The aim of this project was to characterize the surface properties of materials used in tablet formulations with sub-micron resolution by the techniques of Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Scanning Thermal Microscopy (SThM), Nano-TA system, Differential Scanning Calorimeter (DSC), Attenuated Total Reflectance Infrared (ATR-IR), Near-Infrared Spectroscopy (NIR) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). In particular, the work aimed to develop new AFM based methodologies to advance this method both in terms of quantification and mapping. AFM was employed to investigate properties of solid materials such as surface free energy, Young’s modulus, melting point and phase transition temperatures from pharmaceutical materials in blend mixtures with the nanoscale resolution. These approaches developed here provide new tools to understand the process induced changes and stability issues in solid dosage forms such as tablets and inhalation formulations from minute amounts of materials. The surface free energy values of solid materials obtained from AFM adhesion force measurements were described in Chapter 3. The adhesion forces obtained with AFM in low relative humidity environments were used to derive the surface free energy values using the Hertzian and JKR based models. The surface free energy was proposed to be close to the so called dispersion surface free energy since the adhesion forces at low relative humidity mainly resulted from van der Waals forces in the systems studied here. The comparison of surface free energy between AFM and those derived from a contact angle method showed that the dispersion surface free energy values derived from the contact angle method were generally higher than those from AFM. For example, the surface free energy value derived from AFM adhesion force measurements for lactose monohydrate was 33.0 mJ/m2, while from contact angle method the value was 46.8 mJ/m2. Whilst in reasonable agreement, the variation was believed to result from the differences in probe substance (liquid in contact angle and solid in AFM method), scale of measurements (contact area 200 nm2 in AFM, several mm2 in contact angle) and possible polar interactions. However, the surface free energy values derived from direct solid-solid interactions in AFM adhesion force measurements may have more relevances in applications that relate to solid-solid interactions, such as in pharmaceuticals. The influence of polar interaction in AFM adhesion force measurements at low relative humidity was further investigated in Chapter 4. The techniques of colloid probe and plasma polymerized coating were employed: Plasma polymerized hexane and allylamine were coated on the surfaces of glass beads mounted on AFM cantilevers. Plasma Polymerized Hexane had only a dispersion surface free energy while plasma polymerized allylamine had both dispersion and polar surface free energy components. The differences in normalized adhesion forces between these two kinds of colloid probes can reveal the influence of polar interactions at low relative humidity in AFM adhesion force measurements. For most samples, the experimental adhesion forces with plasma polymerized allylamine colloid probes were smaller than the theoretical values calculated from dispersion interactions. The polar interactions in such conditions were repulsive so they had decreased the experimental adhesion forces. So in AFM adhesion force measurements, the polar interactions existed even at very low humidity. However the relative magnitude of polar interactions were smaller than the dispersion interactions and for silicon sample the polar interactions were negligible. In Chapter 5, properties including Young’s modulus, melting points and phase transition temperature were measured at the nanoscale with AFM, SThM and the nano-TA system. The variation of Young’s modulus with temperature, for the excipients hydroxypropylmethylcellulose (HPMC), dibasic calcium phosphate dihydrate (DCPD) was studied. The differences in Young’s modulus between DCPD and its anhydrous form were revealed with AFM measurements. The melting point and phase transition temperature were measured by nano-TA system with sub-100 nm spatial resolution. The thermal properties obtained from nano-TA system were consistent with those from bulk measurements using DSC: e.g. the dehydration of lactose monohydrate (150 ºC) was confirmed by nano-TA system and DSC measurements. In Chapter 6, the methods to derive surface free energy and thermal properties described in previous chapters were employed to spatially locate and characterize an API (AZD 3409 malate salt) and excipient (lactose monohydrate) on the surface of a model tablet at the nanoscale using AFM and the nano-TA system. The API and excipient were mixed with the ratio of 20:80. 50:50 and 80:20 w/w and compressed into discs to create the model tablets. The surfaces of model tablets were first characterized by ATR-IR, NIR and ToF-SIMS. Then AFM adhesion force measurements were carried out to map the location of each component in the mixed discs. In addition, in situ topography AFM images of the discs were recorded. At the position of force mapping, the nano-TA system was employed to correlate the thermal properties including the melting points of both materials and the dehydration of the lactose monohydrate with surface free energy information from force mapping. The surface free energy and thermal properties data were consistent with bulk measurements in previous chapters. In situ correlation between AFM force mapping (surface energy) and nano-TA system (thermal properties) at 5 differences positions on a model disc surface showed consistent identification of the two materials. This proof of principal work can be extended to more complex formulations and has the potential to be employed in early stage solid state stability testing to identify the appearance of new species at surfaces or solid-solid interfaces.

