it is obvious that intraoral transmucosal administration of anticonvulsant drugs such as lorazepam to patient in need is more practical and convenient than parenteral , intranasal or rectal routes . this task can be achieved by means of liquid , preferably sprayable , composition , which can be delivered sublingually or onto mucosal surface of gums , palate , cheeks or lips , especially to unconscious patient or during the ongoing seizures . transmucosal liquid compositions should have a relatively low viscosity to provide a good sprayability and fast formation of an emulsion upon contact with saliva which should transform in a prompt drug delivery and rapid onset of anticonvulsant action . extremely low water solubility of lorazepam (˜ 27 mcg / ml in saline ) causes precipitation of the drug from injectable solution ( ativan ®; a mixture of propylene glycol 80 %, polyethylene glycol 400 18 %, and benzyl alcohol 2 %) upon dilution with water in ratio 1 : 5 and higher . intraoral administration of the injection solution ( ativan ®) to mice demonstrated lack of anti - seizure activity while intraperitoneal delivery provides strong protection even 2 - 3 minutes after injection ( see graph 1 ). low solubility of lorazepam limits option of incorporation of required amount of the drug into oil - in - water emulsions . it was surprisingly found that lorazepam and some other benzodiazepines ( e . g ., diazepam ) form a low melting eutectic mixtures with some organic molecules , and these eutectic mixtures possess much higher solubility in oils than pure lorazepam . eutectic mixtures with seriously enhanced oil solubility were obtained when lorazepam was combined with menthol ( l - menthol ), phenol , chlorobutanol , thymol , and some other molecules . the most pronounced increase in solubility was found for l - menthol and for thymol . solubility at room temperature in different triglyceride oils increased almost 10 times for eutectic mixture lorazepam : l - menthol ( melting point 36 - 37 ° c .) and about one order of magnitude for lorazepam : thymol . menthol or thymol may be used either as crystalline purified materials or as components of naturally available essential oils , such as peppermint oil , spearmint oil , thyme oil , oregano oil , basil oil and some others . additionally it was found that incorporation of eutectic mixture of lorazepam apparently improves easiness of emulsification and allows preparation of self - emulsifying compositions with high concentration of the drug using reasonably low amounts of surfactants and thus decreasing irritation potential of such formulations . the proposed lorazepam compositions for intraoral administration according to the invention is prepared by dissolving lorazepam in combination of eutectic component in hydrophobic ( oil ) phase , containing one or several surfactants . oil phase comprises of glyceride oil , aliphatic or aromatic esters , and free tocopherols and tocopheryl esters of appropriate mixture of these hydrophobic components . the prepared compositions , containing lorazepam , can be administered using dropper , oral syringe or hand pump . for better convenience and patient compliance product may be delivered by a metered dose spray device using manual spray pump , a pressurized device or a propellant based system . a formulation , suitable for spraying , should have low viscosity . to obtain a sprayable formulation of lorazepam for intraoral transmucosal application , a non - toxic organic solvent with low viscosity may be added . it was unexpectedly found that the most efficient transmucosal delivery of lorazepam was achieved when an organic solvent is volatile and at least partially miscible with water . for example , ethyl acetate or mixtures of ethyl acetate with ethyl alcohol provided excellent drug delivery while ethyl alcohol alone or non - volatile polar solvents , such as transcutol ® or propylene glycol , were not very effective . finally , the composition of invention may be delivered to a patient in need intraorally by administering sublingually ( under the tongue ), buccally ( on the cheek mucosa ), on gums or lips or any area of internal surface of the mouth . this is extremely important for treatment of unconscious patient or during the seizures . proposed composition is not irritating and provides fast onset of anti - seizure action , comparable with parenteral administration of lorazepam . the dose is delivered in the form of droplets ; in case of using spray device some part of the composition can be delivered in form of a fine mist . the composition can be easily self - administered . beside treatment of acute seizures , proposed composition can be used for tranquilizing , sedation , premedication for kids and adults , prevention and treatment of panic attacks or sleep disorders . for investigation of anti - seizure activity of invented formulations , a timed intravenous ptz infusion test was employed . the technique of timed i . v . ptz ( pentylenetetrazole ) infusion test ( ivptz ) is a simple , reproducible and fast method for assessment of onset , peak , duration and potency of various anticonvulsants and proconvulsants in animals . this test provides an extremely sensitive parametric method for assessing seizure threshold in individual animals and a quantifiable endpoint can be obtained with a minimal number of animals . different seizure types can be chosen as endpoint in this test . usually , the first seizure occurring during the ptz infusion is a myoclonic twitch , followed by clonic and , later , tonic seizures . this method offers many advantages over the more widely used classical subcutaneous ptz ( scptz ) test . since with ivptz , test effects based on different endpoints are measured in individual animals , the number of animals required for a proper evaluation is much lower than would be needed for standard scptz test . additionally , significantly lower variability is observed during the ivptz technique than during other methods since each animal is used as its own control . the ivptz procedure is based on previously described methods ( giardina and gasior , 2009 ; mandhane et al ., 2007 ). a butterfly catheter ( small animal butterfly catheter infusion set , needle size 27 g , ⅜ in ., harvard apparatus , st . laurent , quebec , canada ) attached to a 5 ml syringe prefilled with heparinized 1 % ptz solution is used . the animal is restrained ( nose cone animal holder , kent scientific , torrington , conn .) and the needle is inserted into the tail vein . the accuracy of needle placement into the vein is confirmed by the appearance of blood in the cannula . the needle is secured to the tail by a plastic tape . the animal is transferred to a transparent plastic box and kept there for the duration of the test that takes only few minutes . the syringe is held in a syringe infusion pump ( syringe pump 22 , harvard apparatus , st . laurent , quebec , canada ) which provides a constant speed infusion ( 0 . 3 ml / min ) of the ptz solution . ptz sterile solution is continuously infused via a thin , very flexible plastic catheter permanently connected to the small gauge ( 27 g ) short needle . this procedure allows animals to move freely in the box without noticeable pain or distress for duration of ptz infusion ( 2 minutes ). during the infusion , mice are observed for the onset of different types of seizures . the time latencies from the start of infusion to the appearance of the first clonus ( characterized by rapid involuntary rhythmic contraction and relaxation of limbs ), lasting longer than 5 seconds , are recorded . infusion is immediately stopped at the appearance of this endpoint . forelimb clonus is the more reliable endpoint with less variation than other types of seizures for the ivptz test . the endpoint for the “ clonic latent period ” was noted at the moment the mouse fell on its side and showed a jerking of the head and forelimbs . the infusion of ptz will be terminated at 2 min , in case of non - appearance of clonic seizures . for such animals , the dose of ptz in mg / kg infused during the course of 2 min is calculated as the threshold dose . the threshold doses of ptz producing clonic seizures are calculated ( in mg / kg ) using the following formula : the higher is threshold level , the more pronounced is anti - seizure activity of the tested composition . e . g ., ptz dose threshold for saline or vehicle ( 5 minutes time lap ) value is about 50 mg / kg ( for selected rate of infusion 300 mcl / min and ptz concentration 10 mg / ml ) while for intraperitoneally administered lorazepam 2 . 5 mg / kg ( positive control ) it reaches ˜ 400 - 120 mg / kg ( at same 5 minutes time point ). lorazepam was dissolved in a solvent vehicle , containing propylene glycol ( 80 %), polyethylene glycol 400 ( 18 %) and benzyl alcohol ( 2 %), forming a clear solution with drug concentration of 2 mg / ml . the prepared solution was stored refrigerated and used in 30 days from the preparation date . after combining of pre - weighed amounts of components they were gently triturated at room temperature ( 20 - 22 ° c .) using a stainless steel spatula until liquid phase is formed . the data in table 1 is presented for illustration purposes . other compounds may also form physiologically acceptable eutectic mixtures with lorazepam , having lower melting points and better oil solubility than individual components . addition of menthol to other vehicle significantly increases lorazepam solubility . in pure capric / caprylic triglycerides ( mct oil ) lorazepam solubility at rt is 4 . 3 mg / ml . addition of 5 % menthol by weight increases solubility by 28 %, to 5 . 5 mg / ml , mct with 8 % menthol dissolves 6 . 8 mg / ml of the drug (˜ 60 % increase ). solubility of lorazepam in peppermint oil , containing about 45 % of menthol , reaches 38 . 