{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T02:50:28Z","timestamp":1787021428368,"version":"build-2736575974"},"reference-count":51,"publisher":"Oxford University Press (OUP)","issue":"6","license":[{"start":{"date-parts":[[2009,6,1]],"date-time":"2009-06-01T00:00:00Z","timestamp":1243814400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2009,6,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>The use of L-carnosine as an excipient in topical ophthalmic formulations containing gellan gum, a carbohydrate polymer with in-situ gelling properties upon mixing with mammalian tear fluid, was developed as a novel platform to extend precorneal duration. Specific utilisation of L-carnosine as a buffer in gellan gum carrying vehicles was characterised.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Buffer capacity was evaluated using 7.5, 13.3, and 44.2 mM L-carnosine in a pH range of 5.5\u20137.5. Accelerated chemical stability was determined by HPLC at L-carnosine concentrations of 5\u2013100 mM. Combinations of 7.5 mM L-carnosine with 0.06\u20130.6% (w\/v) gellan gum were characterised rheologically. L-Carnosine-buffered solutions of gellan gum were tested for acute topical ocular tolerance in vivo in pigmented rabbits. A unique formulation combining timolol (which lowers intraocular pressure) in L-carnosine-buffered gellan gum was compared with Timoptic-XE in normotensive dogs.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Key findings<\/jats:title>\n                    <jats:p>L-Carnosine exhibited optimal pharmaceutical characteristics for use as a buffer in chronically administered topical ocular formulations. Enhancement trends were observed in solution-to-gel transition of L-carnosine-buffered vehicles containing gellan gum vs comparators. Topical tolerability of L-carnosine-buffered gellan gum formulations and lowering of intraocular pressure were equivalent with timolol and Timoptic-XE.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Functional synergy between excipients in gellan gum formulations buffered with L-carnosine has potential for topical ocular dosage forms with sustained precorneal residence.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1211\/jpp.61.06.0005","type":"journal-article","created":{"date-parts":[[2010,10,14]],"date-time":"2010-10-14T09:21:43Z","timestamp":1287048103000},"page":"733-742","source":"Crossref","is-referenced-by-count":21,"title":["<scp>l<\/scp>\n                    -Carnosine: multifunctional dipeptide buffer for sustained-duration topical ophthalmic formulations"],"prefix":"10.1093","volume":"61","author":[{"given":"Swita R","family":"Singh","sequence":"first","affiliation":[{"name":"Department of Pharmaceutical Sciences, University of Nebraska Medical Center , Omaha, Nebraska,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Samantha T","family":"Carreiro","sequence":"additional","affiliation":[{"name":"Department of Ocular Biology, La Jolla Laboratories , San Diego, California,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jessie","family":"Chu","sequence":"additional","affiliation":[{"name":"Department of Ocular Biology, La Jolla Laboratories , San Diego, California,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ganesh","family":"Prasanna","sequence":"additional","affiliation":[{"name":"Department of Ocular Biology, La Jolla Laboratories , San Diego, California,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael R","family":"Niesman","sequence":"additional","affiliation":[{"name":"Department of Ocular Biology, La Jolla Laboratories , San Diego, California,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"suffix":"III","given":"Walter W","family":"Collette","sequence":"additional","affiliation":[{"name":"Department of Drug Safety R&D, La Jolla Laboratories , San Diego, California,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Husam S","family":"Younis","sequence":"additional","affiliation":[{"name":"Department of Drug Safety R&D, La Jolla Laboratories , San Diego, California,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Soisurin","family":"Sartnurak","sequence":"additional","affiliation":[{"name":"Research Science & Technology - Formulations, Pfizer Global Research and Development, La Jolla Laboratories , San Diego, California,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hovhannes J","family":"Gukasyan","sequence":"additional","affiliation":[{"name":"Research Science & Technology - Formulations, Pfizer Global Research and Development, La Jolla Laboratories , San Diego, California,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2009,6,1]]},"reference":[{"key":"2024103109372079100_cit1","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1089\/jop.1986.2.67","article-title":"Topical ocular drug delivery: recent developments and future challenges","volume":"2","author":"Lee","year":"1986","journal-title":"J Ocul Pharmacol"},{"key":"2024103109372079100_cit2","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1016\/0378-5173(89)90305-0","article-title":"Gelrite\u00ae: a novel, ion-activated, in-situ gelling polymer for ophthalmic vehicles. 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