Dear Lahiru Warnakula,

The after taste of bitterness is a common problem for oral suspension. It because in the formulation, we focus on how to mask the bitter agent by using a sweet flavor than the bitterness itself. So that, when someone try to drink it, it will be fine, but after that it will give a bitter taste because of the residue in the mouth.

One of the solution to overcome this problem that you can use a taste masking by Ion-Exchange Resins. Ion-exchange resins (IERs) are high molecular

weight polymers with cationic and anionic

functional groups (most common polymeric network is a copolymer of styrene and divinylbezene. Drug can be bound to the resin by either repeated exposure of the resin to the drug

in a chromate graphic column or by prolonged contact of resin with the drug solution. So that, the drug release does not occur under the salivary pH conditions. This suitably masks the unpleasant taste and odour of drugs. Drug release

from the resin will occur in the GIT.

Dear Lahiru Warnakula Check this out once

Article Masking of bitter taste of clarithromycin by microencapsulat...

Dear Raditya Iswandana

Im preparing a dry syrup here therefore I dont have the option of using a ion exchange resins for this formulation. Also this clarithromycin is already granulated. It contained 27% of clarithromycin in granulated form. Still it gives the bitter taste. What if I use betacyclodextrins to complex with the active material. ?

Dear Lahiru Warnakula,

Ah I see. The option to use beta-cyclodextrin is a good option, since there was also a research by using a beta-cyclodextrin as a making agent for dry syrup. You can read:

Article Formulation and Evaluation of Taste Masked Oral Reconstituta...

Good luck!

Thank you sir,

I will update my results so we can have a more interactive discussion regarding taste masking . Raditya Iswandana

Dear Raditya ,

betacylcodextrin seems works fine . It reduced bitterness . Raditya Iswandana

Also pH really matters in the medium .

Thank you sir for your support

Dear Lahiru Warnakula,

I'm really glad to hear that. Keep success for your work!

Good luck!

dear Raditya Iswandana I have found new problem with the oral suspension.

After reconstituting the taste was good at first. But after one day of reconstitution it will get a foul taste. Not the characteristic bitter taste. But some other taste.

Im suspecting that this might be due to presence of microbs .

Clarithromycin is in granulated form so it wont dissolve into the medium. Therefore this might be some kind of micro organism growing in the media ?.

Also I have seen in a research paper they were using Potassium Sorbate 0.5% w/w (for powder) in their medium.

Dear Lahiru Warnakula,

Based on your description, the growing of microbes are possible. So that, you can add preservative to protect the media. Sorbate is one of example that you can use. Please check the compatibility of the preservative with other subtances in your formula and the pH.

we can use ion exchange resins to mask the bitter taste of the oral suspension