Nasal drug bringing has been recognized as a really promising path for bringing of curative compounds. This involvement arises from the different possible advantages presented by the rhinal pit, such as: the epithelial tissue really vascularized and with a comparatively big surface country available for drug soaking up, the porous endothelial cellar membrane, the direct conveyance of captive drugs into the systemic circulation thereby avoiding the first-pass consequence hepatic nowadays in peroral disposal, the lower enzymatic activity compared with the GI piece of land and the liver ( Ugwoke et al. , 2001 ) . For all these grounds the rhinal path can be considered a utile alternate both to parenteral and unwritten paths ( Edman and Bjork, 1992 ; Turker et al. , 2004 ) . A broad scope of rhinal merchandises is in development, largely in correlativity with the rapid oncoming of action of rhinal path, for illustration, for the intervention of hurting ( rhinal morphia and Ketalar ) and for the intervention of erectile disfunction ( rhinal apomorphine ) ( Illum, 2003 ) . [ 2 ]
However, there are some jobs such as mucociliary clearance and low permeableness of the rhinal mucous membrane to some drugs that have a big influence on the efficiency of the rhinal soaking up of drugs [ 2 ] . Nasal mucociliary clearance is one of the most of import modification factor for rhinal drug bringing. It badly limits the clip allowed for drug soaking up to happen and efficaciously regulations out sustained rhinal drug disposal. However, mucoadhesive readyings have been developed to increase the contact clip between the dose signifier and mucosal beds of rhinal pits therefore heightening drug soaking up [ 3,4 ] . Illum et Al. [ 5 ] introduced mucoadhesive microsphere systems for rhinal bringing and characterized them good. The microspheres form a gel-like bed, which is cleared easy from the rhinal pit, ensuing in a drawn-out abode clip of the drug preparation. [ 3,4 ]
Another of import modification factor in rhinal application is the low permeableness of the rhinal mucous membrane for the drugs with polar and high molecular size. It seems to be necessary to see an soaking up sweetening mechanism for co-administration of drugs with either mucoadhesive polymers or incursion foils or combination of the two [ 9_/11 ] . [ 3,4 ]
Ketorolac tromethamine ( KT ) is a powerful non-narcotic anodyne with moderate anti- inflammatory activity ( 1 ) . [ 5 ] Its usage has been implicated in the figure of acute painful conditions runing from moderate to severe hurting alleviation such as postpartum ( Bloom. eld et Al. 1984 ) and postoperative hurting ( Yee et al. 1984, 1986 ) . [ 6 ] When administered as the conventional preparation, it causes GI ailments such as GI hemorrhage, perforation and peptic ulceration [ 5,6 ] . KT has a shorter mean plasma riddance half life of 4-6 hour. Therefore, it is imperative to plan prolong let go ofing dose signifier in order to cut down the frequence of dosing and inauspicious effects, particularly since continuance of intervention is typically longer for NSAIDS. It is been reportedly known that sustained release preparations of KT such as, sustained release tablet, [ 6 ] transdermic [ 7 ] , rhinal pulverization [ 8 ] , gel [ 9 ] and microspheres [ 10 ] , liposomes [ 11 ] , osmotic tablets [ 12 ] , optic gel [ 13 ] , parenteral microspheres [ 14 ] etc. have been attempted by many research workers. Preparation of mucoadhesive microspheres could be advantageous scheme so as to supply an intimate contact between the drug bringing system and the mucosal membrane. This could be achieved by integrating a mucoadhesive agent in the polymer anchor of microspheres.
Assorted efforts have been made in order to fix mucoadhesive microspheres by spray drying technique utilizing hydroxyl propyl methyl cellulose, carbopol, chitosan, hydroxyl propyl cellulose, polycarbophil with first-class mucoadhesive belongingss ( Harikarnpakdee et al. , 2006 ; Sakagami et al. , 2002 ; Desai & A ; Park, 2005 ) . [ 15,16,17 ] The aim of the present survey was to fix the KT-loaded microspheres by the spray-drying method utilizing Carbopol ( CP ) , Chitosan ( CS ) and Polycarbophil ( PL ) . Prepared microspheres were characterized for their surface morphology, swelling behaviour, mucoahesion, drug release proi¬?le and ex vivo nasal cilio toxicity by utilizing appropriate appraising surveies.
