Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Polysorbates”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34Linked to original sources
PubMed1973

Death and lysis of leptospirae when cultured in asbestos-filtered growth media.

Death and lysis of leptospirae, when cultured in asbestos-filtered bovine albumin polysorbate 80 media, was quantitated. The pathogens (virulent and avirulent) required 2 x 10(6) cells/ml to initiate growth in such media, whereas inocula of 2 to 20 cells/ml grew in control medium. Saprophytic leptospirae initiated growth from 2 cells/ml in asbestos-filtered medium as well as control medium. The adverse action of asbestos-filtered medium was not removed by storage of medium for 2 years at 25 C and was not diminished when such medium was frozen at -80 C. Washing with water, HCl and NaHCO(3)-NaCl, citric acid, and medium components did not remove the lytic activity associated with asbestos-filtered culture medium. Continuous subculture in asbestos-filtered medium was possible from large inocula; however, upon subsequent dilution and reinoculation into asbestos-filtered media, there was no evidence of acquired resistance, and all pathogens failed to grow.

Agglutination Tests↗
PubMed1999

Intranasal immunization with pneumococcal polysaccharide conjugate vaccines protects mice against invasive pneumococcal infections.

Host defenses against Streptococcus pneumoniae depend largely on opsonophagocytosis mediated by antibodies and complement. Since pneumococcus is a respiratory pathogen, mucosal immune responses may play a significant role in the defense against pneumococcal infections. Thus, mucosal vaccination may be an alternative approach to current immunization strategies, but effective adjuvants are required. Protein antigens induce significant mucosal immunoglobulin A (IgA) and systemic IgG responses when administered intranasally (i. n.) with the glyceride-polysorbate based adjuvant RhinoVax (RV) both in experimental animals and humans. The immunogenicity and efficacy of pneumococcal polysaccharide conjugate vaccines (PNC) of serotypes 1 and 3 was studied in mice after i.n. immunization with RV. Antibodies were measured in serum (IgM, IgG, and IgA) and saliva (IgA) and compared to antibody titers induced by parenteral immunization. The PNCs induced significant systemic IgG and IgA antibodies after i.n. immunization only when given with RV and, for serotype 1, serum IgG titers were comparable to titers induced by subcutaneous immunization. In addition, i.n. immunization with PNC-1 in RV elicited detectable mucosal IgA. These results demonstrate that RV is a potent mucosal adjuvant for polysaccharides conjugated to proteins. A majority of the PNC-1-immunized mice were protected against both bacteremia and pneumonia after i.n. challenge with a lethal dose of serotype 1 pneumococci, and protection correlated significantly with the serum IgG titers. Similarly, the survival of mice immunized i.n. with PNC-3 in RV was significantly prolonged. These results indicate that mucosal vaccination with PNC and adjuvants may be an alternative strategy for prevention against pneumococcal infections.

Administration, Intranasal↗
PubMedDate not supplied

Effects of isopropyl unoprostone ophthalmic solution on cultured rabbit corneal epithelial cells.

PURPOSE: To investigate the effects of isopropyl unoprostone (referred to as unoprostone) ophthalmic solution on the barrier function of cultured rabbit corneal epithelium grown on permeable supports. METHODS: Rabbit corneal epithelial cells cultured on collagen-coated filter inserts were administered one of the following for 30 min: unoprostone in vehicle solution (polysorbate 80), unoprostone in vehicle solution with a preservative (benzalkonium chloride), preservative only or vehicle only. For a control, no chemicals were added to the medium. After administration, the transepithelial electrical resistance (TER) measurement, a sensitive method by which to investigate the barrier function, and morphological observation using phase-contrast microscopy were performed before exposure and at 0.5, 1, 3, 6, 12, 24, 48 and 72 h after exposure. The transmission electron-microscopic observation was performed before and 72 h after exposure in all experimental conditions. RESULTS: The cells exposed to unoprostone with the preservative showed a significant decrease in the TER, although no morphological changes were observed. The corneal epithelial cells exposed to unoprostone without preservative, the vehicle only or the preservative only did not show any differences from the control group at any measurements. CONCLUSION: The corneal barrier function is damaged by a combined solution of unoprostone and preservative, but not by a single solution of unoprostone, in vitro.

Animals↗
PubMedDate not supplied

Biodegradation of absorbable sutures in body fluids and pH buffers.

