title: Novel polymeric microcapsules for targeted drug delivery

authors: Lin, Yuewen

subjects: polymer

abstract: Microencapsulation is a technology in which small particles or droplets are entrapped by a coating to give the particles with many useful properties. Microcapsules have been used to protect the encapsulated material from the environmental conditions or to release the active agent in a sustained and controlled manner into the surrounding medium. This thesis investigated how to develop a post-ruminal delivery system based on polymeric microencapsulation. A major criterion was to develop microcapsules with reversible switching in response to changes of pH in the in vivo environment so contents could be released. The microcapsules must have a thin shell strong enough to withstand harsh physical conditions and a large hollow centre, which will maximise drug-carrying capacity. Two processes were developed to manufacture pH-responsive microcapsules - conventional interfacial polymerisation with plasma-induced grafting and a novel phase-inversion technique with chemical grafting. This research demonstrated that microcapsules with a porous shell could be manufactured by interfacial polymerisation. Carboxyl groups introduced onto the pores in the microcapsule by plasma-induced graft polymerisation of acrylic acid allowed pore openings to be controlled by the pH change of the environment. Polyamide microcapsules made by interfacial polymerisation had a hollow core and a porous shell with smooth external and rough internal surfaces. Their average diameter of 28 µm decreased with increased stirring rate during polymerisation. Shell porosity could be changed by adjusting the ratio of amine monomers used to form the microcapsule shell. An argon plasma treatment was developed to graft acrylic acid onto the microcapsule surface. Plasma treatment with 90 seconds produced 0.56 mmol/g of grafting extent. The effect of pH on releasing contents from poly(acrylic acid)-grafted microcapsules was investigated using two different sized molecules (vitamin B12 and cytochrome c) to simulate model drugs. Release rate was not significantly affected by molecular size; contents were retained when pH was between 7 and 5.5 and released when pH was between 5 and 3.5. Full release occurred at pH below 3. Further studies showed that micron-sized microcapsules with a hollow core and a thick matrix wall could be made from polycaprolactone, polysulfone and polystyrene. A modified solvent evaporation process reduced shell thickness but the microcapsules still had a non-porous skin. Process parameters such as polymer concentration, temperature, surfactant, solvent composition, stirring speed, processing pressure, and co-polymer additives influenced structure and internal morphology of the microcapsules. Morphological characteristics of the microcapsules strongly depended on the way the coating polymer is precipitated, particularly the non solvent–polymer–solvent interactions. Chemical grafting was not successful for grafting acrylic acid onto the polycaprolactone and polysulfone microcapsules. Polystyrene microcapsules with a hollow core and porous micro-channel shell structure were successfully produced using a novel formulation in a phase-inversion process. The outer skin could be removed by re-dissolving the formed microcapsules in a suitable solvent. Open pores with inter-connected micro-channels on the microcapsule surface can be produced by carefully controlling the time the microcapsules are in the solvent. The microcapsule was functionalised using free radical polymerisation to graft acrylic acid onto its surface. However, these microcapsules did not completely retain their contents at pH 7 and had a slow release profile when pH was decreased. Recommendations are given on how to improve and optimise the process. Polystyrene microcapsules made with a simple and inexpensive phase-inversion technique have potential as a targeted drug delivery system. They could be re-usable, compared to most other systems that degrade or disintegrate, and may have other applications as a carrier to immobilise desired molecules onto the microcapsules. Further investigations to optimise manufacturing polystyrene microcapsules should include: larger scale trials; further investigations, using orthogonal tests with multi-variation analysis to optimise factors affection microcapsule porosity and extent of grafting; identifying an alternative, faster way to analyse pore size; and developing a mathematical model for the release rate.