Materials and Methods
Ketorolac tromethamine ( KT ) was obtained as a gift sample from Symed Labs Limited, Hydrabad, ( India ) . Carbopol 974A® PNF ( CP ) and Noveon AA-1 ( Polycarbophil, PL ) were obtained as a gift sample from Lubrizol Advanced Materials Inc, Mumbai ( India ) . Chitosan, & gt ; 85 % deacetylation, was kindly contributed from the Central Institute of Fisheries Technology, Kochi, India. All other reagents and dissolver were of analytical class and used without purification.
Preparation of Ketorolac mucoadhesive microspheres
Mucoadhesive microspheres were prepared by spray drying of scattering utilizing a LU-222 spray desiccant ( Lab Ultima, India ) with a standard 0.7 millimeter nose. [ 15 ] For the scattering system, CP and PL were solubilized in de-ionized H2O at different concentrations and CS was solubilized in 1 % v/v aqueous acetic acid solution. KT was dissolved in each polymeric solution per Se, in order to accomplish desired drug-to-polymer ratio of 1:4 and 1:5. The preliminary experiments were carried out to analyze the effects of procedure and preparation parametric quantities on the output and atom size of the resulting microspheres, were studied by puting the pump rate ( 5, 10 and 15 mL/min ) , inlet temperature ( 140° , 160° and 180A°C ) and drug-to-polymer concentration ( 1:4 and 1:5 ) . Each preparation was prepared in triplicate for farther surveies.
Twenty five milligrams of accurately weighed drug loaded mucoadhesive microspheres were added to 100 milliliter of 0.1 N HCl. [ 14 ] The resulting mixture was kept agitating on a mechanical shaker for 24 hour. Then the solution was filtered and 1 milliliter of this solution was suitably diluted with 0.1 N HCl and analyzed spectrophotometrically at 322 nanometer. The drug encapsulation efficiency was calculated utilizing equation ( 1 ) :
. [ 1 ]
Particle size of prepared microspheres was determined utilizing Microscopic imaging analysis technique. [ 18 ] Particle size distribution of microspheres was performed utilizing an AXIOPALN microscope ( Zeiss MPM400 Germany ) that is equipped with a computer-controlled image analysis system ( Zeiss KS300 Germany ) .
Scaning negatron microscope ( SEM )
A scanning negatron microscope ( ESEM TMP with EDAX, Philips, Holland ) was used to qualify the surface topography of the microspheres. The microscope was equipped with electron optical system ( EOS ) dwelling of 0.5-30 kilovolt capacity negatron gun and an negatron sensor. The microspheres were placed on a metallic support with a thin adhesive tape and were coated with gold under vacuity. The surface was scanned and exposures were taken at 30kV speed uping electromotive force for the drug loaded microspheres.
The swelling ability of the microspheres in physiological media was determined by leting the microspheres to swell to their equilibrium. [ 19, 20 ] Accurately weighed sums of microspheres were immersed in a small surplus of Phosphate buffer ( pH 6.6 ) and kept for 24 hour. The undermentioned expression was used for computation of per centum of puffiness:
aˆ¦aˆ¦aˆ¦aˆ¦.. [ 2 ]
Where, Ssw = Percentage puffiness of microspheres ; Wo = initial weight of microspheres ; and Ws = weight of microspheres after swelling.
Mucoadhesion of different microspheres system was assessed utilizing the method reported by Jain SK et Al [ 19 ] with small alteration. A strip of sheep nasal mucous membrane was mounted on a glass slide and accurately weighed bioadhesive microspheres in scattering signifier was placed on the mucous membrane of the bowel. This glass slide was incubated for 15 min in a desiccator at 90 % comparative humidness to let the polymer to interact with the membrane and eventually placed in the cell that was attached to the outer assembly at an angle 45° . Phosphate buffer saline ( pH 6.6 ) , antecedently warmed to 37 A± 0.5 °C, was circulated to the cell over the microspheres and membrane at the rate of 1 mL/min. Washs were collected at different clip intervals and microspheres were separated by centrifugation followed by drying at 50 °C. The weight of microspheres washed out was taken and per centum mucoadhesion was calculated by the undermentioned expression:
aˆ¦.. [ 3 ]
Where, Wo = Weight of microspheres applied ; Wt = Weight of microspheres washed out.
Fourier Transform Infrared Spectroscopy ( FTIR )
The spectra were recorded for pure drug, drug loaded microspheres and clean microspheres utilizing FTIR. Samples were prepared in KBr discs ( 2 milligram sample in 200 milligrams KBr ) . The scanning scope was 400 – 4000 centimeter -1 and the declaration was 2 cm-1.
