A simple and rapid HPLC-UV method for the determination of valproic acid in human plasma using microwave-assisted derivatization with phenylhydrazine hydrochloride.

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.

Comparison of Properties of Acetaminophen Tablets Prepared by Wet Granulation Using Freeze-Dried Versus Phase-Inversion Bacterial Cellulose as Diluent.

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.

Increased bisphenol A levels in Thai children and adolescents with type 1 diabetes mellitus.

BACKGROUND: The incidence of type 1 diabetes mellitus (T1DM) in children and adolescents continues to increase worldwide. The reason for this is unclear. In addition to the role of genetics, bisphenol A (BPA) has been investigated as a possible causal factor for T1DM. This study aimed to determine the correlation between urinary BPA levels and T1DM in Thai children and adolescents. METHODS: A cross-sectional study was conducted in T1DM patients who were followed at the endocrinology clinic at King Chulalongkorn Memorial Hospital from December 2018 to December 2019 and age-matched healthy controls. Urinary BPA levels were analyzed by high-performance liquid chromatography and adjusted by urine creatinine. Anthropometric data were measured in all participants and clinical data were collected for the T1DM patients. All participants completed a questionnaire regarding possible BPA exposures. Multivariate logistic regression analysis was used to estimate the adjusted odds ratio for T1DM. RESULTS: Seventy-five T1DM patients and 113 age-matched controls were included in the study. The mean age for T1DM and control groups were 14.8 ± 5.7 and 14.4 ± 6.2 years, respectively. The T1DM group had a significantly higher median (interquartile range) level of adjusted urinary BPA compared to the control (31.50 [7.87, 69.45] vs 10.1 [0, 54.01] µg/g creatinine, P = 0.02). Urinary BPA of 17 µg/g creatinine or more was significantly associated with TIDM, with adjusted odds ratio (95% Confident interval, CI) of 2.38 (1.27, 4.44), P = 0.006. CONCLUSIONS: Higher urinary BPA level is one of the possible risk factors for T1DM.

Comparison of drug release behavior of bacterial cellulose loaded with ibuprofen and propranolol hydrochloride.

The aim of this study was to investigate the drug release behavior from bacterial cellulose (BC). Ibuprofen and propranolol hydrochloride were used as model drugs to represent low and highly water soluble drugs. The drug was loaded into the BC by immersing the partially swollen BC in a solution of drug concentrations ranging from 0.05 to 0.5 mg mL-1 and then drying by two different methods: air-drying and freeze-drying. The results showed that the type of drug and the drying method influenced the drug loading efficiency and drug release behavior. For ibuprofen, high drug loading efficiency was found when loading the drug into BC at low concentration and vice versa for propranolol hydrochloride. The drug-loaded BC prepared by the freeze-drying method showed a sustained release regardless of drug type and drug-loaded amount. The sustained release followed the Higuchi and Korsmeyer-Peppas models. On the other hand, when using the air-drying method, BC loaded with ibuprofen showed immediate release at every drug-loaded amount. However, BC loaded with propranolol hydrochloride showed immediate release at the high drug-loaded amount but showed sustained release at the low drug-loaded amount. The release of drug from a drug-loaded BC prepared by air-drying method tended to follow first-order kinetics. In conclusion, the drug loading concentration and the drying method in the drug-loaded BC preparation influenced the drug release characteristics of the BC-based drug delivery system.

Molecularly imprinted bacterial cellulose for sustained-release delivery of quercetin.

Bacterial cellulose (BC) has been used in the combination with molecularly imprinted polymer (MIP) for controlled-release drug delivery. In the present study, the molecular imprinting was directly performed on BC to avoid the use of synthetic materials for sustained-release of quercetin, which was used as the template molecule. The phase inversion method was successfully used to prepare molecularly imprinted BC (MI-BC). The molecular recognition ability and controlled drug release behavior of MI-BC were then evaluated. MI-BC was found to have approximately 1.6 times higher ability to bind quercetin than the non-imprinted BC (NI-BC) did. The composite membrane containing MI-BC and quercetin (MI-BC-com) delayed and sustained drug release more effectively than the composite membrane containing NI-BC and quercetin (NI-BC-com). MI-BC-com released quercetin approximately two times more slowly than NI-BC-com did at the final hour of the drug release study. The mechanism of quercetin release followed the Higuchi model. Due to the relatively simple method of preparing the drug delivery system without using synthetic MIP, the application of MI-BC may be of great interest in medicine and pharmaceutics.

Effect of Piperine on Skin Permeation of Curcumin from a Bacterially Derived Cellulose-Composite Double-Layer Membrane for Transdermal Curcumin Delivery.

