Studies On Preparation Of Cefpodoxime Proxetil And Origanum Oil Nanoemulsion

Objective: To study joint efficacy of cefpodoxime proxetil and origanum oil in dosage form of nanoemulsion, the compound cefpodoxime proxetil nanoemulsion(cefpodoxime proxetil and origanum oil nanoemulsion, CFP-OR-NE) was prepared for the first time. Then antibacterial test in vitro and acute toxicity study were conducted. Above what have been done provided a safe and effective new oral drug with the treatment of avian colibacillosis and salmonellosis.Method:(1) CFP-OR-NE prescription screening: preliminary screening method was prescribed by phase transformation. Pseudo-ternary phase diagrams were drafted by water titration method to formulate the nanoemulsion; Then the multi-index orthogonal experiment determined the optimal formulation was proceeded with L9(34) orthogonal test table, regarding bacteriostatic circle diameter and nanoemulsion stability constant Ke as examining index. Three elements, ratio of the mass fraction of cefpodoxime proxetil and origanum oil, pH of aqueous phase and emulsifying temperature were selected as factors.(2) Determinations of contents of CFP-OR-NE were achieved through multi-wavelength ultraviolet spectrophotometry. Tests of recovery, repeatability and precision of intra-day and inter-day were designed afterwards. The quality of CFP-OR-NE was evaluated with examining indexes of structure type, morphology, size and distribution of droplet, zeta potential and expiration date of drugs were established in both content- time regression equations derermined by long-term tests.(3) Antibacterial tests of CFP-OR-NE: MIC and MBC of CFP-OR-NE to enteropathogenic E.coli 、 Salmonella 、 Proteus mirabilis 、Pasteurella 、 Shigella dysenteriae 、 Staphylococcus 、 Streptococcus agalactiae were determined by trace broth dilution method.(4) Safety evaluation of CFP-OR-NE: Maximum tolerated dosage of oral acute toxicity of CFP-OR-NE was got from maximal tolerance dose test and histopathological examinations were also arranged to determinate whether it is harmful to liver, kidney and small intestine or not.Results:(1) The mass fraction of components of preliminary prescription of CFP-ORNE showed as follows: CFP 1.5%, OR 1.5%, EL-40 22.51%, 1,2- propanediol 1.13%, distilled water 73.36%; The optial formulation for enteropathogenic E.coli and Salmonella was CFP 0.33%, OR 2.67%, 1,2- propanediol 1.13%, EL-40 22.51%, 73.36% distilled water.(2) Method of determination of content of CFP-OR-NE was established. The detection wavelength and reference wavelength were 263 nm and 289.8nm, respectively. Then combination determination wavelengths of OR are 261.6 nm、273.2 nm、284.4 nm. Either CFP or OR was found to be linear in the range of 1 μg/mL to 100 μg/mLwith value of r2 0.999 22 and 0.999 70, respectively. All results of recovery tests were in line with requirements between 70% and 110%. RSD of CFP is in range from 0.4% to 8.95% and corresponding data of OR is in range from 0.26 to 5.57%. RSD of repeatability tests which were all less than 0.6% were good with repeatability. RSD of determination of CFP and OR in CFP-OR-NE in precision tests of inter-day and intra-day were less than 5%, having a good precision. The CFP-OR-NE was transparent and faint yellow liquid with the structure type of oil in water(O/W). The droplet was spherical.Average diameter was 18.94 nm and the polydispersity index(PDI) was 0.258. The droplet size was uniform and its distribution was narrow.Under the condition of 25 ℃, pH value of five-fold diluted CFP-OR-NE was 6.39 and zeta potential was(-9.96±6.35) mV. Experiments of acceleration, centrifugation, illumination, temperature gradient, long-term indicated no results of layering, flocculation, phase inversion, demulsification, rancidity and other instability phenomenon and CFP-OR-NE was valid for 21 months.(3) Compared with MIC and MBC of active pharmaceutical ingredient of OR and CFM, CFP-OR-NE had a significant difference(P<0.05).(4) Maximum tolerated dosage of oral acute toxicity of CFP-OR-NE was 1800 in maximal tolerance dose test and histopathological examinations revealed no nephrotoxicity and toxicity of the small intestine. Though a small amount of liver cells demonstrated minor bleeding, degeneration, necrosis, and unclear boundaries in test group, there was no death in mice.Conclusion: Method to determine the content of CFP-OR-NE was established. The quality evaluation of CFP-OR-NE was in accord with requirements.; Antimicrobial tests showed bacteriostatic and bactericidal effects of CFP-OR-NE on G + and G- was difference compared to the same generation cephalosporin CFM; CFP-OR-NE, proved to be a low toxicity drug in MTD test, had no nephrotoxicity and toxicity of the small intestine.