it is the object of the present invention pharmaceutical compositions for intranasal administration consisting of cyclobenzaprine hydrochloride solutions in water with having ph suitable for said administration . particularly , said cyclobenzaprine pharmaceutical compositions , are characterized by a ph value in the range 6 - 7 . 4 . in said range of ph are particularly preferred those ph values comprised between 7 , 0 and 7 , 4 to which corresponds an optimized partial presence of the active principle in a not ionized form , therefore able to go through the mucosa . at a ph higher than 7 . 4 the cyclobenzaprine aqueous solution shows an opalescence formation due to the cyclobenzaprine base not soluble in the buffer solution : to the purpose , to the ph 7 . 4 formulation a small quantity of ethanol has been poured in to avoid the formation of said opalescence . the aqueous solutions containing 5 % of cyclobenzaprine hydrochloride are practically isotonic ( 400 mosmol / l or 0 . 88 g - eq di nacl ), while those at 10 and 15 % are ipertonic , being the contribution of the buffer solutions nearly negligible . combining the concentrations of the indicated range and the possible volume of the pumps available on the market ( 50 - 70 - 100 μl ), various administration posologies can be proposed , for instance : 5 % aqueous cyclobenzaprine hydrochloride solution with 100 μl pump : one supply corresponds to 5 mg active product ; 10 % aqueous cyclobenzaprine hydrochloride solution with 50 μl pump : one supply corresponds to 5 mg active product ; 15 % acqueous cyclobenzaprine hydrochloride solution with 70 μl pump : one supply corresponds to 10 . 5 mg active product and other at intermediate concentrations . the final choice is made on the basis of the local tolerability / plasmatic levels ratio . the compositions object of the invention can also include buffer agents , preservatives , mucoadhesive and absorption enhancer substances . said substances are of the kind traditionally used in the art and , in case of buffer agents , they are preferably selected among phosphates and acetates ; in case of absorption enhancer substances , the preferred ones are chitosan , methylpyrrolidone and sodium cholate ; in case of preservatives the preferred ones are selected among benzyl alcohol , quaternary ammonium salts , hydroxybenzoic esters , such as benzalkonium chloride , methyl and propyl parahydroxybenzoate , while the preferred mucoadhesive substance is sodium hyaluronate . the cyclobenzaprine hydrochloride formulations for intranasal route object of the invention have absorption rapidity , bypass the first hepatic passage and have an excellent tolerability with low tonicity formulations . they do not show any contraindication for the administration of a few days short period . the following examples have the purpose of better illustrate the invention without in any case limiting it . grams 150 . 00 of cyclobenzaprine hydrochloride , to which 300 . 00 ml of purified water and 50 . 00 ml of 95 % ethanol were added , are put under magnetic stirring and further added with 2 . 00 g of benzalkonium chloride . the limpid solution by adding 70 . 00 ml 1n sodium hydroxide is brought to about the final ph value by means of a phmeter and , then , added with 500 , 00 ml of a buffer solution . the ph is adjusted to the desired value by 1n sodium hydroxide and the solution brought to 1 . 00 l final volume with purified water . the resulting solution is limpid and has a ph that may differ , from the desired value , in the range of ± 0 . 2 units . alternatively , the above described process can be carried out substituting the benzalkonium chloride with 10 . 00 g benzyl alcohol . operation is carried out as per the prevoiusly described example 1 , to obtain the below indicated solutions for intranasal use ( 100 ml ). grams 150 . 00 of cyclobenzaprine hydrochloride , added with 300 . 00 ml purified water and 50 . 00 ml 95 % ethanol , are put under magnetic stirring and added with 2 . 00 g benzalkonium chloride and 5 . 00g chitosan . the solution is left under slow stirring for at least six hours , then the limpid solution by adding 70 . 00 ml sodium hydroxide 1n is adjusted to about the final ph value by means of a phmeter and then added with 500 . 00 ml buffer solution . the ph is then adjusted to the desired value with 1n sodium bydroxide and the solution is brought to 1 . 