			Home About us Contact

Oral Delivery (oral + delivery)

Distribution by Scientific Domains

Medical Sciences	36%
Life Sciences	27%
Earth and Environmental Science	9%

Selected Abstracts

Oral delivery of tumor-targeting Salmonella exhibits promising therapeutic efficacy and low toxicity

CANCER SCIENCE, Issue 12 2009
Guo Chen
Tumor-targeting bacteria have been developed as powerful anticancer agents. Salmonella typhimurium VNP20009, a representative tumor-targeting strain, has been systemically administered as a single-agent therapy at doses of 1 × 106 to 3 × 106 colony-forming unit (cfu)/mouse, or in combination with other antitumor agents at doses of 1 × 104 to 2 × 105 cfu/mouse. Recently, we reported that oral delivery of VNP20009 at the dose of 1 × 109 cfu/mouse induced significant anticancer effects comparable to that induced by systemic administration of this strain at 1 × 104 cfu/mouse. To further address the efficacy and safety of oral administration of bacteria, here we performed a systemically comparative analysis of anticancer efficacy and toxicity of VNP20009 administered: (i) orally at a dose of 1 × 109 cfu/mouse (VNP9-oral); (ii) intraperitoneally at a dose of 1 × 104 cfu/mouse (VNP4-i.p.); or (iii) intraperitoneally at a dose of 1 × 106 cfu/mouse in tumor-free and tumor-bearing murine models. The results showed that VNP9-oral, similar to VNP4-i.p., induced significant tumor growth inhibition whereas VNP6-i.p. induced better anticancer effect in the B16F10 melanoma model. Among three treatments, VNP9-oral induced the mildest and reversible toxicity whereas VNP6-i.p. resulted in the most serious and irreversible toxicities when compared to other two treatments. Moreover, the combination of VNP9-oral with a low dose of chemotherapeutics produced comparable antitumor effects but displayed significantly reduced toxicity when compared to VNP6-i.p. The findings demonstrated that oral administration, as a novel avenue in the application of bacteria, is highly safe and effective. Moreover, the present preclinical study should facilitate the optimization of bacterial therapies with improved anticancer efficacy and reduced adverse effects in future clinical trials. (Cancer Sci 2009; 100: 2437,2443) [source]

Oral insulin , a review of current status

DIABETES OBESITY & METABOLISM, Issue 3 2010
Harish Iyer
Oral insulin is one of the most exciting areas of development in the treatment of diabetes because of its potential benefit in patient convenience, rapid insulinization of liver, adequate insulin delivery avoiding peripheral hyperinsulinaemia while potentially avoiding adverse effects of weight gain and hypoglycaemia. Growing evidence that earlier initiation of intensive insulin therapy produces sustained tight glycaemic control resulting in substantial delay in complications makes an effective oral insulin product even more vital for the management of patients with diabetes. Despite knowledge of this unmet medical need, oral delivery of insulin has been unsuccessful because of several barriers. For several decades, researchers have tried to develop oral insulin using various technologies without much clinical or commercial success. This review summarizes the development status of oral insulins which are publicly reported to be undergoing clinical studies. Currently, two oral insulin products are in an advanced stage of clinical development and first data from long-term therapy are expected to be available in the second half of 2010. [source]

Oral vaccination of mice against Helicobacter pylori with recombinant Lactococcus lactis expressing urease subunit B

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2009
Qing Gu
Abstract To determine whether a protective immune response could be elicited by oral delivery of a recombinant live bacterial vaccine, Helicobacter pylori urease subunit B (UreB) was expressed for extracellular expression in food-grade bacterium Lactococcus lactis. The UreB-producing strains were then administered orally to mice, and the immune response to UreB was examined. Orally vaccinated mice produced a significant UreB-specific serum immunoglobulin G (IgG) response. Specific anti-UreB IgA responses could be detected in the feces of mice immunized with the secreting lactococcal strain. Mice vaccinated orally were significantly protected against gastric Helicobacter infection following a challenge with H. pylori strain SS1. In conclusion, mucosal vaccination with L. lactis expressing UreB produced serum IgG and UreB-specific fecal IgA, and prevented gastric infection with H. pylori. [source]

In vitro evaluation of the activity of microencapsulated carvacrol against Escherichia coli with K88 pili

JOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2009
Q. Wang
Abstract Aims:, The aim of the current study is to develop encapsulation of essential oils for oral delivery to the small intestine of pigs in order to retain their antimicrobial activity. Methods and Results:, Carvacrol was used as a model essential oil and successfully encapsulated in microcapsules made from Ca-alginate hydrogel using an emulsion,extrusion technology with high encapsulation efficiency. This encapsulation method did not compromise the antimicrobial activity when tested against Escherichia coli K88 in a culture medium, as well as in a simulated gastrointestinal model. In the simulated gastrointestinal model, <20% of encapsulated carvacrol was released in the simulated gastric fluid; the rest was nearly completely released in the intestinal fluid after 6 h of incubation. Conclusions:, Encapsulation in Ca-alginate microcapsules could effectively reduce the early absorption of carvacrol in the upper gastrointestinal tract after oral administration, therefore, retains its potential antibacterial activity for the small intestine. Significance and Impact of the Study:, The developed encapsulation method is expected to be suitable for encapsulation of other essential oils. The results from this study would increase the likelihood of success in the application of essential oils as antimicrobial agents for controlling enteric diseases in pigs. [source]

Preparation and in vitro evaluation of new pH-sensitive hydrogel beads for oral delivery of protein drugs

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010
I. M. El-Sherbiny
Abstract New biodegradable pH-responsive hydrogel beads based on chemically modified chitosan and sodium alginate were prepared and characterized for the controlled release study of protein drugs in the small intestine. The ionotropic gelation reaction was carried out under mild aqueous conditions, which should be appropriate for the retention of the biological activity of an uploaded protein drug. The equilibrium swelling studies were carried out for the hydrogel beads at 37°C in simulated gastric (SGF) and simulated intestinal (SIF) fluids. Bovine serum albumin (BSA), a model for protein drugs was entrapped in the hydrogels and the in vitro drug release profiles were established at 37°C in SGF and SIF. The preliminary investigation of the hydrogel beads prepared in this study showed high entrapment efficiency (up to 97%) and promising release profiles of BSA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

Bioavailability and Biological Efficacy of a New Oral Formulation of Salmon Calcitonin in Healthy Volunteers,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2002
Thierry Buclin
Abstract Salmon calcitonin (SCT) is a well-tolerated peptide drug with a wide therapeutic margin and is administered parenterally for long-term treatments of bone diseases. Its clinical usefulness would be enhanced by the development of an orally active formulation. In this randomized crossover double-blinded phase I trial, controlled by both a placebo and a parenteral verum, we have tested a new oral formulation of SCT associated with a caprylic acid derivative as carrier. Eight healthy volunteers received single doses of 400, 800, and 1200 ,g of SCT orally, a placebo, and a 10-,g (50 IU) SCT intravenous infusion. SCT was reliably absorbed from the oral formulation, with an absolute bioavailability of 0.5,1.4%, depending on the dose. It induced a marked, dose-dependent drop in blood and urine C-terminal telopeptide of type I collagen (CTX), a sensitive and specific bone resorption marker, with the effects of 1200 ,g exceeding those of 10 ,g intravenously. It also decreased blood calcium and phosphate, and increased the circulating levels of parathyroid hormone (PTH) and, transiently, the urinary excretion of calcium. It was well-tolerated, with some subjects presenting mild and transient nausea, abdominal cramps, diarrheic stools, and headaches. This study shows that oral delivery of SCT is feasible with reproducible absorption and systemic biological efficacy. Such an oral formulation could facilitate the use of SCT in the treatment of osteoporosis and other bone diseases. [source]

Enhanced oral absorption of paclitaxel in N -deoxycholic acid- N, O -hydroxyethyl chitosan micellar system,

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2010
Hong Li
Abstract The overall goal of this study was to develop a micellar system of paclitaxel (PTX) to enhance its oral absorption. An amphiphilic chitosan derivative, N -deoxycholic acid- N, O -hydroxyethyl chitosan (DHC), was synthesized and characterized by FTIR, 1H NMR, elemental analysis, and X-ray diffraction (XRD) techniques. The degree of substitution (DS) of hydroxyethyl group and deoxycholic acid group ranged from 89.5,114.5% and 1.11,8.17%, respectively. The critical micelle concentration (CMC) values of DHC decreased from 0.26 to 0.16,mg/mL as the DS of deoxycholic acid group increased. PTX was successfully loaded in DHC micelles with a high drug loading (31.68,±,0.14%) and entrapment efficiency (77.57,±,0.51%). The particle size of PTX-loaded DHC micelles ranged from 203.35,±,2.19 to 236.70,±,3.40,nm as the DS of deoxycholic acid group increased. After orally administration of PTX-loaded DHC micelles, the bioavailability was threefold compared with that of an orally dosed Taxol®. The single-pass intestinal perfusion studies (SPIP) showed that the intestinal absorption of micelles was via endocytosis involving a saturable process and a p-glycoprotein (P-gp)-independent way. All these indicated that the DHC micelles might be a promising tool for oral delivery of poorly water-soluble drugs. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:4543,4553, 2010 [source]

