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Biomedical subjects

K A Khan

Publications and source records attributed to K A Khan.

At least 19 recordsLinked to original sources
PubMed1992

Sister chromatid exchange and chromosome aberrations in mice after in vivo exposure of green S--a food colorant.

Sister chromatic exchanges (SCE) and chromosome aberrations (CA) in mice after in vivo exposure of Green S were carried out following single acute treatment. Except for the lowest dose (25 mg/kg body weight) a significant increase in the SCEs were observed in all the other doses (50, 100, and 200 mg/kg) tested. In CA study two higher doses (200 and 400 mg/kg) showed a significant increase in CA when compared with control. The minimum effective dose which induced SCE and CA was 50 and 200 mg/kg of body weight, respectively. The trend tests for the evidence of dose response effects were also significant for both SCE and CA. No significant differences were observed in cell replication kinetic (RI) analysis. A significant increase in the mitotic index (MI) was also observed in the highest dose (400 mg/kg) tested when compared with control. Thus the present study indicates that Green S can induce both SCE and CA in vivo in bone marrow cells of mice.

Animals↗
PubMed1992

Sister-chromatid exchange and chromosome aberrations induced by paracetamol in vivo in bone-marrow cells of mice.

Sister-chromatid exchange (SCE) and chromosome aberrations (CA) induced by paracetamol (PC), a common analgesic, were studied in vivo on bone-marrow cells of mice. The trend tests for the evidence of dose-response effects for both SCE and CA were significant. The significant increase in SCE as well as CA induced by PC may be attributed to the fact that PC can induce genotoxicity through DNA damage. Thus, the present study indicates that PC was genotoxic in vivo in bone-marrow cells of mice.

Acetaminophen↗
PubMed1992

Evaluation of the genotoxicity of 4-N-butylamino-1,2,3,4-tetrahydroacridine hydrochloride (centbucridine): a new local anaesthetic.

Centbucridine, a new local anaesthetic, was tested in in vivo genotoxicity assays. Three different endpoints were selected for this purpose. Chromosome aberrations (CA) and sister chromatid exchange (SCE) were analysed in bone marrow cells and DNA-strand breaks (SB) were measured in liver cells of mice following a single acute exposure. No significant differences were observed in the CA, SCE and SB studies, when compared with respective controls. An increase in the mitotic indices (MI) was observed only with the lowest dose tested in the CA study. No significant differences in the MI were observed with the two higher doses tested when compared with solvent controls. Trend tests for linear dose response were negative in all the parameters examined including MI. The overall results of the three endpoints tested indicated that centbucridine was not genotoxic in the mouse.

Anesthetics, Local↗
PubMed1991

A simple and rapid method for the quantification of Eudragit RS100 and RL100 poly(methacrylates) in sustained-release dosage forms.

A colorimetric ion-pair complexation method has been developed which provides a simple and rapid way of quantifying Eudragit RS100 and RL100 in pharmaceutical dosage forms. The quaternary ammonium groupings in these polymers appear to form an ion-pair complex with the dye tropaeolin OOO. When extracted into an organic phase, the optical density at 484 nm is linearly related to polymer concentration. Control of pH is important, and it should be maintained within the range 4.5 to 9.0. A wide range of pharmaceutical excipients commonly used in tablet, pellet, and film-coating formulations did not interfere with formation of the complex, but certain drugs were found to significantly enhance or decrease the assay response. Good reproducibility, precision, and accuracy were demonstrated when the method was applied to a film-coated pellet formulation containing an interfering drug (promethazine hydrochloride). However, removal of interfering substances must be optimized. The method was sufficiently sensitive for the determination of polymer on a single dose unit of encapsulated beads.

Acrylic Resins↗
PubMed1989

Genotoxicity studies on mice after short term inhalation exposure to methyl isocyanate.

Mutagenicity testing is an important aspect of the toxicological evaluation of environmental chemicals for safety. Methyl isocyanate (MIC), a very hazardous chemical used for the manufacture of insecticides, was studied for its genotoxic effects on the somatic cells of mice after inhalation exposure by means of an in vivo micronucleus test and chromosomal analysis of bone marrow cells. Animals were exposed for 10 min to different concentrations (2.40, 4.80 or 7.20 microliters) of MIC in a 22 litre chamber at 0 and 24 h. Bone marrow smears prepared 6 h after the second treatment were examined for the occurrence of micronuclei (MN) in polychromatic (P) and normochromatic (N) erythrocytes. The frequencies of cells with MN and the P/N ratio did not differ significantly from those of the control at all the exposure levels. Chromosomal preparations revealed few structural and numerical abnormalities. Aberrations encountered were of the chromatid type only. Quantitative analyses failed to exhibit any significant increase in aberration rates in the three treated groups. Numerical abnormalities were within the control range.

Administration, Inhalation↗
PubMed1986

Argon laser trabeculoplasty in a residency program.

The following article discusses the outcome of 60 eyes with various forms of glaucoma undergoing resident-performed argon laser trabeculoplasty (ALT). The majority (46/60) of eyes had primary open-angle glaucoma. Decrease in intraocular pressure (IOP) was not as great as reported in the literature. Our results suggest that initially treating 180 degrees of the angle is associated with improved overall results. ALT has proved to be a safe and effective alternative to conventional surgery for glaucoma in a residency training setting.

Adult↗
PubMed1983

Adjustment of precompression force to reduce mixing-time dependence of tablet tensile strength.

The dependence of tablet tensile strength on lubricant mixing time, pre- and main compression pressure was measured with microcrystalline cellulose, dicalcium phosphate dihydrate and starch 1500 on a rotary tablet machine. Loss of tablet tensile strength arising from lubricant overmixing can be substantially reduced in the case of microcrystalline cellulose by adjustment of pre- and main compression. This facility may be used in addition to or instead of reducing mixing time, or displacing lubricant by adding extra formulation components.

Excipients↗
PubMed1981

Effect of slugging pressure on the properties of granules and tablets prepared from potassium phenethicillin.

The mechanism of preparing compacts by precompression has been investigated. The influence of slugging pressure on the bulk and tapped density, particle size distribution and the surface area of precompressed granules has been examined. The slugged granules have been tableted and the effect of compaction force on the weight uniformity, friability, crushing strength, disintegration time, dissolution rate and internal surface area of the tablets has been studied. The results show that the granules obtained from 15.9 mm slugs manufactured at low compaction forces (e.g. 49 MNm-2) had a lower bulk density, higher friability and larger surface area than those made at higher compaction pressures (e.g. 196 MNm-2). The lighter granules compacted into stronger tablets over a range of compaction forces and the effect was attributed to greater intergranular bonding caused by increased plastic flow.

Drug Compounding↗