OBJECTIVE: This study measures the influence of body fluids on the loss of tensile strength of absorbable sutures in vitro. METHODS: Nine synthetic absorbable sutures were incubated in different gastrointestinal fluids, as well as in blood and three buffers. Stretch tests were performed after days 0, 7, 14, and 21. RESULTS: Tensile strength varied from 18.5 to 32.8 N, and elasticity varied from 9.5 to 51% of the initial length. The influence of pH, blood, and gastric juice was negligible on all sutures except PDS II. Except for Monocryl, all sutures, especially Polysorb and Vicryl, lost tensile strength much faster in bile, jejunal and pancreatic juices than in the corresponding buffers. CONCLUSION: The biodegradation of sutures varies greatly in different body fluids independent of differences in pH.

Absorbable Implants↗
PubMed1980

Effect of cannabinoids on estrous cycle, ovulation and reproductive capacity of female A/J mice.

Virgin A/J female mice were intubated daily for 8 days (short term) or 70 days (long term) with 0, 1, 5, or 25 mg/kg delta 9-tetrahydrocannabinol (delta 9-THC) or 0, 3, 15, or 75 mg/kg crude marihuana extract (CME) in a sesame oil:polysorbate 80:saline vehicle. These dosages approximate light, moderate, and heavy human usage. Short-term exposure to CME has no significant effect on PMS-HCG-induced ovulation but appears to: (1) delay entry into proestrus at all dose levels; (2) depress serum progesterone during the luteal phase at the highest CME level used (75 mg/kg), and (3) inhibit female receptivity to males at least at the highest dosage. Long-term oral administration of CME or delta 9-thc had no significant effect on length of estrous cycles or mating (plug formation) but term pregnancies were reduced by 32 and 68% for medium and high dosages, respectively. After a 30-day recovery period, 80% of those females that failed to have successful pregnancies now became pregnant.

Animals↗
PubMed2004

Influence of the surface properties on nanoparticle-mediated transport of drugs to the brain.

Poly(alkyl cyanoacrylate) nanoparticles enable the delivery of a number of drugs, including doxorubicin, loperamide, tubocurarine, the NMDA receptor antagonist MRZ 2/576, and the peptides dalargin and kytorphin across the blood-brain barrier (BBB) after coating with surfactants. However, only the surfactants polysorbate (Tween) 20, 40, 60 and 80, and some poloxamers (Pluronic F 68) can induce this uptake. The mechanism for the delivery across the BBB most likely is endocytosis via the LDL receptor by the endothelial cells lining the brain blood capillaries after injection of the nanoparticles into the blood stream. This endocytotic uptake seems to be mediated by the adsorption of apolipoprotein B and/or E adsorption from the blood. Thus, the nanoparticles could mimic lipoprotein particles and act as "Trojan Horses." The drug, then, may be released either within these cells followed by passive diffusion into the brain or be transported into the brain by transcytosis.

Antineoplastic Agents↗
PubMedDate not supplied

Nanoparticle multilayers: surface modification of photosensitive drug microparticles for increased stability and in vitro bioavailability.

The results of this study report the novel use of electrostatic layer-by-layer nanoassembly of biocompatible nanoparticulate TiO2 multilayers to coat irregular nifedipine (NF) microcrystals to increase the photostability of the drug when exposed to simulated sunlight and to increase the dissolution rate and possibly the bioavailability of the drug after oral administration. The photostability of NF microcrystals (35 microm) coated with multiple bilayers of positively charged PDDA and negatively charged nanosized TiO2 particles (20-25 nm) was measured when exposed to an illuminance of 12 W/m2 corresponding to a light dose of 30 k lux or 25 W/m2 corresponding to light dose of 60 k lux. The dissolution rate of nifedipine from the coated microcrystals was measured in simulated gastric fluid containing 0.05% w/v polysorbate 80. Coating with one TiO2 layer increased the shelf life of nifedipine by 30 hours independent of the intensity of the light exposure. With an increase in the number of TiO2 layers; the photostability of the drug was enhanced even more. A TiO2 monolayer decreased the contact angle by 20 degrees for water and 33 degrees for the dissolution medium as compared with uncoated NF surfaces. This increase in wettability due to a decrease in contact angle increased the dissolution rate of nifedipine microcrystals coated with 1 PDDA/TiO2 bilayer 13-fold after 10 minutes, 5-fold after 1 hour, and 2-fold after 12 hours when compared to uncoated microcrystals. It is assumed that TiO2 increased the photostability because the nanoparticulate multilayers acts as a potential filter protecting the drug from damaging light rays reaching the drug crystals. The dissolution rate was increased because the hydrophilic TiO2 nanoparticles increased the aqueous wettability of the drug crystals thereby preventing aggregation in the dissolution medium. This ensured that the maximum drug surface area was exposed to the dissolution medium.

