Effects of precipitation process on the biophysical properties of highly concentrated proteins

Lim Dae Gon,이재철,Kim Dong Jun,Kim Seong Jun,Yu Hyun Woo,정성훈 한국약제학회 2020 Journal of Pharmaceutical Investigation Vol.50 No.5

Purpose One of the primary challenges in developing highly concentrated protein formulations is ensuring adequate stability of the protein product. Among the many available methods, cold solvent precipitation is useful, and it has been adopted for protein purification. This study aimed to characterize protein stability under various precipitation conditions and to determine the most stable precipitation conditions. Methods Lysozyme was used as a model protein to investigate the effects of various solvents and temperature conditions on the physicochemical properties. Size exclusion chromatography, dynamic light scattering, circular dichroism, and thermodynamic analysis are the primary tools for the protein characterization. Results Changes in the rehydrated particle size, secondary structure, thermodynamic stability, and in vitro activity of lysozyme were observed under various conditions. By analyzing the effect of temperature on protein characteristics, it has been discovered that protein precipitation at a temperature of 4 °C or below is optimal. During the precipitation at – 20 °C, the secondary structures of proteins are adversely affected by the formation of ice crystals. None of the solvents used as precipitants in this study affected the activity of the protein. However, changes in the secondary structure were minimal when ethanol and octanol were used. Conclusion In this study, the feasibility of various precipitation conditions was evaluated for stable reversible precipitation formation. Although further studies are needed, precipitation of proteins using various organic solvents could be used in the development of formulations that purify and concentrate proteins.

One-pot synthesis of dopamine-conjugated hyaluronic acid/polydopamine nanocomplexes to control protein drug release

Lim, Dae Gon,Prim, Racelly Ena,Kang, Eunah,Jeong, Seong Hoon Elsevier 2018 International Journal of Pharmaceutics Vol. No.

<P><B>Abstract</B></P> <P>The self-organizing complexes with hyaluronic acid (HA) and polydopamine (PDA), an adhesion mediator via hydrogen bonding, were investigated for use as protein drug carriers. The complexes were prepared with HA of different molecular weights (20 kDa and 200 kDa) and various molar ratios of dopamine and lysozyme, a model protein. Dopamine-conjugated HA (HADA)/PDA complexes were prepared by one-pot synthesis by relying on the self-polymerization of dopamine under oxidative, weakly basic conditions. Lysozyme was bound via coacervation and hydrogen bonding into HADA/PDA complexes. Complex diameters were 100–300 nm, based on transmission electron microscopy image and dynamic light scattering findings. Circular dichroism and differential scanning calorimetry showed that a stable protein formulation was obtained without degradation while preserving the thermal characteristics of lysozyme. Transition temperature (<I>T<SUB>m</SUB> </I>) of the HADA/PDA/lysozyme complex (1:10:0.05 ratio) was 72.45 °C, which is close to the <I>T</I> <SUB>m</SUB> of the native lysozyme (72.46 °C). The efficacy of complexes was also evaluated to protect the structural stability of lysozyme. Lysozyme (0.33 mol) was complexed with HA monomer; consequently, lysozyme activity in the HADA/PDA complex was not affected from short-term degradation. Protein encapsulation and efficacy of the formulations showed successful complexation as protein carriers, thus suggesting an effective combinatory protein delivery system.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Combinatorial nanodiamond in pharmaceutical and biomedical applications

Lim, Dae Gon,Prim, Racelly Ena,Kim, Ki Hyun,Kang, Eunah,Park, Kinam,Jeong, Seong Hoon Elsevier 2016 International journal of pharmaceutics Vol.514 No.1

