Plasma and Urine Hydroxyurea Levels Might be Useful in the Management of Adult Sickle Cell Disease

Abstract

Hydroxyurea (HU) is useful for treating sickle cell anemia because of its ability to reduce some of the severe clinical events such as painful crises and acute chest syndrome. It may also reduce the need for blood transfusions and frequent hospitalizations and reduce mortality. Nevertheless, no consistent recommendations regarding its therapeutic schedule are defined. Our aim was to improve and validate a high performance liquid chromatography (HPLC) technique to measure HU and to study HU levels in serum and urine of sickle cell anemia patients and relate this to treatment efficacy and compliance. Thirty-seven patients received 1,128 +/- 333 mg of HU per day (8.0 to 28.0 mg/kg/day). Plasma and/or urine were sampled and HU was measured using an HPLC method coupled with UV detection. We validated a specific, sensitive assay with good reproducibility and linearity, and showed a positive relationship between plasma HU concentrations and time elapsed between oral HU intake and sampling. We observed plasma HU concentrations were positively correlated with change in mean corpuscular volume (MCV) before and during the treatment. No correlation was obtained between HU concentration and Hb F level.

Standardization method for measurement of hydroxyurea by Ultra High Efficiency Liquid Chromatography in plasma of patients with sickle cell disease

“…Thus, the quantification method of hydroxyurea in human plasma by UPLC with diode detector (UV) was developed in order to follow up patients treated with this drug. It was developed from the methods of Manouilov et al (1998) and Bachir et al (2007) and is based on the formation of a color reaction between hydroxyurea and solutions A (thiosemicarbazide + sodium chloride + diacetyl monoxime) and B (sulfuric acid + phosphoric acid + ferric chloride) (Manouilov, McGuire, Gwilt et al, 1998;Bachir et al, 2007).…”

“…A wavelength of 440 nm was identified as having the highest absorption. To choose the best mobile phase, adjustments were made in the proportions of acetonitrile/water, and the analysis time obtained was of 13 min, a reduction of 50% compared to the method of Bachir et al (2007), which used 16.7% acetonitrile (Bachir et al, 2007).…”

“…It has been used clinically since the 1960s, primarily in the treatment of Chronic Myeloid Leukemia, acting as a cytotoxic, mutagenic, and recombinogenic antineoplastic agent with specificity to the S phase of the cell cycle (preventing cell division) and with specific action on ribonucleotide reductase (interfering with the conversion of ribonucleotides to deoxyribonucleotides) (Bachir et al, 2007;Ballas, 2012). Since 1998, HU became part of the therapeutic program for patients with sickle cell anemia (SCA), and was the first drug with proven clinical efficacy in the treatment of this disease.…”

“…This method was developed based on the methods described by Manouilov et al (1998) and Bachir et al (2007). We performed modifications in the sample preparation, using a smaller volume of plasma.…”

“…For the colorimetric reaction, no commercial kits were used, while an Ultra High Performance Liquid Chromatography with diode detector (UV) was employed as it affords a higher resolution of the chromatograms analyzed. These modifications in the method de Manouilov (1998) and Bachir et al (2007) resulted in a method with increased sensitivity, lower quantification limit, and reduced time of analysis; nevertheless, its validation is necessary (Manouilov, McGuire, Gwilt, 1998;Bachir et al, 2007).…”