Curcumin is a naturally occurring substance with various pharmacological activities. It has not been developed as a drug because of its low bioavailability due to its low solubility and absorption. Piperine is a natural enhancer that is popularly used to increase the absorption of curcumin in oral applications; however, it has not been applied for transdermal curcumin delivery. This study aims to develop a transdermal curcumin delivery system using piperine as a skin permeation enhancer in the form of composite double-layer membrane; the upper layer consisted of curcumin and the lower layer consisted of piperine. The amount of curcumin was fixed, but the amount of piperine varied at three levels from 1.96% to 7.41%. The composite membrane had moderate mechanical strength (15⁻22 MPa) with a good swelling degree (~435%). From an in vitro skin permeation study, piperine had the effect to increase the permeation of curcumin. The permeation rate was related to the amount of piperine. The composite membrane containing piperine at 7.41% could increase the permeation rate of curcumin by about 1.89 times compared with non-piperine contained membrane. Bacterially-derived cellulose containing curcumin and piperine may have the potential for transdermal curcumin delivery in order to improve curcumin's bioavailability.

In Vitro Antimicrobial Activity of Gel Containing the Herbal Ball Extract against Propionibacterium acnes.

The herbal ball has been used as a Thai traditional medicine for relieving many diseases including acne. However, the application process of the herbal ball in practice is complicated and time consuming. The objective of this work was to utilize an herbal ball extract to formulate a gel to reach a more favorable use of the herbal ball for acne treatment. An herbal ball consisting of Andrographis paniculata, Centella asiatica, the Benchalokawichian remedy and the stem bark powder of Hesperethusa crenulata was prepared. The obtained herbal ball was steamed and squeezed to obtain the extract. Gel formulations containing the herbal ball extract at concentrations of 0.1, 1 and 5% w/w were prepared based on a carbomer gel. The herbal ball extract had antioxidant (EC50 = 219.27 ± 36.98 µg/mL) and anti Propionibacterium acnes activities (minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) = 31.25 µg/mL). The 5% w/w gel formulation had antimicrobial activity against P. acnes, showing an inhibition zone value of 10.00 ± 1.00 mm. This indicates that the developed gel formulation has potential for acne treatment. In comparison to the traditional method of herbal ball usage, the application of herbal ball extract in the form of gel should be more convenient to use.

Higher phthalate concentrations are associated with precocious puberty in normal weight Thai girls.

BACKGROUND: The cause of precocious puberty may be associated with genetics and other conditions such as central nervous system (CNS) insults, or the exposure to endocrine disrupting chemicals (EDCs). Phthalates is known to be one of the EDCs and have estrogenic and antiandrogenic activities, and may be associated with advanced puberty. The objective of the study was to determine the association between urinary phthalate metabolites and advanced puberty. METHODS: A cross-sectional study was conducted in patients with precocious puberty (breast onset <8 years, n=42) and early puberty (breast onset 8-9 years, n=17), compared to age-matched controls (n=77). Anthropometric measurements, estradiol, basal and gonadotropin releasing hormone (GnRH)-stimulated follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels, uterine sizes, ovarian diameters and bone ages (BA) were obtained. Urine samples were collected and mono-methyl phthalate (MMP) and mono-ethyl phthalate (MEP) were analyzed by high performance liquid chromatography (HPLC) and adjusted with urine creatinine. RESULTS: The median adjusted-MEP concentration in girls with precocious puberty, was greater than in normal girls (6105.09 vs. 4633.98 µg/g Cr: p<0.05), and had the same trend among early puberty and normal puberty (5141.41 vs. 4633.98 µg/g Cr: p=0.4), but was not statistically significant. CONCLUSIONS: Precocious puberty girls had an association with increased MEP concentration. This is the first report of the association between urinary phthalate levels and precocious puberty in Thai girls.

Association between urinary phthalates and metabolic abnormalities in obese Thai children and adolescents.

BACKGROUND: Several endocrine disruptors (including phthalates) are considered to be a cause of obesity. However, the current evidence has not conclusively established an association between phthalates and metabolic abnormalities, especially in children. The objective of the study was to evaluate the association between urinary phthalate metabolites and metabolic abnormalities in obese Thai children and adolescents. METHODS: This cross-sectional case-control study was conducted in participants aged 7-18 years and divided into two groups: normal weight and overweight/obesity. Spot urine concentrations of two phthalate metabolites (monomethyl phthalate [MMP] and mono-n-buthyl phthalate [MBP]) were measured by high performance liquid chromatography (HPLC). Anthropometric data, including weight, height, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHTR), were measured and calculated. Fasting plasma glucose, insulin, HbA1c, lipid profiles and hepatic transaminase were analyzed, and insulin resistance indices were calculated. RESULTS: One hundred and fifty-five participants were included. The median MMP level in the normal weight and the overweight/obesity groups were 0 (0, 459.83) and 0 (0, 1623.50) µg/g Cr, respectively (p=0.933). The median MBP level in the normal weight and the overweight/obesity groups were 233.6 (118.1, 633.62) and 206.94 (7.4, 427.7) µg/g Cr, respectively (p=0.083). After adjusting for age, gender and puberty, there was no correlation between MBP and all anthropometric data and metabolic profiles. Participants with hypertriglyceridemia had lower MBP levels than those with normal TG level. MMP levels were not significantly different between the participants with normal and abnormal weight of all metabolic parameters. CONCLUSIONS: Participants with hypertriglyceridemia had lower MBP levels than those with normotriglyceridemia. However, it cannot show the correlation between phthalate and metabolic parameters.

