Kızıltas, Nurgul; Akman, Tugrul Cagri; Karabayir, Yasemin

The co-administration of ibuprofen (IBU) and phenyramidol HCl (PHE) is frequently preferred for the management of musculoskeletal disorders to enhance therapeutic efficacy. This study aimed to develop and validate a rapid, sensitive and cost-effective high–performance liquid chromatography–photodiode array (HPLC–PDA) method for the simultaneous determination of IBU and PHE in human plasma and pharmaceutical preparations, and to demonstrate its applicability in pharmacokinetic studies. Chromatographic separation was achieved on a C18 column using a mobile phase consisting of phosphate buffer (pH 6.0 ± 0.05) and methanol (30:70, v/v) at a flow rate of 1.0 mL·min −1. The retention times of IBU and PHE were 3.7 and 2.7 min, respectively, with a total analysis time of 6 min. The method showed excellent linearity within the range of 0.05–40.0 μg·mL −1 for both drugs, with LLOQ values of 0.05 μg·mL−1 for IBU and 0.0025 μg·mL−1 for PHE. The plasma samples were collected at four time points (0.0, 1.0, 4.0 and 8.0 h) after oral administration of IBU and PHE. Cmax, Tmax and AUC0–8 were calculated, with Cmax of 16.14 μg·mL−1 for IBU and 3.71 μg·mL−1 for PHE, while Tmax was 1.0 h for both. Despite limitations in the number of sampling time points, the method proved highly applicable for determining pharmacokinetic profiles and for routine quality control analyses. Its short analysis time, high sensitivity and low sample volume requirement make it a powerful tool for clinical research and therapeutic monitoring. This is the first validated HPLC–PDA method applied to the simultaneous pharmacokinetic evaluation of IBU and PHE in human plasma.

Akman, Tugrul C

This study presents a novel and efficient method for determining of cyclobenzaprine (CBP) in human plasma and tablets using simple liquid-liquid microextraction and ultra-high performance liquid chromatography-diode-array detector. The developed method was optimized and validated for selectivity, linearity, precision, accuracy, limit of detection (LOD) and limit of quantification (LOQ). The chromatographic separation was achieved using a C18 column with a mobile phase consisting of a mixture of deionized water containing 0.1% TFA and methanol (30:70, v:v) at a flow rate of 1.0 mL/min. The extraction process provided high-efficiency recovery of CBP with a small plasma volume (%94.3). The method showed good linearity within the concentration range of 0.005-10 μg/mL, with a correlation coefficient of 0.999. The LOD and LOQ values were found to be 0.0013 and 0.005 μg/mL, respectively. The intra- and inter-day %RSD were <8%, and %RE were ranged from -0.50 to 0.01%. The proposed method was successfully applied to the analysis of CBP in real human plasma samples and tablets, indicating its applicability in clinical and pharmaceutical research. In conclusion, the simple, low cost, high sensitivity and rapid nature of this method make it an attractive option for the quantification of CBP in human plasma and pharmaceutical dosage forms.

Yaman, Mehmet Emrah; Atila, Alptug; Akman, Tugrul Cagri; Albayrak, Mevlut; Kadioglu, Yucel; Halici, Zekai

For the quantification of flurbiprofen in rat plasma, a simple UPLC-MS/MS method with high sensitivity and short retention time for flurbiprofen was developed and validated using specific parameters. Etodolac was used as internal standard. The transitions (precursor to the product) of flurbiprofen and internal standard were obtained using the electrospray ionization in the negative ion multiple reaction monitoring mode, 243.2 → 199.2, 286.2 → 212.1, respectively. For chromatographic separation, C18 column was used for the stationary phase and gradient elution was used for the mobile phase. This mobile phase consisted of a methanol (A) and a 5 mM ammonium formate solution (B), which varied at a flow rate of 0.4 mL/min. For flurbiprofen, LLOQ was determined as 5 ng/mL. Quantification of flurbiprofen in the rat plasma with a linear calibration curve of 5-5000 ng/mL (r > 0.9991 for plasma) is possible with a retention time of 1.89 min. The total analysis time of the method was 3 min. The proposed method was validated. The intraday and inter-day precision (RSD%) and accuracy (RE%) were within 10% in all cases for flurbiprofen. The stability of flurbiprofen was evaluated under conditions such as short-term, long-term, autosampler and freeze/thaw. After method validation, flurbiprofen was succesfully quantified in real rat plasma samples.