Differential Scanning Calorimetry ( DSC )
Differential scanning calorimetry scans of drug, clean microspheres and drug loaded microspheres were performed utilizing DSC-PYRIS-1. The analysis was performed with a warming scope of 50 – 300oC and a rate of 10 oC min-1.
In vitro diffusion survey
The in vitro drug release trial of the pure drug ( KT ) and prepared microspheres was carried out utilizing an setup called Franz diffusion cell. [ 20,21 ] A dialysis membrane ( cut-off Mw 12,000 ) was placed between the microspheres sample and receptor compartment incorporating phosphate buffer solution ( pH 6.6 ) . The KT loaded microspheres tantamount to 10 milligram of KT were applied to the dialysis membrane. The volume of the receptor compartment was 20 milliliter, which is similar to that of a rhinal pit. The temperature of the receptor medium was adjusted to 37A±1 0C. The content of the receptor compartment was continuously stirred with a magnetic scaremonger. Aliquot of a 1.0 milliliter were withdrawn from the receptor compartment at hourly intervals for 8 hours and replaced with the same sum of fresh buffer solution. The aliquot was analyzed for the drug content at 322 nanometers after appropriate dilutions against mention utilizing phosphate buffer saline pH 6.6 as space. All experiments were performed in triplicate.
In order to understand the mechanism and dynamicss of drug release, the consequences of the in vitro drug release survey were fitted with assorted kinetic equations. [ 22 ] The kinetic theoretical accounts used are zero-order, first-order, Higuchi matrix, and Baker and Lonsdale models19. The Higuchi square root of clip theoretical account has been derived from Fick ‘s first jurisprudence of diffusion and is suited for the mold of drug release from a homogenous planar matrix, presuming that the matrix does non fade out. The Baker and Lonsdale theoretical accounts drug release from diffusion rate-limiting matrixes of spherical form. In order to specify a theoretical account which will stand for a better tantrum for the preparation, drug release informations were analyzed by Peppas equation. r2 values were calculated for the additive curves obtained by arrested development analysis of the above secret plans.
Ex-vivo Nasal cilio toxicity of mucoadhesive microspheres
Newly excised sheep nasal mucous membrane, except for the septum, was collected from the slaughter house in saline phosphate buffer pH 6.6. [ 23,24 ] Four sheep nasal mucous membrane pieces ( N1, N2, N3, N4 ) with unvarying thickness were selected and mounted on Franz diffusion cells. N1 was treated with 0.5 milliliters of saline phosphate buffer pH 6.6 ( negative control ) ; N2 with 0.5 milliliters of isopropyl intoxicant ( positive control ) , N3 with 0.5 milliliters of KT in phosphate buffer pH 6.6 and N4 with 0.5 milliliters of KT loaded polymeric microspheres for 1 hour. After 1 hour, the mucous membrane was treated with saline phosphate buffer pH 6.6 and subjected to histological surveies to measure the toxicities of KT loaded polymeric microspheres.
After remotion of the sheep nasal mucous membrane from diffusion cell, the tissues were placed in 10 % buffered formaldehyde solution, fixed for 72 hour. For the intent of histological survey, tissues were dehydrated in go uping grades of ethylalcohol ( 70, 80, 90, 96, and 99 % v/v ) and consecutive embedded in paraffin wax blocks harmonizing to the standard process, sectioned at 5 Aµ thickness. They were further deparaffined with xylol, and histologic observations were performed after staining for functional nasal tissues by hematoxylin-eosin. The slides were examined utilizing light microscope.
All the reported findings were performed in triplicate. One-way analysis of discrepancy ( ANOVA ) followed by Tuckey ‘s multiple scope trial was performed to find the least important difference for all the reported ratings. The differences were considered as important at P & lt ; 0.05.
