Patent Abstract:
this invention relates to the use of one or more cannabinoids in the treatment of epilepsy and more particularly to the use of one or a combination of cannabinoids in the treatment of generalized or partial seizure . in one embodiment it relates to the use of the cannabinoid thcv , as a pure or isolated compound , or as a plant extract in which significant amounts of any thc naturally present has been selectively removed . in another embodiment the phytocannabinoid is cbd .

Detailed Description:
male wistar rats ( p24 - 29 ; 75 - 110 g ) were used to assess the effects of the cannabinoids : thcv ( bds and pure ) and cbd on the ptz model of generalised seizures . animals were habituated to the test environment , cages , injection protocol and handling prior to experimentation . animals were housed in a room at 21 ° c . on a 12 hour light : dark cycle ( lights on 0900 ) in 50 % humidity , with free access to food and water . five 6 l perspex tanks with lids were placed on a single bench with dividers between them . closed - circuit television ( cctv ) cameras were mounted onto the dividers to observe rat behaviour . sony topica ccd cameras ( bluecherry , usa ) were linked via bnc cables to a low - noise pc via brooktree digital capture cards ( bluecherry , usa ). zoneminder ( http :// www . zoneminder . com ) software was used to monitor rats , start and end recordings and manage video files . in - house linux scripts were used to encode video files into a suitable format for further offline analysis using the observer ( noldus technologies ). a range of doses of ptz ( 50 - 100 mg / kg body weight ) were used to determine the best dose for induction of seizures ( see below ). as a result , doses of 70 and 80 mg / kg injected intra - peritoneally ( ip ; stock solution 50 mg / ml in 0 . 9 % saline ) were used to screen the cannabinoids . on the day of testing , animals received an ip injection with either the cannabinoids ( low , medium or high dose ) or a matched volume of the the cannabinoids vehicle ( 1 : 1 : 18 ethanol : cremophor : 0 . 9 % w / v nacl solution ), which served as the negative control group . animals were then observed for 30 mins , after which time they received an ip injection of 70 or 80 mg / kg ptz . negative vehicle controls were performed in parallel with cannabinoid - dosed subjects . after receiving a dose of ptz , animals were observed and videoed to determine the severity of seizure and latency to several seizure behaviour types ( see in vivo analysis , below ). animals were filmed for half an hour after last sign of seizure , and then returned to their cage . animals were observed during experimental procedures , but all analysis was performed offline on recorded video files using the observer behavioural analysis software ( noldus , netherlands ). a seizure severity scoring system was used to determine the levels of seizure experienced by subjects ( pohl & amp ; mares , 1987 ). all signs of seizure were detailed for all animals . the latency ( in s ) from injection of ptz to first myoclonic jerk ( fmj ; score of 1 ), and to the animal attaining “ forelimb clonus with tonic component and body twist ” ( score of 3 . 5 ) were recorded . fmj is an indicator of the onset of seizure activity , whilst & gt ; 90 % of animals developed scores of 3 . 5 , and so is a good marker of the development of more severe seizures . data are presented as the mean ± s . e . m . within an experimental group . this is given as the median value for each experimental group based on the scoring scale below . the percentage of animals within an experimental group that died as a result of ptz - induced seizures . note that the majority of animals that developed tonic - clonic seizures ( scores of 4 and 5 ) in the thcv ( bds ) study died as a result , and that a score of 6 ( death ) automatically denotes that the animal also experienced tonic - clonic seizures . the time ( in seconds ) from the first sign of seizure ( typically fmj ) to either the last sign of seizure or , in the case of subjects that died , the time of death — separated into animals that survived and those that did not . this is given as the mean ± s . e . m . for each experimental group . differences in latencies and durations were assessed by one - way analysis of variance ( anova ) with post - hoc tukey &# 39 ; s test . p ≦ 0 . 