This thesis explores what UK community pharmacists experience as ethical problems in their work, how they try to resolve such problems and how the community pharmacy setting may be of influence. Utilising existing normative ethical theories, but acknowledging the status of empirical ethics research and also the social context of ethical problems, semi-structured interviews were conducted with a purposive sample of twenty three community pharmacists from the north of England, UK. It was found that pharmacists encountered ethical problems in the routine minutiae of dispensing prescriptions and medicines sales. Ethical problems often involved legal and procedural concerns and could be distinguished from philosophical dilemmas and many pharmacists understood law and ethics synonymously. Ethical passivity emerged as a description of pharmacists who were ethically inattentive, displayed legalistic self-interest and failed to act ethically. Ethical reasoning was often incomplete and involved appeals to consequences, the golden rule, common sense and religious faith. Some pharmacists were ethically active and sensitive to ethical issues and experienced ethical doubt and uncertainty. The code of ethics and the advice of professional bodies were not considered helpful. The community pharmacy setting precipitated ethical problems and was inimical to ethical practice since pharmacists' relative isolation from others precluded ethical discussion and relationships; pharmacists' subordination to doctors precipitated problems and vitiated ethical responsibility; routinization of pharmacists' work meant difficult ethical situations could be avoided. The findings of this thesis raise questions as to how pharmacists can be effectively educated in ethical issues at an under- and post-graduate level; how values can be adequately transmitted within the profession given the ineffectiveness of the code of ethics; whether pharmacists are ethically prepared for new primary care roles; and whether isolation and subordination may be ethically problematic in healthcare more generally.

The potential application of inkjet printing technology to produce precisely dosage care is demonstrated in this thesis. Inkjet printing technology as it offers the opportunity to deliver quantities with high accuracy can produce medicines tailored for each patient. The viability of this method was first demonstrated by using Felodipine as an active pharmaceutical ingredient polyvinyl pirrolidone (PVP) as an excipient. Felodipine is an antihypertensive drug which is poorly soluble in water and PVP is a highly soluble polymer commonly used to improve drugs' bioavailability. These were dissolved at various ratios in a mixture of ethanol and DMSO (95/5). Using a piezoelectric driven dispenser, picolitre size droplets of the solutions were dispensed onto suitable hydrophobic substrates. The dried products were characterized using AFM, localized nano-thermal analysis and high resolution vibrational spectroscopy (ATR-IR and Raman). Results indicate intimate mixing of the micro-dot API and excipient mixtures. Specifically, ATR-IR confirmed the interaction of felodipine and PVP by means of hydrogen bonding. Nanothermal analysis indicates a single glass transition point which is lowered as the API concentration increases. Finally, confocal Raman microscopy mapping on single droplets allows the visualization of the homogeneous distribution of the drug. Also, capozide has been used as a model therapeutic system which could be produced rapidly as a viable formulation using the inkjet printing technology. Capozide consists of captopril, an angiotensin converting enzyme (ACE) inhibitor and hydrochlorothiazide, a thiazide diuretic drug, in varying ratios. These active pharmaceutical ingredients (APIs) and poly(lactic-co-glycolic acid) (PLGA) were dissolved in appropriate solvents and using a piezoelectric driven dispenser and pipetting, picolitre and microlitre size droplets respectively were deposited onto hydrophobic coated glass slides. Captopril and PLGA were dissolved in chloroform, ethanol and DMSO (75/18/7). Hydrochlorothiazide (HCT) and PLGA were dissolved in acetone and DMSO (93/7). The dried products where characterised using AFM and high resolution Raman microscopy. The results showed that both capropril and HCT are phase separated with the PLGA. Also, the dissolution profiles of the final products were measured using HPLC where it has been shown that PLGA can control the release of the drug from the formulation. These results are a promising first step to produce pharmaceutical by means of inkjet printing.

