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동의어 포함

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Title Page

Abstract

Contents

1. Introduction 20

1.1. Alzheimer's disease 20

1.2. Drugs and mechanisms of action for the treatment of Alzheimer's disease 21

1.3. Drug delivery system and limitations for the treatment of Alzheimer's disease 22

1.4. Controlled release drug delivery system for the treatment of Alzheimer's disease 28

1.5. Thermoresponsive hydrogels 30

1.6. Microspheres 33

1.7. Manufacturing method of microsphere 34

1.8. Purpose and strategy of this work 36

2. Materials and method 42

2.1. Materials 42

2.2. Preparation of donepezil-loaded microsphere using monoaxial one-nozzle ultrasonic atomizer 43

2.3. Characterization and morphology evaluation of donepezil-loaded microspheres 44

2.4. Encapsulation efficiency of donepezil-loaded microspheres 45

2.5. Particle size measurement and stability test of donepezil-loaded microsphere 46

2.6. Mechanical properties of donepezil-loaded microsphere 47

2.7. Synthesis and characterization of PCL 47

2.8. Preparation and rheological characterization donepezil-loaded combination formulations 49

2.9. Uniformity evaluation of donepezil-loaded combination formulations during injection 50

2.10. Injectability and injection force evaluation of donepezil-loaded combination formulation 51

2.11. In vitro drug release of donepezil-loaded combination formulation 52

2.12. In vivo subcutaneous injection of donepezil-loaded combination formulation 53

2.13. In vivo drug release of donepezil-loaded combination formulation 55

2.14. In vivo biodegradation evaluation of donepezil-loaded combination formulation 56

2.15. In vivo physicochemical evaluation of donepezil-loaded combination formulation 57

2.16. In vivo biocompatibility evaluation of donepezil-loaded combination formulation 58

2.17. Statistical analyses 60

3. Results and discussion 61

3.1. Preparation and characterization of donepezil-loaded microsphere 61

3.2. Encapsulation and yield of donepezil-loaded microsphere 64

3.3. Comparison of particle size and distribution of donepezil-loaded microspheres 67

3.4. Stability evaluation of donepezil-loaded microsphere 71

3.5. Mechanical property of donepezil-loaded microsphere 73

3.6. Preparation and rheological characterization donepezil-loaded combination formulations 76

3.7. Uniformity evaluation of donepezil-loaded combination formulations during injection 82

3.8. Injectability and injection force evaluation of donepezil-loaded combination formulations 86

3.9. In vitro drug release of donepezil-loaded combination formulations 92

3.10. In vivo subcutaneous injection of donepezil-loaded combination formulations 96

3.11. In vivo drug release of donepezil-loaded combination formulations 104

3.12. In vivo biodegradation and morphology evaluation of donepezil-loaded combination formulations 113

3.13. In vivo biodegradation and physicochemical evaluation of donepezil-loaded combination formulations 119

3.14. In vivo biocompatibility evaluation of donepezil-loaded combination formulations 129

4. Conclusion 140

5. References 142

List of Publications 151

List of Patent 153

List of Book chapter 153

List of Presentations 154

List of Awards 155

Abstract (In Korean) 156

List of Tables

Table 1. Types and characteristics of drug delivery systems. 27

Table 2. Characteristic analysis of Do-PLGA-M and Do-PLA-M. 66

Table 3. Tₘₐₓ, Cₘₐₓ, bioavailability (AUC₀₋ₜ) and drug release rate of the donepezil released from each depot of Do-PLGA-M, Do-PLA-M and Do-PLA-M/PCL. 112

List of Figures

Figure 1. (a) drug for treatment Alzheimer's disease, (b-d) Release drug concentration vs. time plot (b) general drug IV injection system. (c) general drug... 26

Figure 2. Schematic representation for thermoresponsive hydrogel. 32

Figure 3. Schematic representation for single formulation and combination formulation of drug delivery system. 40

Figure 4. Schematic representation of (a) donepezil-loaded microsphere (Do-PLGA-M and Do-PLA-M) with ultrasonic frequency atomizer and (b) reduction of... 41

Figure 5. Characterization of Do-PLGA-M and Do-PLA-M. (a) optical microscopy (x 10), (b) Camscope (x 300), (c) scanning electron microscopy (SEM; x 500). 63

Figure 6. Dynamic light scattering (DLS) of (a) PLA-M, (b) Do-PLGA-M, (c) Do-PLA-M 30%, (d) Do-PLA-M 35% and (e) Do-PLA-M 40%. 70

Figure 7. The change of particle sizes of Do-PLGA-M and Do-PLA-M at (a) 4 ˚C and (b) 37 ˚C for 4 weeks. 72

Figure 8. Nanoindentation tests of Do-PLGA-M and Do-PLA-M. (a) load-displacement curves, (b) Young's (elastic) modulus, (c) hardness of Do-PLGA-M... 75

Figure 9. Preparation and characterization of PCL. (a) preparation scheme of PCL, (b) ¹H-NMR, (c) GPC curve, (d) characterization analysis of PCL. 80

Figure 10. Rheological characterization of PCL, Do-PLGA-M/PCL, Do-PLA-M/PCL, (a) viscosity-temperature curves, (b) viscosity at 25 ˚C and 37 ˚C, (c)... 81

Figure 11. Images of donepezil injectable formulations and fluorescein injectable formulations. (a) optical images of Do-PLGA-M, Do-PLA-M and Fl-PLA-M... 85

Figure 12. Injectability tests of (a) injection solution, PCL, Do-PLGA-M, Do-PLGA-M/PCL, Do-PLA-M, Do-PLA-M/PCL formulation loaded into a syringe,... 91

