| NMR analysis of ion pair formation between timolol and sorbic acid in ophthalmic preparations. | |
| | |
MedLine Citation:
|
PMID: 17145156 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Ion pair formation between timolol and sorbic acid was investigated using NMR spectroscopy in order to clarify their interactions within ophthalmic preparation. (13)C and (1)H NMR spectra of timolol, sorbic acid, and a mixture of the two were obtained, and the signal changes induced by pairing were observed. The carbon signals of the butylaminopropanol moiety of timolol were markedly shifted in the mixture, as were the carboxyl and conjugated carbons assigned to sorbic acid. The localizations of the changes in each molecule revealed the binding sites. The profiles of butylaminopropanol carbon chemical shifts plotted against a molar ratio of sorbate were synchronized, which suggested a single type of interaction with sorbic acid. The Job plot showed a typical pattern with a single-maximum at a mole function of 0.5, indicating the presence of a 1:1 complex of timolol and sorbic acid. The stability constants (K) of the timolol-sorbate and timolol-maleate pairs were 1.9x10(1) and 2.2x10(2)M(-1), respectively. The higher K value of the timolol-maleate interaction suggested that it was dominant to the timolol-sorbate interaction when maleate and sorbate coexisted within a timolol solution. Here, we demonstrated evidence of an interaction between timolol and sorbic acid using simple NMR measurements, which suggested the existence of ion pair formation derived from charge neutralization. Our analysis using NMR spectroscopy should advance the understanding and optimization of formulations that are based on ion pair. |
| | |
Authors:
|
Masayo Higashiyama; Katsuhiro Inada; Akira Ohtori; Kazuaki Kakehi |
Related Documents
:
|
6194816 - Interaction of bleomycin a2 with poly(deoxyadenylylthymidylic acid). a proton nuclear m... 6490816 - Identification of streptococcus bovis and streptococcus salivarius in clinical laborato... 1463786 - Reagent for introducing pyrene residues in oligonucleotides. 15999246 - The promise and peril of continuous in vitro evolution. 9555216 - Erosion on abraded dental hard tissues by acid lozenges: an in situ study. 838226 - Direct and indirect effects of dextrose and amino acids on gut mass. |
Publication Detail:
|
Type: Journal Article Date: 2006-12-04 |
Journal Detail:
|
Title: Journal of pharmaceutical and biomedical analysis Volume: 43 ISSN: 0731-7085 ISO Abbreviation: J Pharm Biomed Anal Publication Date: 2007 Mar |
Date Detail:
|
Created Date: 2007-02-26 Completed Date: 2007-04-25 Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 8309336 Medline TA: J Pharm Biomed Anal Country: England |
Other Details:
|
Languages: eng Pagination: 1335-42 Citation Subset: IM |
Affiliation:
|
Senju Pharmaceutical Co. Ltd., 1-5-4 Murotani, Nishi-Ku, Kobe 651-2241, Japan. m-higashiyama@senju.co.jp |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Chromatography, High Pressure Liquid Ions Magnetic Resonance Spectroscopy / methods* Molecular Structure Octanols / chemistry Ophthalmic Solutions / analysis*, chemistry Sorbic Acid / analysis*, chemistry Timolol / analysis*, chemistry Water / chemistry |
| Chemical | |
Reg. No./Substance:
|
0/Ions; 0/Octanols; 0/Ophthalmic Solutions; 110-44-1/Sorbic Acid; 26839-75-8/Timolol; 7732-18-5/Water |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Breast imaging and reporting data system (BIRADS): magnetic resonance imaging.
Next Document: Quantifying trifluoroacetic acid as a counterion in drug discovery by 19F NMR and capillary electrop...