{"id":5956,"date":"2026-10-19T09:48:14","date_gmt":"2026-10-19T09:48:14","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-lyfjafraedi-pitsiree-praphanwittaya\/"},"modified":"2026-10-19T09:48:14","modified_gmt":"2026-10-19T09:48:14","slug":"doktorsvorn-i-lyfjafraedi-pitsiree-praphanwittaya","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-lyfjafraedi-pitsiree-praphanwittaya\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed lyfjafr\u00e6\u00f0i – Pitsiree Praphanwittaya"},"content":{"rendered":"
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Fimmtudaginn 19. n\u00f3vember ver Pitsiree Praphanwittaya doktorsritger\u00f0 s\u00edna \u00ed lyfjafr\u00e6\u00f0i vi\u00f0 Lyfjafr\u00e6\u00f0ideild H\u00e1sk\u00f3la \u00cdslands. Ritger\u00f0in ber heiti\u00f0: S\u00fdkl\u00f3dextr\u00edn nan\u00f3agnir fyrir markbundna lyfjagj\u00f6f \u00ed augu. Cyclodextrin nanoparticles for targeted ocular delivery of kinase inhibitors.<\/strong><\/p>\n

V\u00f6rninni ver\u00f0ur streymt: https:\/\/livestream.com\/hi\/doktorsvornpitsireepraphanwittaya<\/a><\/strong><\/strong><\/p>\n

Andm\u00e6lendur eru dr. Hanne Hjorth T\u00f8nnesen, pr\u00f3fessor vi\u00f0 H\u00e1sk\u00f3lann \u00ed \u00d3sl\u00f3, og dr. Helena Cabral Marques, pr\u00f3fessor vi\u00f0 H\u00e1sk\u00f3lann \u00ed Lissabon, Port\u00fagal.<\/p>\n

Umsj\u00f3narkennari og lei\u00f0beinandi var dr. \u00deorsteinn Loftsson, pr\u00f3fessor vi\u00f0 Lyfjafr\u00e6\u00f0ideild.<\/p>\n

A\u00f0rir \u00ed doktorsnefnd voru H\u00e1kon Hrafn Sigur\u00f0sson, pr\u00f3fessor vi\u00f0 H\u00e1sk\u00f3la \u00cdslands, Einar Stef\u00e1nsson pr\u00f3fessor vi\u00f0 H\u00e1sk\u00f3la \u00cdslands, Gauti J\u00f3hannesson, pr\u00f3fessor vi\u00f0 Ume\u00e5 Universitet \u00ed Sv\u00ed\u00fej\u00f3\u00f0, og Phatsawee Jansook, pr\u00f3fessor vi\u00f0 Chulalongkorn University \u00ed Thailandi.<\/p>\n

El\u00edn Soff\u00eda \u00d3lafsd\u00f3ttir, pr\u00f3fessor og forseti Lyfjafr\u00e6\u00f0ideildar, stj\u00f3rnar ath\u00f6fninni sem fer fram \u00ed H\u00e1t\u00ed\u00f0asal H\u00e1sk\u00f3la \u00cdslands og hefst kl. 11.00.<\/p>\n

Fj\u00f6ldatakm\u00f6rkun: Einungis 10 manns geta veri\u00f0 \u00ed salnum \u00e1 me\u00f0an doktorsv\u00f6rninni stendur.<\/strong><\/p>\n

\u00c1grip af ranns\u00f3kn<\/strong><\/p>\n

Markmi\u00f0<\/strong> verkefnisins var a\u00f0 \u00fer\u00f3a augndropa fyrir markbundna lyfjagj\u00f6f til sj\u00f3nhimnu augans.<\/p>\n

A\u00f0fer\u00f0:<\/strong> K\u00ednasahemlar (KI) b\u00e6la v\u00f6xt n\u00fdrra \u00e6\u00f0a hj\u00e1 sj\u00faklingum me\u00f0 augnbotnahr\u00f6rnun (Age related Macular Degeneration e\u00f0a AMD). K\u00ednasahemlar eru mj\u00f6g torleysanlegir \u00ed vatni en a\u00f0eins uppleyst lyf getur fl\u00e6tt fr\u00e1 yfirbor\u00f0i augans inn \u00ed auga\u00f0. \u00dev\u00ed \u00fearf a\u00f0 beita a\u00f0fer\u00f0um sem b\u00e6\u00f0i auka leysanleika lyfjanna \u00ed t\u00e1rav\u00f6kvanum og a\u00f0gengi lyfjanna fr\u00e1 yfirbor\u00f0inu inn \u00ed auga\u00f0. \u00cd \u00feessu verkefni var n\u00e1tt\u00farulegt \u03b3-s\u00fdkl\u00f3dextr\u00edn vali\u00f0 til a\u00f0 auka vatnleysanleika og a\u00f0gengi k\u00ednasahemla. Mynda\u00f0ar voru k\u00ednasahemla\/\u03b3-s\u00fdkl\u00f3dextr\u00edn fl\u00e9ttur og fl\u00e9tturnar s\u00ed\u00f0an h\u00f3pa\u00f0ar saman til a\u00f0 mynda vatnsleysanlegar nan\u00f3agnir sem bundust yfirbor\u00f0i augans eftir gj\u00f6f augndropanna. Nan\u00f3agnirnar juku \u00fea\u00f0 magn lyfs sem fr\u00e1soga\u00f0ist inn \u00ed auga\u00f0 og j\u00f3k styrk \u00feess \u00ed sj\u00f3nhimnu. Auk \u03b3-s\u00fdkl\u00f3dextr\u00edns innih\u00e9ldu augndroparnir \u00fdmsar fj\u00f6lli\u00f0ur og \u00f6nnur hj\u00e1lparefni sem auka geymslu\u00feol augndropanna. Alls voru um 10 mismunandi k\u00ednasahemlarar rannsaka\u00f0ir.<\/p>\n

