ropinirole used in the present invention is suitably in the form of the free base or a pharmaceutically acceptable salt thereof . a preferred pharmaceutically acceptable salt of ropinirole is crystalline hydrochloride . suitable procedures for preparing ropinirole hydrochloride include those mentioned in u . s . pat . no . 4 , 997 , 954 , and preferably those mentioned in u . s . pat . no . 5 , 336 , 781 . a medicament for use in preserving dopaminergic function of dopamine nerve cells of patients suffering from parkinson &# 39 ; s disease may be prepared by a mixture of ropinirole or a pharmaceutically acceptable salt or solvate thereof with an appropriate carrier , which may contain a diluent , binder , filler , disintegrant , flavouring agent , colouring agent , lubricant or preservative in conventional manner . preferably , the medicament is in unit dosage form and in a form adapted for use in the medical or veterinarial fields . for example , such preparations may be in a pack form accompanied by written or printed instructions for use in preserving dopaminergic function in parkinsonian patients . the suitable dosage range for ropinirole or a pharmaceutically acceptable salt or solvate depends on the relation of potency to absorbability and the frequency and route of administration . usually an appropriate regimen will be determined for a patient by titration in the usual way for d 2 agonists . ropinirole or a pharmaceutically acceptable salt or solvate thereof may be formulated for administration by any route , and examples are oral , sub - lingual , rectal , topical , parenteral , intravenous or intramuscular administration . preparations may , if desired , be designed to give slow release of the ropinirole or a pharmaceutically acceptable salt or solvate thereof . the medicaments may , for example , be in the form of tablets , capsules , sachets , vials , powders , granules , lozenges , reconstitutable powders , or liquid preparations , for example solutions or suspensions , or suppositories . the medicaments , for example those suitable for oral administration , may contain conventional excipients such as binding agents , for example syrup , acacia , gelatin , sorbitol , tragacanth , or polyvinylpyrrolidone ; fillers , for example lactose , sugar , maize - starch , calcium phosphate , sorbitol or glycerine ; tabletting lubricants , for example magnesium stearate ; disintegrants , for example starch , polyvinylpyrrolidone , sodium starch glycollate or microcrystalline cellulose ; or pharmaceutically acceptable setting agents such as sodium lauryl sulphate . solid medicaments may be obtained by conventional methods of blending , filling , tabletting or the like . repeated blending operations may be used to distribute ropinirole or a salt or solvate thereof throughout those medicaments employing large quantities of fillers . when the medicament is in the form of a tablet , powder , or lozenge , any carrier suitable for formulating solid pharmaceutical compositions may be used , examples being magnesium stearate , starch , glucose , lactose , sucrose , rice flour and chalk . tablets may be coated according to methods well known in normal pharmaceutical practice , in particular with an enteric coating . the medicament may also be in the form of an ingestible capsule , for example of gelatin containing ropinirole or a salt thereof if desired with a carrier or other excipients . medicaments for oral administration as liquids may be in the form of , for example , emulsions , syrups , or elixirs , or may be presented as a dry product for reconstitution with water or other suitable vehicle before use . such liquid medicaments may contain conventional additives such as suspending agents , for example sorbitol , syrup , methyl cellulose , gelatin , hydroxyethylcellulose , carboxymethylcellulose , aluminium stearate gel , hydrogenated edible fats ; emulsifying agents , for example lecithin , sorbitan monooleate , or acacia ; aqueous or non - aqueous vehicles , which include edible oils , for example almond oil , fractionated coconut oil , oily esters , for example esters of glycerine , or propylene glycol , or ethyl alcohol , glycerine , water or normal saline ; preservatives , for example methyl or propyl p - hydroxybenzoate or sorbic acid ; and if desired conventional flavouring or colouring agents . ropinirole or a pharmaceutically acceptable salt or solvate thereof may also be administered by a non - oral route . in accordance with routine pharmaceutical procedure , the medicaments may be formulated , for example for rectal administration as a suppository . they may also be formulated for presentation in an injectable form in an aqueous or non - aqueous solution , suspension or emulsion in a pharmaceutically acceptable liquid , e . g . sterile pyrogen - free water or a parenterally acceptable oil or a mixture of liquids . the liquid may contain bacteriostatic agents , anti - oxidants or other preservatives , buffers or solutes to render the solution isotonic with the blood , thickening agents , suspending agents or other pharmaceutically acceptable additives . such forms will be presented in unit dose form such as ampoules or disposable injection devices or in multi - dose forms such as a bottle from which the appropriate dose may be withdrawn or a solid form or concentrate which can be used to prepare an injectable formulation . as mentioned hereinbefore , the effective dose of the ropinirole or pharmaceutically acceptable salt or solvate depends on the condition of the parkinsonian patient and on the frequency and route of administration . preferably , the composition is in unit dose form . each dosage unit for oral administration contains preferably from 1 to 50 mg ( and for parenteral administration contains preferably from 0 . 1 to 15 mg ) of ropinirole . the daily dosage required for an adult patient may be , for example , an oral dose of between 1 mg and 100 mg , preferably between 1 mg and 50 mg , more preferably 125 mg ; or an intravenous , subcutaneaus or intramuscular dose of between 0 . 1 mg and 50 mg , preferably between 0 . 1 mg and 15 mg , of ropinirole , the compound being administered 1 to 4 times per day . suitably the compound will be administered for a period of continuous therapy . the daily dosage of ropinirole may be increased progressively throughout the period of treatment . for example , a patient may be given 1 - 5 mg / day ropinirole at the start of a treatment programme , and this may be increased to 10 - 25 mg over a period of 6 months to five years or more . the daily dosage may be increased uniformly or non - uniformly throughout this period . in a typical example , a patient may be given 3 - 4 mg / day ropinirole by an oral route at the commencent of a therapy ; this may be increased aggressively to about 10 mg / day over the first 6 months ; and thereafter the daily dosage may be increased more slowly to about 15 - 16 mg / day over the following 4 to 4½ years . preferably the present invention is practised using a controlled release or delayed release formulation containing ropinirole or a pharmaceutically acceptable salt thereof . by controlled release is meant any formulation technique wherein release of the active substance from the dosage from is modified to occur at a slower rater than that from an immediate release product , such as a conventional swallow tablet or capsule . by delayed release is meant any formulation technique wherein release of the active substance from the dosage form is modified to occur at a later time than that from a conventional immediate release product . the subsequent release of active substance from a delayed release formulation may also be controlled as defined above . examples of controlled release formulations which are suitable for incorporating ropinirole are described in : sustained release medications , chemical technology review no . 177 . ed . j . c . johnson . noyes data corporation 1980 . controlled drug delivery , fundamentals and applications , 2nd edition . eds . j . r . robinson , v . h . l . lee . mercel dekkes inc . new york 1987 . examples of delayed release formulations which are suitable for incorporating ropinirole are described in : remington &# 39 ; s pharmaceutical sciences 16th edition , mack publishing company 1980 , ed . a . osol . such controlled release formulations are preferably formulated in a manner such that release of active substance such as ropinirole is effected predominantly during the passage through the stomach and the small intestine , and delayed release formulations are preferably formulated such that release of active substance such as ropinirole is avoided in the stomach and is effected predominantly during passage through the small intestine said formulations are preferably formulated such that the release of the active substance is predominantly 1½ to 3 hours post ingestion . preferred formulations are ultimately enteric coated tablets or caplets , wax or polymer coated tablets or caplets or time - release matrices , or combinations thereof . thus , a particular aspect of the invention involves use of a polymeric controlled release composition comprising a reaction complex formed by the interaction of ( 1 ) a calcium polycarbophil component which is a water - swellable , but water insoluble , fibrous cross - linked carboxy - functional polymer , said polymer containing ( a ) a plurality of repeating units of which at least about 80 % contain at least one carboxyl functionality , and ( b ) about 0 . 