05 was considered significant . the thcv bds comprised a whole extract of a chemovar in which thcv was the predominant cannabinoid . ( i . e . it was the major cannabinoid present in the extract , 80 % by weight of the total cannabinoid content ). thc was the second most prevalent cannabinoid , and was present in significant amounts . ( i . e . it comprised greater than 10 % by weight of the total cannabinoid content , being present at about 16 %), and there were a number of minor cannabinoids identified , each comprising less than 2 % by weight of the total cannabinoid content as measured by hplc analysis . the ratio of thcv to thc in this extract is about 5 : 1 . in fact the thcv content was 67 . 5 % by weight of the extract and the thc content was 13 . 6 % by weight of the extract , with the other identified cannabinoids in total comprising about 3 % by weight of the extract , the remaining 16 % comprising non - cannabinoids . seizures induced by a range of ptz concentrations ( 50 - 100 mg / kg ; the range present in the literature ) in rats were investigated to determine an optimal dose prior to the investigation of the cannabinoid effect . ptz doses of : 50 mg / kg and 60 mg / kg induced very little seizure - like activity ( n = 4 ); 70 mg / kg typically induced clonic seizures ( score of 3 . 5 ; 8 of 13 subjects ); 80 mg / kg regularly induced tonic - clonic seizures ( scores of 4 and 5 ; 6 of 10 subjects ). additionally , it was found that repeated dosing with ptz resulted in increased sensitivity over time ; therefore no experiments were performed on animals that had already received a dose of ptz . the effect of thcv bds on ptz - induced seizures was first assessed against a ptz dose of 70 mg / kg . as described below , this yielded a vehicle control group that did not typically experience severe seizure scores . therefore thcv bds was also screened against an 80 mg / kg dose of ptz . it was felt that the increased seizure severity experienced by vehicle control animals exposed to 80 mg / kg ptz was a more appropriate test of potential anti - convulsant activity . effect of thcv bds on moderately severe ( 70 mg / kg ) ptz - induced seizures three doses of thcv bds were assessed against a concentration of ptz known to induce moderate seizures in rats ( 70 mg / kg ; see pilot , above ). the low , medium and high doses of thcv bds used were 0 . 37 , 3 . 70 and 37 . 04 mg / kg , and yielded actual thcv doses of 0 . 25 , 2 . 5 and 25 mg / kg respectively . these doses were matched by thcv content to those being used for screening pure thcv against ptz - induced seizures . thcv bds did not have any significant effects on latency to first myoclonic jerk or on latency to attaining a severity score of 3 . 5 on the seizure severity scale ( fig1 ). it should be noted that although values for both these variables were higher for animals treated with medium and high dose thcv bds compared to control , this failed to reach significance ( p & gt ; 0 . 05 ). similarly , no significant impact on duration of seizure was seen ( fig2 ). the effects of thcv bds on seizure severity ( fig3 ) and mortality ( fig4 ) in animals that received doses of 70 mg / kg ptz did not conform to a simple pattern . no animal injected with vehicle - alone exceeded the median severity score of 3 . 5 for that group , and no animals died ( n = 10 ). in contrast , 70 mg / kg ptz induced severe tonic - clonic seizures and death in 50 % of animals injected with a low dose of thcv bds , demonstrating a median severity score of 4 . 75 . this increase in severity was not significant . however , animals injected with medium and high doses of thcv bds exhibited a lower median severity score and lower mortality rates than those exposed to low doses ( fig3 & amp ; 4 ). medium and high dose mortality rates were higher than that of the vehicle group , but not significantly so ( p & gt ; 0 . 05 ; fig4 ). however , median severity scores were the same between medium & amp ; high doses ( fig3 ). this pattern of results suggested that a further set of experiments , in which thcv bds was screened against a dose of ptz which would induce severe seizures in control ( vehicle - treated ) animals , was required . the effects of the same three doses of thcv bds on seizures induced by 80 mg / kg ptz were assessed . it is worth noting that 80 mg / kg induced significantly more severe seizures than 70 mg / kg in vehicle control groups ( p = 0 . 009 ), with median seizure severity scores of 6 and 3 . 5 respectively . thcv bds did not have a significant effect on latencies to fmj or a severity score of 3 . 5 ( fig5 ). similarly , no effect was observed on seizure durations ( fig6 ). low dose thcv bds decreased both seizure severity ( fig7 ) and mortality ( fig8 ) in animals that received doses of 80 mg / kg ptz . animals that received low thcv bds had a lower median severity score ( 3 . 5 compared to 6 ) than vehicle controls . however , this difference was not significant ( p & gt ; 0 . 