The HPLC method described herein has sufficient sensitivity to determine the pharmacokinetic parameters of nifedipine in plasma. A single dose cross study was carried out in volunteers comparing the test sustained release nifedipine formulation to Adalat retard tablets. Pharmacokenetic variables were calculated from the nifedipine plasma concentration data and evaluated statistically. The results showed the test formulation to be bioequivalent to the reference tablets.
Nifedipine ; Biological Availability ; tablets

Study on 12 healthy volunteers using 2 types of medication: rifampicin, isoniazid, and pyrazinamid standard separate tablets and in fixed dose combination of rifampicin + isoniazid + pyrazinamid (3- FDC). Results: rifampicin is one of essential anti-tuberculosis drugs that have most advantages of pharmacodynamics on both intra- and extra-cellular bacteria. Cmax (maximum concentration in plasma) and AUC 0-∞ (Area Under the Concentration-Time Curve) of rifampicin in 3- FDC is lower than that in standard separate tablet, Tmax (Time to Maximum Plasma Concentration) of rifampicin in 3- FDC is more slowly than in standard separate tablet. These findings showed that the bioavailability of rifampicin in FDC tablet that was using in treating tuberculosis is much lower than in standard separate tablet.
Biological Availability ; Rifampin ; Tablets

The study was carried out on 18 healthy volunteers (9 men and 9 women), from 21 - 36 years old, all of them don’t be alcohol and smoke addiction. The result: in the experience condition, the plasma concentration of amoxcilin while using 1000mg tablet, 2 times/24 hours is higher than dose 500mg, 3 times/24 hours for both tablet and capsule. The treatment regimen based on 500mg tablet, 3 times/24 hours ensures more rapid absorption than on 500mg capsule, but it don’t change the bioavailable and the bioequivalence of drug
Biological Availability ; Amoxicillin ; Therapeutics

BACKGROUND: Glutathione is a major antioxidant in the body that serves as a substrate for conjugation reactions and regulates cell proliferation. Low levels of glutathione have been linked to cancer, liver problems and other chronic diseases. Studies have shown that oral supplementation is not effective in increasing the glutathione level in the body.

OBJECTIVES: The purpose of the study was to prepare a niosomal formulation of glutathione and to characterize the niosomal formulation. Furthermore, the study compared the effect of the charge inducer in the formulation.

METHODOLOGY: The method was divided to the preparation, characterization and stability study of the niosomal formulation. The niosomal formulation was produced by thin film hydration with varying Span 60 (Sorbitan monostearate) and cholesterol ratios. Niosomal formulation with highest entrapment efficiency was further characterized for mean particle size, surface morphology, and in vitro drug release.

RESULTS AND DISCUSSION: Formulation A entrapped 98.21% of the glutathione. Addition of charge inducer increased its entrapment efficiency to 98.91%. Furthermore, both niosomal formulations released glutathione at pH 7.4 in 1.0M phosphate buffer saline (PBS). The mean vesicular size obtained was 1,242.97 + 40.52nm. Differential Scanning Calorimetry revealed compatibility between glutathione and its excipients. Both formulations do not cause cytotoxicity in human dermal fibroblast. The stability study also revealed that it was stable at 5°C and 40°C for 3 months.

CONCLUSION: Results of this study suggested the potential use of niosomes in the targeted delivery of glutathione. This is the first report on the use of niosomal preparations through thin film hydration technique in the delivery of reduced L-glutathione.

The concentration of paracetamol in rabbit blood is determined by HPLC with UV detection at the wavelength of 257 nm and mobile phase of CH3OH-H2¬O-CH3COOH (20:79:1). We have determined the extent and rate of drug absorption into blood (through Cmax, Tmax and AUC calculated from the blood concentrations) and the extent and rate of dissolution (by the dissolution test mainly based on the paddle method described in USP 23) with 3 different finished products of paracetamol (by two Vietnamese manufacturers and by Smithkline Beecham) of the same dosage form (500 mg tablet). The test was carried out on 5 rabbits for each product and the results showed that there was no significant difference between the domestic and foreign drugs in both dissolution and absorption
Acetaminophen ; Biological Availability ; Pharmaceutical Preparations

This tutorial examines the relationship between CL, F, and hepatic blood flow (Q(H)) quantitatively at oral and i.v. administration as an answer to the quiz set for KSCPT members. In case of oral dosing, when hepatic blood flow increases, the hepatic clearance (CL) and bioavailability (F) increases in high-extraction ratio drugs according to the well-stirred model equations for hepatic clearance: CL(H) = Q(H)·ER = Q(H)·f(u)·CL(int)/(Q(H)+f(u)·CL(int)) and F = 1 - ER Despite such a clear relationship, many students may feel it rather paradoxical that the increased CL (thus decreasing the AUC) causes increased F and thus the AUC (F·Dose/CLH) remains unchanged. This tutorial clarifies that the degree to which CL increase fails to match that of the Q(H) increase, and thus the decreased ER (= CL/Q(H)) that results in the increased F. Contemplating this simple, but seemingly paradoxical phenomenon may help students gain a deeper understanding of the first-pass effect.
Area Under Curve ; Biological Availability ; Humans

Curcumin (diferuloylmethane) is a yellow pigment present in the spice turmeric (Curcuma longa) that has been associated with antioxidant, anti-inflammatory, anticancer, antiviral, and antibacterial activities as indicated by over 6,000 citations. In addition, over one hundred clinical studies have been carried out with curcumin. One of the major problems with curcumin is perceived to be the bioavailability. How curcumin should be delivered in vivo, how bioavailable is it, how well curcumin is absorbed and how it is metabolized, is the focus of this review. Various formulations of curcumin that are currently available are also discussed.
Absorption* ; Biological Availability* ; Curcuma ; Curcumin* ; Metabolism* ; Spices*

Some standards in vivo such as physical and chemical properties, stability, water content, disintegration, dissolution are regular standards of drug quality control. These parameters indicated that the drug manufactured according to procedure. But the parameters of bioavailability in vivo demonstrate the real quality of the drug. They comprise the area under curve (AUC), maximum concentration (Cmax) and time for reaches the Cmax(Tmax). Model of experimental animals play an important role in the tests of bioavailability and bioequivalence.
Pharmaceutical Preparations ; Quality Control ; Biological Availability

In vitro bioavailability of ketoprofen 200mg long acting tablets by the oral were studied. Using basket dissolution tester at 120rpm. Released ketoprofen was determined by a UV – spectrophotometer at 260nm. Ketoprofen plasma levels on carefully chosen 6 healthy volunteers were within treatment which reached from 4 to 36 hours. 200mg ketoprofen LP tablets gradually released ketoprofen within 24 hours and released about 80% after 18 hours. Pharmacological parameter of ketoprofen 200mg long acting tablets have the same value compared with the results which have been published
Biological Availability ; Pharmaceutical Preparations ; Ketoprofen ; tablets ; drugs

AIMTo set up an artificial neural network system and optimize by genetic algorithm (GA) to predict drug bioavailability.

METHODSGenetic algorithm was used to optimize weights of the artificial neural network. The optimal solution of the artificial neural network model at a specific condition was obtained using the good search ability of genetic algorithm in order to predict drug bioavailability. Volume, refractivity, lgP(c), hydration, polarizability, E(HOMO) and E(LUMO) are inputs of the drug bioavailability prediction neural network, and its output is average drug bioavailability.

RESULTSThe prediction precision of average drug bioavailability of the GA- neural network model is 95.9%.

CONCLUSIONThis model can be used in the forecasting of drug bioavailability.