A Portable Reflective Absorbance Spectrophotometric Smartphone Device for the Rapid and Highly Accurate Determination of Amlodipine in Pharmaceutical Formulation and Human Urine Samples.

The simple reflective absorbance spectrophotometric smartphone device for point-of-monitoring amlodipine is presented here for the first time. The immediate analysis of amlodipine in the human urine of the patients who suffered severe side effects of this drug is very important for the diagnosis, treatment, and reduction of the death rate. This measurement technique is based on the charge-transfer complex between amlodipine and picric acid, which forms a yellow product. This product can absorb light intensity from an LED strip and measure through the Blue channel from the RGB mode with a smartphone application. The linear relationship for amlodipine monitoring was found in a wide range from 100.0 μg L to 140.0 mg L (R = 0.999), and the limit of detection was found to be 25.0 μg L. Our proposed method can be applied to different smartphone brands with consistent sensitivity of amlodipine detection. Additionally, the determination of amlodipine in pharmaceutical formulations and human urine samples was demonstrated by our proposed method. The recoveries were indicated in the range of 98.60 - 100.00%, which is at the acceptable level for pharmacy. This method offers an interweaving of basic technology and chemical analysis with being environmentally friendly due to reducing the complex instrument and the amount of organic waste compared to the chromatographic technique and efficient use for the detection of amlodipine. Hence, this method can be applied for prompt medical diagnoses and laboratories with limited budget resources.