ORCID Profile
0000-0002-0692-3223
Current Organisation
The University of Auckland
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Publisher: Bentham Science Publishers Ltd.
Date: 05-2013
DOI: 10.2174/1567201811310030007
Abstract: Dapivirine, formerly known as TMC 120, is a poorly-water soluble anti-HIV drug, currently being developed as a vaginal microbicide. The clinical use of this drug has been limited due to its poor solubility. The aim of this study was to design solid dispersion systems of Dapivirine to improve its solubility. Solid dispersions were prepared by solvent and fusion methods. Dapivirine release from the solid dispersion system was determined by conducting in-vitro dissolution studies. The physicochemical characteristics of the drug and its formulation were studied using Differential Scanning Calorimetry (DSC), powder X-ray Diffraction (XRD), Fourier-transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). A significant improvement in drug dissolution rate was observed with the solid dispersion systems. XRD, SEM and DSC results indicated the transformation of pure Dapivirine which exists in crystalline form into an amorphous form in selected solid dispersion formulations. FTIR and HPLC analysis confirmed the absence of drug-excipient interactions. Solid dispersion systems can be used to improve the dissolution rate of Dapivirine. This improvement could be attributed to the reduction or absence of drug crystallinity, existence of drug particles in an amorphous form and improved wettability of the drug.
Publisher: Elsevier BV
Date: 02-2013
DOI: 10.1016/J.IJPHARM.2013.01.006
Abstract: Intrinsically conducting polymers such as polypyrrole (PPy) are viable platforms for efficient drug delivery, where release rates can be tuned by external electrical stimulus. In this study, the successful fabrication of 3-dimensionally ordered macroporous PPy inverse opal thin films is described, and the viability of such films for controlled drug release evaluated in vitro. The PPy inverse opal thin films were obtained by electropolymerization of PPy through the interstitial voids of a colloidal crystal template composed of poly(methyl methacrylate) colloids of diameter ∼430 nm. Chemical etching of the template yielded macroporous PPy inverse opal scaffolds. The model drug risperidone was loaded into the PPy inverse opal films, and then entrapped by electropolymerization of a non-porous PPy overlayer. The morphology and chemical composition of the PPy scaffolds were evaluated by SEM and FTIR spectroscopy, respectively. The high surface area PPy inverse opal scaffolds exhibited enhanced drug loading and releasing capabilities compared to conventional non-porous PPy films. Drug release profiles could be modified by applying electrical stimulus, which caused actuation of the porous polypyrrole films. The proposed delivery system may find use as an implantable device where drug release can be electrically tuned according to patient requirements.
Publisher: Bentham Science Publishers Ltd.
Date: 10-2012
Publisher: Future Science Ltd
Date: 03-2013
DOI: 10.4155/TDE.12.166
Abstract: Background: Intrinsically conducting polymers, such as polypyrrole (PPy), have been utilized for drug delivery purposes as drug release rates can be tuned by electrical stimulation. Electrical stimulation can be used to switch the redox state of PPy, subsequently changing the electrostatic charge and volume of the polymer. Most literature to date has focused on the delivery of charged bioactives. This study aimed to prepare a PPy film formulation where the release rate of the uncharged drug progesterone could be electrically tuned. Results & discussion: In this study PPy films loaded with progesterone are described. Drug loading levels were influenced by the concentration of drug during manufacture and polymerization time. The polymer formulation was electrically conductive and electroactive, switchable between oxidized and reduced states. Drug release was influenced by the application of electrical stimulation, the greatest release was observed on application of +0.8 V (to oxidize the polymer). Triggered release was observed in response to a period of electrical stimulation (±0.8 V at 0.5 Hz). Conclusion: This study describes the preparation of a PPy film loaded with the uncharged drug progesterone. The release rate could be tuned with electrical stimulation.
No related grants have been discovered for Manisha Sharma.