Pressure-induced encapsulation a novel route to load pharmaceuticals

  • Metinee Hemaprasertsuk

Student thesis: Master's Thesis


The effects of high pressure on polymer matrices can have important implication on pharmaceutical field. This study was employed to investigate the effect of pressure on polyethylene glycol (PEG1000 and PEG10000) in order to create a novel method to encapsulate poorly water-soluble pharmaceutical compounds lead to enhance bioavailability of the model drug. The structural properties of polyethylene glycol (PEG1000 and PEG10000), ibuprofen and the combination of PEG and ibuprofen were investigated by using differential scanning calorimetry (DSC) and Raman scattering technique. At ambient pressure, mixtures of PEG with ibuprofen was analysed before high pressure analysis was performed. The absence and decrease in melting temperature of the DSC thermogram in the ballmilled PEGs and ibuprofen indicated the possibility of drug dissolving in melting polymer.The high pressure experiments were carried out by using diamond anvil cell with the pressure up to approximately 6 GPa to see if pressure could produced drug loaded products. Pure PEG1000 and PEG10000 are revealed to become more disordered into a melted phase at approximately 5 GPa. The pharmaceutical model compound used in this study, ibuprofen, does not show any change in crystal structure under high pressure conditions. The mixtures with 10:1 weight ratio were then carried out with the effect of high pressure. The results illustrate that the ibuprofen compounds could not affect the phase change of PEGs molecules.The 10:1 ballmilled samples of both molecular weights of PEGs were taken forward on high-pressure scale up and drug release studies by using large volume press and Sirius T3 respectively. Three different treated groups were set in this research; unpressurised samples (control),pressurised samples, and pressurised and heated samples. Drug release studies were employed in phosphate buffer pH 6.8 for 2 hour. The first immediate release followed by sustained release profiles was observed on all formulations. PEG1000: ibuprofen present the % drug release at 2 hour 133.34%, 61.95%, and 67.54% for unpressurised, pressurised, and pressurised and heated samples respectively. However, the result from this was scientifically unreasonable. Looking at 10:1PEG10000:ibuprofen samples, the pressurised and heated group show the highest % release which is 24% at 2 hour compared with 21% and 22% for unpressurised and pressurised groups respectively.Unfortunately, there are not statistically significant on drug release of pressurised and unpressurised samples. Overall, the PEGs molecules could increase the water solubility property of poorly soluble drug compounds.
Date of Award30 Nov 2016
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SupervisorIain Oswald (Supervisor) & Philipp Seib (Supervisor)

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