EFFECT OF SODIUM BICARBONATE COADMINISTRATION ON THE PHARMACOKINETICS OF PIROXICAM IN HEALTHY ADULT MALE VOLUNTEERS

Abstract

Abstract
Piroxicam is a non-steroidal anti-inflammatory drug (NSAID) with analgesic, anti-inflammatory and antipyretic properties widely used for pain and inflammation associated to arthritis and infectious diseases. The aim of the study was to determine the effect of sodium bicarbonate coadministration on the pharmacokinetic profile of piroxicam in healthy adult male volunteers. Six (6) healthy adult male volunteers (age 23 ±5 years, weight 56 ± 5kg) were used
for the study. A written consent was provided from each volunteer and ethical clearance for the study was similarly obtained from the Research and Innovation Directorate of Gombe State University, Nigeria. The UV spectrophotometric method adopted was validated by determination of linearity, precision, accuracy, percent recovery, limit of detection and limit of quantification. A calibration curve was constructed using five (5) piroxicam standards by plotting absorbance against concentrations of piroxicam. An in vivo study conducted involved
two phases: phase I involved administration of piroxicam alone orally to the volunteers and phase II involved coadministration of piroxicam with sodium bicarbonate through the oral route. Urine samples were collected at different time intervals as follows: 0, 0.5, 1, 2, 4, 6, 12, 24 and 48 hours respectively. Consequently, urine concentrations of piroxicam were determined by uv spectrophotometric method. Values of the unknown piroxicam urine
concentrations for each volunteer were determined by extrapolation of the standard curve. Pharmacokinetic parameters were obtained using kinetica 5.0 and SPSS PK Calculator and trapezoidal method. Data were presented as Mean ± Standard Deviation and analyzed using one-way analysis of variance (ANOVA). P values less than 0.05 were considered to be statistically significant. The results obtained indicated a calibration curve with linearity between 8 and 32 μg/mL and a correlation coefficient r² = 0.987. UV spectral analysis revealed 300 nm as the wavelength of maximum absorption of piroxicam. Percentage recovery was 97-
100.3% which is within the accepted range of 95 - 105 %. Peak concentration of piroxicam increased significantly (p < 0.05) in piroxicam plus sodium bicarbonate group (32.3 ± 1.8μg/mL) compared to piroxicam alone group. However, elimination half-life significantly (p <0.05) decreased in piroxicam plus sodium bicarbonate group (51.63 ± 94.76 μg/mL) compared to control (98.1 ± 65.29 μg/mL). We can therefore conclude that, coadministration of piroxicam with sodium bicarbonate significantly (p < 0.05) increased the peak concentration (Cmax) of piroxicam and decreased its elimination half-life (t1/2) compared to piroxicam alone group.