Octreotide

Octreotide is a synthetic cyclic octapeptide designed as a metabolically stabilized analog of somatostatin, the naturally occurring 14-amino-acid (or 28-amino-acid, in its extended form) hypothalamic and gastrointestinal hormone that broadly inhibits the secretion of numerous other hormones, including growth hormone, insulin, glucagon, and various gastrointestinal peptides. Octreotide was first synthesized in 1979 by researchers at Sandoz (now Novartis) and reported in the pharmacological literature in 1982, then developed into the drug marketed as Sandostatin, receiving FDA approval in 1988.

At Verified Peptides, we think Octreotide represents a genuine landmark achievement in peptide drug chemistry: native somatostatin, despite its broad and clinically interesting hormone-suppressing activity, has a circulating half-life of only 2-3 minutes due to rapid enzymatic degradation, making it essentially unusable as a practical therapeutic agent requiring continuous intravenous infusion to maintain any sustained effect. Octreotide's specific structural modifications — retaining the four-amino-acid core sequence (Phe-Trp-Lys-Thr) believed essential for somatostatin receptor binding, substituting D-amino acids at key positions, cyclizing the molecule via a disulfide bridge, and replacing the C-terminal amino acid with a reduced threoninol group — extend its functional half-life to roughly 1.5-2 hours, a dramatic and clinically transformative improvement that made sustained-release, practical dosing possible for the first time in this drug class.

Chemically, Octreotide has molecular formula C49H66N10O10S2, molecular weight approximately 1019.25 g/mol, CAS number 83150-76-9 (base compound; acetate salt CAS 79517-01-4), PubChem CID 448601.

Octreotide's cyclic structure, closed by a disulfide bond between its two cysteine residues, mirrors the cyclization strategy used in native somatostatin itself, which forms a 14-amino-acid ring via its own internal disulfide bond — this structural parallel is not coincidental, since the cyclic conformation is understood to be important for proper receptor engagement in both the native hormone and its synthetic analogs. The replacement of the native hormone's much larger 14- or 28-residue structure with Octreotide's minimal 8-residue design, retaining only the receptor-critical core plus stabilizing modifications, reflects a broader medicinal chemistry principle of identifying and preserving a larger natural molecule's essential pharmacophore while discarding structurally unnecessary regions.

At Verified Peptides, we think Octreotide has one of the longest-standing and most thoroughly documented evidence bases in this catalog. The foundational chemistry and pharmacology paper is Bauer et al. (1982, Life Sciences, PMID 6128648, volume 31, issue 11, pages 1133-1140), reporting the synthesis of SMS 201-995 (Octreotide's original development code), finding it three times more potent than native somatostatin in inhibiting growth hormone secretion in vitro, highly resistant to enzymatic degradation, at least 20 times more active than somatostatin in vivo, and substantially more selective for growth hormone suppression relative to insulin suppression than the native hormone — a genuinely foundational structure-activity paper establishing the rationale for the entire subsequent somatostatin-analog drug class.

The pivotal human clinical evidence is Ezzat et al. (1992, Annals of Internal Medicine, PMID 1416572, volume 117, issue 9, pages 711-718), a double-blind, randomized, multicenter study conducted at fourteen university-affiliated medical centers in 115 patients with acromegaly (70% with disease persisting after prior surgery or radiotherapy). A single 100-microgram injection reduced mean serum growth hormone to approximately 30% of baseline within two hours, and after six months of treatment, growth hormone was suppressed below 5 μg/L in 49-53% of patients (depending on dose) and IGF-1 levels normalized in 55-68% of patients, alongside clinical improvements in headache, perspiration, joint pain, and reduced finger circumference in roughly two-thirds of patients. Reported adverse effects included transient diarrhea (10-13%), biliary sludge (10-14%), and gallstones (6-18%), the latter reflecting Octreotide's known effect of reducing gallbladder motility.

