Rectally absorbable form of L-dopa

DETAILED DESCRIPTION What is claimed is: 1.
A pharmaceutical composition for enhancing rectal absorption of L-dopa by administering a formulation comprising a therapeutically effective dosage amount of an ester of L-dopa of the structural formula: ##STR2## wherein R=alkyl(C.
sub.
1 -C.
sub.
20), aryl(C.
sub.
6 -C.
sub.
9), substituted and unsubstituted mono, di or polyhydroxyalkyl(C.
sub.
1 -C.
sub.
20); substituted and unsubstituted aralkyl(C.
sub.
7 -C.
sub.
20) and pharmaceutically acceptable organic or inorganic counterion salts.
2.
The composition of claim 1, wherein R is alkyl.
3.
The composition of claim 2, wherein said alkyl is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, tetradecyl and hexadecyl.
4.
The composition of claim 3, wherein said alkyl is ethyl, isopropyl or butyl.
5.
The composition of claim 1, wherein R is aryl.
6.
The composition of claim 5, wherein said aryl is selected from the group consisting of phenyl and tolyl.
7.
The composition of claim 6, wherein said aryl is tolyl.
8.
The composition of claim 1, wherein R is substituted and unsubstituted aralkyl.
9.
The composition of claim 8, wherein said substituted and unsubstituted aralkyl is selected from the group consisting of benzyl, alkoxybenzyl (C.
sub.
8 -C.
sub.
14), phenylethyl, phenylpropyl, phenylbutyl and phenyloctyl.
10.
The composition of claim 1 wherein R is substituted or unsubstituted mono, di or polyhydroxyalkyl.
11.
The composition of claim 10, wherein R is an unsubstituted mono-hydroxyalkyl.
12.
The composition of claim 11, wherein said mono-hydroxyalkyl is selected from the group consisting of 4-hydroxybutyl, 6-hydroxyhexyl, 2-hydroxypropyl and 5-hydroxypentyl.
13.
The composition of claim 12, wherein said mono-hydroxyalkyl is 4-hydroxybutyl.
14.
The composition of claim 12, wherein said mono-hydroxyalkyl is 2-hydroxypropyl.
15.
The composition of claim 10, wherein R is a dihydroxyalkyl.
16.
The composition of claim 15, wherein R is selected from the group consisting of 2,3-dihydroxypropyl and 1,3-dihydroxypropyl