• YAKHAK HOEJI
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• v.43 no.2
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• pp.150-159
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• 1999

Hollow type suppositories inserted polyvinyl alcohol (PVA) hydrogel capsule containing propranolol·HCI (PPH) were prepared using different bases, polyethylene glycol (PEG), Witepsol H-15 (WH-15) and Witepsol W-35 (WW-35) to improve the controlled release of PPH. The release of PPH from the hollow type suppository inserted PVA hydrogel capsule was retarded than that from PEG, WH-15, or WW-35 hollow type suppositories in rat rectal cavity. When the suppositories were administered to rats, the controlled release of PPH was proved by the plasma concentration-time-profiles of PPH. No significant difference (p〈0.05) among the three different hollow type suppositories was observed in terms of AUC and MRT of PPH. WH-15 hollow type suppository inserted 12% of PVA hydrogel capsule caused irritation to rat rectal mucosa. However, the WH-15 hollow type suppository inserted PVA hydrogel capsule caused no severe irritation on rectal mucosa. The application of the hollow type suppositories using PVA in sustained rectal delivery of drugs might be feasible.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.512-518
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• 2023

To address inherent weaknesses such as low mechanical strength and limited enzyme loading capacity in conventional chitosan or alginate beads, an additional step involving the exchange of anionic surfactants with hydroxide ions was employed to prepare porous chitosan hydrogel capsules for enzyme immobilization. Consequently, excellent thermal stability and long-term storage stability were confirmed. Furthermore, coating the porous chitosan hydrogel capsules with polydopamine not only improved mechanical stability but also exhibited remarkable enzyme immobilization efficiency (97.6% for M1-D0.5). Additionally, it was demonstrated that the scope of application for chitosan hydrogel beads, prepared using conventional methods, could be further expanded by introducing an additional step of polydopamine coating. The enzyme immobilization matrix developed in this study can be selectively applied to suit specific purposes and is expected to be utilized as a support for the adsorption or covalent binding of various substances.

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.257.1-257.1
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• 2000

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.47.1-47.10
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• 2019

Background: Hyaluronic acid (HA) has been applied as a primary biomaterial for temporary soft tissue augmentation and as a carrier for cells and the delivery of growth factors to promote tissue regeneration. Although HA derivatives are the most versatile soft tissue fillers on the market, they are resorbed early, within 3 to 12 months. To overcome their short duration, they can be combined with cells or growth factors. The purpose of this study was to investigate the stimulating effects of human fibroblasts and basic fibroblast growth factors (bFGF) on collagen synthesis during soft tissue augmentation by HA hydrogels and to compare these with the effects of a commercial HA derivative (Restylane^®). Methods: The hydrogel group included four conditions. The first condition consisted of hydrogel (H) alone as a negative control, and the other three conditions were bFGF-containing hydrogel (HB), human fibroblast-containing hydrogel (HF), and human fibroblast/bFGF-containing hydrogel (HBF). In the Restylane^® group (HGF), the hydrogel was replaced with Restylane^® (R, RB, RF, RBF). The gels were implanted subdermally into the back of each nude mouse at four separate sites. Twelve nude mice were used for the hydrogel (n = 6) and Restylane^® groups (n = 6). The specimens were harvested 8 weeks after implantation and assessed histomorphometrically, and collagen synthesis was evaluated by RT-PCR. Results: The hydrogel group showed good biocompatibility with the surrounding tissues and stimulated the formation of a fibrous matrix. HBF and HF showed significantly higher soft tissue synthesis compared to H (p < 0.05), and human collagen type I was well expressed in HB, HF, and HBF; HBF showed the strongest expression. The Restylane^® filler was surrounded by a fibrous capsule without any soft tissue infiltration from the neighboring tissue, and collagen synthesis within the Restylane^® filler could not be observed, even though no inflammatory reactions were observed. Conclusion: This study revealed that HA-based hydrogel alone or hydrogel combined with fibroblasts and/or bFGF can be effectively used for soft tissue augmentation.

• Journal of Periodontal and Implant Science
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• v.48 no.3
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• pp.152-163
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• 2018

Purpose: To determine whether the swelling and mechanical properties of osmotic self-inflating expanders allow or not the induction of intraoral soft tissue expansion in dogs. Methods: Three different volumes (0.15, 0.25, and 0.42 mL; referred to respectively as the S, M, and L groups) of soft tissue expanders (STEs) consisting of a hydrogel core coated with a silicone-perforated membrane were investigated in vitro to assess their swelling behavior (volume swelling ratio) and mechanical properties (tensile strength, tensile strain). For in vivo investigations, the STEs were subperiosteally inserted for 4 weeks in dogs (n=5). Soft tissue expansion was clinically monitored. Histological analyses included the examination of alveolar bone underneath the expanders and thickness measurements of the surrounding fibrous capsule. Results: The volume swelling ratio of all STEs did not exceed 5.2. In tensile mode, the highest mean strain was registered for the L group ($98.03{\pm}0.3g/cm$), whereas the lowest mean value was obtained in the S group ($81.3{\pm}0.1g/cm$), which was a statistically significant difference (P<0.05). In addition, the S and L groups were significantly different in terms of tensile strength ($1.5{\pm}0.1g/cm$ for the S group and $2.2{\pm}0.1g/cm$ for the L group, P<0.05). Clinical monitoring showed successful dilatation of the soft tissues without signs of inflammation up to 28 days. The STEs remained volumetrically stable, with a mean diameter in vivo of 6.98 mm, close to the in vitro post-expansion findings (6.69 mm). Significant histological effects included highly vascularized collagen-rich fibrous encapsulation of the STEs, with a mean thickness of $0.67{\pm}0.12mm$. The bone reaction consisted of resorption underneath the STEs, while apposition was observed at their edges. Conclusions: The swelling and mechanical properties of the STEs enabled clinically successful soft tissue expansion. A tissue reaction consisting of fibrous capsule formation and bone loss were the main histological events.