Mike Easterbrook, Chief Technical Officer and Sanjay Negi, DGM- Film Coatings, Ideal Cures, determine the feasibility of formulating a ready mixed immediate release coating system containing polymer, plasticiser, and a non-talc anti-adherent agent
Talc has been traditionally used as an anti-tack agent in various immediate release and enteric coating formulations. However, it is subject to sedimentation and may cause system instability. Sedimentation of talc can lead to process concerns such as gun clogging which may lead to frequent process interruptions.
The objective is to determine the feasibility of formulating a ready mixed immediate release coating system containing polymer, plasticiser, and a non-talc anti-adherent agent. The experiments mentioned in the article demonstrate the possibility of using capric glycerides as the non-talc anti tack agent.
Coating formulation preparation
PVA – based coating formulations were formulated with either talc or capric glycerides as anti – tack agents. Laboratory scale mixers were used to prepare the coating formulations. The ingredients were added and blended together in the mixer until uniform powder blends were obtained.
Coating suspension preparation and tablet coating
Suspensions of both coating formulations were prepared using a laboratory scale stirrer. These were found to be smooth and sprayable. Plain placebo tablets were coated using these suspensions in a six inch conventional coating pan with pre – determined coating parameters.
Evaluation of coated tablets and stability studies
Coated tablets were evaluated for appearance, disintegration time and coating defects.
The appearance and disintegration characteristics of the coated tablets from both the formulations were comparable. Coated tablets of the talc-based formulations were slightly better in term of gloss than the capric glyceride-based formulations. No coating process related issues were observed with either system during the coating process.
Results and discussion
Coating suspensions that had been reconstituted at 20 per cent w/w were found to be smooth and possess good sprayability. No coating issues were observed during the coating process. In all trials, coated tablet surfaces were found to be good.
Based on these studies it can be concluded that capric glycerides may be used as anti-tack agents to replace talc in ready mix coating formulations. Compared with talc, capric glycerides can be used at lower concentrations (5 per centw/w) thus avoiding the sedimentation and gun clogging issues often seen where talc based formulations (15 per cent w/w) have been used.