title: A rapid hydrolysis method and DABS-Cl derivatization for complete amino acid analysis of octreotide acetate by reversed phase HPLC.
abstract: Octreotide as a synthetic cyclic octapeptide is a somatostatin analog with longer half-life and more selectivity for inhibition of the growth hormone. The acetate salt of octreotide is currently used for medical treatment of somatostatin-related disorders such as endocrine and carcinoid tumors, acromegaly, and gigantism. Octreotide contains both cysteine and tryptophan residues which make the hydrolysis part of its amino acid analysis procedure very challenging. The current paper introduces a fast and additive-free method which preserves tryptophan and cysteine residues during the hydrolysis. Using only 6 M HCl, this hydrolysis process is completed in 30 min at 150 °C. This fast hydrolysis method followed by pre-column derivatization of the released amino acids with 4-N,N-dimethylaminoazobenzene-4'-sulfonyl chloride (DABS-Cl) which takes only 20 min, makes it possible to do the complete amino acid analysis of an octreotide sample in a few hours. The highly stable-colored DABS-Cl derivatives can be detected in 436 nm in a reversed phase chromatographic system, which eliminates spectral interferences to a great extent. The amino acid analysis of octreotide acetate including hydrolysis, derivatization, and reversed phase HPLC determination was validated according to International Conference of Harmonization (ICH) guidelines.
authors.affiliation: Quality Control Department, Tofigh Daru Research and Engineering Company, Tehran, Iran. p.akhlaghi@gmail.com.
authors.forename: Yousef
authors.initials: Y
authors.lastname: Akhlaghi
authors.affiliation: Quality Control Department, Tofigh Daru Research and Engineering Company, Tehran, Iran.|Young Researchers and Elite Club, Pharmaceutical Sciences Branch, Islamic Azad University (IAUPS), Tehran, Iran.
authors.forename: Solmaz
authors.initials: S
authors.lastname: Ghaffari
authors.affiliation: Quality Control Department, Tofigh Daru Research and Engineering Company, Tehran, Iran.|Biotechnology Department, Pharmaceutical Sciences Branch, Islamic Azad University (IAUPS), Tehran, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Attar
authors.affiliation: Quality Control Department, Tofigh Daru Research and Engineering Company, Tehran, Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Alamir Hoor
mesh_terms: D003545:Cysteine / Q000032:analysis* / Q000737:chemistry; D006851:Hydrochloric Acid / Q000737:chemistry; D006868:Hydrolysis; D015282:Octreotide / Q000032:analysis / Q000737:chemistry*; D013004:Somatostatin / Q000032:analysis / Q000737:chemistry; D014364:Tryptophan / Q000032:analysis* / Q000737:chemistry
chemical_list: D013004:Somatostatin; D014364:Tryptophan; D003545:Cysteine; D006851:Hydrochloric Acid; D015282:Octreotide
keywords: Amino acid analysis; DABS-Cl; Hydrolysis; Method development and validation; Octreotide acetate; Reversed phase HPLC