RESUMO
This study presents an efficient high-performance liquid chromatography with ultraviolet detection (HPLC-UV) method for monitoring valproic acid (VPA) level in human plasma. This method is distinguished by its simplicity, cost-effectiveness, and rapid execution, addressing the limitations associated with other advanced analytical techniques like liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), and immunoassays, which are generally complex and costly for routine application. A challenge in analyzing VPA is its non-linear protein binding profile and the absence of a chromophore in its structure, making direct detection difficult. To overcome this, the study developed an efficient HPLC-UV for VPA determination in human plasma, utilizing a simplified and rapid microwave-assisted derivatization process. Due to the lack of a chromophore in VPA structure, this work developed a microwave-assisted derivatization of VPA using phenylhydrazine hydrochloride (PH HCl). The process optimization was achieved at 450 W for 50 s, facilitating effective HPLC-UV detection. The derivatized product was characterized using 1H nuclear magnetic resonance (NMR) and Fourier transform infrared spectrometer (FT-IR). The derivative, identified as (Z)-N-phenyl-2-propylpentanehydrazonic acid, demonstrated specificity in plasma analysis with no detectable interference. The method exhibited a linear response for VPA concentrations ranging from 30 to 150 µg/mL, with a correlation coefficient exceeding 0.99. Recovery varied between 86.7% and 107%, with a maximum coefficient of variation (CV) of 10.0%. The findings suggest that the microwave-assisted derivatization technique substantially improves the feasibility and cost-effectiveness of HPLC-UV for the analysis of VPA in plasma. This method provides a viable alternative to conventional HPLC methodologies, offering a balance of efficiency and economic practicality for VPA quantification.
RESUMO
Bacterial cellulose (BC) is an interesting material for drug delivery applications due to its high purity. This study aimed to compare the properties of tablets prepared by the wet granulation method using bacterial cellulose prepared by different methods as a diluent, using acetaminophen as a model drug. BC used as diluents were prepared using two different methods: freeze-drying (BC-FD) and phase-inversion (BC-PI), and their characteristics were analyzed and compared with that of commercial microcrystalline cellulose PH 101 (Comprecel® M101). Acetaminophen tablets were prepared by wet granulation using BC-FD, BC-PI, or Comprecel® M101 as diluents, and their tablet properties were examined. The result showed that the morphology, polymorph, and crystallinity of BC-PI and Comprecel® M101 were similar but they were different compared with that of BC-FD. Tablets could be successfully formed using BC-PI and Comprecel® M101 as diluents without any physical defects but the tablet prepared using BC-FD as diluent appeared chipped edge. The characteristics (thickness, weight variation, hardness, friability, disintegration, drug content, and dissolution) of the tablets prepared using BC-PI diluent were also similar to those prepared using Comprecel® M101 diluent, but those of BC-FD diluent were inferior. This indicates that BC prepared in BC-PI can potentially be used as a diluent for tablets prepared by wet granulation.