text: Novel polymeric microcapsules for targeted drug delivery Microencapsulation is a technology in which small particles or droplets are entrapped by a coating to give the particles with many useful properties. Microcapsules have been used to protect the encapsulated material from the environmental conditions or to release the active agent in a sustained and controlled manner into the surrounding medium. This thesis investigated how to develop a post-ruminal delivery system based on polymeric microencapsulation. A major criterion was to develop microcapsules with reversible switching in response to changes of pH in the in vivo environment so contents could be released. The microcapsules must have a thin shell strong enough to withstand harsh physical conditions and a large hollow centre, which will maximise drug-carrying capacity. Two processes were developed to manufacture pH-responsive microcapsules - conventional interfacial polymerisation with plasma-induced grafting and a novel phase-inversion technique with chemical grafting. This research demonstrated that microcapsules with a porous shell could be manufactured by interfacial polymerisation. Carboxyl groups introduced onto the pores in the microcapsule by plasma-induced graft polymerisation of acrylic acid allowed pore openings to be controlled by the pH change of the environment. Polyamide microcapsules made by interfacial polymerisation had a hollow core and a porous shell with smooth external and rough internal surfaces. Their average diameter of 28 µm decreased with increased stirring rate during polymerisation. Shell porosity could be changed by adjusting the ratio of amine monomers used to form the microcapsule shell. An argon plasma treatment was developed to graft acrylic acid onto the microcapsule surface. Plasma treatment with 90 seconds produced 0.56 mmol/g of grafting extent. The effect of pH on releasing contents from poly(acrylic acid)-grafted microcapsules was investigated using two different sized molecules (vitamin B12 and cytochrome c) to simulate model drugs. Release rate was not significantly affected by molecular size; contents were retained when pH was between 7 and 5.5 and released when pH was between 5 and 3.5. Full release occurred at pH below 3. Further studies showed that micron-sized microcapsules with a hollow core and a thick matrix wall could be made from polycaprolactone, polysulfone and polystyrene. A modified solvent evaporation process reduced shell thickness but the microcapsules still had a non-porous skin. Process parameters such as polymer concentration, temperature, surfactant, solvent composition, stirring speed, processing pressure, and co-polymer additives influenced structure and internal morphology of the microcapsules. Morphological characteristics of the microcapsules strongly depended on the way the coating polymer is precipitated, particularly the non solvent–polymer–solvent interactions. Chemical grafting was not successful for grafting acrylic acid onto the polycaprolactone and polysulfone microcapsules. Polystyrene microcapsules with a hollow core and porous micro-channel shell structure were successfully produced using a novel formulation in a phase-inversion process. The outer skin could be removed by re-dissolving the formed microcapsules in a suitable solvent. Open pores with inter-connected micro-channels on the microcapsule surface can be produced by carefully controlling the time the microcapsules are in the solvent. The microcapsule was functionalised using free radical polymerisation to graft acrylic acid onto its surface. However, these microcapsules did not completely retain their contents at pH 7 and had a slow release profile when pH was decreased. Recommendations are given on how to improve and optimise the process. Polystyrene microcapsules made with a simple and inexpensive phase-inversion technique have potential as a targeted drug delivery system. They could be re-usable, compared to most other systems that degrade or disintegrate, and may have other applications as a carrier to immobilise desired molecules onto the microcapsules. Further investigations to optimise manufacturing polystyrene microcapsules should include: larger scale trials; further investigations, using orthogonal tests with multi-variation analysis to optimise factors affection microcapsule porosity and extent of grafting; identifying an alternative, faster way to analyse pore size; and developing a mathematical model for the release rate.

year: 2009

title: Opportunities and Challenges of Cultural Heritage Tourism: Socio-economic politics of sustainable tourism in South Sulawesi Province, Indonesia

authors: Junaid, Ilham

subjects: cultural heritage tourism

abstract: The Indonesian constitution has mandated the government to improve the welfare of communities and to maintain cultural identity. Realising the importance of the mandate, different levels of government have adopted sustainability and/or sustainable development in formulating tourism policies and planning. I bring together the theories of postcolonialism and sustainability to examine the conduct of cultural heritage tourism primarily to investigate whether policies of the government have achieved sustainable principles.
  
This research was carried out in Indonesia, a country that has been utilising cultural heritage as tourism attraction. Fieldwork was done in five areas (Makassar, Gowa, Bone, North Toraja and Toraja land) in South Sulawesi that represent the cultural heritage of Bugis, Makassar and Toraja from August 2011 to January 2012. A total of 238 respondents were involved in this study with various methods including 75 interviews (individual and focus group) with government officials, tourism practitioners, local and indigenous communities, people from educational institutions and tourists as well as a questionnaire survey in which 163 respondents participated. A qualitative approach has predominantly guided this research but I also utilised quantitative method (mixed methods) to explore a social and cultural phenomenon from a critical perspective. I concerned with the importance of improving the economic prosperity of local and indigenous people as well as encouraging them to preserve cultural identity through cultural heritage tourism. 

To some extent, cultural heritage tourism provides advantages for those who work in hotels, restaurants as well as for people who work as guides and souvenir sellers. Thus, cultural heritage tourism can be an alternative to preserve cultural heritage and to improve the economic well-being of communities. But in many cases, inequitable benefits of tourism and the poor condition of cultural heritage as well as the low quality of its management indicate that sustainable principles have not been achieved. The reality in the field shows that challenges constrain the implementation of sustainability which are reflected in socio-economic conditions of the communities and political issues. This thesis addresses issues related to these challenges including cultural degradation, tensions between levels of government and the economic problem of communities.
 