<P><B>Abstract</B></P> <P>One of the newly emerging carbon materials, nanodiamond (ND), has been exploited for use in traditional electric materials and this has extended into biomedical and pharmaceutical applications. Recently, NDs have attained significant interests as a multifunctional and combinational drug delivery system. ND studies have provided insights into granting new potentials with their wide ranging surface chemistry, complex formation with biopolymers, and combination with biomolecules. The studies that have proved ND inertness, biocompatibility, and low toxicity have made NDs much more feasible for use in real <I>in vivo</I> applications. This review gives an understanding of NDs in biomedical engineering and pharmaceuticals, focusing on the classified introduction of ND/drug complexes. In addition, the diverse potential applications that can be obtained with chemical modification are presented.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Polyamidoamine-Decorated Nanodiamonds as a Hybrid Gene Delivery Vector and siRNA Structural Characterization at the Charged Interfaces

Lim, Dae Gon,Rajasekaran, Nirmal,Lee, Dukhee,Kim, Nam Ah,Jung, Hun Soon,Hong, Sungyoul,Shin, Young Kee,Kang, Eunah,Jeong, Seong Hoon American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.37

<P>Nanodiamonds have been discovered as a new exogenous material source in biomedical applications. As a new potent form of nanodiamond (ND), polyamidoamine-decorated nanodiamonds (PAMAM-NDs) were prepared for E7 or E6 oncoprotein-suppressing siRNA gene delivery for high risk human papillomavirus-induced cervical cancer, such as types 16 and 18. It is critical to understand the physicochemical properties of siRNA complexes immobilized on cationic solid ND surfaces in the aspect of biomolecular structural and conformational changes, as the new inert carbon material can be extended into the application of a gene delivery vector. A spectral study of siRNA/PAMAM-ND complexes using differential scanning calorimetry and circular dichroism spectroscopy proved that the hydrogen bonding and electrostatic interactions between siRNA and PAMAM-NDs decreased endothermic heat capacity. Moreover, siRNA/PAMAM-ND complexes showed low cell cytotoxicityand significant suppressing effects for forward target E6 and E7 oncogenic genes, proving functional and therapeutic efficacy. The cellular uptake of siRNA/PAMAM-ND complexes at 8 h was visualized by macropinocytes and direct endosomal escape of the siRNA/PAMAM-ND complexes. It is presumed that PAMAM-NDs provided a buffering cushion to adjust the pH and hard mechanical stress to escape endosomes. siRNA/PAMAM-ND complexes provide a potential organic/inorganic hybrid material source for gene delivery carriers.</P>

Comprehensive evaluation of carboxylated nanodiamond as a topical drug delivery system

Lim, Dae Gon,Kim, Ki Hyun,Kang, Eunah,Lim, Sun Hee,Ricci, Jeremy,Sung, Si Kwon,Kwon, Myoung Taek,Jeong, Seong Hoon Dove Medical Press 2016 INTERNATIONAL JOURNAL OF NANOMEDICINE Vol.11 No.-

<P>The best strategy in the development of topical drug delivery systems may be to facilitate the permeation of drugs without any harmful effects, while staying on the skin surface and maintaining stability of the system. Nanodiamonds (NDs) play a key role with their excellent physicochemical properties, including high biocompatibility, physical adsorption, reactive oxygen species (ROS) scavenging capability, and photostabilizing activity. <I>Z</I>-average sizes of carboxylated ND (ND–COOH) agglutinate decreased significantly as the pH increased. Fluorescein-conjugated ND was observed only on the stratum corneum, and no sample diffused into the dermal layer even after 48 hours. Moreover, ND–COOH and ND–COOH/eugenol complex did not show significant toxic effects on murine macrophage cells. ND improved in vitro skin permeation >50% acting as a “drug reservoir” to maintain a high drug concentration in the donor chamber, which was supported by quartz crystal microbalance results. Moreover, ND–COOH could adsorb a drug amount equivalent to 80% of its own weight. A photostability study showed that ND–COOH increased the photostability ~47% with regard to rate constant of the eugenol itself. A significant decrease in ROS was observed in the ND–COOH and ND–COOH/eugenol complex compared with the negative control during intracellular ROS assay. Moreover, ROS and cupric reducing antioxidant capacity evaluation showed that ND–COOH had synergistic effects of antioxidation with eugenol. Therefore, ND–COOH could be used as an excellent topical drug delivery system with improved permeability, higher stability, and minimized safety issue.</P>

