Aging and drug metabolism

Oral dosage forms must initially undergo dissolution, and although the decrease in stomach acid production which accompanies increasing age has sometimes been cited as a factor mitigating against adequate drug absorption, while there is no real evidence for such an effect. It is quite possible that the only clinically important aspect of gastric of gastri pH as regard drug absorption is that it affects gastric motility, with higher pH values favoring absorption by hastening the movement of stomach contents to the small intestine. The role of gastric pH in drug absorption has already been discussed in the previous attempts [Sultana and Arayne 1982]. The present review describes the progress that has been made in understanding the effect of age on drug handling system of the body and the implication that these changes have on the utility of pharmacological agents in treatment of old age patients

Effect of antacids on the dissolution behaviour of methacycline and doxycycline

The effect of antacids on the dissolution behaviour of methacycline and doxycycline capsules from commercial dosage forms were studied. The dissolution of both tetracyclines was found to be markedly retarded by antacids such as magnesium trisilicate and magnesium oxide. An attempt was made to elucidate the mechanism of this effect. The results suggest that the effect of antacids on the dissolution may be due to the absorption of the drugs on antacids particles, as well as to the increased pH of the medium