Adsorptive property of kaolin in some drug formulations

Abstract

Purpose: Kaolin is a known adsorbent, has lubricant property in powders and is therefore proposed as a lubricant in tablet formulations. This study was carried out to evaluate whether kaolin can adsorb some active drugs when mixed with them in tablet formulations even at very low concentrations. Method: Chloroquine and chlorpheniramine tablets were formulated with powder mixtures containing various concentrations of kaolin. The effect of kaolin on the physical properties of the tablets were examined and compared with those of 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 concentrations of kaolin in water. Chemical assay of the drugs in the solutions were determined over time. Results: Kaolin significantly reduced the amount of each of the drugs in the solutions containing kaolin. Conclusion: Kaolin reduces the amount of some drugs when incorporated in drug formulations. Therefore, its inclusion in such drug formulations should not be encouraged.

The Effect of Adding PVP to the Binary Solid Dispersion (Indomethacin: Kaolin) on the Formation of Physically Stable Amorphous Drug

“…The water solubility measurements of the binary mixtures (Fig. 11) have shown a slight decrease in drug solubility for I 1 K 1 and I 1 K 3 mixtures; this can be explained by the adsorption effect of kaolin which is insoluble in water [11,13]. Such water solubility attenuation occurred for several drug/ kaolin formulations [12].…”

“…However, many studies have shown that a decrease in drug solubility can be resulted from adsorption effect and strong interactions between kaolin and drug molecules. This critical aspect was obtained for several pharmaceutical products, e.g., ampicillin, cloxacillin, amoxicillin, clavulanic acid, chloroquine, chlorpheniramine [11], ciprofloxacin, chloroquine, piperazine, phyllocontin, digoxin and diazepam [12], metronidazole [13]. This could undoubtedly limit, in some cases, the use of kaolin in pharmaceutical formulations.…”

In vitro interaction between Zidovudine and some adsorptive antacids

“…Interaction studies between silicate and some hydrophobic molecules showed that the positive charges on the molecules promote adsorption onto silica molecules. 15 Zidovudine essentially has nitrogen atoms in its chemical structure and these provide the binding sites for the silica in magnesium trisilicate. The degree of the adsorption is also dependent on the number of free binding sites available.…”

Determination and characterization of metronidazole–kaolin interaction

“…There are many reports of adsorbed drugs and chemicals onto kaolin, for example; quinidine (Bucci et al, 1981), propranolol (Al-Gohary et al, 1987), mebeverine hydrochloride (al Gohary, 1997); ampicillin, cloxacillin, amoxicillin, clavulanic acid, chloroquine, chlorpheniramine (Onyekweli et al, 2003), Congo red (Vimonses et al, 2009); ciprofloxacin, chloroquine, piperazine, phyllocontin, digoxin and diazepam (Hassan and Ibrahim, 2011).…”