00 l final volume with purified water . the resulting solution is limpid and has a ph that can differ , from the ph desired value , in the range of ± 0 . 2 units . alternatively , the above described process can be carried out replacing the benzalkonium chloride with 10 . 00 g of benzyl alcohol . in order to evaluate the activity of the composition of the invention administered by intranasal route the following texts have been carried out . the plasma levels of cyclobenzaprine ( cbz ) were determined after a single intranasal dose of 1 . 5 mg / kg in a volume of 10 μl , and 3 . 0 mg / kg in a volume of 20 μl , and after a single oral dose of 1 . 5 mg / kg in new zealand albino male rabbits . 1 . the oral administration was performed with a 0 . 15 % solution , the intranasal administration with a 15 % solution . 2 . six male animals / group were treated with a single dose by intranasal or oral route . 3 . fifteen minutes before the drug administration the central artery of the ear was cannulated with a 25 - gauge needle catheter and for each animal 7 blood collections at time 0 ( to , before drug administration ) and at 15 , 30 , 60 , 90 , 120 , 180 minutes after drug administration were performed . three ml of blood sample were collected in heparinized tubes and the volume replaced with a ringer - lactate solution . the plasma samples were obtained from blood samples by centrifugation at 3000 g for 5 min . the plasma samples were be stored at − 20 ± 2 ° c . until the lc / ms / ms analysis . 4 . rabbit plasma concentrations of cbz were determined using a validated lc - ms / ms method in the calibration range of 0 . 25 - 300 ng / ml . aliquots of 250 μl of rabbit plasma were spiked with 5 μl of internal standard ( is ) solution ( containing approximately 5000 ng / ml of is , imipramine hydrochloride ) in water : methanol ( 50 / 50 , v / v ), after vortex - mixing , 250 μl of borate buffer were added . after vortex - mixing , 3 . 5 ml of hexane were added . after vortex - mixing for 10 minutes and centrifugation at 10 . 000 rpm at + 4 ° c . for 10 minutes , aliquots of 3 ml of organic phase were transferred into a single glass tube and dried under vacuum at 40 ° c . using a büchi vacuum system . the residues were re - constituted with 100 μl of 20 mm ammonium acetate buffer solution , 0 . 1 %: acetonitrile ( 50 / 50 , v / v ) solution . the tubes were then capped , vortex - mixed and centrifugated at 4100 rpm at + 4 ° c . for 10 minutes . the final extracts were transferred into an autosampler vial and 4 μl were injected into the lc - ms / ms system . positive ion mode using a api / esi interface and multiple reaction monitoring ( mrm ). calibration curves plot the ratio of the area of the compound and the is ( y ) against the analyte concentration ( x ). a weighted linear regression function ( 1 / x ) is used to fit calibration lines and consequently to calculate cbz concentrations . the lower and upper limits of quantification are 0 . 25 and 300 ng / ml of plasma samples . mean plasma levels (± sd ) after treatments are reported ( fig1 each data is the mean of six rabbits ) the plasma levels of single animals are closed to the mean profile for each treatment ( fig2 - 4 ). the main pk parameters after dose adjusted 3 . 0 mg / kg values resulted as follows . cyclobenzaprine is well absorbed by intranasal route and its rate of absorption is higher compared with oral route . c max and auc resulted linear with the dose by intranasal route , but much higher than by oral route . the results obtained by intranasal administration of the proposed formulations of cyclobenzaprine hydrochloride show a clear enhancement of its therapeutic performance when compared to those obtained by the oral administration .
a pharmaceutical composition , containing as active principle cyclobenzaprine hydrochloride , 3 - cyclo - epten - 5 - yliden )- n , n - dimethyl - 1 - propanamine hydrochloride , in form suitable to be administered by itranasal route , is described . said pharmaceutical composition allows a remarkable absorption rapidity of the active principle , does not undergo the first hepatic passage , has an excellent tolerability with low tonicity formulations and does not show any contraindication in the short period administrations .