* Preparation and Storage of liquid LDN

[Guest guest]

.... according to Dr. Bob Lawrence.

Preparation of Low-dose Naltrexone Suspension for use in the

Treatment of Multiple Sclerosis

The following details are derived from information provided by Dupont

Pharmaceuticals Ltd.

There are described a number of formulations used by individual

researchers not directly employed by Dupont Ltd.

Abboud et al describes a method in which 50 mg tablets were crushed

and dissolved in 50 mls of water, thus providing a solution

containing 1 mg/ ml. This was administered by adding 4 ml of syrup

per ml of solution.

The resulting suspension was found to remain stable for up to 24

hours.

Tsang and Holtsman studied the stability of Naltrexone in simple

syrup at a concentration of 1 mg/ ml. The suspension was prepared by

crushing three 50 mg tablets and dissolving these in 100 mls of

distilled water and 40 mls of simple syrup.

Individual samples were then tested, for five consecutive days,

assessing changes in colour, clarity, crystal formation and pH.

There were no changes in any of these criteria. In addition, there

were no significant changes in naltrexone concentration. It was thus

concluded that this preparation was stable, at room temperature, for

a period of five days.

Fawcett et al examined the stability of crushed tablets in ascorbic

acid 0.5%, sodium benzoate 0.1%, glycerol 20%, with distilled, de-

ionised water to 100%. Crushed tablets or powder were triturated

with the ascorbic acid and sodium benzoate, glycerol was added to

form a paste and the mixture was made up to volume with water.

Stability studies on this mixture indicated that the liquid was

chemically stable, for up to 60 days, when stored in the dark at 4° C.

Further studies, using commercial syrup suspensions, containing

suitable antioxidants and preservatives, have demonstrated an

appropriate clinical response, when stored under similar

circumstances, but no chemical analysis of the active drug has yet

been carried out.

It is therefore suggested that a suspension, using either the method

described by Fawcett, or a suitable commercial preparation, might be

utilised in the preparation of a syrup suspension. This mixture

would contain one 50 mg tablet of naltrexone in 330 ml (providing 1.5

mg/ 10 ml dose) or two 50 mg tablets of naltrexone in 330 ml

(providing 3 mg/ 10 ml dose).

Dr M R Lawrence MRCS; LRCP

Dietary Research Ltd

DIETARY RESEARCH LIMITED, 10 HEOL GERRIG, TREBOETH, SWANSEA SA5 9BP

Company Registered Number 2615367: Tel: 01792 - 417514