Osteoarthritis (OA) is a chronic degenerative disease of the joint. Current treatments for this disease (such as glucocorticoid steroids) aim to reduce pain and increase mobility. Intra-articular injection is used in OA as treatment can be targeted to affected joints only. There is currently a lack of sustained release formulations for intra-articular injection. The aim of this thesis was to produce and characterise an injectable intra-articular drug delivery system capable of providing delivery of the steroid dexamethasone phosphate (DXMP) over 3 months. This would be an injectable hydrogel that contains drug loaded nanoparticles. Initially two systems Pluronic F127 gels and polyelectrolyte complexes between hyaluronic acid (HA) and chitosan, were investigated. The complexes between HA and chitosan were selected for the hydrogel portion of this system as they showed the greatest stability and promise in initial studies. To improve the polyelectrolyte complex properties a modified HA was synthesised. This modified polymer caused faster complex formation and produced stronger, more resilient complexes. DXMP was incorporated into poly(glycerol-adipate) (PGA) nanoparticles. A low but sufficient drug loading was achieved and particles were found to give a sustained drug release over 28 days. Nanoparticles were found to be efficiently incorporated and well retained within complexes. Nanoparticles slightly improved complex formation and properties. Composites were able to be formulated into an injectable form. Drug release from directly loaded complexes was rapid. A full release profile was not determined from composites of nanoparticle loaded complexes, however, over 60% of the loaded drug was recovered after 56 days of release study. Dexamethasone crystals were also incorporated directly into complexes to investigate the necessity of the use of nanoparticles. This gave a sustained drug release over 90 days making this system worthy of further investigation. These results highlight the different responses of these systems using drugs with different hydrophobicities.

In many low-income countries, the disease burden is high but health workers are scarce. To increase the number of health workers, one of the most urgent tasks is to produce more health workers. Grounded in the disciplinary focus of pharmacy, this research looks for alternative, innovative strategies to build the capacity of an education institution in a resource-poor setting. Malawi was chosen as a case study country because of its newly established pharmacy degree programme. A broadly ethnographic approach is employed in order to enhance cultural sensitivity and to understand capacity problems from an insider perspective. The fieldwork took place in 2010 and explored a wide range of pharmaceutical activities in the country. An interpretivist epistemology has also facilitated this research to cross beyond its science-based roots in the ‘human resource for health’ (HRH) research paradigm into other disciplinary areas, notably education and African Studies. The first objective of this study was to explore the roles of pharmacists in Malawi. It was agreed by all stakeholders that pharmacists should become managers of medicines, particularly at the district hospitals. Pharmacists were expected to solve the chronic problems of rampant drug pilferage and shortages in essential drugs. Although pharmacy technicians had traditionally assumed the managerial roles at district hospitals, they were deemed unfit for these roles at present day. Some were even accused of stealing drugs. This phenomenon was caused by multiple contextual factors, including a new perception about professionalism. Because of their professional titles, pharmacists were perceived to be superior to the pharmacy technicians in terms of knowledge, power and ethics. This perception was not supported by concrete evidence of pharmacists’ more superior behaviour. A deeper investigation revealed this perception was most probably shaped by colonial legacies and Western views. Home grown definition of professionalism was suppressed because it was not an agenda deemed important by the community of global health governance. The primary agenda by the global health governance to scale up service delivery, but ignoring the growth of domestic agendas for professionalism, may need reconsidering in post-Millennium Development Goal era. The second objective of the study was to explore capacity problems in pharmacy education in Malawi. Capacity problems faced by the education institution were found to be similar to problems reported in the wider literature of African higher education, which include underfunding, understaffing, lack of university autonomy from the state, small student intake and hence high unit costs. There were also serious problems concerning leadership and accountability. Rather than simply filling up these capacity gaps, this study argues that it is more important to see how the problems are closely linked with local contexts. Several cultural contexts, for instance regionalism and traditional practice of witchcraft, were found to be strong divisive factors threatening cohesiveness in an institution. The euphoria for personal freedom, after a 30-year dictatorship, still had its impact on governance and accountability. Colonial legacies and donor policies, which were often interventionist, left little space to inspire creativity and leadership. To link contexts to capacity building, this research argues for the importance of using an interdisciplinary approach. In fact, the journey of how this study evolved from single to an interdisciplinary was recorded in this thesis. The third objective of the study was to explore stakeholders’ opinions and interests toward supporting capacity building in pharmacy education. Although the study did identify several groups of domestic stakeholders who were able to mobilise resources for the benefits of the education institution, a more serious capacity problem was the absence of initiative from the education institution to engage these stakeholders. However, institution was more eager to engage with foreign stakeholders. Closely linked to the culture of aid dependency, foreign aid was found to have the greatest influence on institutional capacity building. Hence, the question about whether aid is good or bad, as well as how to make aid work, becomes one of the emphases of this research. This study argues that aid does not need to be big, but to be genuinely helpful.