Biological Availability↗
PubMed2006

Insulin loaded eudragit L100 microspheres for oral delivery: preliminary in vitro studies.

Eudragit L100 microspheres were prepared using water-in-oil-in water (w/o/w) emulsion-solvent evaporation with polysorbate 20 as dispersing agent in the internal aqueous phase, and PVA/PVP as stabilizer in the external aqueous phase. Smaller internal and external aqueous phases provided higher drug encapsulation. The PVA-stabilized microspheres having maximum drug encapsulation (84.5 2.8%) released 7% insulin at pH 1.0 in 2 h. In phosphate buffer (pH 7.4), microspheres showed an initial burst release of 21% in 1 h with additional 35% release in the next 5 h. The smaller the volumes of internal and external aqueous phases, the lower the initial burst release. The release of drug from microspheres followed Higuchi kinetics. Scanning electron microscopy of PVA stabilized microspheres demonstrated spherical particles with smooth surface and laser diffractometry revealed a mean particle size (V(m)) of 59.11 30 m.

Administration, Oral↗
PubMed1996

Hypersensitivity reactions to etoposide.

OBJECTIVE: To report a hypersensitivity reaction to etoposide occurring in a patient after 2 months of drug therapy. CASE SUMMARY: A 20-year-old man with a diagnosis of testicular carcinoma was treated with bleomycin, etoposide, and cisplatin (BEP regimen). After dose 20 of etoposide, an exanthema was noted, which was attributed to etoposide. The patient had received 19 doses of etoposide during the previous 2 months without any sign of an allergic reaction. Rechallenging the patient with etoposide from another batch resulted in recurrence of the exanthema. DISCUSSION: Both etoposide and its excipient (polysorbate 80) are suspected of causing hypersensitivity reactions. Although the exact mechanism of the hypersensitivity reaction is not known, it is believed to be of nonimmunogenic origin. CONCLUSIONS: With a lower rate of infusion of etoposide and/or by premedication with antihistamines and/or corticosteroids, hypersensitivity reactions to etoposide might be prevented in patients with a history of hypersensitivity to this drug.

Adult↗
PubMed2003

Epoetins: differences and their relevance to immunogenicity.

Recombinant human erythropoietin (epoetin) is a highly active molecule and as such is used at very low therapeutic concentrations that require stabilisation. Commercially available epoetins differ in the stabilisers used in their formulations, which result in variations between epoetin preparations in storage and handling requirements. The stability and solubility of the epoetins are also affected by differences in the carbohydrate moieties that exist between them. However, it is the difference in stabilising agents that is thought to be the major cause of the upsurge in pure red cell aplasia (PRCA) cases observed predominantly with one epoetin alfa formulation, Eprex (Johnson & Johnson). In 1998 the European formulation of Eprex was changed with the replacement of human serum albumin (HSA), by polysorbate 80 and glycine. This formulation change coincided with an increased incidence of PRCA. In contrast, the incidence of PRCA has remained low with other HSA-containing epoetin alfa products and with epoetin beta. Therefore, it appears that the change in Eprex formulation has resulted in reduced protein stability and increased immunogenicity.

Antibody Formation↗
PubMed2005

Insufficient neutralization in testing a chlorhexidine-containing ethanol-based hand rub can result in a false positive efficacy assessment.

BACKGROUND: Effective neutralization in testing hand hygiene preparations is considered to be a crucial element to ensure validity of the test results, especially with the difficulty to neutralize chlorhexidine gluconate. Aim of the study was to measure the effect of chemical neutralization under practical test conditions according to EN 1500. METHODS: We have investigated two ethanol-based hand rubs (product A, based on 61% ethanol and 1% chlorhexidine gluconate; product B, based on 85% ethanol). The efficacy of products (application of 3 ml for 30 s) was compared to 2-propanol 60% (v/v) (two 3 ml rubs of 30 s each) on hands artificially contaminated with Escherichia coli using a cross-over design with 15 volunteers. Pre-values were obtained by rubbing fingertips for 1 minute in liquid broth. Post-values were determined by sampling immediately after disinfection in liquid broth with and without neutralizers (0.5% lecithin, 4% polysorbate 20). RESULTS: The neutralizers were found to be effective and non-toxic. Without neutralization in the sampling fluid, the reference disinfection reduced the test bacteria by 3.7 log10, product B by 3.3 log10 and product A by 4.8 log10 (P = 0.001; ANOVA). With neutralization the reference disinfection reduced the test bacteria by 3.5 log10, product B by 3.3 log10 and product A by 2.7 log10 (P = 0.011; ANOVA). In comparison to the reference treatment Product B lead to a lower mean reduction than the reference disinfection but the difference was not significant (P > 0.1; Wilcoxon-Wilcox test). Without neutralizing agents in the sampling fluid, product A yielded a significantly higher reduction of test bacteria (4.8; P = 0.02) as compared to the situation with neutralizing agents (2.7; P = 0.033). CONCLUSION: The crucial step of neutralization lies in the sampling fluid itself in order to stop any residual bacteriostatic or bactericidal activity immediately after the application of the preparation, especially with chlorhexidine gluconate-containing preparations. This is particularly important at short application times such as the 30 s.

