the following describes the production of the highly - purified (& gt ; 98 % w / w ) cannabidiol extract which has a known and constant composition which was used for the expanded access trials described in examples below . in summary the drug substance used in the trials is a liquid carbon dioxide extract of high - cbd containing chemotypes of cannabis sativa l . which had been further purified by a solvent crystallization method to yield cbd . the crystallisation process specifically removes other cannabinoids and plant components to yield greater than 95 % cbd w / w , typically greater than 98 % w / w . the cannabis sativa l . plants are grown , harvested , and processed to produce a botanical extract ( intermediate ) and then purified by crystallization to yield the cbd ( drug substance ). the plant starting material is referred to as botanical raw material ( brm ); the botanical extract is the intermediate ; and the active pharmaceutical ingredient ( api ) is cbd , the drug substance . both the botanical starting material and the botanical extract are controlled by specifications . the drug substance specification is described in table 5 below . distinct chemotypes of cannabis sativa l . plant have been produced to maximize the output of the specific chemical constituents , the cannabinoids . one type of plant produces predominantly cbd . only the (-)- trans isomer occurs naturally , furthermore during purification the stereochemistry of cbd is not affected . an overview of the steps to produce a botanical extract , the intermediate , are as follows : 1 . growing 2 . decarboxylation 3 . extraction no . 1 — using liquid co 2 4 . extraction no . 2 —‘ winterization ’ using ethanol 5 . filtration 6 . evaporation high cbd chemovars were grown , harvested and dried and stored in a dry room until required . the botanical raw material ( brm ) was finely chopped using an apex mill fitted with a 1 mm screen . the milled brm was stored in a freezer for up to 3 months prior to extraction . decarboxylation of cbda to cbd was carried out using a large heraeus tray oven . the decarboxylation batch size in the heraeus is approximately 15 kg . trays were placed in the oven and heated to 105 ° c . ; the brm took 96 . 25 minutes to reach 105 ° c . held at 105 ° c . for 15 minutes . oven then set to 150 ° c . ; the brm took 75 . 7 minutes to reach 150 ° c . ; brm held at 150 ° c . for 130 minutes . total time in the oven was 380 minutes , including 45 minutes cooling and 15 minutes venting . extraction no 1 was performed using liquid co 2 at 60 bar / 10 ° c . to produce botanical drug substance ( bds ) which was used for crystallisation to produce the test material . the crude cbd bds was winterised in extraction no 2 under standard conditions ( 2 volumes of ethanol at minus 20 ° c . for around 50 hours ). the precipitated waxes were removed by filtration and the solvent evaporated using the rotary evaporator ( water bath up to 60 ° c .) to yield the bds . the manufacturing steps to produce the drug substance from the intermediate botanical extract are as follows : 1 . crystallization using c5 - c12 straight chain or branched alkane 2 . filtration 3 . optional recrystallization from c5 - c12 straight chain or branched alkane 4 . vacuum drying intermediate botanical extract ( 12 kg ) produced using the methodology above was dispersed in c5 - c12 straight chain or branched alkane ( 9000 ml , 0 . 75 vols ) in a 30 litre stainless steel vessel . the mixture was manually agitated to break up any lumps and the sealed container then placed in a freezer for approximately 48 hours . the crystals were isolated by vacuum filtration , washed with aliquots of cold c5 - c12 straight chain or branched alkane ( total 12000 ml ), and dried under a vacuum of & lt ; 10 mb at a temperature of 60 ° c . until dry before submitting the drug substance for analysis . the dried product was stored in a freezer at minus 20 ° c . in a pharmaceutical grade stainless steel container , with fda food grade approved silicone seal and clamps . the drug product is presented as an oral solution . the oral solution presentation contains 25 mg / ml or 100 mg / ml cbd , with the excipients sesame oil , ethanol , sucralose and flavouring . two product strengths are available to allow dose titration across a wide dose range . the 25 mg / ml solution is appropriate at lower doses and the 100 mg / ml solution at higher doses . the drug product formulation is as described in table 6 below : the composition can be substantially equivalent , by which is meant the functional ingredients can vary from the qualitative composition specified in table 6 by an amount of up to 10 %. example 1 below describes the use of a highly purified cannabis extract comprising cannabidiol ( cbd ) in an expanded access treatment program in children with tre . efficacy of cannabidiol reducing atonic seizures in children and young adults with intractable epilepsy of 137 children and young adults with severe , childhood onset treatment - resistant epilepsy ( tre ), twenty - seven suffered from epilepsy that was characterised by atonic seizures . these subjects were tested with a highly purified extract of cannabidiol ( cbd ) obtained from a cannabis plant . all subjects presented with atonic type seizures , often in addition to other seizures . the participants in the study were part of an expanded access compassionate use program for cbd . the epileptic syndromes that these patients suffered from were as follows : lennox - gastaut syndrome ; tuberous sclerosis complex ; dravet syndrome ; doose syndrome ; aicardi syndrome , cdkl5 and dup15q . all patients entered a baseline period of 4 weeks when parents / caregivers kept prospective seizure diaries , noting all countable seizure types . the patients then received a highly purified cbd extract ( greater than 98 % cbd w / w ) in sesame oil , of known and constant composition , at a dose of 5 mg / kg / day in addition to their baseline anti - epileptic drug ( aed ) regimen . the daily dose was gradually increased by 2 to 5 mg / kg increments until intolerance occurred or a maximum dose of 25 mg / kg / day was achieved . patients were seen at regular intervals of 2 - 4 weeks . laboratory testing for hematologic , liver , kidney function , and concomitant aed levels was performed at baseline , and after 4 weeks of cbd therapy . all patients were taking at least two concomitant anti - epileptic drugs . these included clobazam ; levetiracetam ; topiramate ; stiripentol ; phenobarbital ; lacsamide ; valproic acid ; zonisamide . the average number of concomitant antiepileptic drugs being taken was 2 . 