ABSTRACT
As part of the method development, the injection volume as a critical quality attribute in fast fused-core chromatography was evaluated. Spilanthol, a pharmaceutically interesting N-alkylamide currently under investigation in our laboratory, was chosen as the model compound. Spilanthol was dissolved in both PBS and MeOH/H2O (70/30, v/v) and subsequently analyzed using a fused-core system hereby selecting five chromatographic characteristics (retention time, area, height, theoretical plates and symmetry factor) as responses. We demonstrated that the injection volume significantly influenced both the qualitative and quantitative performance of fused-core chromatography, a phenomenon which is confounded with the nature of the used sample solvent. From 2 mL up to 100 mL injection volume with PBS as solvent, the symmetry factor decreased favorably by 20%. Moreover, the theoretical plates and the quantitative parameters (area and height) increased up to 30%. On the contrary, in this injection volume range, the theoretical plates for the methanol-based samples decreased by more than 60%, while the symmetry factor increased and the height decreased, both by 30%. The injection volume is thus a critical and often overlooked parameter in fused-core method description and validation.
ABSTRACT
OBJECTIVE: To know the accuracy of caudal epidural steroid injection procedure without fluoroscopy guidance, and determine ascending level of injected solution according to injection volume. METHOD: The subjects were 35 patients with low back pain. Needle insertion was performed without fluoroscopy, then we confirm the position of needle with fluoroscopy. The level of injected solution was measured with fluoroscopy and x-ray after injecting every 5 ml of solution, which is mixture of triamcinolone, 2% lidocaine, contrast medium, and normal saline. The effect of treatment was measured by Visual Analogue Scale (VAS). RESULTS: Successful needle placement occurred in 27 cases without fluoroscopy. After injecting 20 ml of solution, the ascending level of solution were S1 in 8 cases, L5 in 12 cases, L4 in 8 cases, L3 in 1 case, L2 in 4 cases, L1 in 2 cases. In the comparison of the VAS before and after treatment, it was 6.3+/-1.2 and 2.9+/-1.3 respectively, which demonstrated statistically significant decrease (p+/-0.05). CONCLUSION: Caudal epidural injection could be performed more accurately under the fluoroscopic guidance. After injecting 20 ml of solution, the ascending level of the solution were restricted at lower lumbosacral area in most of cases.
Subject(s)
Humans , Fluoroscopy , Injections, Epidural , Lidocaine , Low Back Pain , Needles , TriamcinoloneABSTRACT
To study the effect of measurement parameters and hydrocephalus on the pressure volume index(PVI), PVI study was performed in 5 normal and 5 kaolin-induced hydrocephalic cats. The effects of injection volume, speed, laterality and influence of increased intracranial pressure(ICP) in normal and hydrocephalic cats on the PVI value were evaluated. The results were as follows; 1) Larger injection volume, increased ICP by continuous infusion, and presence of ventriculomegaly made the PVI value significantly higher(p<0.01, p<0.001, p<0.05, respectively). 2) Rapid injection made the PVI value significantly lower(p<0.01). 3) Increase of ICP accentuated the effects of injection volume and speed significantly(p<0.01). 4) There was no difference between the PVI values measured with injection into the ipsilateral lateral ventricle and those measured with injection into the cantralateral lateral ventricle. 5) With the above results, it is considered advisable to perform the PVI study with constant injection volume, speed and ICP.