This thesis offers an understanding of the importance of cultural heritage as an opportunity for sustainable tourism development. Empowering communities, strengthening regulation and its implementation, prioritising local and indigenous communities in any cultural and tourism programs, strengthening synergy and coordination among levels of government, educating and training local people and implementing political will and trustworthiness by the government are essential to achieve the goals of sustainable development. Communities should not only rely on the government as the main actor in preservation of cultural heritage and in tourism development. Rather, collaboration between stakeholders should be strengthened. Analytical exploration of economic welfare, cultural heritage preservation and issues embedded in them provides a more critical understanding about cultural tourism in particular and tourism studies in general.

text: Opportunities and Challenges of Cultural Heritage Tourism: Socio-economic politics of sustainable tourism in South Sulawesi Province, Indonesia The Indonesian constitution has mandated the government to improve the welfare of communities and to maintain cultural identity. Realising the importance of the mandate, different levels of government have adopted sustainability and/or sustainable development in formulating tourism policies and planning. I bring together the theories of postcolonialism and sustainability to examine the conduct of cultural heritage tourism primarily to investigate whether policies of the government have achieved sustainable principles.
  
This research was carried out in Indonesia, a country that has been utilising cultural heritage as tourism attraction. Fieldwork was done in five areas (Makassar, Gowa, Bone, North Toraja and Toraja land) in South Sulawesi that represent the cultural heritage of Bugis, Makassar and Toraja from August 2011 to January 2012. A total of 238 respondents were involved in this study with various methods including 75 interviews (individual and focus group) with government officials, tourism practitioners, local and indigenous communities, people from educational institutions and tourists as well as a questionnaire survey in which 163 respondents participated. A qualitative approach has predominantly guided this research but I also utilised quantitative method (mixed methods) to explore a social and cultural phenomenon from a critical perspective. I concerned with the importance of improving the economic prosperity of local and indigenous people as well as encouraging them to preserve cultural identity through cultural heritage tourism. 

To some extent, cultural heritage tourism provides advantages for those who work in hotels, restaurants as well as for people who work as guides and souvenir sellers. Thus, cultural heritage tourism can be an alternative to preserve cultural heritage and to improve the economic well-being of communities. But in many cases, inequitable benefits of tourism and the poor condition of cultural heritage as well as the low quality of its management indicate that sustainable principles have not been achieved. The reality in the field shows that challenges constrain the implementation of sustainability which are reflected in socio-economic conditions of the communities and political issues. This thesis addresses issues related to these challenges including cultural degradation, tensions between levels of government and the economic problem of communities.
 
This thesis offers an understanding of the importance of cultural heritage as an opportunity for sustainable tourism development. Empowering communities, strengthening regulation and its implementation, prioritising local and indigenous communities in any cultural and tourism programs, strengthening synergy and coordination among levels of government, educating and training local people and implementing political will and trustworthiness by the government are essential to achieve the goals of sustainable development. Communities should not only rely on the government as the main actor in preservation of cultural heritage and in tourism development. Rather, collaboration between stakeholders should be strengthened. Analytical exploration of economic welfare, cultural heritage preservation and issues embedded in them provides a more critical understanding about cultural tourism in particular and tourism studies in general.

year: 2014

title: Iarararararī

authors: Maxwell, Te Kahautu

abstract: Poi. Lyrics composed by Raniera Poihipi rāua ko Te Kahautu Maxwell. Musical score composed by Te Kahautu Maxwell, Pixie Rogers, Tama Hata, Raharuha Mitai, Renee Mitai, Maisey Rika, Ramari Sherman, Te Rina Ransfield. Performed by Ōpōtiki Mai Tawhiti (Kapa Haka group) (4mins)

Waiata Tira: Aroha
Whakaeke: Haere mai rā
Mōteatea: Te Pātere a Te Turuki
Poi: Iarararararī
Waiata ā ringa: Taku Mana Māori Motuhake
Haka: Waiwharangi
Whakawātea: Āio

text: Iarararararī Poi. Lyrics composed by Raniera Poihipi rāua ko Te Kahautu Maxwell. Musical score composed by Te Kahautu Maxwell, Pixie Rogers, Tama Hata, Raharuha Mitai, Renee Mitai, Maisey Rika, Ramari Sherman, Te Rina Ransfield. Performed by Ōpōtiki Mai Tawhiti (Kapa Haka group) (4mins)

Waiata Tira: Aroha
Whakaeke: Haere mai rā
Mōteatea: Te Pātere a Te Turuki
Poi: Iarararararī
Waiata ā ringa: Taku Mana Māori Motuhake
Haka: Waiwharangi
Whakawātea: Āio

year: 2020-02-06