BPC-157: Molecular Structure

Molecular Structure and Properties#

BPC-157 is a 15-amino-acid synthetic peptide with the sequence GEPPPGKPADDAGLV and a molecular weight of approximately 1,419 Da.

Amino Acid Sequence#

Molecular identity and primary structure. BPC-157 is a 15–amino-acid peptide derived as a fragment of a human gastric juice protein (“body protection compound”). Multiple peer-reviewed reports list the exact sequence as GEPPPGKPADDAGLV (Gly–Glu–Pro–Pro–Pro–Gly–Lys–Pro–Ala–Asp–Asp–Ala–Gly–Leu–Val), with a reported molecular weight of approximately 1419 Da.

Termini, form, and preparation notes. The commonly used research material is reported at 99% HPLC purity (manufactured by Diagen, Ljubljana, Slovenia). The retrieved sources do not specify terminal modifications or a defined counterion/salt; studies describe the peptide as used without a carrier, dissolved in saline, water (pH 7.0), or formulated into neutral cream (thus, termini are typically assumed free unless otherwise stated).

Physicochemical properties.

• Solubility and stability: BPC-157 is repeatedly described as native and stable in human gastric juice and freely soluble in water at pH 7.0 and in saline (qualitative descriptors in the cited studies).
• Isoelectric point and net charge (calculated): No experimental pI was reported in the retrieved excerpts. From the sequence (GEPPPGKPADDAGLV) and standard residue/terminus pKa values, the theoretical isoelectric point is approximately 3.5–3.6. At physiological pH (~7.4), the predicted net charge is near −2: negatively charged side chains (Glu2, Asp10, Asp11) and the deprotonated C-terminus are balanced by a single Lys7 and the protonated N-terminus. Thus, charge distribution clusters negative charges in the mid/acidic stretch (…PADD…), with a solitary positive Lys at position 7 and standard terminal contributions.
• Structural features: Primary structure contains a proline-rich N-terminal motif (GEPPP…), which can restrict backbone flexibility; the peptide ends with a modestly hydrophobic LV dipeptide. The literature consistently notes gastric stability but does not report specific secondary or tertiary structural determinations.

Common formulations and impurities. Studies administered BPC-157 in saline (parenteral), dissolved in drinking water (oral), and as topical cream; materials are described as 99% HPLC pure, with mention of a 1-des-Gly impurity in some preparations.

Stability and Formulation#

Overview: BPC‑157 (bepecin; PL 14736) is a 15‑mer peptide (GEPPPGKPADDAGLV) commonly described as “stable gastric pentadecapeptide.” Available evidence on its physicochemical behavior is fragmentary but allows several conclusions regarding pH tolerance, temperature/storage claims, degradation pathways, and practical formulation choices.

pH stability and solubility

• Stable in gastric conditions: Multiple reviews of experimental work state that BPC‑157 is native to and remains stable in human gastric juice for more than 24 h, supporting tolerance to strongly acidic pH and enabling oral/enteral administration.
• Aqueous solubility: BPC‑157 is reported as freely soluble in water at pH 7.0 and in isotonic saline, indicating straightforward preparation of neutral aqueous solutions.

Temperature sensitivity and storage

• Room‑temperature storage claim: A pharmacokinetic study explicitly states that BPC‑157 “can be stored at room temperature and is resistant to hydrolysis, enzyme digestion, and even gastric juice.” However, the paper does not provide detailed stability study conditions or time/temperature stress data; thus, the room‑temperature claim should be interpreted cautiously pending quantitative long‑term stability data.

Degradation pathways and metabolism

• In vitro metabolic degradation: Stable‑isotope‑assisted UHPLC‑HRMS characterization shows that BPC‑157 degrades predominantly via peptide bond (amide) cleavage, yielding truncated peptides. Cleavage often proceeds from the C‑terminus, but N‑terminal loss (e.g., Gly1) is also observed; nine metabolites were annotated, and progressive truncation increased polarity/shortened retention times.
• In vivo fate: Radiolabeled ADME data demonstrate rapid metabolic conversion of BPC‑157 into small peptide fragments and ultimately amino acids, with elimination primarily via urine and bile, consistent with proteolysis and amino acid reutilization/excretion.

Formulation considerations

• Vehicles and routes used experimentally: Reports document successful use as simple aqueous solutions (water pH 7.0; saline) for parenteral administration (e.g., intraperitoneal) and oral delivery (including in drinking water), as well as topical creams; an enema formulation (80 mg once daily for 2 weeks) in ulcerative colitis produced minimal systemic exposure, highlighting local action with limited absorption via rectal route.
• Practical implications: Given water/saline solubility at neutral pH and reported tolerance to gastric acid, BPC‑157 can be formulated as neutral aqueous solutions for injection or oral solutions/suspensions. The UHPLC‑HRMS data indicate susceptibility to generic proteolytic/chemical peptide bond cleavage, suggesting standard peptide formulation precautions (minimize repeated freeze–thaw, consider protease‑free handling, and, where stability is critical, use refrigerated storage or lyophilization with appropriate cryo/lyoprotectants), though specific lyophilization/excipient recipes for BPC‑157 were not reported in the cited literature.

