How long does each of the five materials take to absorb?
Two different clocks matter here, and buyers routinely collapse them into one. Time to hemostasis is how fast bleeding stops. Time to absorption is how long the material stays in the body. A product can be fast at the first and slow at the second.
| Material | Chemistry | Time to hemostasis | Stated absorption window | Evidence class | Source |
|---|---|---|---|---|---|
| Surgiclean® MPH absorbable hemostatic particles | Cross-linked potato starch microspheres, 30.8–97 µm, EO sterilized | Within minutes, normally 1 minute | 14 days | Company specification | Surgiclean® MPH technical presentation |
| A***a™ AH (same material class, uncross-linked) | Purified plant starch, microporous polysaccharide hemispheres | "Complete hemostasis can be achieved in minutes" | 24–48 hours | Manufacturer labeling | BD product documentation (see References) |
| Surgiclean® absorbable gauze of oxidized regenerated cellulose | 100% oxidized regenerated cellulose, warp-knitted | About 3 minutes | 28 days | Company specification, plus in-house animal study | Surgiclean® ORC technical presentation |
| Absorbable gelatin sponge (G****m®) | Purified porcine gelatin, dry-heat sterilized | Labeling instructs one to two minutes of light pressure; not stated as a hemostasis endpoint | 4–6 weeks | Manufacturer labeling | G****m® Dental Sponge labeling, revised December 2014 |
| Microfibrillar collagen (A*****e™) | Bovine corium collagen, partial hydrochloric acid salt | Labeling describes removing excess after 5–10 minutes | Up to 90 days | Peer-reviewed systematic review | Cziperle 2021, Medical Devices 14:155–163 |
Read the fourth column as a claim, not a measurement. Only the last column tells you how far to trust it.
Why do the numbers differ - chemistry, not marketing
All five materials are cleared by the body, but not by the same route, and the route sets the speed.
Plant starch microspheres are digested by amylase. Alpha-amylase hydrolyses the glycosidic bonds in starch, so clearance depends on how accessible those bonds are. Uncross-linked starch is exposed and goes in 24–48 hours. Cross-linking creates additional covalent bridges between polymer chains, and those bridges have to be broken before the fragments can be cleared. That is the mechanism we believe explains the gap between 24–48 hours and 14 days for two products made from the same feedstock - the difference is the cross-linking step, not the raw material. (Labelled as inference in our traceability record; we have not published a head-to-head enzyme digest study.)
Oxidized regenerated cellulose is broken down by hydrolysis as well as enzymatically. The oxidation step converts cellulose into a water-soluble, acidic form that the body can split into glucose and cellobiose, which then enter normal carbohydrate metabolism. Our specification for the finished gauze is full absorption within 28 days.
Gelatin and collagen are proteins, and proteins go through proteolysis. Gelatin sponge is digested by tissue peptidases over 4–6 weeks. Collagen is denser and more structurally organised, and microfibrillar collagen is reported absorbing in under 90 days.
The practical consequence for a distributor: absorption time is a design parameter, not a quality grade. A 14-day powder and a 90-day collagen are not better and worse versions of each other; they are different answers to different surgical problems.
What our own in vivo data showed
Most absorption numbers on the market are specifications. We have one product with a time-course resorption dataset behind it, and it is worth walking through because it shows how much the answer depends on where you look and how you look.
Study design, as presented in our ORC technical file:
New Zealand rabbits, subcutaneous implantation, n=21
Test article: Surgiclean® absorbable ORC gauze
Comparator: the market-leading ORC product, anonymised in our source presentation
Timepoints: day 0, 1, 3, 7, 10, 14
Gross observation at day 1, 3, 7, 10 and 14; ultrasound at day 0, 3, 7 and 14
A separate liver-injury model was used for histopathology at 2 and 4 weeks
Gross appearance (a) and ultrasound monitoring (b) of the Surgicleangroup (Surgiclean) and xxxcel group(xxxcel) in New Zealand rabbits at 0d, 3d, 7d, and 14d.
