| Alkyl chain geometry |
4-methyl-heptyl ester (branch in the middle of the C-8 chain) → highly branched, more steric bulk |
2-octyl ester (single methyl branch on C-2, remainder linear) → semi-branched |
| Viscosity (25 °C, neat monomer) |
typically 450 – 550 cP (slightly higher because of the extra branching) |
typically 300 – 400 cP (Dermabond ≈ 350 cP) |
| Polymer film characteristics |
• Very soft/flexible film; high elongation before break• Reported higher breaking strength than n-butyl analogues, but peer-reviewed head-to-head data vs OCA are still scarce |
• Well-studied; 3–4 × stronger volumetric bond than n-butyl CA; balanced toughness & flexibility; clinically proven to remain intact ≥ 7 days on skin |
| Polymerisation rate / exotherm |
Slightly slower set and ~1 – 2 °C lower peak exotherm (bulkier side chain dampens anionic chain-growth) – useful on sensitive tissue |
Sets in ≈ 60 s; peak exotherm typically 45-55 °C when applied as a thin film |
| Biocompatibility & degradation |
Long, branched chain slows hydrolytic scission → even lower formaldehyde release than OCA; in vitro cytotoxicity reported comparable to OCA |
Accepted “gold-standard” medical CA since FDA clearance 1998; low tissue reaction relative to shorter (butyl/ethyl) CAs |
| Regulatory & market status |
Sold mainly as raw material or in a few newer tissue-sealant lines (e.g. Myokling Octa) that claim US FDA-approved molecule but have limited published clinical trials |
Broad commercial availability (Dermabond®, SurgiSeal®, LiquiBand Exceed, etc.); hundreds of clinical papers & device clearances |