The oral route for drug administration offers an efficient and convenient method for drug delivery. However, there is an assortment of drugs which exhibit narrow absorption windows in the upper small intestine and as a result demonstrate limited bioavailabilities. One approach in the improvement of bioavailability in these cases is to retain the delivery system proximal to the absorption window for a prolonged period of time. Although controlled release products are widely available on the market, marketed gastroretentive systems remain elusive. This work explores the manufacture and characterisation of a multi-unit gastroretentive system utilising the biocompatible polymer poly (lactic-coglycolic acid). The novel PGSS technique enables the production of PLGA particles whilst omitting the use of volatile organic solvents. Morphological and microCT analyses of the particles revealed a highly porous matrix with porosity values in the order of 30-40%. The relationship between porosity, density and in vitro floating ability for particles with sizes between 100-2000 J.1m revealed that particle size plays an important role; larger microparticles possess decreased density, higher porosity and increased buoyancy. Encapsulation of two model drugs, riboflavin and furosemide, was carried out during the processing step with high encapsulation efficiencies (80-100%) being revealed. Release of the drugs in PBS (pH7.4) was found to be sustained over a period of 24 hours with a decrease in cumulative release in simulated gastric fluid (pHl.2). The introduction of the hydrophilic polymer poly(ethylene glycol) was found to modulate release rate; PEG with a molecular weight equal of more than 3 KDa increased the rate of release in PBS media up to 20% over hrs, however this was not observed for release in SGF. A comparison of morphology prior to and following exposure to the release media confirms that the emergence of intricate porous channels on exposure to the release medium is related to an increase in release rate. In order to augment the gastroretentive potential of the system the mucoadhesive polymer, chitosan was incorporated both as a post processing surface modification and as part of the initial formulation. ToF-SIMS surface analysis confirmed the presence of chitosan at the surface of the particles in both cases. Initially the potential for the particles to interact with mucus was evaluated utilising in vitro tests. The presence of chitosan significantly improved adsorption of mucin to particles, as well as enhancing adhesion of particles to a mucus producing epithelial cell layer. The thiolated chitosan derivative chitosan-N-acetyl-cysteine demonstrated an increase in adhesion of mucin solution; however the modified chitosan resulted in a decrease in adhesion to mucus producing cell line which was considered to be a result of the mucolytic actions it may exert on the mucus layer. Oral administration of buoyant particles to a rat model improved the pharmacokinetics of the anti-hypoglycaemia drug metformin, with addition of mucoadhesive properties providing further improvement. This study demonstrates that introduction of buoyancy and mucoadhesion functionalities to particles prepared by the PGSS method could improve delivery of drugs demonstrating narrow absorption windows in the upper small intestine.

The blood-borne virus, hepatitis C (HCV), is causing an increasing burden of chronic and terminal liver disease, world-wide. The development of successful drug treatments for this infection has been hampered by the lack of an efficient and physiologically relevant in vitro model of viral pathogenesis. The recent characterisation of the JFH1 clone of HCV, which is capable of both infection and replication in some types of cell lines, has revolutionised the potential of in vitro HCV research. Yet very few studies have been able to investigate the pathogenesis of HCV in normal, healthy hepatocytes, and none has examined the effects of such infection on other human liver cells. This thesis presents the techniques and results of work to optimise human primary liver cell cultures, in order to permit investigation of the JFH1 clone of HCV. A protocol was developed for the isolation of healthy human hepatocytes from surgically resected liver tissue. Methods for the non-viral transfection of primary hepatocytes were then optimised and compared. Finally, the expression of a JFH1 replicon (incorporating the luciferase marker gene) was assessed in human primary hepatocytes, both in monoculture and in three-dimensional co-culture with hepatic stellate cells (HSCs). The level of expression of the JFH1 replicon in human primary hepatocytes was considerably lower than that found in the human hepatoma Huh7 cell line, as expected, and highly dependent upon the batch of primary cells used. Hepatocytes which were grown in co-culture with HSCs showed some evidence of a greater capacity to support the translation and replication of JFH1. Luciferase was largely undetectable by 48 hours, particularly in hepatocyte-HSC co-cultures, suggesting that innate anti-viral mechanisms are preserved in these cultures. Further studies, to examine the intriguing dialogue between these models and JFH1, now have the potential to provide unique insights into the pathogenesis of HCV in the human liver.