급성 관상 동맥 증후군으로 오인된 식도 벽내 혈종 1예

유대곤 ( Dae Gon Ryu ),최철웅 ( Cheol Woong Choi ),강대환 ( Dae Hwan Kang ),김형욱 ( Hyung Wook Kim ),정동일 ( Dong Il Jeong ),김완철 ( Wan Chul Kim ),신재규 ( Jae Gyu Shin ),임태원 ( Tae Won Lim ) 대한소화기학회 2017 대한소화기학회지 Vol.69 No.4

Intramural hematoma of the esophagus is a rare condition that can be spontaneous or secondary to trauma, toxic ingestion, or intervention. If it is the spontaneous type, it usually presents initially with epigastric pain, hematemesis or dysphagia. We present a case of intramural hematoma of the esophagus mimicking acute coronary syndrome. A 63-year-old man presented with severe acute chest pain. He has four coronary stents that were inserted five years ago, from a different hospital, and is on dual antiplatelet agents. Coronary angiography was performed immediately under the suspicion of acute coronary syndrome, and we found that there was no obvious clogging of the coronary arteries. Next, chest computed tomography was performed due to suspected aortic dissection, and the result was also negative. Four days later, endoscopy was performed and intramural hematoma covered with large ulcers was diagnosed. (Korean J Gastroenterol 2017;69:239-242)

Effects of annealing on the physical properties of therapeutic proteins during freeze drying process

Lim, Jun Yeul,Lim, Dae Gon,Kim, Ki Hyun,Park, Sang-Koo,Jeong, Seong Hoon ELSEVIER 2018 INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES Vol.107 No.1

<P><B>Abstract</B></P> <P>Effects of annealing steps during the freeze drying process on etanercept, model protein, were evaluated using various analytical methods. The annealing was introduced in three different ways depending on time and temperature. Residual water contents of dried cakes varied from 2.91% to 6.39% and decreased when the annealing step was adopted, suggesting that they are directly affected by the freeze drying methods Moreover, the samples were more homogenous when annealing was adopted. Transition temperatures of the excipients (sucrose, mannitol, and glycine) were dependent on the freeze drying steps. Size exclusion chromatography showed that monomer contents were high when annealing was adopted and also they decreased less after thermal storage at 60°C. Dynamic light scattering results exhibited that annealing can be helpful in inhibiting aggregation and that thermal storage of freeze-dried samples preferably induced fragmentation over aggregation. Shift of circular dichroism spectrum and of the contents of etanercept secondary structure was observed with different freeze drying steps and thermal storage conditions. All analytical results suggest that the physicochemical properties of etanercept formulation can differ in response to different freeze drying steps and that annealing is beneficial for maintaining stability of protein and reducing the time of freeze drying process.</P>

회귀 알고리즘을 이용한 SOA 기반 소프트웨어 품질 측정 시스템

신대용 ( Dae-yong Sin ),한석희 ( Suk-hee Han ),임건재 ( Gun Jea Lim ),김영곤 ( Young-gon Kim ) 한국정보처리학회 2011 한국정보처리학회 학술대회논문집 Vol.18 No.2

