Bioavailability of etoposide after oral administration of the solution marketed for intravenous use: therapeutic and pharmacoeconomic perspectives.

BACKGROUND: Oral etoposide administration is a suitable alternative to the intravenous route; therefore, commercial capsules have been developed. Before these capsules were available in Mexico, we studied drug bioavailability after oral administration of the intravenous etoposide solution (IVES). METHODS: Eight adult cancer patients received a 50-mg oral etoposide dose as IVES and blood samples were collected over a period of 24 h. Plasma etoposide concentration was determined by high-performance liquid chromatography, plasma concentration against time curves were constructed, and bioavailability parameters were calculated. RESULTS: Oral IVES yielded an adequate bioavailability profile because Cmax was 2.38 +/- 0.30 micrograms/mL, AUC was 12.87 +/- 2.02 micrograms/mL and half-life was 6.72 +/- 0.97 h. CONCLUSIONS: Considering that the pharmacokinetic aim is to maintain plasma concentrations between 0.5 and 1.0 microgram/mL for several hours while avoiding high concentrations, i.e., of 10 micrograms/mL or higher, oral administration of 50-mg etoposide as IVES appears to be a suitable dosing option. In addition, oral IVES is considerably less expensive than intravenous administration in terms of both drug presentation and administration.

Matrix metalloproteinases expressed in squamous cell carcinoma of the oral cavity: correlation with clinicopathologic features and neo-adjuvant chemotherapy response.

Secretion of gelatinases A (MMP-2) and B (MMP-9) from 21 tumoral explants of squamous cell carcinoma (SCC) and five samples of normal mucosa of the oral cavity is demonstrated here. The explants were cultured into fetal bovine serum- and phenol red-deprived medium for 48 hours. The gelatinases secreted into the medium were revealed and quantified by zymography and densitometry, respectively. The results showed high medians of the 66 kDa forms of gelatinase A in tumoral explants, in comparison to normal explants: 31.0 vs 5.9 densitometric units (DU) (p <0.01). There was also a relatioship between clinical response to neo-adjuvant chemotherapy and low activity of 66 kDa form of gelatinase A, as well as 84 kDa and 92 kDa forms of gelatinase B. The median of gelatinolysis of the inactive form of gelatinase A (72 kDa form) was higher in those patients who exhibited a complete response to neo-adjuvant chemotherapy. We conclude that gelatinase A is a useful and objective tool to evaluate the response to chemotherapy and the aggressiveness of carcinomas of the oral cavity.