Fluorescence study of some terbium-oligopeptide complexes in methanolic solution.

This study concerned the use of lanthanide chelates to detect glycyl-leucyl-phenylalanine (GLF) and its homologues. Spectroscopic analysis of peptides without or with terbium complexation revealed the formation of (LF)(3)(Tb)(2), (GF)(3)(Tb)(2), (GLF)(3)(Tb)(2) and (FL)(4)Tb, (FG)(4)Tb complexes with high stability constants in methanolic solutions (pK(d)>13). Lanthanide chelate emission displayed a large Stokes shift (>270 nm), which allowed Tb chelates of GLF and its derivatives to be used for detection purposes. However, this preliminary study indicated some important limitations associated with lanthanide chelation, such as high methanolic content.

Hydrocortisone 17-butyrate degradation in the presence of micro-organisms.

OBJECTIVE: This study compared the degradation of hydrocortisone 17-butyrate (H17B) in the presence of six different bacteria, commonly found on psoriatic skin. METHOD: H17B and its degradation products (hydrocortisone and hydrocortisone 21-butyrate (H21B)) were assayed by HPLC. RESULTS: In the absence of micro-organisms, we observed 16.6 +/- 7.1% degradation. In the presence of micro-organisms and otherwise similar conditions, we noted that H17B degradation was not modified by cocci (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus agalactiae). Three bacilli increased degradation, Escherichia coli 59.1 +/- 19.4%, Klebsiella oxytoca 62.1 +/- 6.7% and Pseudomonas aeruginosa 56.0 +/- 17.9%. CONCLUSION: The degradation of H17B into hydrortisone and H21B may produce a loss of therapeutic activity.

Stability of cisplatin in ethylene vinylacetate portable infusion-pump reservoirs.

The stability of cisplatin in admixture stored in portable pump reservoirs was investigated. Admixtures containing 0.9 or 0.5 mg/ml cisplatin in 0.9% sodium chloride injection were placed in 80-ml ethylene vinylacetate (EVA) drug reservoirs protected from light and 1-ml quantities were withdrawn immediately after preparation and after storage for 1, 2, 3, 4, 7, 14, 28 days at +22 or +35 degrees C. Three samples for each condition from each admixture were tested for drug concentration using a stability-indicating high-performance liquid chromatographic method. No colour change or precipitation was observed, and pH values were stable for the duration of the study. Loss of water through the reservoirs was substantial only when stored at +35 degrees C for 28 days. Cisplatin is stable in the infusion fluid used for 28 days under all the storage conditions considered.

Stability study of cloxacillin in an oily suspension, by high performance liquid chromatography.

A high performance liquid chromatography method, using spectrophotometric detection (254 nm) has been developed for the analysis of cloxacillin in an oily suspension. Analysis was performed by isocratic elution with 0.02M potassium dihydrogen phosphate solution, methanol, 50/50 (V/V). The method was specific, linear, accurate (99.8 +/- 1.4%) and precise (less than 1.0%). A stability study of cloxacillin in the formulation, showed that about 10% degradation occurred for 6 months storage at room temperature, when lyophilized sodium cloxacillin was used. On the contrary, when sodium cloxacillin obtained by precipitation from non aqueous solvent was used, about 6% degradation appeared in the drug for 3 years storage in the same conditions.

Stability of fluorouracil, cytarabine, or doxorubicin hydrochloride in ethylene vinylacetate portable infusion-pump reservoirs.

The stability of fluorouracil, cytarabine, and doxorubicin hydrochloride in admixtures stored in portable infusion-pump reservoirs was investigated. Admixtures containing fluorouracil 50 or 10 mg/mL, cytarabine 25 or 1.25 mg/mL, or doxorubicin hydrochloride 1.25 or 0.5 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection were placed in 80-mL ethylene vinylacetate drug reservoirs protected from light, and 1-mL quantities were withdrawn immediately after preparation and after storage for 1, 2, 3, 4, 7, 14, and 28 days at 4, 22, or 35 degrees C. For each condition, three samples from each admixture were tested for drug concentration by stability-indicating high-performance liquid chromatography. The admixtures were also monitored for precipitation, color change, and pH. Evaporative water loss from the containers was measured. Fluorouracil was stable at all temperatures for 28 days. Cytarabine was stable for 28 days at 4 and 22 degrees C and for 7 days at 35 degrees C. Doxorubicin hydrochloride was stable for 14 days at 4 and 22 degrees C and for 7 days at 35 degrees C. No color change or precipitation was observed, and pH values were stable. Loss of water through the reservoirs was substantial only at 35 degrees C for 28 days. When stored in ethylene vinylacetate portable infusion-pump reservoirs, fluorouracil, cytarabine, and doxorubicin hydrochloride were each stable for at least one week at temperatures up to 35 degrees C. Cytarabine and doxorubicin hydrochloride showed decreasing stability at longer storage times and higher temperatures.