{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,26]],"date-time":"2026-02-26T06:29:46Z","timestamp":1772087386988,"version":"3.50.1"},"reference-count":43,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2022,4,28]],"date-time":"2022-04-28T00:00:00Z","timestamp":1651104000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>In this article, we studied physicochemical and microbiological stability and determined the beyond-use date of two oral solutions of methadone in three storage conditions. For this, two oral solutions of methadone (10 mg\/mL) were prepared, with and without parabens, as preservatives. They were packed in amber glass vials kept unopened until the day of the test, and in a multi-dose umber glass bottle opened daily. They were stored at 5 \u00b1 3 \u00b0C, 25 \u00b1 2 \u00b0C and 40 \u00b1 2 \u00b0C. pH, clarity, and organoleptic characteristics were obtained. A stability-indicating high-performance liquid chromatography method was used to determine methadone. Microbiological quality was studied and antimicrobial effectiveness testing was also determined following European Pharmacopoeia guidelines. Samples were analyzed at days 0, 7, 14, 21, 28, 42, 56, 70, and 91 in triplicate. After 91 days of storage, pH remained stable at about 6.5\u20137 in the two solutions, ensuring no risk of methadone precipitation. The organoleptic characteristics remained stable (colorless, odorless, and bitter taste). The absence of particles was confirmed. No differences were found with the use of preservatives. Methadone concentration remained within 95\u2013105% in all samples. No microbial growth was observed. Hence, the two oral methadone solutions were physically and microbiologically stable at 5 \u00b1 3 \u00b0C, 25 \u00b1 2 \u00b0C, and 40 \u00b1 2 \u00b0C for 91 days in closed and opened amber glass bottles.<\/jats:p>","DOI":"10.3390\/molecules27092812","type":"journal-article","created":{"date-parts":[[2022,4,28]],"date-time":"2022-04-28T22:20:06Z","timestamp":1651184406000},"page":"2812","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Physicochemical and Microbiological Stability of Two Oral Solutions of Methadone Hydrochloride 10 mg\/mL"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7873-8054","authenticated-orcid":false,"given":"Elena Alba","family":"\u00c1lvaro-Alonso","sequence":"first","affiliation":[{"name":"Pharmacy Department, Infanta Leonor University Hospital, Av. Gran V\u00eda del Este, 80, 28031 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7344-2051","authenticated-orcid":false,"given":"Ma Paz","family":"Lorenzo","sequence":"additional","affiliation":[{"name":"Center for Metabolomics and Bioanalysis (CEMBIO), Faculty of Pharmacy, Universidad San Pablo-CEU, CEU Universities, Urbanizaci\u00f3n Montepr\u00edncipe, 28660 Boadilla del Monte, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andrea","family":"Gonzalez-Prieto","sequence":"additional","affiliation":[{"name":"Central Laboratory of Madrid UR Salud, Infanta Sof\u00eda University Hospital, Paseo de Europa, 34, San Sebasti\u00e1n de los Reyes, 28703 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2173-1027","authenticated-orcid":false,"given":"Elsa","family":"Izquierdo-Garc\u00eda","sequence":"additional","affiliation":[{"name":"Pharmacy Department, Infanta Leonor University Hospital, Av. Gran V\u00eda del Este, 80, 28031 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4188-7624","authenticated-orcid":false,"given":"Ismael","family":"Escobar-Rodr\u00edguez","sequence":"additional","affiliation":[{"name":"Pharmacy Department, Infanta Leonor University Hospital, Av. Gran V\u00eda del Este, 80, 28031 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6351-3856","authenticated-orcid":false,"given":"Antonio","family":"Aguilar-Ros","sequence":"additional","affiliation":[{"name":"Faculty of Pharmacy, Universidad San Pablo-CEU, CEU Universities, Urbanizaci\u00f3n Montepr\u00edncipe, 28660 Boadilla del Monte, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,28]]},"reference":[{"key":"ref_1","unstructured":"Spanish Agency of Medicines and Sanitary Products (2022, January 16). 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Acta Helv."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/27\/9\/2812\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:03:34Z","timestamp":1760137414000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/27\/9\/2812"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,4,28]]},"references-count":43,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2022,5]]}},"alternative-id":["molecules27092812"],"URL":"https:\/\/doi.org\/10.3390\/molecules27092812","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,4,28]]}}}