{"id":6246,"date":"2026-10-19T09:48:40","date_gmt":"2026-10-19T09:48:40","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-lyfjavisindum-manisha-prajapati\/"},"modified":"2026-10-19T09:48:40","modified_gmt":"2026-10-19T09:48:40","slug":"doktorsvorn-i-lyfjavisindum-manisha-prajapati","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-lyfjavisindum-manisha-prajapati\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed lyfjav\u00edsindum – Manisha Prajapati"},"content":{"rendered":"
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F\u00f6studaginn 11. febr\u00faar ver Manisha Prajapati doktorsritger\u00f0 s\u00edna \u00ed lyfjav\u00edsindum vi\u00f0 Lyfjafr\u00e6\u00f0ideild H\u00e1sk\u00f3la \u00cdslands. Ritger\u00f0in ber heiti\u00f0: S\u00fdkl\u00f3dextr\u00edn lyfjaferjur \u00ed augnlyfjum. Cyclodextrins as enabling excipients in ophthalmic drug delivery.<\/strong><\/p>\n

Andm\u00e6lendur eru dr. Jarkko Rautio, pr\u00f3fessor vi\u00f0 lyfjafr\u00e6\u00f0ideild University of Eastern Finland, og dr. Helen Hughes, lektor vi\u00f0 Waterford Institute of Technology, \u00cdrlandi.<\/p>\n

Umsj\u00f3narkennari og lei\u00f0beinandi var dr. \u00deorsteinn Loftsson, pr\u00f3fessor. Auk hans s\u00e1tu \u00ed doktorsnefnd dr. Einar Stef\u00e1nsson, dr. H\u00e1kon Hrafn Sigur\u00f0sson, dr.\u00a0 Phatsawee Jansook og dr. Sunna J\u00f3hannsd\u00f3ttir (l\u00e1tin).<\/p>\n

Berglind Eva Benediktsd\u00f3ttir, pr\u00f3fessor og varadeildarforseti Lyfjafr\u00e6\u00f0ideildar, stj\u00f3rnar ath\u00f6fninni sem fer fram \u00ed H\u00e1t\u00ed\u00f0asal H\u00e1sk\u00f3la \u00cdslands og hefst kl. 13.30.\u00a0V\u00f6rninni ver\u00f0ur streymt:\u00a0<\/strong><\/p>\n

https:\/\/livestream.com\/hi\/doktorsvornmanishaprajapati<\/a><\/p>\n

\u00c1grip<\/strong><\/p>\n

S\u00fdkl\u00f3dextr\u00edn eru vatnsleysanleg, hringlaga sykursamb\u00f6nd sem notu\u00f0 eru sem hj\u00e1lparefni \u00ed lyfjaform til a\u00f0 b\u00e6ta st\u00f6\u00f0ugleika og leysni fitus\u00e6kinna lyfja. Fitus\u00e6kin lyf hafa m\u00f6rg mj\u00f6g takmarka\u00f0an leysanleika \u00ed vatni en geta mynda\u00f0 vatnss\u00e6knar fl\u00e9ttur me\u00f0 s\u00fdkl\u00f3dextr\u00ednum.\u00a0 \u00cd vatnslausnum verja s\u00fdkl\u00f3dextr\u00edn lyfjasameindir gegn utana\u00f0komandi \u00e1hrifum, halda \u00feeim \u00ed lausn og auka a\u00f0gengi \u00feeirra a\u00f0 l\u00edfr\u00e6num himnum svo sem hornhimnu augans. N\u00fdlegar ranns\u00f3knir hafa einnig s\u00fdnt a\u00f0 s\u00fdkl\u00f3dextr\u00edn geta mynda\u00f0 fl\u00e9ttur me\u00f0 \u00fdmsum l\u00edfr\u00e6num efnasamb\u00f6ndum eins og k\u00f3lester\u00f3li og \u00fev\u00ed er hugsanlegt a\u00f0 s\u00fdkl\u00f3dextr\u00edn geti haft l\u00e6kningafr\u00e6\u00f0ileg \u00e1hrif \u00e1 sj\u00f3nhimnusj\u00fakd\u00f3ma, svo sem Stargardt-sj\u00fakd\u00f3m og slag\u00e6\u00f0ast\u00edflu \u00ed sj\u00f3nhimnu. Markmi\u00f0 doktorsverkefnisins var a\u00f0 kanna notagildi s\u00fdkl\u00f3dextr\u00edna \u00ed augnlyf, sem hj\u00e1lparefni til a\u00f0 auka leysanleika, st\u00f6\u00f0uleika og a\u00f0gengi augnlyfja.\u00a0 Auk \u00feess sem \u00e1hrif s\u00fdkl\u00f3dextr\u00edna \u00e1 sj\u00f3nhimnu augans voru ranns\u00f6ku\u00f0. \u00ddmsum efnaf\u00e6\u00f0ilegum og e\u00f0lisfr\u00e6\u00f0ilegum a\u00f0fer\u00f0um var beitt til a\u00f0 rannsaka \u00e1hrif s\u00fdkl\u00f3dextr\u00edna og fj\u00f6lli\u00f0a \u00e1 leysanleika og st\u00f6\u00f0ugleika takr\u00f3l\u00edmus og d\u00edfl\u00faprednats. Mynda\u00f0ar voru nan\u00f3agnir af lyfjunum og rannsaka\u00f0 hvernig s\u00fdkl\u00f3dextr\u00edn \u00f6rva fr\u00e1sog lyfja \u00ed gegnum l\u00edfr\u00e6nar himnur. A\u00f0 lokum voru \u00e1hrif s\u00fdkl\u00f3dextr\u00edna \u00e1 sj\u00f3nhimnu augans ranns\u00f6ku\u00f0.<\/p>\n

