Chronic Lithium

Mini-Pumps

From McQuade et al. 2004 PMID 15582915

Two treatment groups of six rats received either, lithium 3 mmol/kg/day or saline vehicle. Drug treatments were administered for 28 days as a constant infusion via subcutaneously placed osmotic pumps (Alzet model 2ML4, DURECT Corporation, Cupertino, CA, USA) implanted under halothane anaesthesia. During drug treatment, in addition to tap water, all rats were given access to 0.9% saline to minimize any ionic chemical imbalances resulting from the diuretic properties of lithium. All rats weighed 160–180 g at the time of implantation. The dose of 0.75 meq/day was based on a predicted average weight of 250 g over the course of the 28-day treatment period ... Mean plasma lithium levels after 28 days chronic lithium treatment were 0.50 ± 0.03 mmol / l.

From Smith and Amdisen 1981 PMID 6121860

We attached a minipump (Alzet Model 2001) filled with a solution of LCl (500 mmol litre-1) bilaterally in the cerebroventicles using the procedure of Biswas and Carlsson (1977)...In vitro studies showed the miniumps to release the LiCl solution at a constant rate (1.08 ul h-1) at 37 ° C.

From Bernstein and Goehler 1983

Osmotic minipumps (Model 2001, Alzet, Alza, Palo Alto, CA) were implanted in the peritoneal cavity of animals under halothane anesthesia. For half of the animals in each diet group ... the minipumps contained 200 ul of a saturated aqueous solution of LiCl (63 g/100 ml). The pumps delivered a relatively constant ip infusion of solution 1 ul per hour) for approximately 9 days.

For Lee Carella's experiment:

Dose: 3 mmol/kg/day.

Body weight: 0.3 kg

LiCl /rat/ day: 0.9 mmol /rat/ day

Flow rate: 0.25 ul / hour (Alzet minipump model 2004)

Flow rate: 6 ul / day

LiCl concentration in pump: 0.9 mmol / 6 ul = 0.9 mol / 6 ml = 150 M !!!

Maximum Concentration of LiCl in the pump: 15 M = 63 g / 100 ml Flow Rate = 6 ul / day LiCl Dose / day = 90 umol