Subcutaneous implant model - gross observation and ultrasound:
| Timepoint | Gross appearance | Ultrasound |
|---|---|---|
| Day 0 | Implant in place | Irregular echoes with skin protrusion |
| Day 1 | Gel-like residues, pale yellow to brownish; material softened | - |
| Day 3 | Marked volume reduction | Protrusion subsided; anechoic areas with hyperechoic foci consistent with hydration |
| Day 7 | Only traces | Hypoechoic with punctate signals |
| Day 10 | Minimal residues | - |
| Day 14 | No visible residues in either group | Indistinguishable from native tissue |
Liver-injury model - histopathology (H&E):
| Timepoint | Finding |
|---|---|
| Week 2 | Granulation tissue with fibrous hyperplasia, inflammatory infiltration and degrading material fragments in both groups; adjacent liver tissue normal |
| Week 4 | Granulation tissue matured; no material remained in either group |
Both materials showed closely matched degradation rates, with complete degradation by 28 days.
What changes absorption time for the same product?
If absorption were a fixed property of a material, every study would return the same number. They do not, because at least five variables move the clock.
1. Enzyme availability in the patient. Amylase clears starch. The A****a labeling notes that amylase activity is reported to be reduced in newborns up to 10 months of age, and that absorption in that population may take longer than 48 hours. The material is identical; the patient's enzyme profile is not.
2. Processing and sterilization history. The G****m labeling warns against resterilizing by heat "because heating may change absorption time." Absorption is a property of the finished, processed device, not of the polymer in the abstract.
3. How much material is left behind. Both the A****a and Surgiclean instructions direct the user to irrigate and remove excess material once hemostasis is achieved. Material that is washed out is not cleared biologically, so the burden on the tissue is what was applied minus what was removed. More retained material means more to resorb.
4. The tissue bed. Our own data show a subcutaneous implant cleared macroscopically by day 14 while histology of a liver injury still found fragments at week 2. Vascularity, mechanical loading and local enzyme concentration all differ by site.
5. The endpoint and the instrument. Gross observation, ultrasound and histology do not agree with each other by construction. Add MRI or CT and the number changes again, because imaging detects physical presence with different sensitivity than a stained section.
Is a faster-absorbing hemostat better?
No, and a slower one is not automatically safer either. Absorption time buys and costs different things.
What a shorter window buys: less foreign material at the site for less time, which matters where a residual mass could press on a sensitive structure or act as a focus for infection. The G****m labeling itself notes that the sponge "may form a nidus of infection and abscess," and a systematic review of collagen hemostats records adverse effects when absorbable agents exert pressure on structures in bony or neural spaces after they have absorbed blood.
What a longer window buys: mechanical presence. A gelatin or collagen sponge still present at four weeks is still providing a scaffold over an oozing parenchymal surface, which is the reason slow-resorbing classes remain in use for liver, spleen and bone surfaces.
What neither buys: a guarantee. Clearance that finishes before the vessel has sealed is a rebleeding risk in principle; retention in a closed space is a compression and infection risk in principle. The right question is not "which is fastest" but "which window matches this wound, this tissue and this closure."
Where Surgiclean's two materials sit
We make two absorbable hemostats, and they sit at different points on this scale on purpose.
Surgiclean® MPH absorbable hemostatic particles - cross-linked plant starch microspheres, EO sterilized, thrombin-free, supplied in 0.5 g to 5 g with four applicators for open and laparoscopic delivery. Hemostasis is normally achieved in about one minute, and the specified absorption window is 14 days. If you need the powder specification, MOQ and private-label terms, start from the absorbable hemostatic powder product page.
Surgiclean® absorbable gauze of oxidized regenerated cellulose - 100% ORC, warp-knitted, with hemostasis normally within about 3 minutes and a specified absorption window of 28 days, supported by the implant and histology data above. Product detail sits on the absorbable hemostatic dressing page.