English abstract<\/strong><\/p>\n

Cyclodextrins (CDs) have been widely used as pharmaceutical excipients for formulation purposes for different drug delivery systems and has been extensively employed to overcome the challenges in ophthalmic drug delivery recently. As we know, CDs can be used to improve the stability and solubility of hydrophobic drugs in aqueous CD solutions through the formation of drug\/CD complexes. Not only this but the use of CDs as solubilisers has helped in the permeation properties of different hydrophobic drugs. In addition to this, recent studies have shown that CDs are able to form complexes with a variety of biomolecules, such as cholesterol. This has subsequently paved the way for the possibility of using CDs in retinal diseases, such as Stargardt disease and retinal artery occlusion, where CDs could absorb cholesterol, but the studies on the retinal toxicity of CDs are limited. This study aimed to explore the applicability of CDs in ophthalmic delivery as solubilisers\/stabilisers for various hydrophobic drugs (tacrolimus and difluprednate) to develop a vehicle for aqueous eye drops, their concentration effect on important parameters for formulation like permeation, and to examine the retinal toxicity of different CDs and their localisation within retinal tissues.<\/p>\n

Different kinetics, stability, and solubility studies showed that cyclodextrins were able to improve the stability and solubility of both drugs tacrolimus and difluprednate in aqueous solution while the stability improved further with the combination of cyclodextrin and polymers. Different studies like NMR, DSC, FTIR confirmed the presence of drug\/CD complex. Permeation studies showed that the concentration of different solubilisers (HP\u03b2CD, ethanol, and sodium lauryl sulfate; SLS) had a pronounced effect on the permeation of hydrocortisone across different membrane barriers shown by the flux profiles. Cytotoxicity studies showed that RM\u03b2CD was more toxic to retinal explants when compared to HP\u03b2CD, which the retina can safely tolerate at levels as high as 10 mM.<\/p>\n

To conclude, tacrolimus was not adequately chemically stable to be formulated as aqueous eye drops. In the case of difluprednate, it was possible to solubilise 0.1% difluprednate in an aqueous HP\u03b3CD solution and stabilise in an aqueous solution using a combination of CD and polymer. In addition to this, the solubiliser concentration does play a critical role in the permeation capability of the drug molecule across the barrier membrane which is, in turn, related to the thermodynamic activity of the drug molecule. Lastly, HP\u03b2CD was found to be a safer option than RM\u03b2CD for retinal drug delivery and may advance the use of CDs in the development of drugs in this field. Hopefully, these obtained results could be beneficial in further exploration of CDs in various fields of ophthalmic drug delivery either as drug carriers or the drug itself.<\/strong><\/p>\n

Um doktorsefni\u00f0<\/strong><\/p>\n

Manisha Prajapati f\u00e6ddist \u00ed Nepal \u00feann 30. apr\u00edl 1990. \u00c1ri\u00f0 2013 lauk h\u00fan BS-pr\u00f3fi \u00ed lyfjafr\u00e6\u00f0i fr\u00e1 Kathmandu University \u00ed Nepal og MS-pr\u00f3fi \u00ed lyfjafr\u00e6\u00f0i fr\u00e1 Kaupmannahafnarh\u00e1sk\u00f3la \u00e1ri\u00f0 2017.\u00a0 H\u00fan h\u00f3f doktorspr\u00f3f vi\u00f0 H\u00e1sk\u00f3la \u00cdslands \u00e1ri\u00f0 2018 \u00fear sem h\u00fan vann a\u00f0 ranns\u00f3knum \u00e1 notkun s\u00fdkl\u00f3dextr\u00edna \u00ed augnlyf. Verkefni hennar er hluti af Marie Sklodowska Horizon 2020 ITN verkefninu transMed (http:\/\/www.transmed-itn.eu\/<\/a>), sem styrkt var af Evr\u00f3pusambandinu.<\/p>\n<\/div><\/div>","protected":false},"featured_media":5065,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2022-02-11T13:30:00+00:00","_phd_date_end":"2022-02-11T16:30:00+00:00","_phd_location":"A\u00f0albygging H\u00e1t\u00ed\u00f0asalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"S\u00fdkl\u00f3dextr\u00edn lyfjaferjur \u00ed augnlyfjum. 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