ABSTRACT
A novel series of schiff bases of 2-amino-4-(o-chloro anilino)-1, 3-thiazole (3a-3j) were synthesized and screened for their antibacterial and antifungal activities. The structures of these compounds were ascertained by UV, IR, 1H NMR, mass spectra and elemental analysis. The antibacterial activity of the synthesized schiff bases were evaluated against Gram positive bacteria such as Staphylococcus aureus, Bacillus subtilis and Gram negative bacteria like Escherichia coli and Klebsiella pneumonia. All the compounds had shown moderate to significant antibacterial activity amongst them; compound 3e exhibited more significant activity against the tested bacteria. The antifungal activity was screened against two strains of fungi such as Candida albicans and Aspergillus niger. Similar to antibacterial activity compound 3e exhibited significant antifungal activity. The standard drugs Amoxycillin and Amphotericin B were used to screen antibacterial and antifungal activity at 10μg/ml respectively. Interestingly compound 3e had shown more prominent inhibitory activity against the tested bacteria and fungi.
ABSTRACT
An attempt has been made to design suitable liposome and niosome-encapsulated drug delivery system for rifampicin and evaluated the same in vitro and in vivo. A modified lipid layer hydration method was employed to prepare these vesicular carriers. The formulated systems were characterized in vitro for size distribution analysis, drug entrapment, drug release profiles and vesicular stability at different conditions of storage. In vivo drug kinetics was evaluated in normal, healthy albino rats for niosomal formulation upon subcutaneous injection and various pharmacokinetic parameters were determined. Niosomes and liposomes exhibited mean diameter of 9.73 and 11.87 microns with entrapment efficiencies of 30.5 and 34.2% respectively. Both the products exhibited sustained release characteristics in vitro with zero order drug release kinetics up to initial 10 hr. Stability evaluation indicated that both formulations were not significantly leaky over a period of one month. Niosomal formulation elevated plasma elimination half life and decreased elimination rate constants for rifampicin in vivo suggested that encapsulation retarded the removal of the drug from circulation compared to free drug due to slow drug release into systemic circulation. A five-fold increase in the area under plasma rifampicin concentration-time curve for niosomal rifampicin as compared to free drug indicated better bioavailability of encapsulated drug. It is evident from this study that niosomes and liposomes could be promising delivery systems for rifampicin with prolonged drug release profiles and reasonably good stability characteristics.