Antipyrine pharmacokinetics were studied in 6 healthy women before and 2, 8 and 12 weeks after administering the injectable progestagen (progestin), norethisterone (norethindrone) enanthate 200mg intramuscularly. Additionally, antipyrine kinetics in 5 women who had previously used the injectable contraceptive for 8 to 14 months were compared with values obtained in 14 non-users. Antipyrine was measured in saliva using a spectrophotometric method, following an oral dose of 18 mg/kg bodyweight. In the 6 women studied prospectively the mean salivary antipyrine half-life was 14.91 +/- 1.5 hours (SEM) before administering the injection, and 13.56 +/- 0.73 at 2 weeks, 15.13 +/- 1.86 at 8 weeks and 15.21 +/- 2.46 hours at 12 weeks after the injection. The mean antipyrine half-life in the 5 long term users of injectable progestagen was 14.21 +/- 2.53 hours compared with 13.66 +/- 0.98 hours in non-users. The results of this study suggest that - in contrast to published data on combined oral contraceptives - neither short nor long term use of parenteral norethisterone enanthate in Indian women is associated with significant alterations in antipyrine clearance.

Iron deficiency is a common nutritional deficiency, which leads to structural functional and enzymatic changes in the body that may affect the pharmacokinetics of drugs. The present study in 7 normal volunteers and 8 adult male patients with iron deficiency anaemia (IDA) was done to investigate the effect of iron deficiency and its treatment with total dose iron (TDI) on the bioavailability of a single dose of phenytoin. Phenytoin bioavailability was investigated before and 3 and 28 days after TDI. The bioavailability parameters Cmax, tmax, AUC and 2 h phenytoin concentrations were not significantly different in anaemic patients as compared to normal volunteers before or after treatment, except for an increase in tmax 28 days after TDI treatment.

A bioequivalence study of three brands of regular diltiazem--Angizem (A), Dilzem (B) and Herbesser (C) has been carried out in 5 healthy, male volunteers. After a single oral dose of 60 mg of each preparation, the mean AUC (0-8 h) and Cmax of preparation B was significantly higher than of brands A and C. The tmax of A and B was significantly lower than of C. B had a higher dissolution rate in vitro (98.8% dissolved in 45 min) than A and C. Thus, there was bioinequivalence of the three brands of diltiazem, due partly to differences in dissolution and perhaps in part to a first pass effect.

1. The extent of phenformin absorption and its rate of urinary excretion have been assessed in adult patients with iron deficiency anaemia, a condition which compromises gastrointestinal function. 2. Phenformin (100 mg) was administered orally to patients before treatment, three days after the start of a course of iron treatment (oral 300 mg b.d. or total intravenous iron) and at the end of 28 days, when haemoglobin was over 10 gm%. 3. No significant difference was found between mean total amounts of phenformin and 4-hydroxyphenformin excreted in urine, before treatment or after 3 or 28 days replacement therapy. It is concluded that phenformin absorption is not affected by iron deficiency. 4. In addition, iron deficiency had no significant effect on phenformin elimination half-life.

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