5 ). the low thcv bds dose group also had a mortality rate half that of the vehicle control group ( 30 % vs 60 %). groups treated with medium and high doses of thcv bds had a lower seizure severity score of 4 . 75 ( p & gt ; 0 . 5 vs control ), and a lower mortality rate of 50 %, compared to 6 and 60 % respectively . screening of thcv bds in the ptz model did not appear to have any significant anti - or pro - convulsant effects on either moderate or severe ptz - induced seizures . however , a trend towards lower severity and mortality was seen in animals that received a low dose of thcv bds prior to induction of severe ( 80 mg / kg ptz ) seizures , compared to vehicle controls . it is possible that this effect is masked at higher doses of thcv bds by higher levels of other cannabinoid constituents ( such as thc ) present in the non - thcv content of the thcv bds . higher doses of thcv bds will contain increasing doses of non - thcv content , such as thc , which may oppose any potential positive effects of thcv . low ( 0 . 025 mg / kg ), medium ( 0 . 25 mg / kg ) and high ( 2 . 5 mg / kg ) doses of pure thcv were assessed for their effects on ptz - induced seizures . it is worth noting at this point , for comparisons to example 1 ( thcv bds ), that differing doses of pure thcv were used compared to thcv bds . see table 2 below . 80 mg / kg ptz successfully induced seizures of varying severities in animals from all 4 experimental groups ( n = 16 per group ). ptz - induced seizures led to the death of 44 % of animals that received vehicle alone . groups that received low , medium and high thcv all exhibited lower mortality rates of 41 %, 33 % and 38 % respectively ; however these values were not significantly different from that of the vehicle group ( p & gt ; 0 . 05 , binomial test ). the mean values for latency to first seizure sign , and to scores of [ 3 ] and [ 5 ] on the seizure scoring scale used , as well as the duration of seizure for surviving animals , are described in fig9 a - d . it can be seen that seizures started later , as shown by increased latency to first manifestation of seizure - like behaviour ( fig9 a ) in animals that received thcv compared to vehicle controls . the delay of onset was significant at the highest dose of thcv ( p = 0 . 02 ). a similar pattern was seen for latencies to scores of [ 3 ] and [ 5 ] ( fig9 b and 9c ) with all thcv doses exhibiting increased latencies , reaching a significant level at the highest dose of thcv ( p = 0 . 017 and 0 . 013 for [ 3 ] and [ 5 ] respectively ). it was also observed that duration of ptz - induced seizures in animals that survived the experimental period were significantly shorter after administration of the medium dose of thcv compared to vehicle controls ( fig9 d ; p = 0 . 03 ). table 3 below displays the values for median seizure severity in each experimental group . the median maximum severities and % of animals that did not experience any signs of seizure for each experimental group are given ( n = 16 for each value ). * indicates significant difference from vehicle group ( binomial significance test , p & lt ; 0 . 05 ). vehicle control animals exhibited a median seizure severity of 4 . 25 , whereas all groups which received thcv had a median severity score of 3 . 5 . this decrease was not significantly different . 12 . 5 % vehicle control animals displayed no indicators of seizure , suggesting these animals did not develop seizures after ptz administration . a significantly higher number of animals ( 33 . 3 %) displayed no signs of seizure in the group that received 0 . 25 mg / kg ( table 3 ; p = 0 . 031 ). this data suggests that the medium dose of 0 . 25 mg / kg thcv protected against the development of seizures . the effects of the high dose of thcv on latency values suggest that thcv can delay both onset and seizure development , whilst the significant effects of the medium dose on the incidence of seizure at medium ( 0 . 25 mg / kg ) thcv doses suggest a significant anticonvulsive action on ptz - induced seizures . in addition to thcv , cbd was also screened in the ptz model . the results strongly indicate that cbd ( at levels of 100 mg / kg ) in this model is anti - convulsant as it significantly decreased the mortality rate and incidence of the most severe seizures compared to vehicle control animals . pure cbd was injected intra - peritoneally ( ip ) in the standard vehicle ( 1 : 1 : 18 ethanol : cremophor : 0 . 9 % w / v nacl ) at doses of 1 , 10 and 100 mg / kg alongside animals that received vehicle alone at a matched volume ( n = 15 for each group ). 60 minutes later ptz ( 80 mg / kg , ip ) was administered . 46 . 7 % of control animals that received vehicle alone died within 30 minutes of ptz administration ( fig1 ). in contrast only 6 . 