Comparative application of biological and ninhydrin- derivatized spectrophotometric assays in the evaluation and validation of amikacin sulfate injection

Abstract Instrumental techniques are preferred over bioassay methods for antibiotic quantification mainly due to speed and ability to quantify metabolites in biological samples; however, the potency and biological activity of these drugs cannot be assessed. Two methods - agar well diffusion (bio-assay) and spectrophotometric methods were used to evaluate amikacin sulfate injection. Agar plates were inoculated with S. aureus inoculum; zones of inhibition from its susceptibility to amikacin were obtained, while spectrophotometric absorption at 650 nm of ninhydrin- derivatized amikacin in phosphate buffer (pH 8) was measured. Methods performance showed linearity from 1 - 16 µgmL-1 (bioassay, r = 0.9994) and 10-50 µgmL-1 (spectrophotometric, r = 0.9998). Molar absorptivity was 2.595 x 104 Lmol-1cm-1. Limits of detection and quantification were 1.07 and 3.24 µgmL-1 respectively for bioassay method, while corresponding values for spectrophotometric method were 0.98 and 2.97 µg mL-1. Relative standard deviations were ≤ 2.0% for both methods, with recoveries from 95.93 - 100.25%. Amikacin in brands ranged from 97.53 ± 2.68 to 100.84 ± 1.82%, student's t-test was ≤ 2.78 (n = 4) with respect to label claim for both methods. Experimental paired t-test (t = 2.07; n = 4) and F-test (F = 3.94; n = 4) values indicated no significant difference between both methods, hence comparable and can jointly be used in quality control assessment of antibiotics

Protective effects of Baicalin injection on severe acute pancreatitis through regulating follistatin-like-1 signaling pathway by down-regulating miR-429 expression in mice

Abstract In China, Scutellaria is used for treating inflammatory-related diseases. Baicalin is the main active component of Scutellaria and has protective effects on acute pancreatitis. However, the mechanism of Baicalin is still unclear. In this study, the protective effects of baicalin on acute pancreatitis induced by taurocholate and its mechanism are investigated. In this study, mice were randomly divided into three groups: sham operation, model, and treatment groups. Acute pancreatitis in mice was induced by intraperitoneal injection of taurocholate (35 mg/kg). The treatment group was given baicalin (100 mg/kg) 2 h before acute pancreatitis induction. The mRNA expression levels of miR-429, nuclear factor kappa B65(NF-kB65), toll-like receptor 4(TLR4), TNF receptor associated factor6 (TRAF6), NF-kappa-B inhibitor(IkB), Follistatin-like 1 (FSTL1), and interleukin-1 receptor-associated kinase (IRAK) in the liver tissues 24 h after intraperitoneal injection were detected by RT-PCR. Then, the expression levels of NF-kB65, p-NF-κB65, TLR4, TRAF6, IkB, FSTL1, IRAK, p- IRAK, and p- IkB-а proteins were detected by Western blot. IL-6, TNF-α and IL-1 ß in plasma were measured by ELISA, and histopathological changes in the pancreases of the mice were observed. The results showed that after baicalin treatment, miR-429 expression in the pancreatic tissues and the expression levels of NF-kB65, TLR4, TRAF6, p-IkB-а, FSTL1, and p-IRAK decreased. Similarly, pancreatic myeloperoxidase (MPO) activity and the plasma levels of IL-6, TNF-а, IL-12, IL-1ß1, endotoxin, serum amylase, and lipase were reduced. Thus, the pancreatic injury induced by taurocholate was alleviated. The present study indicates that pretreatment with Baicalin can alleviate acute pancreatic injury induced by taurocholate in mice. The mechanism may be associated with the decreased miR-429 expression, reduced FSTL1 signaling pathway activity, TLR4 and TLR4/MyD88 signaling pathway inhibition, and reduced pancreatic inflammation. FSTL1 is the regulatory target for miR-429