Aurasorn Saraphanchotiwitthaya

Immunomodulatory activities of Clausena excavata Burm. f. wood extracts.

In vitro immunomodulatory activities of aqueous extract, acetone extract and the Thai folklore extract of Clausena excavata Burm. f. on mouse immune system were investigated. The phagocytic activity of macrophages and splenocyte proliferation in the absence and presence of mitogens (lipopolysaccharide, LPS) or pokeweed mitogen, PWM) were assayed. The aqueous extract exhibited the maximum effect on both respiratory burst response and lysosomal enzyme activity more than the acetone extract and the Thai folklore extract indicating effective phagocytic activation. For splenocyte proliferation assay, the Thai folklore extract with LPS gave the maximum activity higher than that with PWM, suggesting specificity towards B cell proliferation through T cell independent pathway the same as LPS. The present study revealed the immunomodulating activity, which could be explained the traditional use of this plant in Thailand.

A simple bioanalytical assay for determination of montelukast in human plasma: application to a pharmacokinetic study.

An analytical method based on high-performance liquid chromatographic (HPLC) was developed for the determination of montelukast in human plasma using mefenamic acid as an internal standard. After precipitation of plasma proteins with acetonitrile, chromatographic separation was carried out using a Zorbax Eclipse XDB C8 (150 mm x 4.6 mm i.d., 5 microm) with mobile phase consisted of methanol-acetonitrile-0.04M disodium hydrogen orthophosphate (22:22:56, v/v, pH 4.9). The wavelengths of fluorescence detection were set at 350 nm for excitation and 450 nm for emission. The linearity was confirmed in the concentration range of 5-1000 ng/ml in human plasma. Intra- and inter-day accuracy determined from quality control samples were 101.50 and 107.24%, and 97.15 and 100.37%, respectively. Intra- and inter-day precision measured as coefficient of variation were < or =4.72 and < or =9.00%, respectively. Extraction recoveries of drug from plasma were >48.14%. The protocol herein described was employed in a pharmacokinetic study of tablet formulation of montelukast in healthy Thai male volunteers.

Effect of Bacopa monniera Linn. extract on murine immune response in vitro

The study was to investigate and compare the effects of the Bacopa monniera Linn. extract and bacoside A on the ICR mice immune system in vitro. Splenocyte proliferation without or with mitogen (lipopolysaccharide, pokeweed mitogen, phytohaemagglutinin and concanavalin A) and phagocytic activity were assayed. The results showed that B. monniera extract at 0.001–1 mg/mL slightly suppressed splenocyte proliferation (SI 0.7) and decreased T‐lymphocyte proliferation (SI 0.4) at 0.001 and 0.1 mg/mL with concanavalin A. Bacoside A at 0.001 mg/mL gave the highest splenocyte proliferation (SI 1.5) and strongly increased T‐lymphocyte proliferation (SI 2.0) at 0.1 mg/mL with concanavalin A. Thus, it is possible to attribute the effect of B. monniera extract on splenocyte proliferation to the presence of bacoside A with other combined components. However, only B. monniera extract at 10 mg/mL produced a slight increase in lysosomal enzyme activity (PI 1.2), indicating a weak effect on phagocytic activation. It might be concluded that B. monniera manifests various effects on the murine immune system depending on the immune cell types, in accordance with its folklore uses. New assays are being carried out to study its mechanisms and to further investigate its applications in the treatment of human immune mediated diseases. Copyright

Bioequivalence Evaluation of Two Formulations of Doxazosin Tablet in Healthy Thai Male Volunteers

ABSTRACT The bioequivalence of two doxazosin 2 mg tablets was determined in 24 healthy Thai male volunteers after one single dose in a randomized cross-over study with a one week washout period. The study was conducted at Faculty of Pharmaceutical Sciences and Health Sciences Research Institute, Naresuan University, Phitsanulok, Thailand. Reference (Cardura®, Heinrich Mack Nachf. GmbH & Co. GK, Illertissen, Germany) and test (Dozozin-2®, Umeda Co., Ltd., Bangkok Thailand) were administered to volunteers after overnight fasting. Blood samples were collected at specified time intervals and plasma was separated. The validated HPLC method with fluorescence detection was used for quantification of doxazosin in plasma samples. The pharmacokinetic parameters, Tmax, Cmax, AUCt, AUC∞, T1/2, λz, Cl and Vd, were determined from plasma concentration time profile of both formulations by using non-compartment analysis. The calculated pharmacokinetic parameters were compared statistically to evaluate bioequivalence between the two brands. The analysis of variance (ANOVA) using log-transformed Cmax, AUCt, and AUC∞ did not show any significant difference between two formulations. The point estimates and 90% confidence intervals for Cmax, AUCt and AUC∞ were within the acceptance range (0.80–1.25), satisfying the bioequivalence criteria of the Thailand Food and Drug Administration Guidelines. These results indicate that Dozozin-2® is bioequivalent to Cardura® and, thus, may be prescribed interchangeably.

Comparative Study on the Bioequivalence of Two Formulations of Pioglitazone Tablet in Healthy Thai Male Volunteers

The bioequivalence study of two 30 mg pioglitazone formulations was determined in healthy Thai male volunteers after a single dose administration in a randomized cross-over study with a 1-week washout period. Due to the high variability of the rate and extent of absorption of pioglitazone, an add-on subject study was required to assess bioequivalence. Reference product (Actos®, Takeda Chemical Industries, Ltd., Osaka, Japan) and test product (Glubosil®, Silom Medical Co. Ltd., Bangkok, Thailand) were given to 35 volunteers after overnight fasting. Blood samples were collected at specified time intervals. Plasma was analyzed for pioglitazone concentration using a validated HPLC method. Pharmacokinetic parameters were compared between test and reference products from plasma concentration-time profile by using non-compartment analysis. The statistical comparison of Cmax and AUC0−t, AUCt−∞ clearly indicated that no significant difference in two products of pioglitazone tablets in add-on subject study. The 90% confidence intervals for the mean ratio (test/reference) of Cmax and AUC0−t, AUCt−∞ were within the Thailand Food and Drug Administration acceptance range. Based on the pharmacokinetic and statistical results of this study, we can conclude that Glubosil® is bioequivalent to Actos®, and that two products can be considered interchangeable in medical practice.

An In Vitro Model for Fibroblast Photoaging Comparing Single and Repeated UVA Irradiations

The current method for efficient evaluation of antiphotoaging compounds is an in vitro skin culture model using a single ultraviolet A (UVA) irradiation of fibroblasts. However, skin photoaging is caused by repeated exposure to UVA radiation. The objective of this study was to develop an appropriate model for in vitro skin photoaging by comparing the different effects of single (5 J cm−2) and repeated exposures (5 J cm−2 × 3 times) of fibroblasts to UVA irradiation. Our results demonstrated that a single and repeated exposure to UVA irradiation had different effects on fibroblasts. In the single UVA‐irradiated group, collagen lattice contraction and the protein levels of type I procollagen and matrix metalloproteinase‐1 (MMP‐1) increased, while the levels of fibronectin and alpha‐smooth muscle actin (α‐SMA) were unchanged, compared to levels in the non‐UVA‐irradiated group (control). In contrast, repeated UVA exposure significantly induced G0/G1 cell cycle arrest, reduced collagen lattice contraction and type I procollagen and fibronectin expression, and increased MMP‐1 expression. There was no difference in α‐SMA expression when comparing repeatedly irradiated and non‐UVA‐irradiated fibroblasts. Our findings clearly indicate that repeated UVA irradiation of cells induces malfunctions found in photoaged skin and is an appropriate in vitro skin model of photoaging.