A note on one detail we deliberately do not quote: the market-leading ORC product is an established device (S****L®, PMA N12159 in the FDA database). We have not verified its current labeled absorption window against its own instructions for use in preparing this article, so we do not print a number for it. Read it from the current IFU if you are building a comparison table.
What this article does not establish
We have not published a head-to-head enzyme digestion study comparing cross-linked and uncross-linked starch. The cross-linking explanation is a mechanism, not a result.
The 14-day figure for MPH is our product specification. The time-course dataset in this article is for the ORC gauze.
Our comparator is anonymised in the source presentation as "xxxcel." We have not unblinded it in this article.
Absorption times are species- and site-dependent. Nothing here converts a rabbit study into a human clearance prediction.
We publish these limits because an absorption claim without an endpoint and a model is not a data point. It is a phrase.
FAQ
How long does absorbable hemostat take to dissolve?
It depends on the material, and the honest range runs from 24 hours to about 90 days. Uncross-linked plant starch microspheres are cleared in 24–48 hours. Cross-linked starch microspheres are specified at 14 days. Oxidized regenerated cellulose gauze is specified at about 28 days. Gelatin sponge takes 4–6 weeks. Microfibrillar collagen is the slowest, at up to 90 days.
Which absorbable hemostat is absorbed fastest?
Of the five materials compared here, uncross-linked plant starch microspheres are fastest, typically absorbed within 24–48 hours. Cross-linked starch microspheres are the next fastest at 14 days. Speed is a design choice: the cross-linking that slows clearance also changes how long the material stays in place as a mechanical scaffold.
How long does oxidized regenerated cellulose take to absorb?
Our Surgiclean® ORC gauze is specified for full absorption within 28 days. In a rabbit subcutaneous implant study the material was no longer visible by day 14, and histology of a separate liver-injury model showed degrading fragments at 2 weeks with none remaining at 4 weeks. Macroscopic and microscopic endpoints resolve on different schedules.
Why is cross-linked starch slower to absorb than plain starch?
Both are digested by alpha-amylase. Cross-linking adds covalent bridges between polymer chains, and those bridges must be broken before fragments can be cleared. That is our stated mechanism for the difference between 24–48 hours and 14 days, and we label it as inference: we have not published a head-to-head enzyme digestion study.
Is a faster-absorbing hemostat safer?
Not by itself. Faster clearance means less foreign material at the site for less time, which reduces the risk of a residual mass acting as an infection focus or pressing on a sensitive structure. But a material that clears before the vessel has sealed offers no ongoing mechanical support. The correct choice depends on the tissue, the bleeding pattern and the closure.
Does the amount of powder applied change absorption time?
It changes the amount of material the body has to clear, which is not the same thing. Both the A****a and Surgiclean instructions call for irrigating and removing excess product after hemostasis. Material washed out is not resorbed, so the residual dose is what was applied minus what was removed. Ask any supplier what their study left in place.
What should a distributor ask for before accepting an absorption claim?
Five things: the endpoint used (gross, imaging, histology or specification), the species and tissue, the sample size and whether a control was included, how much material was removed versus left in place, and whether the number is a study result or a specification. If the supplier cannot name the endpoint, the number is not usable in a technical comparison.
Related reading
Are hemostatic particles sterile, and how is that verified?
Our device registrations and certificates
Absorbable hemostatic powder - specification and applicator range
References
BD. Arista™ AH Absorbable Hemostatic Particles - product documentation and FAQ.
Pharmacia & Upjohn / Pfizer. Gelfoam® Dental Sponge labeling, revised December 2014. Labeling text: "When implanted in tissues, GELFOAM Dental Sponges are completely absorbed within four to six weeks without inducing excessive scar tissue."
Surgiclean®. Absorbable Gauze of Oxidized Regenerated Cellulose - technical presentation (in-house preclinical and clinical data, formulation and certificate list).
Surgiclean®. MPH Absorbable Hemostatic Particles - technical presentation (formulation, specification and applicator range).