EFFECT OF L-ALPHA-LYSOPHOSPHATIDYLCHOLINE ON THE NASAL ABSORPTION OF HUMAN GROWTH-HORMONE IN 3 ANIMAL SPECIES

The effect of L-alpha-lysophosphatidylcholine (LPC) on the nasal absorption of human growth hormone (hGH) in anaesthetised rats, conscious rabbits and sheep, has been examined. LPC was shown to be an effective enhancer of nasal hGH absorption in three different animal models- In the rat, concentrations of LPC in the range 0-1.0% co-administered with hGH gave absorption values, relative to subcutaneous administration (S/C), from 2.3 to 16.3%. In the rabbit, concentrations of LPC of 0 and 0.2% co-administered with hGH gave absorption values, relative to S/C, of 1.4 and 72.8% respectively. In the sheep, concentrations of LPC in the range 0-0.59% co-administered with hGH gave absorption values, relative to S/C, from 0.2 to 16.0%. The amount of hGH absorbed was directly proportional to the concentration of LPC co-administered, and in sheep this relationship was linear, with a correlation coefficient of 0.99. The shapes of the plasma concentration vs time curves were similar in all three species.