• Journal of Periodontal and Implant Science
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• v.35 no.4
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• pp.877-889
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• 2005

This study was designed to compare the effects of treatment using chitosan membrane $(Nanogide-C^{(R)})$ resorbable barrier with control treated by polylactic acid/polylacticglycolic acid membrane(PLA/PLGA membrane, $Biomesh^{(R)}$). 44 furcation defecs from 44 patients with class 2 furcation degree were used for this study, 22 sites of them were treated by chitosan membrane as experimental group and 22 site were treated by PLA/PLGA membrane as control group. Clinical parameters including probing depth, gingival recession, attachment level and radiographic examination were evlauated at base line, 1 month, 2 month and 3 month. after surgery. Statistical test used to analyze these data included paired t-test, one way ANOVA. The results are as follows : 1. Probing depth was significanlly decreased in the two group and there were significant differences between groups(p<0.05). 2. Gingival recession was not significanlly increased in the two group and there were no significant differences between groups(p<0.05). 3. Loss of attachment was statistically decreased in the two group and there were no significant differences between groups(p<0.05). 4. Horizontal bone level was significanlly increased in the two group and there were significant differences between groups(p<0.05). On the basis of these results, chitoans resorbable membrane has similar potential to PLA/PLGA membrane in GTR for furcation defect.

• Journal of Pharmaceutical Investigation
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• v.31 no.4
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• pp.257-263
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• 2001

The microspheres have been developed as a new drug delivery system. Although many particulate drug carriers, such as liposome, niosome and emulsion, have been introduced, injectable and biodegradable microspheres appears to be a particularly ideal delivery system because the local anesthesia is not necessary for the insertion of large implants and for the removal of the device after the drug release is finished. Biodegradable microspheres with nicotine and triamcinolone acetonide are prepared and evaluated. As biodegradible polymers, PLA (M.W. 15,000, PLA-0015), PLGA (M.W. 17,000, RG 502) and PLGA (M.W. 8,600, RG 502H) are used. This study attempted to prepare and evaluate the nicotine and triamcinolone acetonide-incorporated microspheres, which were prepared by two methods, solvent-evaporation and spray-drying methods. The microspheres, as a disperse system for injections, were evaluated by particle size, size distribution, entrapment efficiency, and in vitro drug release patterns. The differences of preparation method, partition coefficient, types of polymer, and preparation conditions of microspheres influence the particle size, entrapment efficiency, and in vitro drug release patterns.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.100.1-100.1
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• 2003

Tissue engineering has arisen to address the extreme shortage of tissues and organs for transplantation and repair. One of the most successful techniques has been the seeding and culturing cells on three-dimensional biodegradable scaffolds in vitro followed by implantaion in vivo. We used PLA and PLGA as biodegradable polymers and rabbit chondrocytes were isolated and applied to PLA and PLGA to make artificial cartilage. To evaluate the biocompatibility and biological safety of polymers, in vitro cytotoxicity and in vivo animal tests were investigated. (omitted)

• Macromolecular Research
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• v.10 no.3
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• pp.158-167
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• 2002

In order to endow with new bioactive functionality from small intestine submucosa (SIS) powder as natural source to poly (L-lactide) (PLA) and poly (lactide-co-glycolide) (PLGA) synthetic biodegradable polymer, porous SIS/PLA and SIS/PLGA as natural/synthetic composite scaffolds were prepared by means of the solvent casting/salt leaching methods for the possibility of the application of tissue engineered bone and cartilage. A uniform distribution of good interconnected pores from the surface to core region was observed the pore size of 40~500 ${\mu}{\textrm}{m}$ independent with SIS amount using the solvent casting/salt leaching method. Porosities, specific pore areas as well as pore size distribution also were almost same. After the fabrication of SIS/PLA hybrid scaffolds, the wetting properties was greatly enhanced resulting in more uniform cell seeding and distribution. Five groups as PGA non-woven mesh without glutaraldehyde (GA) treatment, PLA scaffold without or with GA treatment, and SIS/PLA (Code No.3 ; 1 : 12 of salt content, (0.4 : 1 of SIS content, and 144 ${\mu}{\textrm}{m}$ of median pore size) without or with GA treatment were implanted into the back of nude mouse to observe the effect of SIS on the induction of cells proliferation by hematoxylin and eosin, and von Kossa staining for 8 weeks. It was observed that the effect of SIS/PLA scaffolds with GA treatment on bone induction are stronger than PLA scaffolds, that is to say, in the order of PLA/SIS scaffolds with GA treatment > PLA/SIS scaffolds without GA treatment > PGA nonwoven > PLA scaffolds only with GA treatment = PLA scaffolds only without GA treatment for the osteoinduction activity. The possible explanations are (1) many kinds of secreted, circulating, and extracellular matrix-bound growth factors from SIS to significantly affect critical processes of tissue development and differentiation, (2) the exposure of SIS to GA resulted in significantly calcification, and (3) peri-implant fibrosis due to covalent bonding between collagen molecule by crosslinking reaction. In conclusion, it seems that SIS plays an important role for bone induction in SIS/PLA scaffolds for the application of tissue engineering area.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.227.2-228
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• 2003

In many biodegradable polymers recently investigated, poly(lactic acid)(PLA) or poly(lactic-co-glycolic acid)(PLGA) have extensively been utilized as drug delivery systems for sustained release drug delivery. Recently, there has been increased interest in electrospinning, which can produce fibers that are sub-micron in diameter. This technique has been applied to various micro/nano fabrication areas using numerous polymers but very few uses in the sharmaceutical area have been reported. (omitted)

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.91-109
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• 2001