9 mg / ml . self - emulsifying drug delivery systems ( sedds ) are well known , but each composition of self - emulsifying drug delivery system must be developed separately for combination of an active compound and selected excipients since even minor variations in composition requires careful choice of components such as surfactants , co - surfactants , oils , solvents their weigh relations and preparation process . all surfactants and oil phase constituents , other excipients were pharmacopoeial or food grade and selected to assure safety and physiological compatibility of the prepared formulations . vehicle contains 80 % propylene glycol , 18 % polyethylene glycol 400 , and 2 % benzyl alcohol ; lorazepam ( 10 mg / ml ) was dissolved in the vehicle and stored tightly closed in refrigerator . vehicle contains 2 % of peppermint oil ( nf grade ), 2 % polysorbate - 20 ( tween ®- 20 , nf ) and 96 % of di ( ethylene glycol ) monoethyl ether ( transcutol ®, ep ). lorazepam ( 10 mg / ml ) was dissolved in the vehicle and stored tightly closed in refrigerator . vehicle was prepared by dissolving of crystalline l - menthol ( 3 %) and acetylated monoglyrerides ( 42 %), containing lecithin and anhydrous alcohol ( 6 . 5 % of each ), alpha - d - tocopherol ( 2 %), polysorbate - 20 ( 18 %) and polyethoxylated hydrogenated castor oil ( 22 %). lorazepam ( 10 mg / ml ) was dissolved in the vehicle at 40 - 45 ° c ., and prepared solution was stored tightly closed in refrigerator . vehicle was prepared by mixing acetylated monoglyrerides ( 45 %), lecithin and anhydrous alcohol ( 6 . 5 % each ), alpha - d - tocopherol ( 2 %), polysorbate - 20 ( 18 %) and polyethoxylated hydrogenated castor oil ( 22 %). lorazepam ( 10 mg / ml ) was dissolved in the vehicle at 40 - 45 ° c ., and prepared solution was stored tightly closed in refrigerator . other vehicles for transmucosal intraoral delivery of lorazepam were prepared in similar manner , using dry and anhydrous components ( see tables 3 - 7 ). behavior of the composition on contact with water was examined using artificial saliva . in most cases after mixing with water media a stable micellar solution , emulsion or submicron emulsion ( nanoemulsion ) were immediately formed , depending on used constituents . nevertheless , in some cases formed colloidal dispersions were coarse and unstable , followed by visible phase separation . several of prepared formulations of lorazepam were tested for seizure protection properties ( ivptz test ). as a comparator , a marketed solution of lorazepam in water miscible combination of polyethylene glycol , propylene glycol and benzyl alcohol was used . intraperitoneal administration of lorazepam solution in dose 2 . 5 mg / kg leads to pronounced increase of ptz threshold , confirming a prominent anti - seizure activity of lorazepam , while same formulations , administered intraorally on the mucosal surface of the mouth demonstrated total lack of such activity ( graph 1 ). incorporation of lorazepam in formulations , that have ability to prevent precipitation of the benzodiazepine after contact with water media , may improve anti - seizure activity of lorazepam . for example addition of menthol , increasing solubility of the drug in the oil phase causes significant improvement of anticonvulsive properties , as shown in graph 2 . onset of anti - seizure action can be very fast . in some formulations high level of protection was observed even in 2 minutes after delivery of formulation , in other compositions onset could be delayed , but at 5 minutes it was clearly developed , as shown at graph 3 . formulations , containing no organic solvents , have high viscosity and , despite pronounced and fast onset of action are not convenient for delivery since viscous materials ( visc . & gt ; 50 - 100 cp ) are difficult to spray . use of non - volatile solvents , such as polyethylene glycols , propylene glycol or transcutol ®, led to relatively viscous products ( viscosity & gt ; 50 cp ) with mediocre anti - seizure activity . dilution of compositions with volatile ethyl alcohol provides easily sprayable compositions with low viscosity ( example 52 : lorazepam was dissolved in mixture of 8 parts of example 18 and 2 parts of anhydrous alcohol ). nevertheless , due to tanning action of alcohol in high concentrations , which causes protein coagulation , penetration of the drug through mucosal layer may be significantly suppressed . use of volatile ethyl acetate , which is only partially miscible with water , for vehicle dilution ( lorazepam was dissolved in mixture of 8 parts of example 18 and 2 parts of dry ethyl acetate ; example 54 ) do not cause protein coagulation and shows improvement in activity . best results were observed using combination of these volatile solvents ( example 53 ). such mixture provides excellent anti - seizure protection and fast onset of the action , as presented on graph 4 . ant - seizure action of different tested lorazepam formulations develops gradually . for parenterally administered lorazepam maximal protection is reached in approximately 5 minutes , protection after delivery of intraoral transmucosal formulations increases steadily to 20 minutes , while effective level of protection is reached after 5 minutes ( graph 5 ). further optimization of the viscosity and solubility parameters allowed to obtain formulation , showing excellent anti - seizures activity and fast onset of action , comparable with parenteral administration of lorazepam ( graph 6 ). graph 7 illustrates median particle size and size distribution of the oil droplets for nanoemulsion , formed by dilution of the example 18 formulation with artificial saliva . this nanoemulsion has mean size around 40 nm and a narrow ( pdi & lt ; 0 . 