{"id":{"repo_id":"ku","oai_identifier":"oai:kuscholarworks.ku.edu:1808/39408"},"canonical_url":"https://search.dev.ndltd.org/etd/ku/oai:kuscholarworks.ku.edu:1808/39408","repository":{"repo_id":"ku","name":"University of Kansas","base_url":"https://kuscholarworks.ku.edu/server/oai/request"},"display":{"title":"Investigation of ocular drug metabolism and pharmacokinetics using multi-omics and in-situ microdialysis","abstract":"Ocular drug disposition is governed by a complex interplay of anatomical barriers, local metabolic activity, transporter expression, and tissue-specific physiological processes. However, quantitative understanding of drug-metabolizing enzymes and transporters in ocular tissues remains limited, which has hindered mechanistic interpretation of ocular pharmacokinetics and the development of effective ophthalmic therapeutics. The overall goal of this dissertation was to improve the mechanistic understanding of ocular drug metabolism and disposition by integrating comparative transcriptomics, targeted proteomics, functional enzymatic activity, and in vivo ocular pharmacokinetic characterization in rabbit tissues.","abstract_html":"Ocular drug disposition is governed by a complex interplay of anatomical barriers, local metabolic activity, transporter expression, and tissue-specific physiological processes. However, quantitative understanding of drug-metabolizing enzymes and transporters in ocular tissues remains limited, which has hindered mechanistic interpretation of ocular pharmacokinetics and the development of effective ophthalmic therapeutics. The overall goal of this dissertation was to improve the mechanistic understanding of ocular drug metabolism and disposition by integrating comparative transcriptomics, targeted proteomics, functional enzymatic activity, and in vivo ocular pharmacokinetic characterization in rabbit tissues.","abstract_has_math":false,"creators":["LI, MENGYUE"],"institution":"University of Kansas","degree_name":"Ph.D.","degree_level":null,"degree_discipline":"Pharmaceutical Chemistry","degree_department":null,"school":null,"contributors":[],"advisors":["Wang, Michael Z"],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-05-31","date_published":"2026-05-31","updated_at":"2026-07-24T02:46:40Z","subjects":[],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["https://www.proquest.com/LegacyDocView/DISSNUM/32701783"],"render_values":[{"text":"https://www.proquest.com/LegacyDocView/DISSNUM/32701783","href":"https://www.proquest.com/LegacyDocView/DISSNUM/32701783","code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/1808/39408","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Wang, Michael Z"]},{"key":"dc:creator","label":"Author","values":["LI, MENGYUE"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2026-07-13T21:49:08Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2026-07-13T21:49:08Z"]},{"key":"dc:date.issued","label":"Date","values":["2026-05-31"]},{"key":"dc:publisher","label":"Institution","values":["University of Kansas"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Pharmaceutical Chemistry"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["https://www.proquest.com/LegacyDocView/DISSNUM/32701783"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/1808/39408"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Ocular drug disposition is governed by a complex interplay of anatomical barriers, local metabolic activity, transporter expression, and tissue-specific physiological processes. However, quantitative understanding of drug-metabolizing enzymes and transporters in ocular tissues remains limited, which has hindered mechanistic interpretation of ocular pharmacokinetics and the development of effective ophthalmic therapeutics. The overall goal of this dissertation was to improve the mechanistic understanding of ocular drug metabolism and disposition by integrating comparative transcriptomics, targeted proteomics, functional enzymatic activity, and in vivo ocular pharmacokinetic characterization in rabbit tissues.","Chapter 2 characterized the expression of drug-metabolizing enzymes and drug transporters across rabbit ocular subtissues, liver, and duodenum using next-generation RNA sequencing. The results showed that ocular tissues possess distinct and tissue-specific expression profiles of DMEs and DTs, differencing substantially from classical drug disposition organs like liver and duodenum. Many major hepatic cytochrome P450 enzymes were expressed at relatively low levels in ocular tissues, whereas hydrolases, such as carboxylesterases and peptidases, and antioxidant enzymes were abundantly expressed, suggest that ocular drug metabolism may rely less on classic hepatic oxidation and more on localized hydrolysis, detoxification, and oxidative stress defense. In addition, the major efflux transporter pumps such as P-gp, MRPs, and BCRP showed high expression across ocular tissues, particularly in the