OBJECTIVETo prepare the gastric retenting and chronopharmacologic drug delivery tablets containing sinomenine hydrochloride as a model drug, evaluate the effects of the coating layers formulation and technics on drug release behavior, and to elucidate the mechanism of drug release based on obtained results.

METHODThe gastric retenting and chronopharmacologic drug delivery tablets were prepared by press-coated technics. The types of disintegrants were chosen according to the expanding rate and the lag-time. The effects of formulation and technics of coating layer on the release characteristic of the drug were investigated by dissolution testing. The mechanism of drug release was proved by erosion test.

RESULTThe tablets had typical chronopharmacologic drug delivery properties with a lag time followed by a rapid release phase. CMS-Na was selected as the disintegrant. The lag-time was prolonged with the increase of the ratio of HPMC/carrrageenan and the amount of matrix material in coating layer. The compressing pressure and preparation method of coat material had minor influence on the lag-time of the tablets. Coating layer erosion and tablet core swelling were involved in the mechanism of drug release.

CONCLUSIONThe tablets had typical chronopharmacologic drug delivery properties. A suitable lag-time can be achieved by adjusting formulation of coating layer to meet the requirement of chronotherapy.

Chemistry, Pharmaceutical ; Drug Chronotherapy ; Drug Delivery Systems ; methods ; Humans ; Morphinans ; chemistry ; pharmacokinetics ; Stomach ; drug effects ; Tablets, Enteric-Coated ; chemistry ; pharmacokinetics

OBJECTIVETo investigate the loss of heterozygosity (LOH) on chromosomal arms 13q and 14q in nasopharyngeal carcinoma (NPC) using 21 microsatellite polymorphic markers and to study whether there is a correlation between LOH and clinicopathologic parameters and/or Epstein-Barr virus (EBV) infection in NPC.

METHODSSixty cases of NPC were studied using polymerase chain reaction based microsatellite analysis with genescan and genotyping techniques.

RESULTSLOH was detected on 13q in 78% of NPC tumors, high frequency LOH loci (more than 30%) clustered to 13q12.3-q14.3 and 13q32. On chromosome 14q, LOH was detected in 80% of NPC tumors; high frequency LOH loci clustered to 14q11-q13, 14q21-q24 and 14q32. High frequency LOH at 13q31-q32 correlated with a lower level of EBV infection; LOH on chromosome 14q was closely associated with poor differentiation of NPC tumor cells.

CONCLUSIONOur results suggest that in NPC, LOH on chromosome 13q and 14q are common genetic events, and putative tumor suppressor genes (TSG) residing in these regions may be involved in tumorigenesis.

Adult ; Aged ; Chromosomes, Human, Pair 13 ; genetics ; Chromosomes, Human, Pair 14 ; genetics ; DNA, Neoplasm ; genetics ; Female ; Gene Frequency ; Humans ; Loss of Heterozygosity ; Male ; Microsatellite Repeats ; Middle Aged ; Nasopharyngeal Neoplasms ; genetics ; pathology ; Statistics as Topic