At Verified Peptides, we sell research-grade Octreotide exclusively for laboratory research, and we think this compound's nearly four-and-a-half-decade research and clinical history, spanning foundational chemistry through modern long-acting depot formulations, makes it one of the more thoroughly characterized somatostatin-pathway compounds available for research reference in this catalog.

We also want to note that Octreotide's real-world clinical evidence has continued to accumulate well beyond its original approval trials. Retrospective real-world studies of long-acting release formulations, along with head-to-head comparative trials against newer somatostatin analogs including lanreotide and pasireotide (a related somatostatin analog also built elsewhere in this catalog), have continued to refine understanding of its comparative efficacy and adverse event profile in acromegaly management specifically, since these comparative trials in more recent decades have used more standardized IGF-1 and growth hormone normalization endpoints than were universally applied in the earliest 1990s-era studies.

Somatostatin's extremely short native half-life (2-3 minutes) reflects a broader pattern seen with several other native regulatory peptide hormones profiled in this catalog, including native GnRH (Gonadorelin, also built on this site), which similarly requires structural modification to achieve clinically practical dosing intervals — a recurring theme in peptide pharmacology where the native signaling molecule's rapid degradation, useful for tight physiological regulation, must be deliberately engineered away to create a practical drug.

Octreotide's use in somatostatin receptor scintigraphy (a nuclear medicine imaging technique using radiolabeled Octreotide, historically Indium-111-pentetreotide) to visualize SSTR2-expressing neuroendocrine tumors throughout the body predates and directly informed the more recent development of related radiolabeled somatostatin analogs used in both diagnostic PET imaging and, in newer applications, targeted radionuclide therapy for neuroendocrine tumors — an active and expanding area of nuclear oncology built directly on Octreotide's original receptor-targeting chemistry. Octreotide's discovery is also frequently cited as an early and influential example of successful rational peptide drug design based on a natural hormone template, predating much of the modern structure-based drug design toolkit, and its commercial and clinical success helped establish somatostatin analogs as a viable therapeutic drug class, motivating subsequent development of related compounds including lanreotide and pasireotide.

Long-acting release (LAR, depot) formulations of Octreotide, requiring only monthly intramuscular injection compared to the original formulation's three-times-daily subcutaneous dosing, were approved in France in 1995 and the United States in 1998, reflecting the same general formulation-innovation trajectory toward reduced dosing frequency seen with several other peptide drugs in this catalog, including the GnRH agonist analogs.

At Verified Peptides, we require independent third-party HPLC purity testing and mass spectrometry identity confirmation for every batch of research-grade Octreotide we offer, with a Certificate of Analysis (COA) available for each lot. As a cyclic peptide stabilized by a disulfide bridge, correct ring closure and disulfide bond formation should be confirmed as part of identity testing, since incomplete or incorrect cyclization would represent a structurally different, non-functional molecule.

We source exclusively from manufacturers operating under Good Manufacturing Practice (GMP)-aligned quality systems, and every lot is independently verified rather than accepted solely on a supplier's internal documentation. Researchers should always request and review the specific COA for the lot they receive, confirming purity percentage and molecular identity before use in any experimental protocol. Mass spectrometry analysis confirming the correct monoisotopic mass is particularly informative for cyclic disulfide-bridged peptides, since a reduced (non-cyclized) form of the same linear sequence would show a mass shift of approximately 2 daltons relative to the properly oxidized, cyclized product.

Lyophilized Octreotide is stable when stored at -20°C, protected from light and moisture. At Verified Peptides, we ship lyophilized peptide with appropriate cold-chain packaging to preserve stability in transit.

Once reconstituted, solution should be stored refrigerated at 2–8°C and used within the timeframe indicated on the product's documentation, avoiding repeated freeze-thaw cycles. As a disulfide-cyclized peptide, Octreotide may be sensitive to reducing conditions that could disrupt the disulfide bridge, so researchers should follow lot-specific handling guidance to preserve structural integrity, avoiding exposure to strong reducing agents or conditions that could cleave the disulfide bond and revert the molecule to its linear, non-cyclized (and presumably non-functional) form.