Limitations and gaps

• Despite frequent assertions of “stability,” peer‑reviewed sources provide limited quantitative stability profiles across pH ranges or temperatures, and do not provide validated long‑term shelf‑life data or defined degradation kinetics in formulated products. No BPC‑157–specific patent/regulatory dossiers with detailed stability studies were identified in the present search. Accordingly, while gastric and enzymatic robustness is repeatedly claimed, formal ICH‑style stability data (e.g., Arrhenius, forced degradation, real‑time/accelerated) remain to be established in the public domain.

Pharmacokinetics#

Preclinical pharmacokinetic studies in rats and beagle dogs show that BPC‑157 (a 15–amino‑acid peptide) is rapidly absorbed after intramuscular (IM) administration, exhibits a short plasma half‑life for the parent peptide, undergoes rapid peptide degradation to small fragments and amino acids, distributes broadly with higher levels in reticuloendothelial and excretory organs, and is eliminated primarily via urine and bile; absolute IM bioavailability is low in rats and moderate in dogs, and no primary oral, subcutaneous, intraperitoneal, or human PK data were identified in the extracted evidence.

Absorption

• Rats (IM 20, 100, 500 μg/kg): very rapid absorption with Tmax consistently 3 minutes across doses, and dose‑proportional increases in Cmax and AUC, indicating linear pharmacokinetics.
• Beagle dogs (IM 6, 30, 150 μg/kg): rapid absorption with Tmax approximately 6–9 minutes; Cmax and AUC increased proportionally with dose.
• Across both species, the parent compound was typically undetectable by 4 h post‑dose, consistent with rapid absorption and elimination of the prototype peptide.

Distribution

• IV volume of distribution: rats Vss ≈ 36.4 ml/kg; dogs Vss ≈ 243 ± 162 ml/kg (noting high variance in dogs).
• Radiolabeled [3H]-BPC‑157 tissue distribution in rats demonstrated early whole‑body exposure with higher levels in kidney, liver, stomach wall, spleen, and thymus; concentrations in intestinal tract, lungs, and skin were similar to plasma; lowest in brain and body fat, indicating relatively limited CNS and adipose penetration.

Metabolism

• In vivo metabolism is rapid: [3H]-BPC‑157 was degraded into multiple small peptide fragments, with identification of [3H]proline as a metabolite; labeling studies indicate that ultimately single amino acids enter normal amino‑acid metabolic pathways.

Elimination

• Major excretory pathways: urine and bile, with low fecal recovery of radioactivity; in bile‑duct‑cannulated rats, 0–72 h recoveries were approximately urine ~17.8% and bile ~9.1%, consistent with renal and biliary elimination of metabolites.
• Substantial residual radioactivity persisted in carcass/tissues over days, reflecting retention of metabolites rather than parent peptide.

Half‑life

• Parent (prototype) peptide: short elimination half‑life in both species. Rat IV t1/2 ≈ 15.2 minutes; repeated‑dose rat IM t1/2 ≈ 18.5 minutes; dog IV t1/2 ≈ 5.27 minutes; dog IM effective terminal half‑life approximately 20–30 minutes; overall, prototype t1/2 reported as <30 minutes.
• Total radioactivity (reflecting metabolites plus parent): markedly longer persistence; mean residence time ~33.2 h and terminal t1/2 ~102 h in radiolabel studies, indicating prolonged presence of labeled fragments/metabolites rather than intact peptide.

Bioavailability

• Absolute IM bioavailability (Fa): rats ~14%–19% across 20–500 μg/kg doses; beagle dogs ~45%–51% across 6–150 μg/kg, indicating species‑dependent systemic availability after IM administration.
• No primary data located in the extracted evidence for absolute oral, subcutaneous, or intraperitoneal bioavailability.

Clearance

• Plasma clearance: rats CL ≈ 50.1 ml/min/kg after IV dosing; dogs CL ≈ 90.8 ± 40.1 ml/min/kg after IV dosing, consistent with rapid elimination of the parent peptide.

Methodological and evidence notes

• The summarized values derive from a single preclinical study with LC‑MS/MS quantification for parent and radiolabel tracking for total radioactivity; linear PK across IM dose ranges and minimal change with short‑term repeat dosing were reported.
• Gaps: No primary oral, SC, or IP PK or bioavailability data, and no human PK were identified in the extracted evidence; thus, human and oral properties remain undetermined here.

Conclusion In rats and beagle dogs, BPC‑157 shows rapid IM absorption (Tmax minutes), small‑to‑moderate distribution volume, rapid enzymatic degradation to peptide fragments and amino acids, elimination via urine and bile, and a short plasma half‑life for the parent peptide (<30 minutes); absolute IM bioavailability is ~14–19% in rats and ~45–51% in dogs. Prolonged radiolabel persistence reflects metabolites rather than intact BPC‑157. No primary oral, SC, IP, or human PK/bioavailability data were identified in the extracted sources.

Related Reading#

• BPC-157 overview and research guide
• Peptides similar to BPC-157
• BPC-157 research evidence