythrocyte encapsulated adenosine deaminase (ADA) therapy in a patient with adult‐type ADA deficiency

Adenosine deaminase (ADA) deficiency is an inherited disorder which leads to elevated cellular levels of deoxyadenosine triphosphate (dATP) and systemic accumulation of its precursor, 2-deoxyadenosine. These metabolites impair lymphocyte function, and inactivate S-adenosylhomocysteine hydrolase (SAHH) respectively, leading to severe immunodeficiency. Enzyme replacement therapy with polyethylene glycol-conjugated ADA is available, but its efficacy is reduced by anti-ADA neutralising antibody formation. We report here carrier erythrocyte encapsulated native ADA therapy in an adult-type ADA deficient patient. Encapsulated enzyme is protected from antigenic responses and therapeutic activities are sustained. ADA-loaded autologous carrier erythrocytes were prepared using a hypo-osmotic dialysis procedure. Over a 9-yr period 225 treatment cycles were administered at 2-3 weekly intervals. Therapeutic efficacy was determined by monitoring immunological and metabolic parameters. After 9 yr of therapy, erythrocyte dATP concentration ranged between 24 and 44 micromol/L (diagnosis, 234) and SAHH activity between 1.69 and 2.29 nmol/h/mg haemoglobin (diagnosis, 0.34). Erythrocyte ADA activities were above the reference range of 40-100 nmol/h/mg haemoglobin (0 at diagnosis). Initial increases in absolute lymphocyte counts were not sustained; however, despite subnormal circulating CD20(+) cell numbers, serum immunoglobulin levels were normal. The patient tolerated the treatment well. The frequency of respiratory problems was reduced and the decline in the forced expiratory volume in 1 s and vital capacity reduced compared with the 4 yr preceding carrier erythrocyte therapy. Carrier erythrocyte-ADA therapy in an adult patient with ADA deficiency was shown to be metabolically and clinically effective.

Preparation and in vitro evaluation of carrier erythrocytes for RES-targeted delivery of interferon-alpha 2b

Carrier erythrocytes is one of the most promising systemic drug delivery systems investigated in recent decades. In this study, human erythrocytes have been loaded with interferon-α 2b (IFN) with the aim to benefit the reticuloendothelial system (RES) targeting potential of the carrier cells. Hypotonic preswelling method was used for drug loading in erythrocytes and the entire loading procedure was evaluated and validated. The loaded amount, entrapment efficiency and cell recovery of the loading procedure were 2906.33 ± 588.35 IU/0.1 ml, 14.53 ± 2.94%, and 83.61 ± 0.49%, respectively, all being practically feasible. The carrier erythrocytes were characterized in vitro in terms of their drug release kinetics, hematological indices, particle size distribution, SEM analysis, and osmotic and turbulence fragility. IFN release from carrier cells was a relatively rapid process in comparison to the cell lysis kinetics, which is unusual considering the whole body of data published on this delivery system and other protein drugs, so far. All the tested in vitro characteristics showed significant, sometimes notable changes upon drug loading procedure, both with and without the drug.

Preparation and in vitro characterization of carrier erythrocytes for vaccine delivery

Erythrocytes as the most readily available and abundant cells within the body, have been studied extensively for their potential application as drug delivery carriers. In this study, human erythrocytes have been loaded by bovine serum albumin (BSA) as a model antigen/protein using hypotonic preswelling method for targeted delivery of this antigen to antigen-presenting cells (APCs). A series of in vitro tests have been carried out to characterize the carrier cells in vitro, including loading parameters, BSA and hemoglobin release kinetics, hematological indices, particle size distribution, SEM analysis, osmotic and turbulence fragility, and osmotic competency. BSA was loaded in erythrocytes with a loaded amount of 1.98 ± 0.009 mg with antigen release from carrier cells showing a zero-order kinetic consistent to that of the cell lysis. The apparent cell sizes, measured using laser scattering, were not significantly different from normal erythrocytes, but the real sizes, measured using SEM, and surface topologies were quite different between loaded and unloaded cells. The BSA-loaded cells were remarkably more fragile and less deformable compared to the normal cells. Totally, BSA-loaded erythrocytes seem to be a promising delivery system for reticuloendothelial system (RES) targeting of the antigens.