Genetically engineered normal flora for oral polypeptide delivery: Dose,absorption response

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2009
Gagan Kaushal
Abstract Genetically modified Lactococcus lactis (L. lactis), a probiotic bacterium, able to secrete ,-lactamase (29 kDa), was used as a vector for the oral delivery of ,-lactamase to the rats. Three different doses of L. lactis were administered to the rats, and the resulted ,-lactamase oral bioavailability was studied, and compared to the solution form. The oral administration of 1.2,×,107, 3,×,107, and 8,×,107 colony-forming units of L. lactis led to 145, 209, and 364 mU of ,-lactamase absorbed, and the corresponding bioavailability was 8.7%, 15.5%, and 20.8% based on the in vitro production of ,-lactamase by L. lactis. The oral administration of 504 mU and 1008 mU ,-lactamase free solution resulted in 30 and 47 mU absorbed, a bioavailability of 5.9% and 4.7%, respectively. L. lactis significantly (p,<,0.01) increased the oral bioavailability compared to the free solution form. A significant (p,<,0.01) increase in the MAT value as compared to the solution, demonstrated that L. lactis can be used as a sustained delivery system. In conclusion, there is a linear relationship between L. lactis dose and these absorption PK parameters within L. lactis dose range of the current study. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:2573,2580, 2009 [source]

Development of clinical dosage forms for a poorly water-soluble drug II: Formulation and characterization of a novel solid microemulsion preconcentrate system for oral delivery of a poorly water-soluble drug

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2009
Ping Li
Abstract The solution of a poorly water-soluble drug in a liquid lipid,surfactant mixture, which served as a microemulsion preconcentrate, was converted into a solid form by incorporating it in a solid polyethylene glycol (PEG) matrix. The solid microemulsion preconcentrates thus formed consisted of Capmul PG8 (propylene glycol monocaprylate) as oil, Cremophor EL (polyoxyl 35 castor oil) as surfactant, and hydrophilic polymer PEG 3350 as solid matrix. The drug (aqueous solubility: 0.17 µg/mL at pH 1,8 and 25°C) was dissolved in a melt of the mixture at 65,70°C and then the hot solution was filled into hard gelatin capsules; the liquid gradually solidified upon cooling below 55°C. The solid system was characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), confocal Raman microscopy (CRM), and the dispersion testing in water. It was confirmed that a solid microemulsion preconcentrate is a two-phase system, where clusters of crystalline PEG 3350 formed the solid structure (m.p. 55,60°C) and the liquid microemulsion preconcentrate dispersed in between PEG 3350 crystals as a separate phase. The drug remained dissolved in the liquid phase. In vitro release testing showed that the preconcentrate dispersed readily in water forming a microemulsion with the drug dissolved in the oil particles (<150 nm) and the presence of PEG 3350 did not interfere with the process of self-microemulsification. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:1750,1764, 2009 [source]

Preparation and evaluation of poly-butylcyanoacrylate nanoparticles for oral delivery of thymopentin

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2008
Weiling He
Abstract Thymopentin (Tp5) was loaded in poly-butylcyanoacrylate (PBCA) nanoparticles (NP) in order to enhance the oral bioavailability of Tp5. PBCA-Tp5-NP was prepared by nanoprecipitation methods. Dialyzing membrane method was employed to examine the in vitro release of PBCA-Tp5-NP in PBS, and Tp5 samples in the release medium were detected by HPLC. The cell proliferation test (3H-thymidine) was conducted to verify the PBCA-Tp5-NP bioactivity in vitro. The pharmacodynamical studies were performed on preimmunoinhibited rats and in flow cytometer. The size and the entrapment efficiency of PBCA-Tp5-NP were 178,±,39 nm and 92.21,±,1.08%, respectively. In vitro release data show that less than 60% Tp5 was released from lyophilized PBCA-Tp5-NP while 80% Tp5 was released from the colloidal PBCA-Tp5-NPs in 48 h. The proliferation test showed that PBCA-Tp5-NP had the similar effect as Tp5. The in vivo data showed that oral PBCA-Tp5-NPs had similar function as what intravenous Tp5 did. The oral bioavailability of Tp5 could be enhanced by PBCA nanoparticles. PBCA-Tp5-NP had the property of sustained-release and the efficacy of Tp5 was not changed after formulation. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:2249,2258, 2008 [source]