05 to about 1 . 5 % cross - linking agent substantially free from polyalkenyl polyether , said percentages being based upon the weights of unpolymerised repeating unit and cross - linking agent , respectively , with ( 2 ) water , in the presence of ropinirole . the amount of calcium polycarbophil present is from about 0 . 1 to about 99 % by weight , for example about 10 %. the amount of active agent present is from about 0 . 0001 to about 65 % by weight , for example between about 5 and 20 %: the amount of water present is from about 5 to about 200 % by weight , for example between about 5 and 10 %. the interaction is carried out at a ph of between about 3 and about 10 , for example about 6 to 7 . the calcium polycarbophil is originally present in the form of a calcium salt containing from about 5 to about 25 % calcium . thus , a further particular aspect involves use of a system for the controlled release of ropinirole , comprising ( a ) a deposit - core comprising an effective amount of ropinirole and having defined geometric form , and ( b ) a support - platform applied to said deposit - core , wherein said deposit - core contains ropinirole , and at least one member selected from the group consisting of ( 1 ) a polymeric material which swells on contact with water or aqueous liquids and a gellable polymeric material wherein the ratio of the said swellable polymeric material to said gellable polymeric material is in the range 1 : 9 to 9 : 1 , and ( 2 ) a single polymeric material having both swelling and gelling properties , and wherein the support - platform is an elastic support , applied to said deposit - core so that it partially covers the surface of the deposit - core and follows changes due to hydration of the deposit - core and is slowly soluble and / or slowly gellable in aqueous fluids . the support - platform may comprise polymers such as hydroxypropylmethylcellulose , plasticizers such as a glyceride , binders such as polyvinylpyrrolidone , hydrophilic agents such as lactose and silica , and / or hydrophobic agents such as magnesium stearate and glycerides . the polymer ( s ) typically make up 30 to 90 % by weight of the support - platform , for example about 35 to 40 %. plasticizer may make up at least 2 % by weight of the support - platform , for example about 15 to 20 %. binder ( s ), hydrophilic agent ( s ) and hydrophobic agent ( s ) typically total up to about 50 % by weight of the support - platform , for example about 40 to 50 %. the present invention further provides a pharmaceutical composition for use a therapeutic treatment to preserve dopaminergic function in parkinsonian patients , which composition comprises an effective amount of ropinirole or a pharmaceutically acceptable salt or solvate thereof and a pharmaceutically acceptable carrier . such compositions may be prepared in the manner as hereinbefore described . one hundred and twenty patients with early parkinson &# 39 ; s disease , and no previous exposure to 1 - dopa or dopamine agonists . a double - blind , multicentre , parallel group , two year study of ropinirole at a flexible dose ( 0 . 75 - 24 mg / day ) versus 1 - dopa ( sinemet , 50 - 1 , 000 mg / day ). there was a placebo run - in phase of up to 2 weeks . over the first 4 week titration period of active medication all patients were titrated to dose levels of 3 mg / day ropinirole or 200 mg / day 1 - dopa . there was an optional visit halfway through the titration period . starting at the week 4 visit , patients received dose levels of 4 mg / day ropinirole or 300 mg / day 1 - dopa , after which dose levels were flexible . for patients who satisfactorily completed the 4 week titration phase , an initial pet scan took place within the following 2 months . a final pet scan took place at the end of the study at 2 years . efficacy was also assessed by means of the updrs motor score and cgi severity of illness ( measured at baseline and every subsequent visit ), cgi global improvement ( assessed at every post - baseline visit up to 12 months ) and the need for 1 - dopa rescue during the study . no motor score assessment was required at the optional 2 week visit . ophthalmic examinations including electroretinograms were performed on all patients except those whose medical history and concomitant medication precluded this . the examinations were performed within 2 months of completion of the fixed titration period , then at least 6 months after this initial examination and finally at 2 years to detect possible retinal dysfunction . in addition , at one centre only , electro - oculograms ( eog ) were performed as part of the