Ni\u00f0urst\u00f6\u00f0ur:<\/strong> \u00a0Augndroparnir juku styrk k\u00ednasahemla \u00ed sj\u00f3nhimnu og \u00f6\u00f0rum vefjum bakhluta augans.\u00a0 S\u00fdnt var fram \u00e1 a\u00f0 geymslu\u00feol augndropanna var a\u00f0 minnsta kosti 6 m\u00e1nu\u00f0ir vi\u00f0 stofuhita.<\/p>\n

Abstract<\/strong><\/p>\n

Background: <\/strong>Age-related macular degeneration (AMD) causes vision loss in elderly people due to neovascularization. The first line treatments<\/a> are intravitreal injections which can induce severe pain. Oral administration still produces side effects. Cyclodextrins (CDs) can self-assemble into aggregates or larger nanoparticle platform that can deliver drugs to the back of eye. Thus, CD-based eye drops can be a more favorable formulation for AMD.<\/p>\n

Introduction:<\/strong> Tyrosine kinase inhibitors (KIs) suppress the growth of new blood vessels in AMD. The obstacle of delivery of KIs is their very low aqueous solubility. Here \u03b3CD was used as a solubilizing complexing agent but the efficiency remained inadequate. In addition, the KI salt tended to degrade at elevated temperatures during preparation of KI\/\u03b3CD complexes. Hence, the aim of this research was to enhance the \u03b3CD solubilization of KIs by additional techniques such as by including hydrophilic polymers or counter ions, and to develop the thermally stable eye drops for delivery of KI to the targeted site.<\/p>\n

Method: <\/strong>Two different heating methods were used in preparation of KI\/CD complexes. Mild heat in the form of ultrasonication at 30oC for 30 min, was applied to thermolabile drugs while heat stable drugs were autoclaved at 121oC for 20 min which was also beneficial for sterilization of eye drops. All complex characterizations used samples from the supernatants. The physicochemical properties of the aqueous eye drop micro-suspensions were also evaluated.<\/p>\n

Results: <\/strong>Dovitinib had the best solubility performance due to the high affinity for \u03b3CD, followed by motesanib. KIs were more soluble at low pH. The tested hydrophilic polymers affected the KI solubility in complexation media. Besides that, the formulation vehicle could also solubilize KI\/\u03b3CD complexes, mainly influenced by salt formation. Hexadimethrine bromide (HDMBr) generally enhanced the \u03b3CD solubilization via a synergist effect. The presence of HDMBr increased \u03b3CD solubilization and formed ternary complex.<\/p>\n

Salt formation was observed in formulation vehicle systems and, thus, several acidic counter ions were introduced to enhance the solubility of the weakly basic drug\/CD complex. Citrate was the most powerful counter ion that reinforced CD efficiency by salt formation and\/or charge-charge interactions. In vitro drug permeation did not increase as result of increased CD solubilization.\u00a0<\/p>\n

KI salt was used in formulation studies because salt formation had a greater capacity to solubilize the drug. An unexpected problem occurred regarding the dovitinib salt. Here cediranib maleate (CM) was selected for eye drops due to its noteworthy performance and high intrinsic solubility. Riboflavin could thermally stabilize CM dissolved in 15% (w\/v) \u03b3CD solution. The combination of riboflavin and other excipients (i.e. polymer and co-solvent) reduced the thermal degradation in micro-suspensions. The optimized eye drops did deliver the drug into the back of eye. This product was stable at 25oC for six months.<\/p>\n

Conclusion:<\/strong> The \u03b3CD solubilization and complexation of KIs was increased by additional techniques including the addition of hydrophilic polymers or counter ions. An appropriate stabilizer could protect the KI salt from thermal degradation in a concentrated complexation media. The thermally stable eye drops achieved ocular delivery and had a shelf life of at least six months.<\/p>\n

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

Pitsiree Praphanwittaya f\u00e6ddist \u00ed Thailandi \u00feann 26. mars 1990.\u00a0 \u00c1ri\u00f0 2013 lauk h\u00fan BS-pr\u00f3fi \u00ed lyfjafr\u00e6\u00f0i fr\u00e1 Silpakorn University \u00ed Ta\u00edlandi og MS-pr\u00f3fi \u00ed lyfjafr\u00e6\u00f0i fr\u00e1 sama sk\u00f3la \u00e1ri\u00f0 2016. 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