Cytotoxicity evaluation of enzyme inhibitors and absorption enhancers in Caco-2 cells for oral delivery of salmon calcitonin

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2004
Rakhi B. Shah
Abstract The usefulness of enzyme inhibitors and absorption enhancers with least mucosal cell cytotoxicity was evaluated on Caco-2 cell monolayers. The temporal cytotoxicity of several protease inhibitors at 500 ,g/mL (e.g., turkey and chicken ovomucoids, aprotinin, and Protease Inhibitor Cocktail) and absorption enhancers [e.g., cholate (3%), glycocholate (3%), glycosursodeoxycholate (3%), ethylenediaminetetraacetic acid (EDTA, 0.1%), hydroxypropyl-,-cyclodextrin (HP-,-CD, 5%), hydroxypropyl-,-cylcodextrin (HP-,-CD, 5%), ,-cylcodextrin (,-CD, 5%), tetradecyl-,- D -maltoside (0.25%), octylglucoside (0.25%), citric acid (10%), glycyrrhetinic acid (0.34 mM), and Tween-80® (0.1%)] was measured by monitoring their effect on Caco-2 cell viability. Cell viability was measured by mannitol permeability measurements, transepithelial electrical resistance (TEER) measurements, DNA-propidium iodide staining assay, and WST-1 assay (tetrazolium salt based assay). Sodium dodecyl sulfate (0.1%), a potent surfactant, was used as a positive control. Chicken and turkey ovomucoids were nontoxic to cells as evaluated by all the methods used. Aprotinin decreased the TEER, whereas plasma membrane damage was seen with Protease Inhibitor Cocktail after a 24-h period. With respect to the absorption enhancers, the toxicity increased directly as a result of an increase in the time of incubation. The enhancers EDTA and HP-,-CD can be used safely for a short period of time, whereas glycosursodeoxycholate, glycyrrhetinic acid, octylglucoside, HP-,-CD, and ,-CD can be used for a longer period. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 93: 1070,1082, 2004 [source]

Development and in-vivo evaluation of insulin-loaded chitosan phthalate microspheres for oral delivery

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2007
Udhumansha Ubaidulla
Novel chitosan phthalate microspheres containing insulin were prepared by emulsion cross-linking technique. The feasibility of these microspheres as oral insulin delivery carriers was evaluated. The pH-responsive release behaviour of insulin from microspheres was analysed. The ability of chitosan phthalate-insulin microspheres to enhance intestinal absorption and improve the relative pharmacological availability of insulin was investigated by monitoring the plasma glucose and insulin level of streptozotocin-induced diabetic rats after oral administration of microspheres at insulin dose of 20 IU kg,1. In simulated gastric fluid (pH 2.0), insulin release from the microspheres was very slow. However, as the pH of the medium was changed to simulated intestinal fluid (pH 7.4), a rapid release of insulin occurred. The relative pharmacological efficacy for chitosan phthalate microspheres (18.66 ± 3.84%) was almost four-fold higher than the efficacy of the chitosan phthalate-insulin solution administration (4.08 ± 1.52%). Chitosan phthalate microspheres sustained the plasma glucose at pre-diabetic level for at least 16 h. These findings suggest that the microsphere is a promising carrier as oral insulin delivery system. [source]

Oral sustained delivery of theophylline from thermally reversible xyloglucan gels in rabbits

