Influence of water-soluble channeling agents on the release of diclofenac sodium from Irvingia malayana wax matrix tablets.

Irvingia malayana wax (IW) is majorly composed of esters of medium chain fatty acids. Its melting point is low and closed to the body temperature. This study aimed at investigating the potential of IW as a matrix-forming agent and evaluate the effect of soluble channeling agents on the release of diclofenac sodium (DS) from IW matrix tablets. The preformulation study by infrared spectroscopy and differential scanning calorimetry showed no incompatibility between IW and DS or soluble channeling agents, namely PEG 4000, PEG 6000 and lactose. IW retarded the release of DS from the matrix tablets more efficiently than carnauba wax due to its greater hydrophobicity and its ability to become partial molten wax at 37° C. Factors affecting the release of DS from IW matrix were drug concentrations, and types and concentrations of channeling agents. The release of DS significantly improved when DS concentration reached approximately 33%. The fast dissolving channeling agent, lactose, could enhance the drug release rate more effectively than PEG 4000 and PEG 6000, respectively. The linear relationship between the DS release rate and the concentration of the chosen channeling agent, PEG 6000, was found (r2=0.9866).

Effect of pH on complex formation between debranched waxy rice starch and fatty acids.

Complex formations between debranched waxy rice starch (DBS) and fatty acids (FA) of different hydrocarbon chain lengths (8:0, 10:0, 12:0, 14:0, 16:0, and 18:0) were studied in an aqueous solution by measuring the blue colour stained with iodine. The objective of this study was to understand the effects of the solubility and hydrophobicity of guest molecules (FA) on the complex formation with DBS. Lauric acid (12:0) displayed the greatest complex forming ability with DBS by showing the least blue colour developed with iodine. The effect of pH (3-7) on the DBS/FA complex formation was evaluated by measuring the iodine-scanning spectra of the mixture. Short-chain FA (8:0) displayed less complex formation at pH>or=5, above the pK(a) of fatty acid (approximately 4.8), which suggested that the charge formation of the short-chain FA caused a lower partitioning of the FA into the hydrophobic cavity of the DBS single helix. On the contrary, FA of 10:0-18:0 displayed an increased complex formation at pH>5, which could be attributed to increased solubility of these longer-chain FA at a dissociated and ionized form. The hydrocarbon chain length of the FA had an important impact on the extent of the complex formation. A FA that had a shorter hydrocarbon chain was more soluble in an aqueous solution and more readily formed a complex with DBS. At pH 6 and 7 (above the pK(a)), 10:0 formed less inclusion complexes with DBS than did 12:0. Iodine-scanning spectra showed that the absorbances of all iodine-stained DBS/FA solutions at higher wavelength were substantially lower than that of the iodine-stained DBS alone, suggesting that FA preferentially formed inclusion complexes with DBS of longer chains.

Bioequivalence study of the two 1.5 g cefoperazone and sulbactam IM injections in Thai healthy male volunteers.

OBJECTIVE: To perform a bioequivalence study of the two 1.5 g cefoperazone (1.0 g) and sulbactam (0.5 g) between Cefper and Sulperazon injections. MATERIAL AND METHOD: The present study was performed in 24 Thai healthy male volunteers who were intramuscularly injected a single dose of 1.5 g cefoperazone and sulbactam. A single dose, two periods, two sequences, double blind randomized crossover with a one-week washout period was used. Blood samples were collected before and at 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 4, 6, 8, and 12 hours after intramuscular injection and determined for cefoperazone and sulbactam plasma concentration by validated HPLC-UV methods. The pharmacokinetic parameters were analyzed by noncompartmental analysis and the ANOVA was carried out. RESULTS: Tax of both cefoperazone and sulbactam for volunteers who were injected with either Cefper or Sulperazon injection were not significantly different (p > 0.05). The 90% confidence intervals of the log of ratio of either C(max) or AUC(last) or AUC(inf) of both cefoperazone and sulbactam between 1.5 g Cefper and Sulperazon injections were within the bioequivalence range of 0.80-1.25. CONCLUSION: The 1.5 g cefoperazone and sulbactam injection of Cefper and Sulperazone used in the present study are bioequivalent.