Chlorhexidine↗
PubMed1998

Paradoxical role of ascorbic acid and riboflavin in solutions of total parenteral nutrition: implication in photoinduced peroxide generation.

In the presence of light, a multivitamin preparation is the main source of peroxides in solutions of total parenteral nutrition (TPN). This preparation contains two photosensitive products, 5'-phosphate flavin mononucleotide (FMN) and polysorbates (PS), as well as electron donors such as ascorbate (AH). We hypothesized that the admixture of FMN or PS with electron donors generates peroxides in TPN and alters the quality of nutrients. Using xylenol orange, peroxide concentrations were measured in solutions containing AH, FMN, and/or PS in water, a dextrose solution, an amino acid preparation, and a lipid emulsion. Thiol functions were evaluated by reduction of 5,5-dithiobis(2-nitrobenzoic acid) in the amino acid preparation. After 24-h light exposure, dextrose solutions with admixtures of AH + FMN or AH + FMN + PS generated peroxides at concentrations similar to those observed in a 1% multivitamin solution, and over three times higher than those observed with FMN, PS, or AH alone. However, in the presence of amino acids, FMN alone induced a generation of peroxides comparable to that observed with FMN + AH. In the lipid emulsion, peroxides increased over 3-fold in the presence of FMN or FMN + AH. The addition of catalase suggested that lipid peroxides and H2O2 were produced, and the loss of thiol function suggested that an oxidation of amino acids occurred. When exposed to light, FMN induces reactions with amino acids, polyunsaturated fatty acids, and even AH, altering the quality of nutrients. Paradoxically, AH without FMN has a protective effect on peroxide generation in TPN.

Ascorbic Acid↗
PubMed2003

Optimizing the crystal size and habit of beta-sitosterol in suspension.

The aim of this work was to survey how processing parameters affect the crystal growth of beta-sitosterol in suspension. The process variables studied were the cooling temperature, stirring time and stirring rate during recrystallization. In addition, we investigated the effect a commonly used surfactant, polysorbate 80, has on crystal size distribution and the polymorphic form. This study describes the optimization of the crystallization process, with the object of preparing crystals as small as possible. Particle size distribution and habit were analyzed using optical microscopy, and the crystal structure was analyzed using X-ray diffractometry. The cooling temperature had a remarkable influence on the crystal size. Crystals with a median crystal length of approximately 23 microm were achieved with a low cooling temperature (<10 degrees C); however, a fairly large number of crystals over 50 microm appeared. Higher cooling temperatures (>30 degrees C) caused notable crystal growth both in length and width. Rapid (250 rpm), continuous stirring until the suspensions had cooled to room temperature created small, less than 50 micro m long (median <20 microm), needle-shaped crystals. The addition of surfactant slightly reduced the size of the initially large crystals. Both hemihydrate and monohydrate crystal forms occurred throughout, regardless of the processing parameters. By using an optimized process, it was possible to obtain a microcrystalline suspension, with a smooth texture.

Chemistry, Pharmaceutical↗
PubMed2005

Conceival, a novel noncontraceptive vaginal vehicle for lipophilic microbicides.

