Postmarketing pharmacokinetic and pharmacodynamic equivalence of generic and brand atenolol in Egypt.

Concerns have been raised regarding the postmarketing quality of generic drugs. This study assessed the pharmacokinetic and pharmacodynamic equivalence of generic and brand atenolol tablets in 24 healthy male volunteers in a single-dose, open, randomized, two-period crossover study under fasting conditions. Blood samples were collected for 24 h post dosing and assayed for atenolol using HPLC. Blood pressure and heart rate were measured at baseline and throughout blood sampling. The mean plasma concentration-time curves for both products were similar. Pharmacokinetic and statistical analysis indicated bioequivalence based on the mean ratios of log-transformed Cmax and AUC values. Both products had similar time courses of pharmacodynamic activity with a significant fall in blood pressure and heart rate (maximum after ~5 h) followed by a gradual increase towards baseline. Both products were well tolerated. Both atenolol products were bioequivalent in the postmarketing setting and can be used interchangeably in clinical practice.

Postmarketing pharmacokinetic and pharmacodynamic equivalence of generic and brand atenolol in Egypt

Concerns have raised regarding the postmarketing quality of generic drugs. This study assessed the pharmacokinetic and pharmacodynamic equivalence of generic and brand atenolol tablets in 24 healthy male volunteers in a single-dose, open, randomized, two-period crossover study under fasting conditions. Blood samples were collected for 24 h post dosing and assayed for atenolol using HPLC. Blood pressure and heart rate were measured at baseline and throughout blood sampling. The mean plasma concentration-time curves for both products were similar. Pharmacokinetic and statistical analysis indicated bioequivalence based on the mean ratios of log-transformed Cmax and AUC values. Both products had similar time courses of pharmacodynamic activity with a significant fall in blood pressure and heart rate [maximum after ~5 h] followed by a gradual increase towards baseline. Both products were well tolerated. Both atenolol products were bioequivalent in the postmarketing setting and can be used interchangeably in clinical practice

Could chemical enhancement of gold nanoparticle penetration be extrapolated from established approaches for drug permeation?

BACKGROUND AND AIM: Investigations on chemical enhancement of skin penetration of gold nanoparticles are considered crucial to have a deeper insight into the main barrier of particle penetration. METHODS: In this study, penetration of gold nanoparticles in the presence of several chemical enhancers - urea, sodium lauryl sulphate, polysorbate 80 and dimethyl sulfoxide (DMSO) - through human skin was studied. RESULTS: Among the tested chemical enhancers, DMSO could induce the penetration of hydrophilic (citrate-stabilized) gold colloid of no intrinsic penetration ability in a concentration-dependent manner. Pretreatment of the skin with DMSO however reduced the penetration of hydrophobic (cetrimide-coated) gold nanoparticles as a result of aggregation in the top layers of the stratum corneum limiting penetration into the deeper skin layers. In addition, nanoparticles-vehicle interaction and the stability of the nanoparticles in the applied vehicle were found important determinants of skin penetration. CONCLUSION: Our results demonstrate that the already established approaches for chemical permeation enhancement of drug molecules and their postulated mechanisms could be used as preliminary guidelines for enhancing the penetration of nanoparticles. At this size range of 15 nm, intercellular lipids provide the main barrier to particle penetration through the stratum corneum.

Formulation of wax oxybenzone microparticles using a factorial approach.

Oxybenzone wax microparticles (MPs) were prepared by the hydrophobic congealable disperse phase method. The formulation of oxybenzone-loaded MPs was optimized using a 24 experimental design. Factorial analysis indicated that the main MP characteristics were influenced by initial drug loading, emulsification speed, emulsifier concentration and hydrophilic-lipophilic balance. MPs were spherical with 50.5­88.1 µm size range, 17.8­38.9 drug content in mg/100 mg MPs and 33.1­87.2% oxybenzone release in 1 h. A wide range of sunscreen delivery systems suitable for different formulation purposes were generated which may contribute to the advanced formulation of sunscreen products with improved performance.

Assessment of the pharmaceutical quality of omeprazole capsule brands marketed in Egypt.

The pharmaceutical quality of 7 local omeprazole capsule brands in Egypt was assessed relative to the proprietary product (Losec). Drug content, content uniformity, drug release (using USP test for enteric coated articles and a modified release test) were determined. Products were subjected to a 3-month stability study. Of the 7 brands, 6 had satisfactory drug content and content uniformity. All brands passed the USP drug release test. The modified release test proved to be more discriminative. After 3 months storage, drug content of 3 brands remained > 90% and 2 of these brands maintained drug release above 75%. Changes in pellet appearance during storage were indicative of omeprazole chemical degradation.

Assessment of the pharmaceutical quality of omeprazole capsule brands marketed in Egypt

The pharmaceutical quality of 7 local omeprazole capsule brands in Egypt was assessed relative to the proprietary product [Losec[R]]. Drug content, content uniformity, drug release [using USP test for enteric coated articles and a modified release test] were determined. Products were subjected to a 3-month stability study. Of the 7 brands, 6 had satisfactory drug content and content uniformity. All brands passed the USP drug release test. The modified release test proved to be more discriminative. After 3 months storage, drug content of 3 brands remained > 90% and 2 of these brands maintained drug release above 75%. Changes in pellet appearance during storage were indicative of omeprazole chemical degradation

Manipulation of powder characteristics by interactions at the solid-liquid interface: 1-sulphadiazine.

A solvent-treatment technique aiming at manipulating the properties of powdered materials is reported. Potentials of the technique were assessed using sulphadiazine (SD). A suspension of the drug in a preselected solvent (5% aqueous ammonia solution) was stirred under controlled conditions. The solvent was subsequently removed and the material dried. The effect of experimental variables such as stirring speed and time, powder/solvent ratio and inclusion of additives (Tween 80, sodium chloride and PVP) on the properties of solvent treated SD was assessed. Data obtained were compared with those for SD recrystallized under identical conditions. Solvent treatment of SD in the absence of additives resulted in a limited change in crystal morphology as indicated by SEM. This was associated with improved flowability and a limited reduction in dissolution rate relative to untreated SD. On the other hand, recrystallized SD exhibited superior flowability but a considerably low dissolution rate. Solvent treatment of SD in the presence of 2% PVP produced a microgranular directly compressible material.

The effect of hydrotropic agents on the heat coagulation of bovine serum albumin.

The effect of two hydrotrophic solubilizers on the heat coagulation of bovine serum albumin (BSA) has been investigated. Photon correlation spectroscopy indicated possible unfolding of BSA molecules in solutions of sodium benzoate and sodium salicylate at 25 degrees C. The effect of these hydrotropes on the heat coagulation of BSA was concentration-dependent. Relatively low concentrations stabilized the protein structure as indicated by the increase in the transition temperature(Tm) and induced gelation at temperatures and BSA concentrations lower than those required in the absence of hydrotropes. Higher concentrations of the hydrotropes considerably reduced Tm and inhibited gelation of BSA, the effect of sodium salicylate being more pronounced, as was the lower aggregation rate of BSA. The behaviour of these hydrotropes as protein denaturants differs from that of neutral electrolytes but is similar to that of concentrated solutions of urea.