In this study, the effect of methanol extract of whole aerial parts of Phyllantus niruri on some specific and non-specific immune response was investigated. The effects of P. niruri on in vivo leucocyte mobilization, delayed type hypersensitivity (DTHR) response, and humoral antibody (HA) response were determined in rats. Acute toxicity profile of P. niruri was evaluated in mice. The Agar induced in vivo leucocytes mobilization into the rats peritoneal fluid was (P<0.05) increased by P. niruri N (200 and 400 mg/kg) in a dose related manner. The total leucocytes count was higher in the extract treated group than the control group. Polymorphonuclear neutrophils (PMNS) were more mobilized than the lymphocytes. P. niruri at 100, 200 and 400 mg/kg body weight produced significant (P<0.05) inhibition of DTH response in rat by 30.55, 66.67 and 44.44%, respectively with 200 mg/kg being most significant. The primary and secondary sheep red blood cell antibody titres were significantly elevated when compared with the control group. P. niruri administered orally showed no death or signs of acute intoxication at doses up to 5000 mg/kg after 24 h of observation. The result of this study showed that the methanol extract of P. niruri whole plant possess immunomodulatory activities and warrant further investigation to determine the specific constituent(s) of the plant responsible for this property.

The study seeks to evaluate nanoparticles based on chitosan for enhanced delivery of ampicillin in plasmid-mediated drug resistance. Serial dilutions of a mixed population of E. coli was plated on nutrient agar and streaked on Replica-plate 25 random colonies using MacConkey agar with or without ampicillin (100 µg/ml) daily for 96 h. Nanoparticles were prepared by cross-linking chitosan with sodium tripolyphosphate with ampicillin trihydrate adsorbed. Three different batches were prepared for optimization. The nanoparticles were optimized based on encapsulation efficiency, in vitro drug release, pH stability and microbiological assay using two laboratory strains of E. coli. Increased resistance to ampicillin due to possible plasmid transfer was established in vitro after 96 h. The encapsulation efficiency of the three batches was between 21-57 %. The drug release showed a burst effect and slow extended release over 8 h and reached a peak of about 19 % release at the 6 and 7 h in Batch A, B and C. The pH of the particles was stable over a period of 6 d. The nanoparticles containing only 0.075 mg of ampicillin dropped in an agar well plate inoculated with 1 ml of E. coli J62 lac pro trp hispFlac::Tn3 (AmpR) gave an IZD of ≥ 25 mm. Chitosan nanoparticles holds good potentials in potentiating the antibacterial effect of ampicillin against possible plasmid-mediated drug resistance