7 . the majority took either clobazam and / or valproic acid . there were 27 children and young adult patients all of whom suffered from atonic seizures received treatment with cbd for at least 12 weeks . a summary of the 50 % responders , based on 12 weeks of treatment are summarized in table 7 below . table 7 shows that after 3 months of therapy , a remarkable 63 % of patients had an equal to or greater than & gt ; 50 % reduction in atonic seizures , these data infer that the cbd is very effective at reducing this type of seizure . these data indicate that cbd significantly reduces the number of atonic seizures in a high proportion of patients that do not respond well to existing aed . it was surprising that in this group of patients which are treatment - resistant such a high number were able to gain an effect . the fact that nearly two thirds of the patients ( 63 %) benefitted from at least a fifty percent reduction in the number of atonic seizures that they suffered from was remarkable . furthermore when these data are compared to the other sub - types of generalised seizure , it can clearly be seen that cbd was able to selectively reduce the occurrence of atonic seizures . table 8 below details these findings . from table 8 it can be seen that when the number of atonic seizures recorded is compared with other generalised seizure types such as tonic seizures ( 49 % of patients experienced a greater than 50 % reduction in seizure ), tonic - clonic seizures ( 43 % of patients experienced a greater than 50 % reduction in seizure ), and myoclonic seizures ( 43 % of patients experienced a greater than 50 % reduction in seizure ) the fact that nearly two thirds ( 63 %) of patients experiencing atonic seizures had a greater than 50 % reduction in the number of seizures that occurred is very surprising . ames f r and cridland s ( 1986 ). “ anticonvulsant effects of cannabidiol .” s afr med j 69 : 14 . consroe p , martin p , eisenstein d . ( 1977 ). “ anticonvulsant drug antagonism of delta - 9 - tetrahydrocannabinol induced seizures in rabbits .” res commun chem pathol pharmacol . 16 : 1 - 13 consroe p , benedicto m a , leite j r , carlini e a , mechoulam r . ( 1982 ). “ effects of cannabidiol on behavioural seizures caused by convulsant drugs or current in mice .” eur j pharmaco . 83 : 293 - 8 cunha j m , carlini e a , pereira a e , ramos o l , pimental c , gagliardi r et al . ( 1980 ). “ chronic administration of cannabidiol to healthy volunteers and epileptic patient .” pharmacology . 21 : 175 - 85 dravet c . the core dravet syndrome phenotype . epilepsia . 2011 apr ; 52 suppl 2 : 3 - 9 . eadie , m j ( december 2012 ). “ shortcomings in the current treatment of epilepsy .” expert review of neurotherapeutics 12 ( 12 ): 1419 - 27 . geffrey a , pollack s , paolini j , bruno p , thiele e ( 2014 ) “ cannabidiol ( cbd ) treatment for refractory epilepsy in tuberous sclerosis complex ( tsc ).” american epilepsy society annual meeting . 5 - 9 december 2014 . kwan p , arzimanoglou a , berg a t , brodie m j , hauser w a , mathern g , moshe s l , perucca e , wiebe s , french j . ( 2009 ) “ definition of drug resistant epilepsy : consensus proposal by the ad hoc task force of the ilae commission on therapeutic strategies .” epilepsia . maa e and figi p ( 2014 ). “ the case for medical marijuana in epilepsy ”, epilepsia 55 ( 6 ): 783 - 786 mechoulam r and carlini e a ( 1978 ). “ toward drugs derived from cannabis .” die naturwissenschaften 65 : 174 - 9 . pelliccia a , grassi g , romano a , crocchialo p ( 2005 ). “ treatment with cbd in oily solution of drug resistant paediatric epilepsies ”. congress of cannabis and the cannabinoids , leiden , the netherlands . international association for cannabis as a medicine . p14 . porter b e , jacobson c ( december 2013 ). “ report of a parent survey of cannabidiol - enriched cannabis use in paediatric treatment resistant epilepsy ” epilepsy behaviour . 29 ( 3 ) 574 - 7 thurman , d j ; beghi , e ; begley , c e ; berg , a t ; buchhalter , j r ; ding , d ; hesdorffer , d c ; hauser , w a ; kazis , l ; kobau , r ; kroner , b ; labiner , d ; liow , k ; logroscino , g ; medina , m t ; newton , c r ; parko , k ; paschal , a ; preux , p m ; sander , j w ; selassie , a ; theodore , w ; tomson , t ; wiebe , s ; ilae commission on , epidemiology ( september 2011 ). “ standards for epidemiologic studies and surveillance of epilepsy .” epilepsia . 52 suppl 7 : 2 - 26
the present disclosure relates to the use of cannabidiol for the treatment of atonic seizures . in particular the cbd appears particularly effective in reducing atonic seizures in patients suffering with etiologies that include : lennox - gastaut syndrome ; tuberous sclerosis complex ; dravet syndrome ; doose syndrome ; aicardi syndrome ; cdkl5 and dup15q in comparison to other seizure types . the disclosure further relates to the use of cbd in combination with one or more anti - epileptic drugs .