Adsorptive property of kaolin in some drug formulations

Purpose: Kaolin is a known ad sorbent, has lubricant property in po wders and is therefore proposed as a lubricant in tablet formulations. This study was carried out to evaluate whether kaolin can ad sorb some a ctive d rugs when mixed with them in tablet f ormulations even a t very low concentrations. Method: Chloroquine and chlorpheniramine tablets were formulated with po wder mixtures containing various concentrations of kaolin. The effect of kaolin on the physical properties of the tablets were e xamined and compared with those o f standard lubricants like magnesium stearate and talc. Chloroquine and chlorpheniramine tablets and powders of amoxicillin/clavulanic acid oral powder and ampicillin/cloxacillin injection were also mixed with and without various c oncentrations of kaolin in water. Chemical assay of t he d rugs in the solutions were determined over time. Results: Kaolin significantly reduced the a mount of each o f t he d rugs in the solutions containing kaolin. Conclusion: Kaolin reduces the a mount of some d rugs when incorporated in d rug formulations. Therefore, its inclusion in such drug formulations should not be encouraged.