blood-vessel-enriched iris-ciliary body and retina-choroid complex, supporting their likely roles in limiting drug penetration and protecting ocular tissues from xenobiotic accumulation. Several SLC transporters with potential relevance to drug uptake were also highly expressed, including OATPs, OAT1, OCTN2, and MATE1. These data suggest that ocular drug delivery is not governed solely by passive barriers, but also by active uptake and efflux processes that may either restrict or facilitate ocular drug exposure.","Chapter 3 extended this by quantitatively characterizing CES1, CES2, and CES3 at the protein level and by evaluating CES-associated hydrolytic activity across rabbit ocular subtissues, liver, and duodenum. Tissue weight and total protein content across the tissues were first determined to provide a physiological basis for tissue-level scaling. Total cell lysate was justified as the most practical matrix for targeted CES proteomics. Targeted proteomic analysis demonstrated that CES1 and CES2 are the primary CES in rabbit ocular tissues, whereas CES3 was not detected in the eye. CES1 showed tissue-specific and generally higher ocular expression than CES2, with the highest abundance observed in iris-ciliary body and cornea, appreciable expression in retina-choroid and vitreous humor, and minimal expression in aqueous humor and lens. CES2 expression was comparable across various ocular subtissues and present at much lower levels. Activity assays further showed that oseltamivir hydrolysis following a clear tissue-dependent pattern and was strongly correlated with CES1 abundance, whereas procaine hydrolysis was more broadly distributed and did not corelate significantly with CES2 abundance. Together, these findings suggest that localized ocular CES1-associated hydrolysis in the rabbit eye is highly tissue-specific and CES2-asscoiated hydrolysis in the rabbit eye is broadly similar.","Chapter 4 translated these molecular and ex vivo findings into the in vivo setting by establishing a dual-probe ocular microdialysis model in rabbits and applying it to the study of latanoprost ophthalmic solution. This study demonstrated that concentric probes were more suitable than linear probes for aqueous humor and vitreous humor microdialysis sampling because they provide improved sealing at the insertion site, reduced the need for surgical glue, and showed more favorable recovery behavior. In vitro recovery experiments revealed a substantial temporal lag in the microdialysis system that was much longer than predicted from dead volume alone, highlighting the importance of lag correction for accurate PK interpretation. Application of dual-probe microdialysis to latanoprost PK investigation showed rapid disappearance of the parent drug from tear film and rapid appearance of latanoprost acid, with exposure largely confined to the anterior segment under anesthetized conditions. Additionally, latanoprost acid reached measurable nanomolar concentrations and showed a delay-corrected Tmax broadly comparable to previous reported human aqueous humor data after dose normalization.","Taken together, this dissertation demonstrated that ocular drug disposition is highly tissue-specific and reflects the combined influence of anatomical barriers, localized metabolism, transporter expression, and compartmental physiology. The integrated datasets generated in this work provide a quantitative and mechanistic foundation for understanding localized ocular metabolism and pharmacokinetics in rabbits. These findings also provide practical support for future studies of ester-containing ophthalmic drugs, interspecies translation, and development of ocular physiologically-based pharmacokinetic models."]},{"key":"dc:title","label":"Title","values":["Investigation of ocular drug metabolism and pharmacokinetics using multi-omics and in-situ microdialysis"]}]}],"canonical_facts":{"dc:contributor.advisor":["Wang, Michael Z"],"dc:creator":["LI, MENGYUE"],"dc:date.accessioned":["2026-07-13T21:49:08Z"],"dc:date.available":["2026-07-13T21:49:08Z"],"dc:date.issued":["2026-05-31"],"dc:description.abstract":["Ocular drug disposition is governed by a complex interplay of anatomical barriers, local metabolic activity, transporter expression, and tissue-specific physiological processes. However, quantitative understanding of drug-metabolizing enzymes and transporters in ocular tissues remains limited, which has hindered mechanistic interpretation of ocular pharmacokinetics and the development of effective ophthalmic therapeutics. The overall goal of this dissertation was to improve the mechanistic understanding of ocular drug metabolism and disposition by integrating comparative transcriptomics, targeted proteomics, functional enzymatic activity, and in vivo ocular pharmacokinetic characterization in rabbit tissues.","Chapter 2 characterized the expression of drug-metabolizing enzymes and drug transporters across rabbit ocular subtissues, liver, and