The objective of this study was to develop a nontoxic and noncontraceptive vaginal drug delivery vehicle for lipophilic anti-human immunodeficiency virus (HIV) microbicides. Three representative poorly water-soluble novel broad-spectrum anti-HIV microbicides, PHI-113, PHI-346, and PHI-443, were evaluated in 11 different solvent systems. Based on their solubility profiles, a novel nonspermicidal self-emulsifying gel (viz Conceival) composed of pharmaceutical excipients, sorbitol, polyethylene glycol 400, polysorbate 80, microcrystalline cellulose, xanthan gum, and water was optimized. Conceival enhanced the solubility of these poorly water-soluble (<0.001 mg/mL) anti-HIV drugs by at least 150- to 270-fold. Conceival was evaluated in vivo in the New Zealand white rabbit model for the preservation of sperm function based on pregnancy outcome and the potential for vaginal irritation following single and multiple intravaginal applications, respectively. Conceival administered intravaginally immediately prior to artificial insemination with semen had no adverse effects on subsequent reproductive performance, neonatal survival, or pup development when compared with untreated control group. Histologic evaluation of vaginal tissues of rabbits exposed intravaginally to Conceival for 14 consecutive days revealed lack of epithelial, submucosal, and vascular changes at the gel application site (total irritation score <3 out of a possible 16). These findings indicate that Conceival has potential to become a clinically useful, safe noncontraceptive vaginal vehicle for lipophilic microbicides.

Administration, Intravaginal↗
PubMed2005

Eudragit S100 entrapped insulin microspheres for oral delivery.

The purpose of this research was to investigate whether Eudragit S100 microspheres have the potential to serve as an oral carrier for peptide drugs like insulin. Microspheres were prepared using water-in oil-in water emulsion solvent evaporation technique with polysorbate 20 as a dispersing agent in the internal aqueous phase and polyvinyl alcohol (PVA)/polyvinyl pyrrolidone as a stabilizer in the external aqueous phase. The use of smaller internal aqueous-phase volume (50 microL) and external aqueous-phase volume (25 mL) containing PVA in the manufacturing process resulted in maximum encapsulation efficiency (81.8% +/- 0.9%). PVA-stabilized microspheres having maximum drug encapsulation released 2.5% insulin at pH 1.0 in 2 hours. In phosphate buffer (pH 7.4), microspheres showed an initial burst release of 22% in 1 hour with an additional 28% release in the next 5 hours. The smaller the volumes of internal and external aqueous phase, the lower the initial burst release. The release of drug from microspheres followed Higuchi kinetics. Scanning electron microscopy of PVA-stabilized microspheres demonstrated spherical particles with smooth surface, and laser diffractometry revealed a mean particle size of 32.51 +/- 20 microm. Oral administration of PVA stabilized microspheres in normal albino rabbits (equivalent to 6.6 IU insulin/kg of animal weight) demonstrated a 24% reduction in blood glucose level, with maximum plasma glucose reduction of 76 +/- 3.0% in 2 hours and effect continuing up to 6 hours. The area under the percentage glucose reduction-time curve was 93.75%. Thus, our results indicate that Eudragit S100 microspheres on oral administration can protect insulin from proteolytic degradation in the gastrointestinal tract and produce hypoglycemic effect.

Administration, Oral↗
PubMed2000

Recombinant factor VIII SQ--stability of VIII: C in homogenates from porcine, monkey and human subcutaneous tissue.

The aim of this paper was to investigate whether a formulation-based approach to understanding and addressing stability could generate a subcutaneous factor VIII preparation for patients as an alternative to the existing intravenous products. The low bioavailability of subcutaneously administered factor VIII could have several causes: proteolytic degradation of the protein in the interstitium; adsorption to tissue, in particular to acidic phospholipids such as L-alpha phosphatidyl-L-serine (phosphatidylserine); the absence of free von Willebrand factor in the interstitium; phagocytosis by macrophages in the interstitium or in the lymph nodes; and coagulation could be initiated upon injection. This study was undertaken to investigate the first three factors in-vitro (i.e., proteolytic degradation, adsorption to tissue and the protective effect of von Willebrand factor). The influence of some other macromolecular stabilisers and protease inhibitors was also investigated. The stability of factor VIII activity (VIII: C) was investigated in homogenates from porcine, monkey and human subcutaneous tissue. Possible coagulation was prevented in these studies by the presence of both citrate and antithrombin. An exploratory in-vivo study was performed in the pig; plasma samples were assayed with a factor VIII:Ag (90kDa) ELISA. The decrease in VIII:C appeared to be more pronounced in homogenates from monkey and human tissues than in porcine homogenate. The results from human tissue homogenate resembled the degradation profile seen in monkey homogenate. Both the von Willebrand factor and phosphatidylserine/phosphatidylcholine (PS/PC) liposomes showed a significant stabilising effect on VIII:C in the tissue homogenates. The qualitative pattern was similar in porcine, monkey and human tissue. A combination of several protease inhibitors seemed to have a protective effect on the stability of VIII: C albeit at high concentrations of inhibitors and the effect was less than that of PS/PC. An exploratory in-vivo study was performed in the pig with phosphatidylserine in two formulations; either in the form of PS/PC liposomes or together with Polysorbate 80 in the form of mixed micelles (phosphatidylserine/P80). Including phosphatidylserine in the formulations appeared to increase the availability, of subcutaneously administered r-VIII SQ in the pig. However, further studies are necessary, preferably in the monkey where in-vitro studies indicate a closer resemblance to the human. In conclusion, a proposed inactivation mechanism for r-VIII SQ in subcutaneous tissue could be adsorption to phospholipid surfaces followed by proteolytic degradation. However, additional studies are required due to the multitude of factors influencing the subcutaneous absorption route. A combination of protease inhibitor(s) together with phosphatidylserine-containing liposomes are suggested for further investigation, preferably in a monkey animal model.