Increased levels of bisphenol A (BPA) in Thai girls with precocious puberty.

BACKGROUND: Reports on the secular trend of pubertal onset indicate a recent earlier start especially in girls. Bisphenol A (BPA), which posses estrogenic activity, might be a cause of advanced puberty. The objective of the study was to determine the association between BPA and advanced puberty. METHODS: A cross-sectional study was conducted in patients with advanced puberty (n=41) compared to age-matched controls (n=47). Anthropometric measurements, estradiol, basal and gonadotropin releasing hormone (GnRH)-stimulated follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels, uterine sizes, ovarian diameters and bone ages were obtained. Urinary BPA concentrations were analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC/MSMS) with the lower limit of quantification (LLOQ) of 0.05 ng/mL. RESULTS: The median adjust-BPA concentration in advanced puberty group was higher than in control groups [1.44 vs. 0.59 µg/g creatinine (Cr): p<0.05]. We also found that the median adjust-BPA concentration in girls with advanced puberty who were overweight/obese, was greater than in the normal pubertal overweight/obese girls (1.74 vs. 0.59 µg/g Cr: p<0.05), and was in the same trend among normal weight girls with advanced and normal puberty (0.83 vs. 0.49 µg/g Cr: p=0.09), but not statistically significant. CONCLUSIONS: The present findings suggest that BPA exposure appears to be related to an earlier age at onset of puberty especially in obese girls.

Development of a pH-responsive drug delivery system for enantioselective-controlled delivery of racemic drugs.

This study aimed to develop enantioselective-controlled drug delivery systems for selective release of the required (S)-enantiomer in a dose formulation containing a racemic drug in response to pH stimuli. The recognition system was obtained from a nanoparticle-on-microsphere (NOM) molecularly imprinted polymer (MIP) with a multifunctional chiral cinchona anchor synthesised by suspension polymerisation using ethylene glycol dimethacrylate as a cross-linker. (S)-omeprazole was used as an imprinting molecule conferring stereoselectivity upon the polymers. The ability of the prepared recognition polymers to selectively rebind (S)-omeprazole was evident at different pH levels (the highest being at pH 7.4). The partial selective-release phenomenon of the (S)-enantiomer in MIP-containing composite cellulose membranes with increased vehicular racemic omeprazole concentrations was highly pH-dependent. Cinchona-bonded polymers imprinted with (S)-omeprazole could recognise the moldable contact site of (S)-omeprazole independently of its chirality; this is responsible for the delivery of (S)-enantiomer from racemic omeprazole. The controlled-release drug devices were fabricated with synthesised composite latex, and consisted of a pH stimuli-responsive poly(hydroxyethyl methacrylate) (HEMA) and polycaprolactone-triol (PCL-T) blend, and a MIP with preloaded drug, along with pH 7.4 buffer in the device's interior. The results demonstrate that drug delivery systems containing (S)-omeprazole imprinted cinchona-polymer nanoparticle-on-microspheres may maximise efficacy while minimising dose frequency.

S-propranolol imprinted polymer nanoparticle-on-microsphere composite porous cellulose membrane for the enantioselectively controlled delivery of racemic propranolol.

Molecularly imprinted polymer (MIP) nanoparticle-on-microspheres (NOM) selective for S-propranolol were successfully prepared using suspension polymerization involving agitation of the reaction mixture at high speed. The integration of the MIP-NOM into a self-assembled porous cellulose membrane allowed a controlled distribution and availability of the molecule recognition sites within a porous structure. The nature of the membrane-included microparticles determined the degree of porosity whilst the adherent nanoparticles provided an increased surface area enabling the composite membrane to be employed efficiently for the trans-membrane transport of the imprinted molecule. The MIP-NOM within the membrane were easily accessible for binding of the imprinted molecule and appeared to maintain high selectivity, indicating that the composite membranes may potentially provide valuable affinity matrices. In this study, the application for MIP-NOM composite cellulose membranes were investigated for their potential to act as transdermal drug delivery systems for the S-enantiomers from racemic propranolol, its ester prodrugs (cyclopropanoyl- and valeryl-propranolol) or other beta-blockers (pindolol and oxprenolol). The enantioselective release of the fluorescently active 1-pyrene-butyryl ester prodrug of S-propranolol from MIP-NOM composite membranes and its diffusion and transit across excised rat skin was monitored by confocal laser scanning microscopy. The mechanism underlying the release of S-propranolol from the MIP-NOM composite membrane was found to involve specific adsorption and mobility of this enantiomer at the binding site in the MIP-NOM as the latter undergo a transition from the dry to wet state. The proposed MIP-NOM composite membrane controlled release system may be applicable for fabrication of novel membranes with self-controllable permeability responding to the presence of target solutes.