The Medicines Use Review and Prescription Intervention (MUR) service was commissioned as part of the 2005 community pharmacy contract for England and Wales. The aim of the MUR service is to improve patients’ knowledge and use of medicines and to reduce avoidable medicines waste. MURs form part of a Government strategy that aims to improve patients’ adherence to medicines in order to optimise health gain and reduce cost associated with unused medicines. MURs are also seen as a ‘concordance review’ and pharmacy’s professional bodies acknowledge the service as a means to further the professional role of community pharmacists. However, it remains uncertain from studies investigating the outcomes of MURs, the extent to which the service is benefitting patients. One significant drawback to previous studies is the lack of in-depth investigation of the MUR consultation and the patients’ perspective of the service. This thesis provides valuable insights into what occurs during an MUR consultation and investigates the patient’s perspective of the service and that of the pharmacy staff. This work also explores whether the MUR policy aims are being realised in practice and translated into more effective use of medicines. Ten weeks of fieldwork observations were undertaken in two English community pharmacies. One-week placements were made over a 12-month period between November 2008 and October 2009. Observations were made of all pharmacy activities, including fifty-four MUR consultations. Thirty-four patients subsequently agreed to be interviewed about their experience of the MUR. Eight patients were observed to decline the offer of an MUR, of which three patients were interviewed about the reasons why they declined. After the pharmacy observations were completed, five pharmacists and twelve support staff interviews were held to discuss professional perspectives of MURs. The findings from this study suggest that the MUR service is a modern and developing service but one that remains unestablished. Patient awareness of MURs was poor and nearly all MURs were initiated by the pharmacist; no patients were referred from the GP. Pharmacy staff did not actively seek to recruit patients who may benefit most from an MUR and the majority were invited in ad hoc manner. Patients were given little time to consider whether to take part in an MUR and were insufficiently informed of their purpose or personal value. MURs were framed as a monitoring activity and most patients reported that the MUR did little to improve their knowledge of their medicines and rarely affected their use. They perceived their GP to have the main authority over their medicines. Patients considered that significant medicine-related problems would be best resolved by talking to the GP rather than with the pharmacist during an MUR. In effect, a supplier induced demand for MURs was observed. Nevertheless, all patients reported feeling comfortable speaking to the pharmacist during an MUR and most described the consultation in positive terms. Most patients viewed the pharmacist as a knowledgeable expert and some felt reassured about their medicines following an MUR. Observations of the MUR consultation revealed pharmacists were subordinate to the ‘technology’ of the MUR form and adhered to its ‘tick-box’ format. Pharmacists used predominantly closed questions which enabled the MUR form to be completed efficiently, but this forestalled wider discussion of the patient’s health and medicines. The MUR service was at odds with the intention to create a patient-centred service. When complex or indeterminate issues were raised, these were often circumvented or the patient referred to the GP. Pharmacists reported in their interviews that they welcomed MURs and the resultant potential to raise their profile with patients. However, they were unclear about what they wanted to advise during an MUR and how patients might gain maximum benefit from the review. They also reported concerns over patient recruitment, organisational pressures to pursue a target number of MURs and difficulties integrating MURs within their existing activities. MURs were pragmatically accommodated alongside existing duties without additional resource. Support staff reported feeling discomfort when they were left to explain to patients and customers why the pharmacist was absent during an MUR and described using various strategies and personal judgements to deal with waiting patients. This study has important implications for patients, professionals and policy makers. Patients should be aware that the MUR service is funded by the NHS and is available for them to use. More support from GPs is needed to identify patients who may most benefit from an MUR. This study highlights the need for consultation and communication skills training for pharmacists, so they are able to effectively elicit patient beliefs, concerns and preferences about medicines during the MUR. Organisations also need to reconsider the way they motivate pharmacists to undertake MURs to avoid unintended consequences for patient care. Policy makers should reconsider strategies that are based on rationalised policies as a means to improving patient adherence to medicines. Effective services need to be responsive to the patient’s individual circumstance and preference. Further research is needed into MURs in a wider and more diverse range of pharmacy settings in order to explore these issues further.

