Sub Topic | Secondary Topic: Analytical Methodology | HPLC (Biopharmaceutical Molecule)
Authors: Rachna Nayak, Creighton University (Main Author, Presenting Author); Alekha Dash, Creighton University; Somnath Singh, Creighton University
Presenting Author: Rachna Nayak
Purpose: Diabetic retinopathy is a chronic progressive disease caused due to prolonged uncontrolled hyperglycemia. This disease is associated with and characterized by small microvascular alterations of the retinal blood vessels such as increased permeability, angiogenesis, hemorrhage along with the proliferation of retinal pigment epithelium. An increase in the extracellular levels of glutamate is observed in diabetic retinopathy which causes excitotoxicity leading to death of retinal neurons. The progression of the disease may lead to blindness if left untreated. Therefore, an ideal therapy for diabetic retinopathy should target both – preventing angiogenesis and neurodegeneration, whereas the current therapy focuses mainly on the angiogenesis. Celecoxib is a drug belonging to the class of COX-2 (cyclo-oxygenase-2) selective non-steroidal anti-inflammatory drugs (NSAID’s) that has been proven to be effective in decreasing VEGF levels in the retina, reducing the vascular permeability of the retinal capillaries and decreasing the proliferation of the retinal pigment epithelium along with its COX-2 inhibiting activity. Memantine is a competitive NMDA (N-methyl-D-aspartate) receptor antagonist that can act as a neuroprotectant by blocking the action of increased concentration of NMDA agonist glutamate. Thus, a controlled release delivery system containing both drugs (i.e. celecoxib and memantine) can target both angiogenesis and neuroprotection providing better and improved outcomes for diabetic neuropathy. The development of such delivery system needs a method of simultaneous quantification for both drugs which is not reported in literature.
Methods: Celecoxib and Memantine were detected using simple isocratic chromatographic separation using Kinetex EVO C18 100 Å column (50mm x 3.0mm, 5μm) and mass spectrometric detection using QTrap 5500 (AB Sciex) LC-MS/MS wherein the mobile phase used consists of 0.1% formic acid in acetonitrile and 0.1% formic acid in water in the ratio of 55:45 respectively. The total run time of all the samples are for a span of 3 min and the column temperature was maintained 40°C. The compound and source parameters are mentioned in Table1. The retention time for memantine and celecoxib was found to be 0.37min and 1.37 min respectively. The mass transitions measured for celecoxib was found to be 381.6→362.0 and for memantine as 179.7→163.2.
Results: The standard curves were found to be linear in the concentration range of 19.5- 5000 ng/ml for celecoxib (R2=0.9989) and 19.5-1250 ng/ml (R2= 0.9988) for memantine.
Conclusion: The LC-MS/MS method was developed in detecting celecoxib and memantine simultaneously in aqueous phase which can be used for quantification of both the drugs in a drug delivery system utilized for combinatorial therapy in diabetic retinopathy.
See attached abstract pdf for images.