Effectss of procedure variables on the features of the microspheres
The consequences of the influence of readying parametric quantities on the features of the mucoadhesive microspheres are shown in Table 1. It was apparent from the survey that procedure variables such as drug to polymer ratio, recess temperature and pump flow rate greatly affect the size and output of microspheres. The different polymer concentrations were employed for the readying of microspheres but low polymer concentrations ( 1:1 to 1:3 ) was non able to give the coveted atom size as the droplet size was little and most of the portion of bead consisted of dissolver which would vaporize go forthing the little atoms ( informations non reported ) . Therefore, the polymer concentration was increased and optimized at 1:4 and 1:5 w/v for different preparations. The inlet temperature did non supply any influence on atom size by altering the temperature from 140 to 180 A°C but it greatly affected output of the attendant microspheres as revealed from the tabular array 1. We found the optimal output at 160 A°C for mucoadhesive microspheres with several polymers. The size of the prepared microspheres under the status of a faster pump rate was big. It might be attributed to the formation of larger droplets during the procedure. There was an evident lessening in atom size from 18.03 to 11.27 Aµm for CP microspheres, 17.20 to 9.47 Aµm for PL microspheres, 18.90 to 12.35 Aµm for CS microspheres when the air flow rate was increased from 5 to 15 ml/min. hence, the processing conditions were selected from preliminary experiments as follow: recess air temperature of 160 °C, pump scene of 10 ml/min, force per unit area saloon at ~ 2 standard pressure.
KT loaded microspheres were produced with a high drug encapsulation efficiency ( Table 2 ) . The sum of KT encapsulated in the microspheres was in the scope of 79.03 A± 3.08 and 92.19 A± 3.21 % . More efficient drug burden was achieved for microspheres that were prepared from Chitosan than for those prepared from Carbopol or Polycarbophil. Furthermore, a important difference ( p & lt ; 0.05 ) in the entrapment efficiency with ( SDKTS2 ) was observed when compared it with mucoadhesive microspheres prepared with CP and PL microspheres. Spray drying technique is by and large characterized by high drug encapsulation efficiency [ 23 ] .
Particle size and SEM
The atom size of prepared mucoadhesive microspheres is shown in Table 1. Average sizes of the microspheres preparations ranged from 10.29 to 16.75 Aµm. Microspheres prepared with PL and CS as polymer did non demo any singular differences in footings of size. SEM photomicrographs of KT loaded CP, PL and CS microspheres are reported in Figure 3. SEM analysis of the samples revealed that all prepared microspheres had spherical form and similar surface morphology, irrespective of the type and/or polymeric composing of spray-dried systems. The SEM images indicated towards smooth, nonporous and spherical microspheres. Some of the atoms appeared to be in sums, but without verification of any fall ining atoms.
The grade of swelling ( Ssw ) in mucoadhesive microspheres of drug in microspheres controlled the burden and release features of prepared microspheres, therefore the puffiness of microspheres was evaluated as shown in Figure 3. There was no important difference between swelling belongingss of KT-loaded CP and PL microspheres, due to hydrophilic nature of KT. The microspheres prepared with CP and PL reveal maximal grade of puffiness of 398 % ( SDKTC2 ) and 408 % ( SDKTP1 ) severally. While, maximal grade of swelling was decreased for CS microspheres to 372 % ( SDKTS2 ) . Harmonizing to consequences of one manner ANOVA test the swelling profiles of prepared mucoadhesive microspheres was found to be different ( p & lt ; 0.05 ) at each clip point.
Mucoadhesion surveies were carried out to guarantee the adhesion of the microspheres to the mucous membrane for a drawn-out period of clip at the site of soaking up. The consequences of in-vitro mucoadhesion trials, expressed as per centum of affiliated microspheres are reported in Fig. 3. The consequences showed that the microspheres had good mucoadhesive belongingss as the per centums found in the scope of 73-89 % and could adequately adhere on rhinal mucous membrane. The mucoadhesion of prepared microspheres were ranked, CS & gt ; CP & gt ; PL microspheres. Microspheres based on chitosan ( SDKTS1 ) possessed significantly ( P & lt ; 0.001 ) higher adhesion than CP and PL microspheres.
FTIR and DSC
The IR spectra of prepared microspheres were recorded in comparing with IR spectra of both pure KT and clean microspheres. The IR spectra of KT showed extremums at 3360, 1588 and 1278 nanometer stand foring the -COOH stretching, -C=O stretching and -C-N stretching severally. The extremums at 1561 nanometer and 730 nanometer showed as major extremums for drug. All the above extremums were present in drug loaded microspheres that confirms the presence of drug in the polymer without any interaction.
The thermic behaviours of prepared microspheres were recorded in comparing with thermograms of both pure KT and clean microspheres. The DSC-thermogram of pure KT showed endothermal extremum at 159 A°C, matching to its runing point. KT loaded polymeric microspheres exhibited a individual thaw extremum at 153 A°C due to presence of KT in polymeric matrix. However there was little lessening in the thaw point of drug when prepared in the signifier of microspheres. The rating of the thermograms obtained from DSC revealed some interaction between the polymer and the drug in the microspheres.