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 9 2001
Shozo Miyazaki
Thermally reversible gels formed in-situ following the oral administration of dilute aqueous solutions of an enzyme-degraded xyloglucan to rabbits were evaluated as sustained-release vehicles for the delivery of theophylline. In-vitro release of theophylline from gels formed by warming xyloglucan sols (0.5, 1.0 and 1.5% w/w) to 37°C followed root-time kinetics over a period of 4 h. Gels formed after oral administration to rabbits of chilled 1.5% w/w aqueous solutions of xyloglucan containing dissolved drug showed sustained-release characteristics with a maximum plasma concentration at 4.5 h. The theophylline bioavailability from a 1.5% w/w xyloglucan gel was 1.7,2.5 times that of commercial oral sustained-release liquid dosage forms containing an identical theophylline concentration. It was concluded that dilute solutions of the enzyme-degraded xyloglucan had suitable rheological properties and in-situ gelling characteristics for use as sustained-release vehicles for oral drug delivery. The in-vivo release characteristics of theophylline in a rabbit model suggested the potential for the use of these vehicles in humans for the oral delivery of this drug. [source]

Effects of Oral Administration of Specific Antibodies to Rainbow Trout Oncorhynchus mykiss

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2003
Michael Engelbrecht Nielsen
A new product called oralized fish serum concentrate (OFSC) was evaluated for a possible effect against various bacterial pathogens in rainbow trout. The OFSC produced from immune trout sera was found to contain fully functional antibodies and complement component C3. The antibodies detected in the serum concentrate were specific to Vibrio anguillarum (O1 and O2) and Aeromonas salmonicida, which had been used for vaccination of the fish prior to serum collection. The functionality of the specific antibodies in OFSC was not reduced after 6 wk storage at -20 C, 5 C, and 20 C. The serum was mixed with commercial trout feed and used for feeding rainbow trout fry (first feed period). After oral delivery of OFSC to rainbow trout for 1 mo, samples of gut content and gut tissue contained functional antibodies. In gutted fish no functional antibodies were found. This suggests that antibodies from OFSC are unable to be transferred across the gut wall in a functional state. Oral administration of OFSC did not increase survival of rainbow trout in an immersion challenge with Vibrio anguillarum. [source]

Oral vaccination with envelope protein VP28 against white spot syndrome virus in Procambarus clarkii using Bacillus subtilis as delivery vehicles

LETTERS IN APPLIED MICROBIOLOGY, Issue 5 2008
L.L. Fu
Abstract Aims:, To achieve high-level expression and secretion of active VP28 directed by a processing-efficient signal peptide in Bacillus subtilis WB600 and exploit the possibility of obtaining an oral vaccine against white spot syndrome virus (WSSV) using vegetative cells or spores as delivery vehicles. Methods and Results:, The polymerase chain reaction (PCR)-amplified vp28 gene was inserted into a shuttle expression vector with a novel signal peptide sequence. After electro-transformation, time-courses for recombinant VP28 (rVP28) secretion level in B. subtilis WB600 were analysed. Crayfish were divided into three groups subsequently challenged by 7-h immersion at different time points after vaccination. Subgroups including 20 inter-moult crayfish with an average weight of 15 g in triplicate were vaccinated by feeding coated food pellets with vegetative cells or spores for 20 days. Vaccination trials showed that rVP28 by spore delivery induced a higher resistance than using vegetative cells. Challenged at 14 days postvaccination, the relative per cent survival (RPS) values of groups of rVP28-bv and rVP28-bs was 51·7% and 78·3%, respectively. Conclusions:, The recombinant B. subtilis strain with the ability of high-level secretion of rVP28 can evoke protection of crayfish against WSSV by oral delivery. Significance and Impact of the Study:, Oral vaccination by the B. subtilis vehicle containing VP28 opens a new way for designing practical vaccines to control WSSV. [source]

Paired comparison of bathwater versus oral delivery of 8-methoxypsoralen in psoralen plus ultraviolet A therapy for chronic palmoplantar psoriasis

PHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 1 2006
A. Hofer
Background: Both bath psoralen plus ultraviolet A (PUVA) and oral PUVA with 8-methoxypsoralen (8-MOP) have been successfully used for the treatment of recalcitrant palmoplantar psoriasis. This trial was designed to assess the efficacy and side effects of the different treatment modalities in a randomized half-side comparison. Methods: Eight patients with moderate-to-severe psoriasis on soles (n=6) and/or palms (n=8) were randomly assigned to receive bath PUVA treatment on one side and oral PUVA on the other. Initial treatment dose was 50% of the minimal phototoxic dose evaluated for bath PUVA and oral PUVA. Treatment was given three times a week for 4 weeks. Before treatment and every week a severity index (SI) was assessed by summing the scores of erythema, infiltration, scaling and vesicles evaluated on a scale from 0 to 4. After 4 weeks of treatment the half-side trial was finished and the treatment was continued on both sides with the more effective treatment regimen. Results: Both bath PUVA and oral PUVA achieved a reduction of the mean initial SI from 5.9 (95% confidence intervals (CI) 4.5,8.0) to 3.3 (1.8,6.0) (44% SI reduction, P<0.005, Student's paired t -test) and 6.0 (5.0,7.8) to 2.9 (1.8,4.0) (52% SI reduction; P<0.005), respectively. The statistical comparison of the entire 4-week study period revealed a significant better effect in lesions treated with oral PUVA compared with bath PUVA (P=0.033). However, at 4 weeks, there was no significant difference between the achieved SI reduction of oral PUVA and bath PUVA. Systemic side effects (nausea and/or dizziness) were only observed after oral PUVA. Conclusion: This study gives evidence that in the first 4 treatment weeks oral PUVA is slightly more effective than bath PUVA but the former has more systemic side effects. [source]

Approaches to achieve high-level heterologous protein production in plants

PLANT BIOTECHNOLOGY JOURNAL, Issue 1 2007
Stephen J. Streatfield
Summary Plants offer an alternative to microbial fermentation and animal cell cultures for the production of recombinant proteins. For protein pharmaceuticals, plant systems are inherently safer than native and even recombinant animal sources. In addition, post-translational modifications, such as glycosylation, which cannot be achieved with bacterial fermentation, can be accomplished using plants. The main advantage foreseen for plant systems is reduced production costs. Plants should have a particular advantage for proteins produced in bulk, such as industrial enzymes, for which product pricing is low. In addition, edible plant tissues are well suited to the expression of vaccine antigens and pharmaceuticals for oral delivery. Three approaches have been followed to express recombinant proteins in plants: expression from the plant nuclear genome; expression from the plastid genome; and expression from plant tissues carrying recombinant plant viral sequences. The most important factor in moving plant-produced heterologous proteins from developmental research to commercial products is to ensure competitive production costs, and the best way to achieve this is to boost expression. Thus, considerable research effort has been made to increase the amount of recombinant protein produced in plants. This research includes molecular technologies to increase replication, to boost transcription, to direct transcription in tissues suited for protein accumulation, to stabilize transcripts, to optimize translation, to target proteins to subcellular locations optimal for their accumulation, and to engineer proteins to stabilize them. Other methods include plant breeding to increase transgene copy number and to utilize germplasm suited to protein accumulation. Large-scale commercialization of plant-produced recombinant proteins will require a combination of these technologies. [source]

Oral vaccination trials with crayfish, Procambarus clarkii, to induce resistance to the white spot syndrome virus

AQUACULTURE RESEARCH, Issue 15 2009
Fei Zhu
Abstract The potential of oral vaccination against white spot syndrome virus (WSSV) in crayfish Procambarus clarkii was investigated. The protective effect of binary ethylenimine (BEI)-inactivated WSSV was tested by oral vaccination, followed by an oral challenge with WSSV. The crayfish fed with feed pellets coated with BEI-inactivated WSSV showed a resistance to WSSV on the seventh day post vaccination (dpv). The relative percentage survival values were 60%, 70% and 75% for the vaccinated once, twice and thrice with inactivated WSSV. Following an intramuscular injection experiment, no mortality was recorded in the inactivated WSSV group and the negative control at 17 days post challenge. The cumulative mortalities in the heated WSSV group and WSSV group were 100%. Shrimp that survived the WSSV challenge on the seventh day after cessation of oral vaccination were positive for the presence of WSSV by a polymerase chain reaction assay specific for WSSV. This result indicated that inactivated WSSV could protect crayfish against WSSV by oral delivery. [source]

A DNA replicon system for rapid high-level production of virus-like particles in plants

