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    Investigation of injection moulding for novel drug delivery systems. An investigation into the use of injection moulding to produce pharmaceutical dosage forms and to understand the relationship between materials, processing conditions and performance, in particular drug release and stability

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    PhD Thesis - Vols. I and II (13.64Mb)
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    Publication date
    2015
    Author
    Deshmukh, Shivprasad S.
    Supervisor
    Kelly, Adrian L.
    Paradkar, Anant R.
    Keyword
    Hot melt extrusion; Injection moulding; Solid dispersion; Crystallisation; Ibuprofen; Felodipine; HPMCAS; Soluplus®; Controlled release; Drug delivery
    Rights
    Creative Commons License
    The University of Bradford theses are licenced under a Creative Commons Licence.
    Institution
    University of Bradford
    Department
    School of Life Sciences
    Awarded
    2015
    
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    Abstract
    The feasibility of the injection moulding (IM) was explored for the development of novel drug delivery systems. Controlled release formulations were developed using a substituted cellulose derivative, hydroxypropyl methyl cellulose acetate succinate (HPMCAS) and a graft co-polymer (Soluplus®). BCS class II drugs ibuprofen and the felodipine were selected based on their physicochemical properties. In the present work, a homogenous dispersion of drugs in the polymer matrices was achieved using Hot Melt Extrusion (HME) and extruded pellets obtained were used for the development of the injection moulded systems. Four systems were developed using the IM consisting of ibuprofen-HPMCAS, ibuprofen-Soluplus®, felodipine-PEO-HPMCAS and felodipine-Soluplus®. The ibuprofen acts as a good plasticiser compared to felodipine therefore, felodipine containing IM systems required a plasticiser (PEO) when processed with HPMCAS. The analysis of extruded pellets and injection moulded systems using modulated DSC (MDSC) and Raman spectroscopy confirmed the formation of an amorphous molecular dispersion (i.e solid solution) in the case of all four systems. The phase separation behaviour and the amorphous stability of the systems was studied at various stress conditions. This revealed the “surface crystallisation” behaviour of the ibuprofen-HPMCAS systems. Temperature-composition phase diagram constructed based on the melting point depression and the Flory-Huggins lattice solution theory provided the explanation for the phase separation and crystallisation behaviour of ibuprofen-HPMCAS systems. The advanced characterisation techniques like DMA, 2D XRD and 3D laser microscopy provided the detailed understanding of crystal habits, phase seperation and surface crystallisation. The significant effect of the stress conditions on the rate of shrinkage was observed where, higher shrinkage tendency of a HPMCAS IM system was observed compared to Soluplus® IM systems. The extruded pellets provided the faster drug release compared to the moulded tablets suggests the effect of particle size as well as the densification during IM on the dissolution rate of the dosage form. The nature of the polymer and processing history were the contributing factors for the dissolution of the dosage forms.
    URI
    http://hdl.handle.net/10454/14302
    Type
    Thesis
    Qualification name
    PhD
    Notes
    The thesis is hardbound in two volumes. Volume II starts at Chapter 5, page 135.
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