7 % ( only 1 of 15 ) of animals that received 100 mg / kg cbd died , a marked reduction that proved to be significant ( p & lt ; 0 . 001 ). additionally only 6 . 7 % of animals that received 100 mg / kg cbd experienced the most severe seizures ( score of 5 ) in comparison to 53 . 3 % of vehicle control animals , a decrease that was also significant ( p & lt ; 0 . 001 ; fig1 in vivo ). in contrast to pure thcv , no significant increases in latency of seizure development were observed . however , the marked and significant reductions indicate a striking anti - convulsant effect on ptz - induced seizures . screening and analysis of pure cbd in the ptz model at high dose ( 100 mg / kg ) of cbd on mortality levels and incidence of the most severe seizures suggests that cbd can attenuate the severity of ptz - induced seizures pure thcv was injected intra - peritoneally ( ip ) in the standard vehicle ( 1 : 1 : 18 ethanol : cremophor : 0 . 9 % w / v nacl ) at doses of 0 . 025 , 0 . 25 and 2 . 5 mg / kg alongside animals that received vehicle alone at a matched volume ( n ≧ 14 for each group ). 15 minutes later methylscopolamine ( 1 mg / kg ; to reduce peripheral muscarinic effects of pilocarpine ) was administered followed , 45 minutes later by pilocarpine ( 380 mg / kg , ip ) administration . no significant effect of thcv at any dose was observed upon latency to the onset of seizure ( p & gt ; 0 . 5 for all doses vs control ; 1 - way anova with tukey &# 39 ; s post - hoc test ). no significant change in percentage mortality vs control was seen for any thcv dose ( fig1 ). in addition thcv had no effect upon the mean maximum severity of seizure reached per animal group ( fig1 ). the percentage of animals in each group that reach a particular seizure state ( unilateral forelimb clonus , bilateral forelimb clonus , bilateral forelimb clonus with rearing and falling and tonic - clonic ) was also assessed ( fig1 a - d ). thcv caused no significant changes in the percentage of animals showing unilateral forelimb clonus , bilateral forelimb clonus or tonic - clonic seizures at any dose . interestingly , 0 . 25 mg / kg thcv caused a significant increase in the percentage of animals showing bilateral forelimb clonus with rearing and falling although this effect was not seen at any other dose . pure cbd was injected intra - peritoneally ( ip ) in the standard vehicle ( 1 : 1 : 18 ethanol : cremophor : 0 . 9 % u w / v nacl ) at doses of 1 , 10 and 100 mg / kg alongside animals that received vehicle alone at a matched volume ( n ≧ 14 for each group ). 15 minutes later methylscopolamine ( 1 mg / kg ; to reduce peripheral muscarinic effects of pilocarpine ) was administered followed , 45 minutes later by pilocarpine ( 380 mg / kg , ip ) administration . no significant effect of cbd at any dose was observed upon latency to the onset of seizure ( p & gt ; 0 . 5 for all doses vs control ; 1 - way anova with tukey &# 39 ; s post - hoc test ). a significant increase in percentage mortality vs control was seen for the 10 mg / kg cbd dose as shown in fig1 . fig1 details that cbd had no effect upon the mean maximum severity of seizure reached per animal group . fig1 a - d detail the percentage of animals in each group that reached particular seizure states ( unilateral forelimb clonus , bilateral forelimb clonus , bilateral forelimb clonus with rearing and falling and tonic - clonic ). cbd caused significant decreases in the percentage of animals showing unilateral forelimb clonus at cbd doses & gt ; 1 mg / kg , interestingly , although no significant differences in the percentage of animals exhibiting bilateral forelimb clonus were found , the percentage of animals manifesting with bilateral forelimb clonus with rearing and falling were significantly reduces at all cbd doses & gt ; 1 mg / kg . the percentage of animals exhibiting tonic - clonic seizures was significantly reduced at cbd doses of 1 mg / kg and 100 mg / kg but not 10 mg / kg ( c . f . fig1 ). the effects of cbd upon tonic - clonic seizure events by examining the mean frequency of tonic - clonic events as is shown in fig1 . cbd caused a significant reduction in mean tonic - clonic frequency at all doses tested . cbd effects upon the mean frequency of all other seizure scores were also assessed in the same way but no significant differences vs control were found ( p & gt ; 0 . 5 for all ). the percentage duration of time spent in a tonic - clonic state compared to the total duration of the seizure period was examined ( fig1 ). cbd significantly reduced the percentage duration at doses of 1 mg / kg and 100 mg / kg but not 10 mg / kg . cbd ( 1 , 10 and 100 mg / kg ) or cbd vehicle ( 1 : 1 : 18 ethanol : cremophor : 0 . 