In vitro diffusion survey
The in vitro release profiles obtained from the drug-loaded microspheres, compared to the release profile of the drug entirely is shown in fig. 4. The rate of disintegration of KT pulverization was significantly faster ( about more than 98 % of the drug dissolved in 2 H ) . The burden of KT into polymeric matrices led to drawn-out dissolution/release rate. The lessening in the rate of release was dependent on the sort of polymer used and on the drug to polymer ratio. In fact, about 85-95 % of released drug was achieved up to 8 H from the spray-dried microspheres.
Harmonizing to the consequences of one-way ANOVA, the drug release was found to be significantly different at each clip degree ( P & lt ; 0.001 ) every bit good as among the drug merchandises ( P & lt ; 0.05 ) implying that the disintegration profiles were non parallel ( Figure 5 ) . Harmonizing to consequences of, Tukey ‘s Multiple Range trial, it was found that the per centum released of prepared microspheres demonstrated statistically different ( P & lt ; 0.05 ) at the clip points after 30 min ( & gt ; 20 % drug release ) , 4 H ( & gt ; 50 % drug release ) and 8 H ( & gt ; 85 % drug release ) . It is revealed from the consequences of the one-way ANOVA method that the release profiles had differing forms, in footings of class of release and per centum released, SDKTS1 demonstrated the satisfactory drug release belongings.
The in vitro release informations obtained were fitted in to assorted kinetic equations. Correlations of single batch with applied equation are given in Table 4. The release rates were determined from the incline of the appropriate secret plans. All the prepared microspheres showed higher correlativity with Higuchi secret plan than zero order and first order. To happen out release mechanism the in vitro release informations were applied in Korsmeyer-Peppas equation. The release advocate N was determined and given in Table 4. Microspheres prepared with CP and CS demonstrated ( n & lt ; 0.5 ) fickian diffusion. While microspheres prepared with PL showed ( n & gt ; 0.5 ) anomalous ( non-fickian ) diffusion.
Nasal Cilia Toxicity
The batches which demonstrated a satisfactory encapsulation, mucoadhesion and drug release belongings from among all the prepared batches were chosen for ex vivo tests. Nasal cilio-toxicity surveies were carried out in an effort to measure the possible toxic effects of excipients and KT used in the preparations on the rhinal mucous membrane. The rhinal mucous membrane treated with phosphate buffer pH 6.6 ( negative control ) showed no nasocilliary harm and the rhinal membrane remained integral, whereas an extended harm to nasal mucous membranes coupled with loss of rhinal cilia was observed with positive control. However, the application of KT on nasal mucous membrane showed mild rhinal mucosal harm associated with loss of few rhinal cilia. No evident nasal mucosal harm was observed in rhinal mucous membrane treated with KT loaded microspheres, therefore confirming the safety of the excipients and drug used in the preparations.
Spray drying is an of import method for the readying of rhinal microspheres. It will give rise to microspheres in which active drug will be in the matrix of the polymer. In this survey mucoadhesive microspheres were prepared by utilizing three different polymers viz. , CP, PL and CS. The ideal microsphere particle size demand for rhinal bringing should run from 10 to 50 Aµm as smaller atoms than this will come in the lungs. [ 25 ] In order to optimise the atom size and output, we carried out spray drying procedure by changing the procedure parametric quantities viz. , inlet air temperature, pump flow rate and drug to polymer ratio.
