Stability of ready-to-use temsirolimus infusion solution (100mg/L) in polypropylene containers under different storage conditions.

The aim of this study was to determine the stability of ready-to-use temsirolimus infusion solutions under different storage conditions. Solutions were prepared in polypropylene containers by adding temsirolimus injection to 0.9% sodium chloride infusion to reach a final concentration of 100mg/L. The following storage conditions were tested: (i) 4(o)C in the refrigerator; (ii) 20(o)C under room light exposure and light protection; and (iii) outdoor temperature with sunlight exposure. Moreover, stress testing was performed on drug substance at 20(o)C under ultraviolet (UV) radiation (365 nm). A stability-indicating high-performance liquid chromatography (HPLC) method with UV detection was developed for this analysis. Precision was below 4% and accuracy ranged from 97 to 102%. The lower limit of quantitation was 0.1mg/L. The degradation products produced after UV light exposure were detected upon further analysis by mass spectrometry detection. The stability of temsirolimus is light and temperature dependent. After storage at 20(o)C with room light exposure, the rate of degradation was around 0.25%/h; after 1 day, 92.5% of the initial temsirolimus concentration was recovered. When protected from light, at 4 and 20(o)C, losses were decelerated; the decrease in drug concentration was 1.0 and 1.56% per day, respectively. Under daylight exposure, a substantial decrease in drug concentration was observed; after 1h, losses were higher than 10%. Exposed to UV light, half of the drug was lost after 45 min. In conclusion, temsirolimus 100mg/L in infusion polypropylene bags containing 0.9% sodium chloride was chemically stable when protected from light for 4 and 3 days at 4 and 20(o)C, respectively.

Stability of amphotericin B and nystatin in antifungal mouthrinses containing sodium hydrogen carbonate.

Amphotericin B and nystatin are two polyene antibiotics that are potent antifungal agents. These drugs are active against most pathogenic fungi like Aspergillus and Candida. Mouthrinses containing these drugs are used for preventive and curative treatment of fungal infections like oral candidiasis, which can cause multiple diseases in cancer patients. Because there were no marketed antifungal mouthrinses available, their preparations were performed at the hospital and town pharmacies. To date, there are no data available on the stability of both these drugs in the form of mouthrinses. Therefore, each mouthrinse had to be prepared extemporaneously. The aim of this study was to investigate the stability of amphotericin B (Fungizone) and nystatin (Mycostatine) in the form of mouthrinses containing 1.4% sodium hydrogen carbonate. The stability of these solutions was tested at different temperatures (4-37 degrees C) with or without electric- or sunlight exposure and in two types of containers (glass and polypropylene) over a 15-day period. The admixtures were also monitored for colour change and pH. Amphotericin B and nystatin were quantified by high-performance liquid chromatography. At 4 degrees C, amphotericin B and nystatin were stable for 15 days in polypropylene. When stored in polypropylene at room temperature, with or without light protection, amphotericin B and nystatin were stable for 3 and 4 days, respectively.

Simultaneous determination of dexamethasone and 6 beta-hydroxydexamethasone in urine using solid-phase extraction and liquid chromatography: applications to in vivo measurement of cytochrome P450 3A4 activity.

It has been demonstrated that the formation of the hydrophilic metabolites of dexamethasone, 6 alpha- and 6 beta-hydroxydexamethasone, correlated with cytochrome P450 (CYP) 3A4 enzyme levels. So, the 6 beta-hydroxydexamethasone/dexamethasone urinary ratio could be a specific marker for human CYP3A4 activity. We have developed a sensitive and specific high-performance liquid chromatographic method for the simultaneous quantification of urinary free dexamethasone and 6 beta-hydroxydexamethasone using 6 alpha-methylprednisolone as internal standard. This method involved a solid phase extraction of the three compounds from urine using Oasis HLB Waters cartridges with an elution solvent of ethyl acetate (2 ml) followed by diethyl ether (1 ml). Separation of the three analytes was achieved within 24 min using a reversed-phase Nova-Pak C(18) analytical column (4 microm, 300 mm x 3.9 mm i.d.). An ultraviolet detector operated at 245 nm was used with a linear response observed from 10 to 100 ng/ml for dexamethasone and from 25 to 1000 ng/ml for 6 beta-hydroxydexamethasone. Obtained from the method validation, inter-assay precision was below 15% and accuracy ranged from 95.7 to 110%. The extraction efficiency of the assay was approximately of 99% and was constant across the calibration range. The lower limit of quantitation was 10 ng/ml for dexamethasone and 25 ng/ml for 6 beta-hydroxydexamethasone; at these levels, precision was below 16% and accuracy was 99-109%. This method was applied to in vivo measure of the CYP3A4 activity.

Carcinoembryonic antigen continuous epitopes determined by the spot method.

Carcinoembryonic antigen (CEA) is a heavily glycosylated tumor-associated protein with an N-A1-B1-A2-B2-A3-B3 domain structure. Circulating CEA immunoassays are used for monitoring digestive cancer patients, and radiolabeled anti-CEA monoclonal antibodies (MAb) are used for the diagnosis and therapy of CEA-positive tumors. The five major nonoverlapping epitopes (Gold 1-5) have been broadly correlated with the domain organization, but there is no precise localization of the epitopes at the sequence level. In an attempt to identify the peptide sequences corresponding to the five Gold epitopes on the CEA molecule, we prepared a set of 227 overlapping fifteen-mer peptides corresponding to the complete CEA sequence with the SPOT method. Using five high affinity MAbs directed against the five CEA Gold epitopes, we demonstrated that none of these epitopes could be mimicked by a fifteen-mer peptide sequence. However, using rabbit and goat anti-CEA sera, we identified six major continuous antigenic regions. All are included in the Ig-like domains of the CEA: two in the A1 domain (residues 120-134 and 153-164), one each in the A2 (329-337) and A3 domains (508-513), one at the junction between the A3 and B3 domains (553-561) and one in the B3 domain (565-573). A very homologous sequence (common residues VSPRL) was mapped in each of the three A domains. Thus, in terms of occurrence of continuous epitopes, the Ig-like domains A1, A2, A3 and B3 seem to be the most antigenic parts of CEA. These peptide sequences should be good candidates for the future development of site-specific anti-CEA MAbs.