Magnetite-Loaded Carrier Erythrocytes as Contrast Agents for Magnetic Resonance Imaging

Superparamagnetic iron oxide nanoparticles (SPIONs) are commonly used in magnetic resonance imaging (MRI), but their fast phagocytosis makes them less than ideal for this application. To circumvent the lymphocyte-macrophage system, we encapsulated SPIONs into red blood cells (RBCs). For loading, the RBC's membrane was opened by swelling under hypoosmotic conditions and subsequently resealed. In this work, we demonstrate that SPIONs can be loaded into RBCs in a concentration sufficient to obtain strong contrast enhancement in MRI.

The mouse immune response to carrier erythrocyte entrapped antigens

This study investigated the potential of a single administration of carrier erythrocyte entrapped antigen to elicit humoral responses in the Balb/c mouse. Humoral responses to primary immunizations of erythrocyte encapsulated antigens were compared with those obtained with adjuvanted antigen administered via the subcutaneous route. Ig isotype responses to primary immunizations of erythrocyte entrapped antigen and subcutaneous antigen were compared to responses observed in mice that subsequently received booster immunizations with un-entrapped antigen. This study demonstrates that a single administration of antigen-loaded carrier erythrocytes is able to elicit humoral immune responses comparable or superior to those obtained via the adjuvanted subcutaneous vaccination route. The IgG isotype profiles demonstrate that the erythrocyte entrapment of antigens is another mechanism by which the Th responses to antigens maybe modulated.

Detoxification of formate by formate dehydrogenase-loaded erythrocytes and carbicarb in folate-deficient methanol-intoxicated rats

Background Formic acid is a toxic metabolite responsible for the metabolic acidosis in methanol poisoning. Formate dehydrogenase (EC 1.2.1.2) converts formate into CO 2 in the presence of NAD. We examined the in vitro and in vivo efficiency of formate dehydrogenase-loaded carrier erythrocytes along with carbicarb in eliminating the formate in methanol-intoxicated folate-deficient rats. Method Formate dehydrogenase-loaded erythrocytes were prepared by hypotonic dialysis method. Carbicarb (carb) (equimolar solution of sodium carbonate and sodium bicarbonate) was used to treat metabolic acidosis. Folate depletion was induced by methotrexate (MTX) treatment. Experimental design consisted of 8 groups: saline control, methanol control, MTX control, ELE control, MTX–methanol control, MTX–methanol–carb, MTX–methanol–carb–ELE, and MTX–MeOH–ELE group. Male Wistar rats treated with MTX (0.3 mg/kg) for a week were injected (i.p.) with methanol (4 g/kg). Twelve hours later, the carbicarb solution was infused, and then a formate dehydrogenase-loaded erythrocytes suspension (40% hematocrit) was infused (i.v.) in bolus. Blood samples were collected every hour for 4 h from the cannulated left jugular vein. Blood methanol and formate were estimated respectively with HPLC and fluorimetric assay. Blood pH, blood pO 2, pCO 2 and bicarbonate were also measured. Results There was marked elimination of formate in selected groups. Conclusion Formate dehydrogenase-loaded erythrocytes, along with carbicarb, facilitates removal of formate, in methanol poisoning.

Encapsulation and In Vitro Evaluation of Amikacin-Loaded Erythrocytes

The aim of our present work was to establish the effect of the osmolality of the hypotonic buffer on the encapsulated amount and the in vitro properties of Amikacin-loaded erythrocytes. Amikacin was encapsulated in rat erythrocytes using a hypotonic dialysis method with hypotonic buffers of different osmolalities with mean values around 90 and 150 mOsm/kg. Morphological examination of the ghost erythrocytes was accomplished using scanning electron microscopy (SEM). The osmotic fragility of normal and loaded erythrocytes was tested using hypotonic solutions. Evaluation of the hematological parameters of the control and loaded erythrocytes was carried out using a hematology system analyzer. Amikacin release from loaded erythrocytes was tested in autologous plasma at 37°C over a 24-h period. The quantification of Amikacin in loaded erythrocytes and in autologous plasma was performed using an HPLC technique. A higher osmotic fragility of loaded erythrocytes was observed using a low osmolality buffer. Some hematological parameters showed statistically significant differences between the loaded erythrocytes obtained using two buffers of different osmolalities with respect to untreated erythrocytes. According to our results, Amikacin carrier erythrocytes obtained by hypotonic dialysis using a low osmolality buffer (90 mOsm/kg) should afford a good encapsulation yield, appropriate morphological properties, and sustained release in vitro.