Animals↗
PubMed2002

In-vitro release and oral bioactivity of insulin in diabetic rats using nanocapsules dispersed in biocompatible microemulsion.

This study evaluated the potential of poly(iso-butyl cyanoacrylate) (PBCA) nanocapsules dispersed in a biocompatible microemulsion to facilitate the absorption of insulin following intragastric administration to diabetic rats. Insulin-loaded PBCA nanocapsules were prepared in-situ in a biocompatible water-in-oil microemulsion by interfacial polymerisation. The microemulsion consisted of a mixture of medium-chain mono-, di- and tri-glycerides as the oil component, polysorbate 80 and sorbitan mono-oleate as surfactants and an aqueous solution of insulin. Resulting nanocapsules were approximately 200 nm in diameter and demonstrated a high efficiency of insulin entrapment (> 80%). In-vitro release studies showed that PBCA nanocapsules could suppress insulin release in acidic media and that release at near neutral conditions could be manipulated by varying the amount of monomer used for polymerisation. Subcutaneous administration of insulin-loaded nanocapsules to diabetic rats demonstrated that the bioactivity of insulin was largely retained following this method of preparing peptide-loaded nanocapsules and that the pharmacodynamic response was dependent on the amount of monomer used for polymerisation. The intragastric administration of insulin-loaded nanocapsules dispersed in the biocompatible microemulsion resulted in a significantly greater reduction in blood glucose levels of diabetic rats than an aqueous insulin solution or insulin formulated in the same microemulsion. This study demonstrates that the formulation of peptides within PBCA nanocapsules that are administered dispersed in a microemulsion can facilitate the oral absorption of encapsulated peptide. Such a system can be prepared in-situ by the interfacial polymerisation of a water-in-oil biocompatible microemulsion.

Administration, Oral↗
PubMed2005

The influence of Surelease and sodium alginate on the in-vitro release of tamsulosin hydrochloride in pellet dosage form.

The objective of this study was to prepare controlled-release pellets containing 0.2 mg tamsulosin hydrochloride using a pelletizer-equipped piston extruder and double-arm counter-rotating rollers with Surelease and sodium alginate. The release of tamsulosin HCl from pellets coated with the commercial aqueous ethylcellulose dispersion (Surelease) was investigated at different coating loads. In addition, the effect of sodium alginate on drug release was investigated by varying the ratio of sodium alginate to microcrystalline cellulose (MCC). Dissolution studies were first performed in 500 mL simulated gastric fluid (pH 1.2) containing 0.003% (w/w) polysorbate 80 and then in simulated intestinal fluids (pH 7.2). The morphology of pellet surfaces and cross sections were examined by scanning electron microscopy (SEM). Apparently, the spherical pellets were prepared using a pelletizer-equipped piston extruder and double-arm counter-rotating rollers. The release profiles of tamsulosin HCl from Surelease-coated pellets were significantly affected by changing the content of Surelease, the pH of the dissolution medium and the ratio of sodium alginate to MCC. The drug release rates not only decreased with increase in the coating load, but also increased when the pH of the dissolution medium was increased from 1.2 to 7.2 regardless of the sodium alginate-to-MCC ratio. Moreover, the drug release rate at pH 7.2 was gradually increased by increasing the ratio of sodium alginate to MCC. SEM showed smooth surfaces of Surelease-coated pellets. These results suggest that Surelease and sodium alginate would be useful excipients in the preparation of controlled-release pellets with the desired release profiles.

Alginates↗