2 ) size distribution pattern . lorazepam formulations , based on eutectic mixtures of benzodiazepine with menthol or thymol and forming nanoemulsions after application onto mucosa or contact with saliva or other water media , demonstrated fast and efficient protection against ptz - induced seizures when administered via intraoral transmucosal route . combination of eutectic mixture nanoemulsion vehicle with volatile organic solvents helps to prepare sprayable formulations , suitable for intraoral buccal or sublingual delivery and provides fast and effective anti - seizure action . graph 1 . ptz induced seizures protection by marketed injectable formulation of lorazepam ( 2 . 5 mg / kg ), given parenterally and sublingually , compared to vehicle graph 2 . ptz induced seizures protection by different transmucosal formulations of lorazepam ( 2 . 5 mg / kg ) with or without menthol ex . 1 — 2 % of peppermint oil (˜ 40 % menthol content ) based formulation ; forms micellar solution ex . 2 — 2 . 4 % of crystalline l - menthol , no peppermint oil ; self - nanoemulsifying formulation ex . 3 — does not contain menthol or peppermint oil ; self - nanoemulsifying formulation graph 3 . ptz induced seizures protection by transmucosal formulations of lorazepam ( 2 . 5 mg / kg ), administered sublingually 2 and 5 minutes before ptz infusion initiation graph 4 . comparative seizure protection activity of transmucosal formulations of lorazepam ( 2 . 5 mg / kg ), containing volatile solvents graph 5 . development of seizure protection activity of transmucosal lorazepam ( 2 . 5 mg / kg ) with time ( injectable solution and formulation of example 47 ) graph 6 . development of seizure protection activity of transmucosal lorazepam ( 2 . 5 mg / kg ) with time ( injectable solution and optimized sprayable formulation ) graph 7 . particle size and size distribution for nanoemulsion of example 18 giovannone d . et al . liquid compositions for oral administration of lorazepam ” wo 2004 / 004783 a1 baek ; myoung - ki ; et al . intranasal anticonvulsive pharmaceutical composition comprising poorly soluble anticonvulsant . united states patent application 20110172211 behrouz r ., chen s ., tatum w . o . evaluation and management of status epilepticus in the neurological intensive care unit . j am osteopath assoc . 2009 , 109 ( 4 ), pp . 237 - 245 . tatum w . o . iv , french j . a ., benbadis s . r ., kaplan p . w . the etiology and diagnosis of status epilepticus . epilepsy behav . 2001 , 2 ( 4 ), pp . 311 - 317 . wermeling d . p . intranasal delivery of antiepileptic medications for treatment of seizures . neurotherapeutics , 2009 , 6 ( 2 ), pp . 352 - 358 . anderson g . d ., saneto r . p . current oral and non - oral routes of antiepileptic drug delivery . adv . drug deliv . rev . 2012 , 64 ( 10 ), pp . 911 - 8 . jevon p . buccolam ® ( buccal midazolam ): a review of its use for the treatment of prolonged acute convulsive seizures in the dental practice . british dental journal , 2012 , 213 , pp . 81 - 82 . lau s . w . j ., slattery j . t . absorption of diazepam and lorazepam following intranasal administration . int . j . pharm . 1989 , 54 ( 2 ), pp . 171 - 174 . li l ., nandi i ., kim k . h . development of an ethyl laurate - based microemulsion for rapid - onset intranasal delivery of diazepam . int j pharm . 2002 , 237 ( 1 - 2 ), pp . 77 - 85 . hammad m . a ., müller b . w . solubility and stability of lorazepam in bile salt / soya phosphatidylcholine - mixed micelles . drug dev ind pharm . 1999 , 25 ( 4 ), pp . 409 - 417 . giardina w . j , gasior m . acute seizure tests in epilepsy research : electroshock - and chemical - induced convulsions in the mouse . curr protoc pharmacol . 2009 , chapter 5 , unit 5 . 22 . mandhane s . n ., aavula k ., rajamannar t . timed pentylenetetrazol infusion test : a comparative analysis with s . c . ptz and mes models of anticonvulsant screening in mice . seizure . 2007 , 16 ( 7 ), pp . 636 - 644 .
the current application relates to a liquid pharmaceutical composition for intiaoral transmucosal administration of a benzodiazepine drag to a mammal the composition comprises a physiologically acceptable hydrophobic phase , a eutectic mixture of benzodiazepine compound providing high solubility of the benzodiazepine in said hydrophobic phase , at least one physiologically acceptable organic solvent and at least one physiologically acceptable surfactant .