Figure 13. In vitro drug release of donepezil-loaded injectable formulation (Do-PLGA-M, Do-PLA-M and Do-PLA-M/PCL). (a) accumulated in vitro release... 95

Figure 14. In vivo donepezil-loaded depots after injection of donepezil-loaded injectable formulations. (a) images of Do-PLA-M/PCL depot formed and removed... 102

Figure 15. In vivo drug release of donepezil-loaded depot after injection of donepezil-loaded injectable formulations. (a) accumulated in vivo release behavior... 111

Figure 16. (a) Camscope (optical) images of surface images and (b) SEM images of cross-sections image of Do-PLGA-M, Do-PLA-M and Do-PLA-M/PCL depots... 118

Figure 17. In vivo physicochemical and biodegradation evaluation of PLGA-M, PLA-M, PLA-M/PCL depots formed after in vivo subcutaneous injection of... 125

Figure 18. (a, b) ¹H-NMR signals of PLGA-M, PLA-M and PLA-M/PC depot removed from SD rats at 1, 3, 6, 8 weeks after in vivo subcutaneous injection of... 127

Figure 19. In vivo physicochemical and biodegradation of PLGA-M, PLA-M and PLA-M/PCL depots formed in vivo subcutaneous injection of injectable... 128

Figure 20. H&E-stained histological sections of Do-PLGA-M, Do-PLA-M and Do-PLA-M/PCL depots removed from SD rats at 1, 3, 6 and 8 weeks after in vivo... 137

Figure 21. (a) ED1-stained histological sections of donepezil-loaded depots removed from SD rats at 1, 3, 6 and 8 weeks after subcutaneous injection of... 138

Figure 22. (a) CD4-stained histological sections of donepezil-loaded depots removed from SD rats at 1, 3, 6 and 8 weeks after subcutaneous injection of... 139

초록보기

 도네페질(Do)은 알츠하이머 질환 환자에게 경구 투여 제형으로 응용되고 있다. 하지만 부작용 유발 가능성과 함께 매일 투여해야 하는 불편함이 있다. 따라서 최근 서방형 약물 전달을 위해 도네페질과 함께 PLGA 혹은 PLA 로 제조한 마이크로스피어(Do-PLGA-M or Do-PLA-M)를 제조하여 주입형 제형으로서 연구되고 있다. 하지만 이러한 마이크로스피어 제형은 초기 과량 약물 방출 현상(initial burst)으로 인하여 보통 4 주 이내로 약효 지속 시간이 끝나게 되며, 만성질환인 알츠하이머 환자에게 불편함을 초래한다. 따라서 이번 연구에서는 Do-PLA-M 를 methoxy poly(ethylene glycol)-b-poly(ε-caprolactone) hydrogel (PCL)과 섞은 combination 제형(Do-PLA-M/PCL)으로 제조하였으며, 마이크로스피어의 initial burst 를 억제하고, 약물 방출 기간을 연장하고자 하였다. 초음파 분사법을 이용하여 제조한 Do-PLGA-M, Do-PLA-M 은 약 93% 이상의 높은 약물 봉입률, 수율과 함께 입자 크기가 매우 균일하게 제조되었다. 이는 기존의 마이크로스피어 제조 방식보다 효율이 뛰어나며, 최적화된 방법으로서 재현성이 증명되었다. Do-PLA-M/PCL 은 성공적으로 합성된 PCL 과 Do-PLA-M 을 함께 상온에서 균일하게 섞이면서 쉽게 제조할 수 있었다. Do-PLA-M/PCL 을 주입 용이성 및 온도감응성 평가를 진행하였을때 체내에 막히는 것 없이 쉽고 균일하게 주입할 수 있었다. 또한, 하이드로겔을 잘 형성하는 것을 통해 적절한 주입형 제형으로서 비침습적으로 환자에게 주입할 수 있음을 확인하였다. In vitro 및 in vivo 약물 방출 평가를 진행하였을 때 Do-PLGA-M 보다 Do-PLA-M 이 더 지속적으로 약물을 방출할 수 있었으며, matrix polymer 의 특성에 따른 마이크로스피어의 물성 및 생분해 속도 차이에 의해 약물 방출 거동이 달라질 수 있음을 확인하였다. Do-PLA-M/PCL 은 PCL 하이드로겔이 Do-PLA-M 을 감싸는 barrier 역할을 함으로써 initial burst 를 효과적으로 억제하였으며, Do-PLA-M 의 생분해를 지연시켰다. 결과적으로 Do-PLA-M/PCL 의 약물 방출 기간은 약 8 주 이상으로 안정적으로 연장되었다. 도네페질이 담지된 주입형 제형(Do-PLGA-M, Do-PLA-M, Do-PLA-M/PCL)들의 생분해 속도를 비교하기 위해 micro-CT, SEM, NMR, GPC 을 진행하였다. Do-PLGA-M 이 가장 생분해 속도가 빨랐으며, Do-PLA-M/PCL 이 가장 느렸다. 이러한 결과는 약물 방출 속도의 경향과 일치하였다. 또한 생체적합성 및 염증 발현도 평가를 진행하였을 때, Do-PLGA-M 은 Do-PLA-M/PCL 보다 더 높은 염증 반응을 보였으며, PLGA 의 빠른 생분해로 인한 산성부산물의 축적이 더 강한 염증 반응을 유도함을 확인하였다. 결과를 종합하였을 때, Do-PLA-M 과 PCL hydrogel 을 combination 제형으로 응용하면 약물 방출 기간 연장과 함께 비침습적 주입형 제형으로서 투약 빈도를 줄이고 치료 효율 상승 및 알츠하이머 환자의 편의성을 증대시킬 수 있다.