BIOTECHNOLOGY & BIOENGINEERING, Issue 4 2009
Zhong Huang
Abstract Recombinant virus-like particles (VLPs) represent a safe and effective vaccine strategy. We previously described a stable transgenic plant system for inexpensive production and oral delivery of VLP vaccines. However, the relatively low-level antigen accumulation and long-time frame to produce transgenic plants are the two major roadblocks in the practical development of plant-based VLP production. In this article, we describe the optimization of geminivirus-derived DNA replicon vectors for rapid, high-yield plant-based production of VLPs. Co-delivery of bean yellow dwarf virus (BeYDV)-derived vector and Rep/RepA-supplying vector by agroinfiltration of Nicotiana benthamiana leaves resulted in efficient replicon amplification and robust protein production within 5 days. Co-expression of the P19 protein of tomato bush stunt virus, a gene silencing inhibitor, further enhanced VLP accumulation by stabilizing the mRNA. With this system, hepatitis B core antigen (HBc) and Norwalk virus capsid protein (NVCP) were produced at 0.80 and 0.34 mg/g leaf fresh weight, respectively. Sedimentation analysis and electron microscopy of transiently expressed antigens verified the efficient assembly of VLPs. Furthermore, a single replicon vector containing a built-in Rep/RepA cassette without P19 drove protein expression at similar levels as the three-component system. These results demonstrate the advantages of fast and high-level production of VLP-based vaccines using the BeYDV-derived DNA replicon system for transient expression in plants. Biotechnol. Bioeng. 2009;103: 706,714. © 2009 Wiley Periodicals, Inc. [source]

Production of biopharmaceuticals and vaccines in plants via the chloroplast genome

BIOTECHNOLOGY JOURNAL, Issue 10 2006
Henry Daniell Dr.Article first published online: 27 SEP 200
Abstract Transgenic plants offer many advantages, including low cost of production (by elimination of fermenters), storage and transportation; heat stability; and absence of human pathogens. When therapeutic proteins are orally delivered, plant cells protect antigens in the stomach through bioencapsulation and eliminate the need for expensive purification and sterile injections, in addition to development of both systemic and mucosal immunity. Chloroplast genetic engineering offers several advantages, including high levels of transgene expression, transgene containment via maternal inheritance and multi-gene expression in a single transformation event. Hyper-expression of vaccine antigens against cholera, tetanus, anthrax, plague or canine parvovirus (4,31% of total soluble protein, tsp) in transgenic chloroplasts (leaves) or non-green plastids (carrots, tomato), as well as the availability of antibiotic-free selectable markers or the ability to excise selectable marker genes, facilitate oral delivery. Hyper-expression of several therapeutic proteins, including human serum albumin (11.1% tsp), somatotropin (7% tsp), interferon-gamma (6% tsp), anti-microbial peptide (21.5% tsp), facilitates efficient and economic purification. Also, the presence of chaperones and enzymes in chloroplasts facilitate assembly of complex multi-subunit proteins and correct folding of human blood proteins with proper disulfide bonds. Functionality of chloroplast-derived vaccine antigens and therapeutic proteins has been demonstrated by several assays, including the macrophage lysis assay, GM1-ganglioside binding assay, protection of HeLa cells or human lung carcinoma cells against encephalomyocarditis virus, systemic immune response, protection against pathogen challenge, and growth or inhibition of cell cultures. Thus, transgenic chloroplasts are ideal bioreactors for production of functional human and animal therapeutic proteins in an environmentally friendly manner. [source]

Oral delivery of tumor-targeting Salmonella exhibits promising therapeutic efficacy and low toxicity

Evaluation of the conformational propensities of peptide isosteres as a basis for selecting bioactive pseudopeptides

CHEMICAL BIOLOGY & DRUG DESIGN, Issue 6 2001
S. Gupta
Abstract: Our aim was to compare the repertoires of conformers formed by the model zwitterionic peptides AA and AAA in aqueous solution with the conformational profiles of a range of their peptide isosteres, so as to facilitate selection of isosteres for synthesis and testing as biologically stable surrogates of bioactive di- and tripeptides. Comparisons were based upon the results of conformational analysis using a random search approach implemented within the SYBYL molecular modelling package, using zwitterionic molecules, simulated aqueous solvation using a dielectric constant of 80 and allowing all torsions to vary. For each compound, individual conformers were grouped on the basis of specific combinations of psi, phi and omega torsions and, using their energies, the aggregated percentage for each group was calculated using a Boltzmann distribution and displayed using a 3D pseudo Ramachandran plot relating percentage conformer to psi and phi torsions. Retroamide, N -methylamide and thioamide isosteres showed the best match to natural peptides and to the molecular recognition parameters defined for substrates of peptide transporters. The results should aid rational design of therapeutic agents in various areas, e.g. oral delivery of drugs by peptide transporters and of peptidase inhibitors. This approach may usefully be applied to various biochemical and pharmaceutical topics. [source]