• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.4
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• pp.212-230
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• 2001

Recent advances in recombinant DNA technology have resulted in development of many new protein drugs. Due to the unique properties of protein druges, they have to be delivered by parenteral injection Although delivery of protein drugs by other routes, such as pulmonary and nasal routes, has shown some promises, to date most protein drugs are administered by par-enteral routs. For long-term delivery of protein drugs by parenteral administration, they have been formulated into biodegradable microspheres. A number of microencapsulation methods have been developed, and the currently used microencapsulation methods are reviewed here, The microen-capsulation methods have been divided based on the method used. They are: solvent evapora-tion/extraction; phase separation (coacervation);spray drying; ionotropic gelation/polyelectrolyte complexation; interfacial polyumerization and supercritical fluid precipitation. Each method is de-scribed fro its applications, advantages, and limitations.

• Journal of Pharmaceutical Investigation
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• v.34 no.5
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• pp.369-377
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• 2004

The objective of this study was to investigate the patterns of protein leaching to an external phase during an ethyl acetate-based, double emulsion microencapsulation process. An aqueous protein solution (lactoglobulin, lysozyme, or ribonuclease; $W_1$) was emulsified in ethyl acetate containing poly-d,l-lactide-co-glycolide 75:25. The $W_1/O$ emulsion was transferred to a 0.5% polyvinyl alcohol solution saturated with ethyl acetate $(W_2)$. After the double emulsion was stirred for 5, 15, 30, or 45 min, additional 0.5% polyvinyl alcohol $(W_3)$ was quickly added into the emulsion. This so-called quenching step helped convert emulsion microdroplets into microspheres. After 2-hr stirring, microspheres were collected and dried. The degree of protein leaching to $W_2$ and/or $W_3$ phase was monitored during the microencapsulation process. In a separate, comparative experiment, the profile of protein leaching to an external phase was investigated during the conventional methylene chloride-based microencapsulation process. When ethyl acetate was used as a dispersed solvent, proteins continued diffusing to the $W_2$ phase, as stirring went on. Therefore, the timing of ethyl acetate quenching played an important role in determining the degree of protein microencapsulation efficiency. For example, when quenching was peformed after 5-min stirring of the primary $W_1/O$ emulsion, the encapsulation efficiencies of lactoglobulin and ribonuclease were $55.1{\pm}4.2\;and\;45.3{\pm}7.6%$, respectively. In contrast, when quenching was carried out in 45 min, their respective encapsulation efficiencies were $39.6{\pm}3.2\;and\;29.9{\pm}11.2%$. By sharp contrast, different results were attained with the methylene-chloride based process: up to 2 hr-stirring of the primary and double emulsions, less than 5% of a protein appeared in $W_2$. Afterwards, it started to partition from $W_1\;to\;W_2/W_3$, and such a tendency was affected by the amount of PLGA75:25 used to make microspheres. Different solvent properties (e.g., water miscibility) and their effect on microsphere hardening were to be held answerable for such marked differences observed with the two microencapsulation processes.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.4
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• pp.213-213
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• 2001

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.6
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• pp.920-922
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• 1996

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.274-276
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• 1999

Sardine oil was microencapsulated by spray drying method in wall systems containing corn syrup in combination with sodium casein or wheat protein. Analysis of microencapsulation yield of sardine oil was carried out by a modified soxhlet method which could reduce the extraction time of surface oil. Microencapsulation yield of sardine oil was ranged from 65.3 to 93.5 % depending on the sodium casein content.

• Journal of Pharmaceutical Investigation
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• v.31 no.3
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• pp.191-196
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• 2001

Biodegradable polymeric microspheres were studied for their usefulness as carriers for the delivery of vaccine antigens. However, protein antigen could be denatured during microencapsulation processes due to the exposure to the organic phase and stress condition of cavitation and shear force. Therefore this study was carried out to re-evaluate the degree of protein denaturation during microencapsulation with poly(lactide-co-glycolide) (PLGA) copolymer. PLGA microspheres containing ovalbumin (OVA), prepared by W/O/W multiple emulsification method, were suspended in pH 7.4 PBS and incubated with shaking at $37.5^{\circ}C$. Drug released medium was collected periodically and analyzed for protein contents by micro-BCA protein assay. In order to evaluate the protein integrity, release medium was subjected to the analyses of SDS-PAGE and size exclusion chromatography (SEC). And enzyme-linked immunosorbent assay (ELISA) was introduced to measure the immunoreactivity of entrapped OVA and to get an insight into the three-dimensional structure of epitope. The structures of entrapped protein were not affected significantly by the results of SDS-PAGE and SEC. However, immunoreactivity of released antigen was varied, revealing the possibility of protein denaturation in some microspheres when it was evaluate by ELISA method. Therefore, in order to express the degree of protein denaturation, antigenicity ratio (AR) was obtained as follows: amount of immunoreactivity of OVA/total amount of OVA released ${\times}100(%)$. ELISA method was an efficient tool to detect a protein denaturation during microencapsulation and the comparison of AR values resulted in more accurate evaluation for immunoreactivity of entrapped protein.