The purpose of this study is to evaluate histologically the resorption and tissue response of various resorbale membranes used for guided tissue regneration procedures, using a subcutaneous model on the dorsal surface of the rat. In this study, 12 Sprague-Dawley male rats(mean BW 150gm) were used and the commercially available materials included dense collagen membrane, freeze-dried bovine dura mater loos collagen membrane, PLA/PLGA membrane. Animals were sacrificed at 3, 6 and 8 weeks after implantation of various resorbable membranes. Specimens were prepared with Hematoxylin-Eosin stain for light microscopic evaluation. The results of this study were as follows: 1. Resorption : Loose collagen membrane group was resorbed most rapidly. Dense collagen membrane group and freeze-dried bovine dura mater group were rarely resorbed. 2. Inflammatory reactions : PLA/PLGA membrane group showed persistent and severe inflammatory reactions for 3 to 8 weeks. Moderate inflammatory reactions and the ectopic formation of calcified material were observed in dense collagen membrane group. Freeze-dried bovine dura mater group and loose collagen membrane group showed mild inflammatory reactions 3. In PLA/PLGA membrane group, multinucleated giant cells by foreign body reactions were observed. In conclusion, the resorption of freeze-dried bovine dura mater didn't happen for 3-6weeks, which showed the best bio-compatibility. Therefore, freeze-dried bovine dura mater was considered proper resorbable membrane for guided tissue regeneration.

• Polymer(Korea)
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• v.34 no.3
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• pp.274-281
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• 2010

In this study, PEG-PLA(or PLGA) amphiphilic di-block copolymers were synthesized by ring opening polymerization of D,L-lactide(or glycolide) and applied to polymeric micelle system for solubilization of a rosiglitazone as diabetes drug. The drug could be efficiently loaded into the polymer micelle by solid dispersion technique, and the drug-loaded micelles were characterized and evaluated as a drug delivery carrier by fluorescence spectrometer, DSC, and DLS measurements. The colloidal stability of drug loaded micelles in aqueous media could be enhanced by addition of 2-hydroxy-N-picolylnitinamide as a hydrotropic agent. The polymer micelles also showed biocompatible and nontoxic properties in vitro cell viability using MTT assay, and the drug loaded micelles were observed to be more effective than free drug for decreasing glucose in blood of rats.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.218-220
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• 2003

지방족 폴리에스터계 고분자인 폴리락타이드 (polylactide, PLA), 폴리글리콜라이드 (polyglycolide, PGA) 및 이들의 공중합체인 락타이드-글라이콜라이드 공중합체 (PLGA)는 생체 친화성이고 생분해성이며 물리적 강도가 우수하고 쉽게 성형할 수 있다. 그리고, 전기방사는 수 마이크로에서 수십 나노크기의 지름을 가지는 초극세 섬유인 나노섬유의 제조 기술로서 기존의 섬유 방사방식과는 근본적으로 다른 새로운 방사기술로 산업적인 융용 가능성이 무한한 미래지향적 기술로 최근 주목을 받고 있다. (중략)

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.550-553
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• 2000

The polymeric matrices made with poly(D,L-lactide-co-glycolide) were prepared using copolymer of poly(D,L-lactide) and poly(ethylene glycol) for application of drug delivery systems. Catalyst made use of stannous actoate. Particle size were differ greatly$(435.3{\pm}11.2{\sim}2284.1{\pm}188.5)$ that nanoparticle made use of according to solvent of various kinds. Polymer could a sharp distinction with copolymerized among LE-1, LE-2 and LE-3 of PLA and PEG of content that to examine $^1H-NMR$ of copolymer make refine and reprecipitation. Drug delivery effect at PLGA nanoparticle : PLA amount more then proved highly drug delivery amount that each LE-1, LE-2, LE-3, drug and solvent was 40mg, 20mg and 10mg. Drug delivery effect proved higher 20mg that change(10mg, 20mg, 40mg) at drug feeding amount with LE-2. The first a lot of drug proved delivery. LE-3 most lactide content proved much delivery since biodegradable on PLGA copolymer result from lactide. Also biodegradable rate was highest at LE-3 much of lactide content, because influence at biodegradable effect of lactide by inclusive of soft PEG.

• Journal of Periodontal and Implant Science
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• v.35 no.3
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• pp.703-718
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• 2005

The purpose of this study was to evaluate the clinical efficacy of guided tissue regeneration(GTR) technique using chitosan nanofiber membrane and to compare it to the clinical efficacy following GTR using PLA/PLGA(copolymer of polvlactic acid and polylacticglycolic acid) membrane in mandibular class II furcation defects in human. The chitosan nanofiber membranes were applied to the mandibular class II furcation defects of 13 patients(test group) and PLA/PLGA membranes were applied to those of 11 patients(control group). Probing pocket depth, clinical attachment level, gingival recession, plaque index and gingival index were measured at baseline and 3 months postoperatively. Vertical and horizontal furcation defect depth were measured at surgery. Both groups were statistically analyzed by Wilcoxon signed Ranks Test and Mann-Whitney Test using SPSS program. The results were as follows: 1. Probing pocket depth, clinical attachment loss and gingival index were significantly reduced at 3 months postoperatively compared to values of baseline in both groups(p<0.05). 2. Gingival recession and plaque index were not significantly decreased at 3 months postoperatively compared to values of baseline in both groups. 3. No significant difference between two groups could be detected with regard to changes of probing pocket depth, gingival recession, clinical attachment level, plaque index and gingival index at 3 months postoperatively. In conclusion, chitosan nanofiber membrane is effective in the treatment of human mandibular class II furcation defects and a longer period study is needed to fully evaluate the outcomes.