I made injectable bone substitute from hydroxyapatite and gelatin with HPMC (hydroxy propyl methyl cellulose) as suspending agent. I want to know about how long it will take this suspension to sediment, but I don't know about this resuspension process.
thank you mr. Ahmad
do you handbook or literature that explain about suspension clearly?
Are you sonicating your suspension? Because in thiscase the biggest one will sediment in 15-20 minutes, but you will have a lot of nanometer sized particles that will stay in suspension forever but are only visible by EM microscopy.
If you are using gelatin and other thickening agent probably even the biggest particle after sonication will stay resuspended forever because of the viscosity: I was talking about HA in water.
Thank you Mr. Danilo, i don't sonicate my suspension. That's true that the sedimentation will be occurred after around 20 minutes. i still don't get the meaning of resuspension process. Like, how it happen? what are factors that affect resuspension process?
Maybe, you can help me
Dear Dr. Putra, try to sonicate HA in water before adding the gelatin powder to obtain the concentration of it that you want and then, when all the mixture is ready, I would vortex it briefly, the crystals will be uniformly suspended in the gel and stay in place due to their dimension and the final product viscosity (I imagine that is your goal). I will not sonicate the gel because to break the HA crystals you need to put the equipment at high power for 5' and this will affect the cross linking of the components plus is going to raise the temperature. Sedimentation happens by gravity and is affected by the factor I mentioned before: particle size (the smaller the longer will be the sedimentation time), and by the viscosity of the media in which the particle are resuspended
I see, i'll try it. thank you so much Mr. Zangani. Your answer helps me a lot
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