Caffeine

A simple, precise, and rapid high performance liquid chromatography (HPLC) method for the determination of acetaminophen level in human plasma using caffeine as an internal standard (IS) was developed and validated. 0.5 ml plasma samples containing acetaminophen were mixed with 50 µg of the IS. After adding 30 µl of 50% perchloric acid, the mixture was vortexed for one minute and then centrifuged for 5 minutes at 13200 rpm. The clear supernatant was transferred into an auto-sampler vial and 100 µl was injected into the HPLC system with a run time of 7.0 min. The compounds of interest were efficiently separated on Symmetry C18 (4.6 x 150 mm, 5-µm) column, and were detected with a photodiode array detector set at 245 nm. The mobile phase consisted of water, methanol, and acetonitrile (80:10:10, v:v:v) and was delivered at a flow rate of 0.9 ml/min. No interference in blank plasma or by commonly used drugs was observed; and the detection limit of acetaminophen was 0.05 µg/ml. The relationship between acetaminophen concentration in plasma and peak area ratio of acetaminophen /IS was linear (r2 ≥ 0.9991) in the range of 0.1– 40 µg/ml. Intra- and inter-day coefficient of variations (CV) and biases were ≤11.6%  and  ≤10.8%, and ≤≤14.0 and ≤12.8, respectively. Extraction recovery of acetaminophen and the IS from the plasma samples was ≥99% and 86%, respectively. Using the method, acetaminophen was found to be stable under conditions generally encountered in the clinical laboratory (≥99% and 91% in processed and unprocessed samples, respectively). Further, the method was successfully used to measure acetaminophen level in plasma samples from a healthy volunteer.

Purpose of this study was to develop a stability-indicating RP-HPLC method for routine analysis of Paracetamol (PARA), Caffeine (CAF) and Ibuprofen (IBU) in their combined solid dosage forms. The new RP-HPLC method was validated as per ICH, FDA and USP guidelines with respect to accuracy, precision, specificity, linearity, solution stability, robustness, sensitivity and system suitability. The method was developed by using a binary gradient mode of phosphate buffer (pH 7.2) and acetonitrile at a flow rate of 1.3mL/min for 15 minutes over C-18 (ODS, 150 x 4.6 mm, 5µm) column at ambient temperature. Injection volume was 20µL for both standard and sample solutions and the eluents were monitored with UV detection at 230nm.Accuracy was determined by the recovery tests of the drugs and found to be within a range of 99.89% to 100.33%. Intraday and inter-day precisions were demonstrated by a relative standard deviation being far less than maximum allowable limit (2.0%, according to FDA). The method showed linear response with a correlation coefficient (r2) value of 0.999 for all three drugs. Forced degradation studies in acidic, basic, oxidation and reduction media were carried out to establish the stability indicating tolerance of this method. Specificity was shown by the separation of drugs with high degree of resolution between them and absence of any interference from the excipients or degradation products. This method was successfully applied to assay the drugs in tablets and capsules. Hence this newly developed method can be considered suitable and reliable for the routine analysis of PARA, CAF and IBU in their solid dosage forms.

A simple, sensitive, accurate and precise simultaneous UV spectrophotometric method has been developed for the estimation of Ibuprofen, Paracetamol and Caffeine in tablet dosage form. The absorption maxima of the drugs were found to be 223, 248 and 272 nm for Ibuprofen, Paracetamol and Caffeine respectively, in methanol, using a Shimadzu UV–Visible spectrophotometer (model UV-1800). Ibuprofen, Paracetamol and Caffeine obeyed Beer’s law in the concentration range of 10-70 µg ml-1, 10-60 µg ml-1 and 10-70 µg ml-1 respectively. The correlation coefficient was found to be 0.999, 0.999, and 0.999 for Ibuprofen, Paracetamol and Caffeine respectively. The method was validated for various parameters according to ICH guidelines. The low relative standard deviation values indicate good precision and high recovery values indicate accuracy of the proposed method. Assay results were in good agreement with label claim.