Water-compatible molecularly imprinted polymer as a sorbent for the selective extraction and purification of adefovir from human serum and urine.

A molecularly imprinted polymer has been synthesized to specifically extract adefovir, an antiviral drug, from serum and urine by dispersive solid-phase extraction before high-performance liquid chromatography with UV analysis. The imprinted polymers were prepared by bulk polymerization by a noncovalent imprinting method that involved the use of adefovir (template molecule) and functional monomer (methacrylic acid) complex prior to polymerization, ethylene glycol dimethacrylate as cross-linker, and chloroform as porogen. Molecular recognition properties, binding capacity, and selectivity of the molecularly imprinted polymers were evaluated and the results show that the obtained polymers have high specific retention and enrichment for adefovir in aqueous medium. The new imprinted polymer was utilized as a molecular sorbent for the separation of adefovir from human serum and urine. The serum and urine extraction of adefovir by the molecularly imprinted polymer followed by high-performance liquid chromatography showed a linear calibration curve in the range of 20-100 µg/L with excellent precisions (2.5 and 2.8% for 50 µg/L), respectively. The limit of detection and limit of quantization were determined in serum (7.62 and 15.1 µg/L), and urine (5.45 and 16 µg/L). The recoveries for serum and urine samples were found to be 88.2-93.5 and 84.3-90.2%, respectively.

Molecularly imprinted nanoparticles prepared by miniemulsion polymerization as a sorbent for selective extraction and purification of efavirenz from human serum and urine.

A molecularly imprinted polymer (MIP) has been synthesized in order to specifically extract efavirenz from serum and urine by dispersive solid-phase extraction following by HPLC-UV analysis. The imprinted nanoparticles were prepared by miniemulsion polymerization method using efavirenz as template molecule and methacrylic acid as functional monomer. Molecular recognition properties, binding capacity and selectivity of the MIPs were evaluated and the results revealed that the obtained MIPs had high specific retention for efavirenz in aqueous medium. The MIP was used as a molecular sorbent for the separation of efavirenz from human serum and urine. The extraction of efavirenz by MIP coupled with HPLC analysis showed a linear calibration curve in the range of 50-300 µg/L with exellent precisions (3.66% and 4.6% for 100 and 300 µg/L respectively). The limit of detection (LOD) and limit of quantification (LOQ) were determind in serum (17.3 and 57.5 µg/L) and urine (10.6 and 36.2 µg/L). The maximum recoveries for serum and urine samples were found to be 95.2% and 92.7% respectively. Due to the high precision and accuracy, this method may be the UV-HPLC choice with MIP extraction for bioequivalence analysis of efavirenz in serum and urine.

Selective extraction of lamivudine in human serum and urine using molecularly imprinted polymer technique.

In this work, a novel technique is described for determination of lamivudine in biological fluids by molecularly imprinted polymers (MIPs) as the sample clean-up method joint with high performance liquid chromatography (HPLC). MIPs were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinker, acetonitrile and tetrahydrofuran as porogen and lamivudine as the template molecule. The new imprinted polymer was used as a molecular sorbent for the separation of lamivudine from human serum and urine. Molecular recognition properties, binding capacity and selectivity of the MIPs were evaluated and the results showed that the obtained MIPs have a high affinity for lamivudine in aqueous medium. HPLC analyses showed that the extraction of lamivudine from serum and urine by MIPs had a linear calibration curve in the range of 60-700µg/L with excellent precisions of 2.73% for serum and 2.60% for urine. The limit of detection and quantization of lamivudine was 19.34 and 58.6µg/L in serum and 7.95 and 24.05µg/L in urine respectively. MIP extraction provided about 10 fold LOQ improvement in serum and 5 fold LOQ improvement in urine samples. The recoveries of lamivudine in serum and urine samples were found to be 84.2-93.5% and 82.5-90.8% respectively. Due to the high precision and accuracy, this method may be the UV-HPLC choice with MIP extraction for bioequivalence analysis of lamivudine in serum and urine.

Solid carriers for improved solubility of glipizide in osmotically controlled oral drug delivery system.

The purpose of this study was to increase the solubility of glipizide (gli) by solid dispersions SDs technique with polyvinylpyrrolidone (PVP) in aqueous media. The gli-PVP solid dispersion systems was prepared by physical mixing or spray drying method, and characterized by differential scanning calorimetry (DSC), X-ray powder diffraction (XRD) analysis, Fourier transformation-infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The elementary osmotic pumps (EOPs) were prepared with gli-PVP complex and the effect of the PVP percentages on the enhancing of gli dissolution rate was studied. The influences of various parameters e.g., drug- PVP ratio, level of solubility modifier, coating weight gain and diameter of drug releasing orifice on drug release profiles were also investigated. The solubility and dissolution rates of gli were significantly increased by solid dispersion using spray dried method as well as their physical mixture. The obtained results indicated that gli-PVP solid dispersion system has suitable solubility behavior in EOP tablets.