• Journal of Nutrition and Health
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• v.45 no.5
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• pp.443-451
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• 2012

We compared the effects of grapefruit seed extract (GFSE), green tea extract (GT) and their microencapsulated extract on anti-inflammatory activities in murine RAW 264.7 macrophages cell line. In order to protect the bioactive compounds in the extracts, they were microencapsulated with maltodextrin and $H_2O$. Nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), inducible nitric oxide synthase (iNOS) protein expression and thiobarbiturate reactive substances (TBARS) were analyzed in LPS activated RAW 264.7 macrophages. The green tea extract at the range of $100-600{\mu}g/mL$ inhibited NO, PGE2 production and iNOS protein expression without cytotoxicity in a dose-dependent manner. Grapefruit seed extract had strong inhibitory effects on NO and PGE production and iNOS protein expression at the range of $5-20{\mu}g/mL$ without cytotoxicity. Microencapsulation of green tea extract had further inhibitory effects on NO and PGE2 production and on iNOS protein expression, whereas microencapsulated GFSE did not show any further inhibitory effects on these parameters. Taken together, our results suggest that GSFE might be a promising candidate for preventing inflammation related diseases, such as cardiovascular disease, cancer or diabetes, and the microencapsulation of green tea extract could improve its bioactivity.

• Animal Bioscience
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• v.36 no.8
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• pp.1252-1262
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• 2023

Objective: Microencapsulation technologies have been developed and successfully applied to protect the probiotic bacterial cells damaged by environmental exposure. This study aimed to investigate the effects of microencapsulation of Lactobacillus plantarum MB001 on the growth performance, ileal nutrient digestibility, jejunal histomorphology and cecal microbiome of broiler chickens in a tropical climate. Methods: A total of 288 one-day-old female broilers (Ross 308) were randomly allocated into 4 groups (6 replicates of 12 birds). Treatments included, i) a basal diet (NC), ii) NC + avilamycin (10 mg/kg) (PC), iii) NC + non-encapsulated L. plantarum MB001 (1×10⁸ colony-forming unit [CFU]/kg of diet) (N-LP), iv) NC + microencapsulated L. plantarum MB001 (1×10⁸ CFU/kg of diet) (ME-LP). Results: Dietary supplementation of ME-LP improved average daily gain, and feed conversion ratio of broilers throughout the 42-d trial period (p<0.05), whereas ME-LP did not affect average daily feed intake compared with NC group. Both N-LP and ME-LP improved apparent ileal digestibility of crude protein and ether extract compared with NC group (p<0.05). The broilers fed ME-LP supplemented diet exhibited a beneficial effect on jejunal histomorphology of villus height (VH), crypt depth (CD) and villus height to crypt depth ratio (VH:CD) of broilers compared to NC group (p<0.05). At the phylum level, Firmicutes was enriched (p<0.05) and Proteobacteria was decreased (p<0.05) only in the ME-LP group. At the genus level, the ME-LP diets increased (p<0.05) the number of both Lactobacillus and Enterococcus compared to NC, PC, and N-LP groups (p<0.05). Conclusion: Microencapsulation assists the efficient functioning of probiotics. ME-LP could be potentially used as a feed additive for improvement of cecal microbiota, gut integrity and nutrient utilization, leading to better performance of broilers.

• Food Science of Animal Resources
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• v.39 no.3
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• pp.459-473
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• 2019

Lactobacillus rhamnosus GG (LGG) has low resistance to low pH and bile salt in the gastrointestinal juice. In this study, the gel made from whey protein concentrate (WPC) and pullulan (PUL) was used as the wall material to prepare the microencapsulation for LGG protection. The gelation process was optimized and the properties of gel were also determined. The results showed the optimal gel was made from 10% WPC and 8.0% PUL at pH 7.5, which could get the best protective effect; the viable counts of LGG were 6.61 Log CFU/g after exposure to simulated gastric juice (SGJ) and 9.40 Log CFU/g to simulated intestinal juice (SIJ) for 4 h. Sodium dodecyl sulphite polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that the WPC-PUL gel had low solubility in SGJ, but dissolved well in SIJ, which suggested that the gel can protect LGG under SGJ condition and release probiotics in the SIJ. Moreover, when the gel has highest hardness and water-holding capacity, the viable counts of LGG were not the best, suggesting the relationship between the protection and the properties of the gel was non-linear.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.572-584
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• 2002

Rapid development in molecular biology and recent advancement in recombinant technology increase identification and commercialization of potential protein drugs. Traditional forms of administrations for the peptide and protein drugs often rely on their parenteral injection, since the bioavailability of these therapeutic agents is poor when administered nonparenterally. Tremendous efforts by numerous investigators in the world have been put to improve protein formulations and as a result, a few successful formulations have been developed including sustained-release human growth hormone. For a promising protein delivery technology, efficacy and safety are the first requirement to meet. However, these systems still require periodic injection and increase the incidence of patient compliance. The development of an oral dosage form that improves the absorption of peptide and especially protein drugs is the most desirable formulation but one of the greatest challenges in the pharmaceutical field. The major barriers to developing oral formulations for peptides and proteins are metabolic enzymes and impermeable mucosal tissues in the intestine. Furthermore, chemical and conformational instability of protein drugs is not a small issue in protein pharmaceuticals. Conventional pharmaceutical approaches to address these barriers, which have been successful with traditional organic drug molecules, have not been effective for peptide and protein formulations. It is likely that effective oral formulations for peptides and proteins will remain highly compound specific. A number of innovative oral drug delivery approaches have been recently developed, including the drug entrapment within small vesicles or their passage through the intestinal paracellular pathway. This review provides a summary of the novel approaches currently in progress in the protein oral delivery followed by factors affecting protein oral absorption.