9 % w / v nacl ) was administered i . p . to adult male wistar rats (& gt ; 250g ). one week prior to this , animals had been surgically implanted with a cannula into the right lateral ventricle under anaesthesia . one hour after cbd administration , 150 iu penicillin was infused into the right lateral ventricle in 1 . 5 μl saline solution over one minute and seizure behaviour video recorded for two hours . following detailed examination of animal responses to penicillin alone ( using data obtained from vehicle control groups , a finalised seizure scoring scale for penicillin - induced partial seizures has been derived . the following scoring system which was derived from several existing and published scoring systems for this model , will therefore be used for analysis of drug effects upon such seizures . seven of the twelve vehicle - treated animals developed the most severe seizures ( tonic - clonic seizures without postural control ; fig1 a ), whereas , administration of 100 mg / kg cbd completely prevented development of these seizures in a significant manner ( p = 0 . 001 ). near - significant decreases in development of these seizures were observed in animals treated with 1 and 10 mg / kg cbd ( fig1 a , p = 0 . 076 for both ). the frequency with which animals experienced the most severe seizures was also significantly affected ( anova , p = 0 . 009 ; fig1 b ), with a significant decrease compared to the vehicle group at 100 mg / kg cbd ( p = 0 . 006 ) and a near - significant effect at 10 mg / kg ( p = 0 . 071 ). the effect of cbd treatment on seizure severity and animal mortality is described in fig2 a - c . a dose of 100 mg / kg cbd significantly reduced the median severity of penicillin - induced seizures compared to vehicle - treated animals ( anova p = 0 . 024 ; difference between vehicle and 100 mg / kg cbd p = 0 . 012 ; fig2 a ). interestingly , all doses of cbd ( 1 , 10 and 100 mg / kg ) significantly increased the proportion of animals that remained seizure - free ( p & lt ; 0 . 001 for all doses ; fig2 b ). finally , 100 mg / kg had a near - significant effect on mortality compared to vehicle ( p = 0 . 057 ). from these studies it would appear that both thcv ( pure ) and cbd ( pure ) show promise as an anti - epileptic for generalized seizure , particularly clonic / tonic seizure . the data generated for a thcv rich extract , containing other cannabinoids including significant amounts of thc , suggest that the thc may be countering the effect of the thcv and that a cannabinoid extract which contains thcv as a major or predominant cannabinoid , but which also contains minimal , or substantially no , thc would be desirable for treating epilepsy . furthermore the results with pure cbd suggest that an extract containing significant amounts of both thcv and cbd , but again , minimal or substantially no thc may provide an optimum combination . accordingly it may prove desirable to prepare a thcv predominant extract in which thc is selectively , and substantially , removed ( to levels of less than a few percent ). this could be mixed with a cbd rich extract ( which contains much lower levels of thc ) in which cbd is the major and predominant cannabinoid ( also with low levels of thc ) to produce an extract with clearly defined , and significant levels of both thcv and cbd , but with insignificant levels of thc . such an extract may contain other cannabinoids and the non - cannabinoid components which result from extraction , by for example , carbon dioxide as disclosed in wo04 / 016277 , which components may support an “ entourage ” effect in the endocannabinoid system . on dosage , a rat / human conversion factor (× 6 ) suggests a cbd daily dose of at least 600 mg ( and optionally between 400 mg and 800 mg ) and for thcv at least 1 . 5 mg ( medium ) to preferably at least 15 mg ( high ). where a phytocannabinoid extract is to be used , an extract with low or negligible levels of thc and therapeutically effective levels of thcv and / or cbd is desired . the data described in the examples above clearly show that although cbd shows some anti - convulsant properties in all of the three models tested , it would appear best in treating generalized or partial seizures . in contrast thcv was only effective in the ptz - model . this finding suggests that the two cannabinoids may have different mechanisms of action and that the combination may provide for more general treatments . in this regard thcv appears selective for generalized seizures , more particularly tonic - clonic seizures and cbd appears to be most effective in generalized and partial seizures . alger , b . e . 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