electrophysiological examinations . adverse experiences , changes to concomitant medication and vital signs ( sitting bp and pulse ) were recorded at each visit from the baseline visit . laboratory evaluations of blood chemistry and haematology were made at screening , month 12 and month 24 . in an ongoing five year , double - blind , multicentre study , patients with early pakinson &# 39 ; s disease ( hoehn & amp ; yahr i - iii ) were randomised to receive either ropinirole or levodopa . of those enrolled , 37 patients were scanned using 18 fluoro - dopa pet scanning within the first year and then approximately two years later to measure the gradual decline in basal ganglia dopaminergic function . images from both the better ( less deteriorated ) and worse ( more deteriorated ) sides of the brain were analysed ; however these results focus on the average of both sides of the brain . the following endpoints were assessed : 1 mean percent change in putamen dopaminergic function in all patients ( hoehn & amp ; yahr i - iii ) 2 mean percent change in putamen dopaminergic function in parkinson &# 39 ; s disease patients with symptoms present for under two years 3 mean percent change in putamen dopaminergic function in parkinson &# 39 ; s disease patients with symptoms present for more than two years when considering all patients who entered the study , there appeared to be a slower loss of putamen dopaminergic function for patients treated with ropinirole compared with those treated with levodopa ( 13 % versus 18 % respectively ). in the subgroup pf patients with parkinson &# 39 ; s disease for less than 2 years , this difference became more obvious , the decrease in putamen dopaminergic function was also less for patients treated with ropinirole ( 14 %) versus levodopa treated patients ( 28 %). there was no statistically significant difference between treatment groups for patients with parkinson &# 39 ; s disease for more than two years . overall , patients treated with ropinirole who have had parkinson &# 39 ; s disease for less than two years demonstrated the greatest preservation of putamen dopaminergic function . in a three year , international , multicentre , double - blind comparative clinical trial , parkinson &# 39 ; s patients were randomised to receive either ropinirole ( n = 168 ) or bromocriptine ( n = 167 ). 33 % of patients received selegiline concomitantly with either ropinirole or bromocriptine . of those enrolled , 214 patients completed the study ( approximately 39 % of patients treated with ropinirole and 33 % of patients treated with bromocriptine withdrew from the study ). efficacy was based on the following : 1 mean unified parkinson &# 39 ; s disease rating scale ( updrs ) activities of daily living ( adl ) score ( part ii ) at completion 3 percentage of patients who were considered responders , defined as those with at least a 30 % reduction from baseline in total motor examination score on the updrs among patients who completed the study , patients treated with ropinirole demonstrated a statistically significantly mean improvement ( p = 0 . 009 ) in the updrs adl score versus patients treated with bromocriptine . in this same patient population , patients treated with ropinirole also showed a greater mean improvement in updrs motor score than patients in the bromocriptine group ( 31 % versus 22 %, respectively ). at the study &# 39 ; s completion , 53 % of patients treated with ropinirole were considered responders compared with 42 % for the bromocriptine group . in addition , the average improvement in the combined adl and motor scores were statistically significantly greater for patients treated with ropinirole ( p = 0 . 018 ) versus bromocriptine - treated patients . fewer patients treated with ropinirole than expected required supplemental levodopa ( 34 % versus 42 % for bromocriptine ). there was a very low incidence of dyskinesias for both treatment groups ( 8 % for ropinirole versus 7 % for bromocriptine ).
a therapeutic method for preserving the dopaminergic function of patients suffering from parkinson &# 39 ; s disease , which method comprises administering an effective amount of ropinirole or a pharmaceutically acceptable salt or solvate thereof to a human or animal patient in need thereof . typically , said patient has had parkinson &# 39 ; s disease for a period of less than three years since diagnosis . preferably the invention comprises administering to said patient an effective amount of ropinirole or a pharmaceutically acceptable salt or solvate thereof , optionally in combination with one or more other dopamine agonists , in the absence of levodopa or any other dopamine precursor , and thereafter treating the patient with levodopa .