Supplying safe, appropriate and effective non-prescription medicines for customers in community pharmacies is a key role of pharmacists and pharmacy assistants in every country. However, in low and middle-income countries, including Vietnam, the quality of professional services from pharmacies is limited, unclear and has often been questioned. There is limited research about the real situation surrounding non-prescription medicine supply in community pharmacies in Vietnam. The factors that influence the supply of non-prescription medicines to customers and to what extent the service provision could be improved for the benefit of pharmacy customers needs to be explored. This study aimed to investigate non-prescription medicines supply in community pharmacies in Hanoi, Vietnam in order to provide scientific evidence about the situation. A mixed method approach was used in this study to provide valuable insights into what occurs during pharmacy staff-customer transactions. Following ethical approval, fieldwork observations were undertaken in five community pharmacies over a five week period from March to May 2011, this was followed by 22 semi-structured interviews with eight pharmacists and 14 pharmacy assistants who had been observed. The interviews enabled participants to express their perceptions and experiences regarding the supply of non-prescription medicines to customers in community pharmacies. Survey research, using a structured questionnaire, was conducted with 505 pharmacy customers who were asked to evaluate the pharmacy service that they had just received. Results from the three sources were triangulated and validated by comparing, contrasting, complementing and confirming in order to provide a better understanding of non-prescription medicines supply and make recommendations for improving the service provision in community pharmacies in Vietnam. The findings from this study indicate that factors influencing the supply of non-prescription medicines in community pharmacies include attitudes of pharmacy staff, their medical and pharmaceutical knowledge and their communication skills. The influence of the pharmacy settings, customer factors such as customers’ complex and diverse demands, the irrational use of medicines, using medicines following the suggestions of others, and tough customers were all factors that impacted on staff-customer transactions. Being conveniently located, the pharmacy offering reasonably priced medicines and being a large pharmacy with a good reputation were also considered important impacting on customer selection of community pharmacy. The results of this research show that there are limitations in pharmacy service provision and there is a discrepancy between pharmacy staff perceptions and actual practice in terms of attitudes. Poor performance, in many situations, did not come from a lack of knowledge; rather it appeared to result from the negative attitudes of pharmacy staff. Such negative attitudes of pharmacy staff are likely to be related to their focus on just short-term profit rather than focusing on a balance between short-term and long-term benefits for both customers and pharmacies. Positive attitudes, taking greater responsibility, customer loyalty and long-term benefits were ignored. Poor performance of pharmacy staff, to some extent, was also affected by their education and training. Some educational organisations have commercialised their training activities and paid too much attention to the quantity of graduated students rather than the quality of their education and training. This study has important implications for the improvement of the responsible supply of non-prescription medicines in community pharmacies in Vietnam including the identified needs for attitude interventions and training. New subjects should be added to the pharmacy students’ curricula and training should be developed for pharmacy assistants in areas such as communication skills, customer psychology, selling skills and patient safety. For pharmacists and pharmacy assistants, gaining treatment experience from customers’ feedback and keeping up to date with new information should be a continuous activity. Close co-operation between health authorities, policy makers and researchers needs to be developed in conducting further research and implementing appropriate policies, in order to improve the service provision in community pharmacies in Vietnam.

The formation of three-dimensional (3D) models for tissue engineering purpose provides a more conducive environment to enable complex biological interactions and processes between cells, biomaterials and bioactive molecules. Microparticles (MP) can be used as supporting matrix for 3D construct in cells and a carrier to deliver bioactive agents for cell development and differentiation, particularly for bone tissue engineering. Poly(glycerol adipate) (PGA) is a potential polymer for tissue engineering purposes as it is biodegradable and has biocompatibility with several cells. The aim of this study is to modify PGA polymer for MP with well-defined properties for drug encapsulation and release, promote cell-MP interaction and evaluate the osteogenic differentiation with MP incorporation in mouse embryonic stem (mES) and osteoblast cells. The PGA polymer has been modified by substituting 40% pendant hydroxyl groups onto the polymer backbone with stearoyl (C18) groups to increase encapsulation efficiency of drug within MP. Further modification was tethering one carboxyl terminus in PGA polymer with maleimide-poly(ethylene glycol) (MIHA-PEG-NH2) linker for ligand attachment on the surface of MP. Collagen, as a ligand, was modified by attaching iminothiolane to give a functional thiol group for interaction with maleimide group on the surface of 40%C18-PGA-PEG-MIHA MP. The microparticles were prepared using an emulsification method. Dexamethasone phosphate (DXMP) and simvastatin (SIM) were encapsulated within the MP. The MP-cell aggregate formation was evaluated as well as cell metabolism activity. The effect of polymer modification on drug release from MP was evaluated in the cells by analyzing osteogenic differentiation in cells. The MP prepared from modified PGA polymer exhibited high encapsulation efficiency of SIM in MP. By adjusting the formulation parameters, the release of SIM from MP could be extended to 21 days. The collagen attachment on the surface of 40%C18-PGA-PEG-MIHA MP promoted cell metabolic activity and produced more extensive markers related to osteogenic differentiation.