Quality assessment of morphine hydrochloride solutions.

The therapeutic substances in solution prepared in pharmaceutical laboratories (prescribed drugs) must preserve their activity. Therefore, they must be stable throughout the period of storage in home conditions. The maintenance of stability is particularly difficult for morphine hydrochloride solutions administered orally to cancer patients at the last stage of the disease being at home. This study, aiming at the assessment of stability of morphine hydrochloride solutions, was performed on samples of 0.5% water solutions of the drug alone, 0.25% and 0.5% solutions of the drug in water with chloroform as well as injection solutions (Morphinum hydrochloricum, 20 mg, Polfa Warsaw). All the samples were kept at 20 degrees C for six months. Throughout this time observations were made to detect changes in their appearence and pH values. Their qualitative composition was determined by TLC and the content of morphine was checked by UV spectrophotometry in an environment of 0.1 mol/l of hydrochloric acid at 285 nm. Results of the kinetic study permitted drawing conclusions as to the mechanism of the decomposition of morphine hydrochloride in the solutions studied - according to a simple first order reaction and determination of the rate constants (k, s(-1)) of the process. Results of the chromatographic and spectrophotometric study did not show differences in the stability of water and chloroform/water solutions of morphine hydrochloride studied after 4 weeks and 6 months. After that time the decrease of morphine content was 10 and 25%, respectively.

Methods for the assessment of quality and stability of azidocillin.

UV and VIS spectrophotometric methods, after previous chromatographic separation (TLC/UV) and iodometric methods were adapted for the determination of azidocillin in presence of its breakdown products. These methods were applied for kinetic measurement of changes in the azidocillin concentration with time in water solutions and solid state. Using thin layer chromatography several decomposition products of azidocillin were detected.

Kinetics of talampicillin decomposition in solutions.

Talampicillin stability in aqueous solutions was studied in a broad range of pH values using as medium solutions of hydrochloric acid (pH 0.4-1.8), phosphate buffers (pH 2.05-3.13 and 6.03-8.04), acetate buffer (pH 3.87-5.28) and borate buffer (pH 8.90-9.10) as well as sodium hydroxide solution (pH 11.48). For the determination of talampicillin concentration changes in kinetic studies, two methods were used: iodometric and spectrophotometric in UV (lambda(max) = 254.5 nm). The catalytic velocity constants (k(H+), k(x), k(o)) were established, the log k-pH profile (35 degrees C) was found, thermodynamic parameters were calculated of the hydrolysis reaction of the beta-lactam bond (k(H+): E(A)= 67.9 kJ mol(-1), delta S = -92.4 J K(-1) mol(-1), delta G = 92.6 kJ mol(-1); k(x): E(A) = 31.8 kJ mol(-1), delta S = -347.1 J K(-1) mol(-1), delta G = 131.1 kJ mol(-1); k(o), pH = 5.28: E(A) = 98.0 kJ mol(-1), delta S = -50.3 J K(-1) mol(-1), delta G = 110.3 kJ mol(-1) at 20 degrees C), and the stability of the lactone bond was studied in the medium with the highest stability of beta-lactam bond of talampicillin (pH 5.28: k(o): E(A)= 32.5 kJ mol(-1), delta S = -220.5 J K(-1) mol(-1), delta G = 94.7 kJ mol(-1) in 20 degrees C), at controlled ionic strength (mu = 0.5 mol l(-1)).

Sterility and antibacterial activity of some antibiotics sterilized by irradiation.

Sterility and antibacterial activity of several antibiotics (including some penicillins and their salts, gramicidin and neomycin) subjected to sterilization by irradiation has been studied. The compounds in solid phase have been exposed to gamma irradiation in air atmosphere at room temperature, with a dose of 25 kGy, and afterwards they have been subjected to tests recommended by FP V (volume I, 1990) checking their sterility and activity. The results have shown that the majority of initial compounds have been to a slight degree contaminated by bacteria from the genera Bacillus and Micrococcus, the number of bacteria did not exceed 10(2) CFU, and fungi up to 10 CFU in 1 g of the compound. All compounds subjected to sterilization with a dose of 25 kGy were sterile and preserved the activity required by FP V. The decrease in activity observed for some compounds was always within the limits of FP specification. The results have proved that the penicillins analysed, gramicidin and neomycin can be sterilized by irradiation with a dose of 25 kGy, without any detrimental effect on their properties and antibacterial activity.