The influence of the concentration of polymers on the atom size and output studied at two different concentrations with the same sum of drug. Increasing the concentration of the polymers resulted in an addition in atom size. This is due to the greater sum of polymers enclosed in the same volume of a liquid droplet as the concentration of polymers is increased. These consequences are understanding with those of Pavenetto et Al. ( 1994 ) , Wagenaar and MuA? ller ( 1994 ) . [ 26 ] A alteration in the recess temperature of the equipment can impact the drying rate. Therefore, survey was carried out utilizing three degrees of the recess temperature i.e. 140, 160, 180A°c and the effects were observed. The addition in the recess temperature of the equipment shows minimum diminution of the mean atom size. The influence of pump rate on atom size was studied by utilizing three degrees of the pump velocity i.e. 5, 10, 15 ml/min. Average particle size of microspheres is increased as flow rate is increasing. This may be due to the formation of the bigger droplets as more sum of the liquid is available for the crop-dusting. But the output of the merchandise decreases with addition in the flow rate, which may be due to the loss of the merchandise in the un-dried signifier due to deposition on the drying chamber walls since bigger droplets require more drying clip to organize microspheres. [ 25 ]
High encapsulation efficiency of the microspheres may be due to formation of more integral matrix web by the spray drying procedure. This slows down the diffusion of extremely H2O soluble KT in the aqueous solution in which the microspheres are prepared. Percentage encapsulation efficiency for microspheres prepared with CP and PL as polymer was lower as compared to CS as polymer and was decreased as polymer sum increased this may be due to saturation concentration [ mucoadhsive ; cp glipzide and metoprlol Cp Pl ] . [ 26,27,28 ]
The microspheres were unvarying in size for each batch. Particle size was chiefly governed by the polymer concentration. Particle size increased with increasing polymer concentration which may be due to increased viscousness of the scattering, which affects the public presentation of crop-dusting of the mixture and consequences in the formation of larger droplets. There were no drug particles on the surface of the microspheres, and no marks of recrystallization or collection were observed. The surface of the drug-free microspheres was smooth. [ muco pl Glucotrol ] [ 29 ]
Different swelling behaviour of KT loaded mucoadhesive microspheres can be explained by sing the province of the polymers every bit good as the drug to polymer ratio. The high swelling belongings of CP and PL microspheres could be attributed to their ionised ability to uncoil the polymer into an drawn-out construction. High molecular weight of CP and PL could be the possible ground for higher puffiness of CP and PL microspheres than CS microspheres. However, the swelling capacity of the PL microspheres increased well on increasing the sum of PL, which was comparable to old surveies performed by utilizing PL as polymer. The H2O consumption in hydrogels depends upon the extent of hydrodynamic free volume and handiness of hydrophilic functional groups for the H2O to set up H bonds. [ 30,31,32 ]
Highest mucoadhesion of CS microspheres may be due to electrostatic attractive force between CS and mucin. This can be evidenced from strong interaction between CS microspheres and mucose glycoprotein and/or mucosal surfaces. Mucoadhesion of CS microspheres increases because more sum of polymer consequences in higher sum of free -NH2 groups, which are responsible for adhering with sialic acid groups in mucous secretion membrane and therefore consequences in addition in mucoadhesive belongingss of microspheres. Decrease in mucoadhesion of CP microspheres after KT incorporation could be explained by lower polymer concentration in the matrix. CP microspheres had negative charge in phosphate buffer ( pH 6.6 ) , doing negative charge repulsive force with mucous secretion, legion hydrophilic functional groups such as carboxyl groups in CP molecules could organize hydrogen bonds with mucose molecules, therefore bring forthing some adhesive force of this polymer. Mucoadhesion of PL microspheres was hapless this may be due to its nonionized belongings and the presence of the drug molecule could forestall formation of H bonds, which are responsible for mucoadhesion. In add-on type, sum, and molecular weight of polymer might hold played a important function on mucoadhesion. [ 33,34,35 ]
The consequence of different polymers on the belongingss of microspheres can be visualized through in vitro drug release form of microspheres in a much better manner. Swelling of microspheres is an of import factor impacting the diffusion of integrated drug. It has been found that drug diffusion in extremely hydrated CP and PL microspheres is faster than that in less hydrous CS microspheres. Slow cumulative drug release from microspheres may be attributed to the addition in the denseness of the polymer matrix and besides an addition in the diffusional way length that the drug molecules have to track. The polymeric gel might hold acted as a barrier to incursion of the medium, thereby stamp downing the diffusion of KT from the conceited polymeric matrix. It may be demonstrated that high swelling ability of KT loaded microspheres, big contact surface between conceited microspheres and little nucleuss due to spray-drying lead to similar release profiles for all the microspheres. [ 36,37,38 ]
For all preparations no terrible harm was found on the unity of nasal mucous membrane ( Fig. 4 ) . The ascertained alterations on rhinal mucous membrane can be summarized as epithelial tissue break and complete loss of some parts of the epithelial tissue ( Fig. 4 ) . Morphologic alterations in the nasal epithelia exposed to microspheres were milder than those exposed to KT entirely and Isopropyl intoxicant ( Fig. 4 ) . The difference seems to lie in the preparation, i.e. , there would be negative effects when the KT is applied in the signifier of a pulverization as opposed to when the application is in microspheric signifier. Besides this consequence reveals the fact that the mucous membrane remains integral after the microsphere exposure and retains a good morphology. The indecent consequence of KT pulverization may be due to its acidic construction [ 23,24 ] .