현재 SOA 기반 소프트웨어의 중요성이 인식되면서 국내외 SOA 기반 소프트웨어 시장이 급격히 증가하고 있는 추세이다. 이에 따라 SOA 기반 소프트웨어에 대한 고신뢰성과 고품질소프트웨어의 요구가 증대되고 있다. 그러나 SOA기반 소프트웨어의 특성을 반영한 품질평가 체계는 아직 구축되어 있지 않은 실정이며 최근의 소프트웨어 개발 방법의 추세로 볼 때 시급한 구축이 요구되고 있다. 본 연구에서는 SOA 기반 소프트웨어의 품질을 평가하기 위해 품질을 시험하여 측정하고 그 결과를 적절한 기준에 따라 판정하는 방법에 대해 연구를 수행하였다. 주요 연구내용으로는 SOA기반 소프트웨어 품질 측정 설문에 답을 회귀 알고리즘에 적용하여 소프트웨어의 품질을 측정하고 해결책을 제시함으로써 소프트웨어의 부족한 부분을 좀더 보안해줄것을 기대한다. 본 연구를 통해 국제표준을 수용한 SOA 기반 소프트웨어 품질 시험 측정 방법을 구축하였고 이를 활용하여 국내SOA 기반 소프트웨어의 품질 수준 향상을 위해 적용할 수 있을 것이며 국내 SOA 기반 소프트웨어의 품질 향상을 통해 관련 시장의 품질 안정성을 확보하고 고품질 SOA 기반소프트웨어 개발 의욕을 제고할 수 있으리라 기대한다.

南韓에 있어서의 豪雨 : 그 分布와 傾向을 中心으로 Its Distribution and Trend of Appearance

李炳坤,林永大 慶北大學校 文理科大學 1974 文理學叢 Vol.2 No.-

This study puts the main purpose on the clarification of the distribution, factors and trend of appearance of heavy-rainfall in South Korea, and its relation to precipitation. For this study, I have used the data of heavy-rainfall appearance which had been observated at 14 meteorological observatories in South Korean during last 30 years(1941-70) The results may be summarized as follows: 1. Many heavy-rainfalls come in summer which is the rainy season, particularly it peaks in July when typhoon and the rain-front periods are overlapped. 2. Regional distribution of heavy-rainfall is corresponded with that of precipitations. That is to say, it forms the minimum appearance region in the central southern inland around Chopungnyong, and it increases gradually going from here to north and south, and finally forms some maximum appearance regions in the southern part of Seoul to the west and of Kangnung to the east. 3. Except Ullung island where has low frequency of appearance in spite of being a region of heavy precipitation in Korea owing to its particular precipitation type, generally the more precipitation a region has, the higher the frequency of heavy-rainfall' appearance is. 4. However, the precipitation of the whole year except those of heavy-rainfalls are the main factor deciding the annual precipitations of each region, though the heavy-rainfalls are stronger in intensity. 5. Most heavy-rainfalls are caused by the rain-front and typoon, particularly by the typoon. 6. Owing to the attack direction of the rain-fronts and typoons, and land-forms (the arrangement of mountains), in the coastal regions(Mokpo, Pusan, Yosu, Ulsan, Kangnung, Pohang) but central western coast, and islands (Cheju, Ullung), the heavy-rainfalls of typoon type are frequent, in the central western coast, i.e., Kyungin regions(Seoul, Inchon) the heavy rainfalls of the rain-front are frequent. On the other hand, in inland (Chopungnyung, Taegu, Chonju, Kwangju), heavy-rainfalls of various types are mixed. 7. During the last 30 years, the heavy-rainfall in South Korea has increased insignificantly in its frequency of appearance. The regional distribution may be summarized as follows; it forms a decrease region in the central southern region part around Chopungnung, and in islands; to north and south from here it shows an increasing trend, and finally it peaks in the south eastern coast around Ulsan, southern coast around Yosu and in Kyungin region around Seoul.

Osteoid osteoma of the third metatarsal bone: A case report

Moon, Dae Gon,Nam, Kwang Woo,Hyun, Chang Lim,Seo, Kyu Bum Institute for Medical Science 2018 The Journal of Medicine and Life Science Vol.15 No.1

Osteoid osteoma is a benign bone tumor composed of osteoid and atypical bone. The most commonly known sites of following tumor are long tubular bones, especially femur and tibia. Yet, development of osteoid osteoma in the foot is unusual, and there aren't much reported literatures of metatarsal osteoid osteoma. In this article, we report a case of the osteoid osteoma in the 3rd metatarsal bone of a 14-year-old male patient.