duodenum using next-generation RNA sequencing. The results showed that ocular tissues possess distinct and tissue-specific expression profiles of DMEs and DTs, differencing substantially from classical drug disposition organs like liver and duodenum. Many major hepatic cytochrome P450 enzymes were expressed at relatively low levels in ocular tissues, whereas hydrolases, such as carboxylesterases and peptidases, and antioxidant enzymes were abundantly expressed, suggest that ocular drug metabolism may rely less on classic hepatic oxidation and more on localized hydrolysis, detoxification, and oxidative stress defense. In addition, the major efflux transporter pumps such as P-gp, MRPs, and BCRP showed high expression across ocular tissues, particularly in the blood-vessel-enriched iris-ciliary body and retina-choroid complex, supporting their likely roles in limiting drug penetration and protecting ocular tissues from xenobiotic accumulation. Several SLC transporters with potential relevance to drug uptake were also highly expressed, including OATPs, OAT1, OCTN2, and MATE1. These data suggest that ocular drug delivery is not governed solely by passive barriers, but also by active uptake and efflux processes that may either restrict or facilitate ocular drug exposure.","Chapter 3 extended this by quantitatively characterizing CES1, CES2, and CES3 at the protein level and by evaluating CES-associated hydrolytic activity across rabbit ocular subtissues, liver, and duodenum. Tissue weight and total protein content across the tissues were first determined to provide a physiological basis for tissue-level scaling. Total cell lysate was justified as the most practical matrix for targeted CES proteomics. Targeted proteomic analysis demonstrated that CES1 and CES2 are the primary CES in rabbit ocular tissues, whereas CES3 was not detected in the eye. CES1 showed tissue-specific and generally higher ocular expression than CES2, with the highest abundance observed in iris-ciliary body and cornea, appreciable expression in retina-choroid and vitreous humor, and minimal expression in aqueous humor and lens. CES2 expression was comparable across various ocular subtissues and present at much lower levels. Activity assays further showed that oseltamivir hydrolysis following a clear tissue-dependent pattern and was strongly correlated with CES1 abundance, whereas procaine hydrolysis was more broadly distributed and did not corelate significantly with CES2 abundance. Together, these findings suggest that localized ocular CES1-associated hydrolysis in the rabbit eye is highly tissue-specific and CES2-asscoiated hydrolysis in the rabbit eye is broadly similar.","Chapter 4 translated these molecular and ex vivo findings into the in vivo setting by establishing a dual-probe ocular microdialysis model in rabbits and applying it to the study of latanoprost ophthalmic solution. This study demonstrated that concentric probes were more suitable than linear probes for aqueous humor and vitreous humor microdialysis sampling because they provide improved sealing at the insertion site, reduced the need for surgical glue, and showed more favorable recovery behavior. In vitro recovery experiments revealed a substantial temporal lag in the microdialysis system that was much longer than predicted from dead volume alone, highlighting the importance of lag correction for accurate PK interpretation. Application of dual-probe microdialysis to latanoprost PK investigation showed rapid disappearance of the parent drug from tear film and rapid appearance of latanoprost acid, with exposure largely confined to the anterior segment under anesthetized conditions. Additionally, latanoprost acid reached measurable nanomolar concentrations and showed a delay-corrected Tmax broadly comparable to previous reported human aqueous humor data after dose normalization.","Taken together, this dissertation demonstrated that ocular drug disposition is highly tissue-specific and reflects the combined influence of anatomical barriers, localized metabolism, transporter expression, and compartmental physiology. The integrated datasets generated in this work provide a quantitative and mechanistic foundation for understanding localized ocular metabolism and pharmacokinetics in rabbits. These findings also provide practical support for future studies of ester-containing ophthalmic drugs, interspecies translation, and development of ocular physiologically-based pharmacokinetic models."],"dc:identifier.other":["https://www.proquest.com/LegacyDocView/DISSNUM/32701783"],"dc:identifier.uri":["https://hdl.handle.net/1808/39408"],"dc:language.iso":["en"],"dc:publisher":["University of Kansas"],"dc:title":["Investigation of ocular drug metabolism and pharmacokinetics using multi-omics and in-situ microdialysis"],"dc:type":["Dissertation"],"thesis:degree_discipline":["Pharmaceutical Chemistry"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-24T02:46:40Z"}