Effect of antacid pretreatment on the pharmacokinetics of AS-924, a novel ester-type cephem antibiotic--comparison with cefteram-pivoxil

Effective in-vivo utilization of lipid-based nanoparticles as drug carrier for carvedilol phosphate

Objectives

Lipid nanoparticles as carrier for oral drug administration improve gastrointestinal solubility of poorly soluble drugs and thus enhance bioavailability. However, basic drugs may undergo rapid dissolution from such solid dispersions in the stomach and precipitate in the intestine due to their higher solubility in acidic medium. Therefore, the objective of this work was to study the enhancement in bioavailability of carvedilol phosphate (basic drug) by providing an alkaline gastric environment to drug-loaded solid lipid nanoparticles.

Methods

An alkaline gastric environment in rats was created and maintained with oral administration of an antacid suspension 5 min before and 30 min post dosing.

Key findings

The formulation administered orally exhibited enhanced bioavailability (∼27%) when compared with drug suspension and sustained release behaviour when compared with formulation under ideal gastric conditions. The enhanced bioavailability is due to the presence of lipid nanoparticles as drug carrier while the sustained-release characteristic may be attributed to the presence of antacid, which resulted in elevation of gastric pH and reduced the drug's solubility.

Conclusions

It may be concluded that although lipid nanoparticles can be instrumental in improving bioavailability, additional sustained release may be achieved by targeting intestinal release of basic drugs from lipid vehicles, which is possible by incorporating them into suitable enteric-coated formulations.

Effects of the quantity of water and milk ingested concomitantly with AS-924, a novel ester-type cephem antibiotic, on its pharmacokinetics

The effect of the quantity of water ingested concomitantly with drugs, on the absorption of AS-924, a novel prodrug-type cephem antibiotic, was studied in five healthy adult volunteers by a cross-over method, using cefteram-pivoxil (CTER-PI) as the control drug. In addition, the effect of milk on the absorption of AS-924 was also investigated. The absorption of CTER-PI was significantly reduced when administered together with 30 ml of water compared with its absorption when administered together with 150 ml of water, whereas no such reduction was found in the case of AS-924. Ingestion of milk did not significantly affect the absorption of AS-924. These results confirm that absorption of AS-924 after oral administration is not likely to be affected by the quantity of water taken concomitantly with the drug, nor by milk.

Effects of gastrointestinal stimulant and suppressant pretreatment on the pharmacokinetics of AS-924, a novel ester-type cephem antibiotic

The effects of pretreatment with the gastrointestinal stimulant domperidone and the suppressant scopolamine butylbromide on the absorption of AS-924, a novel prodrug-type cephem antibiotic, were investigated in six healthy adult male volunteers by a cross-over method. The T(max) of ceftizoxime (CTIZ), the active moiety of AS-924, was slightly prolonged by scopolamine butylbromide (T(max)=1.8 vs. 1.5 h for the group without pretreatment). However, there were no significant differences in pharmacokinetic parameters including T(max), cumulative urinary excretion rates of CTIZ and cumulative urinary excretion rates of pivaloylcarnitine for 12 h after the dosing between the pretreated and control groups. Domperidone did not affect the absorption of AS-924.