The purpose of the research was to develop a polyose based compaction coated tablet of Secnidazole. Core tablets of Secnidazole were compaction coated with assorted proportions of Guar gum, Xanthan gum and Chitosan. Drug release surveies were performed in fake stomachic fluid ( SGF ) for 2 H followed by fake enteric fluid ( SIF ) ( phosphate buffer pH 7.4 ) up to 24 h. The disintegration informations demonstrated that the rate of drug release is dependent upon the nature and concentration of polymer used in the preparation. The tablets coat incorporating cluster bean gum or xanthan gum entirely showed 30-40 % drug release in 8 h. The tablets incorporating cluster bean gum or xanthan gum with chitosan or combination of cluster bean gum, xanthan gum and chitosan showed merely 30-45 % drug release in 8 h. Further, in vitro disintegration surveies performed in the disintegration media with rat caceal contents showed 54.48±0.24-60.42±0.16 % of drug release. The drug release from the prepared preparations followed super-case ?†?† conveyance.
Amebiasis is an infection of the big bowel caused by Entamoeba histolytica, a individual celled protozoon parasite. The trophozoite signifier E. histolytica can occupy the colonic epithelial tissue ; doing amebic inflammatory bowel disease [ 1 ] . Secnidazole, tinidazole, ornidazole and metronidazole are preferred drugs used in the intervention of enteric amebiasis, giardiasis and tricomoniasis [ 2 ] . These drugs are delivered to the colon for their effectual action against E. histolytica. Secnidazole is wholly absorbed after unwritten disposal. The disposal of this drug in conventional tablet dose signifier provides minimum sum of Secnidazole for local action in the colon, still ensuing in the alleviation of amebiasis, but with unwanted side effects like metallic gustatory sensation, glossitis, sickness, purging and abdominal hurting [ 3,4 ] . Therefore, the targeting of Secnidazole to the colon for local action may be good in avoiding the unwanted side effects every bit good as a lower dosage of Secnidazole may be sufficient to handle amebiasis [ 4 ] .
The bringing systems intended to let go of drugs in the colon require protection of the drug from the hostile environment of tummy and little bowel. This mark specific release is required for the topical intervention of diseases associated with colon such as amebiasis, ulcerative inflammatory bowel disease, Crohn ‘s disease and colon malignant neoplastic disease. This is because the colon provides a less volatile environment for drugs caused by the low diverseness and strength of digestive enzymatic activities every bit good as close impersonal pH [ 1 ] .
Site-specific drug bringing to colon may hence be achieved by different attacks. Which include covalent linkage of a drug with a bearer, surfacing with pH-sensitive polymers, clip dependent release systems and the usage of bearers that are degraded entirely by colonic bacteriums [ 5 ] . Enteric coated systems are the most normally used for colonic drug bringing, but the disadvantage of this system is that the pH difference between little bowel and colon is non being really pronounced. The restriction of clip dependent release system is that it is non able to feel any fluctuation in the upper gastro-intestinal piece of land theodolite clip, any fluctuation in stomachic emptying clip may take to drug release in little bowel before reaching to colon. Apparently, the most convenient attack for site-specific drug bringing to colon is the usage of bearers that are degraded entirely by colonic bacteriums [ 5,6 ] .
To better the specificity of drug release, several polyoses are investigated as bearers for colonic drug bringing like pectin [ 5 ] , chondroitin sulfate [ 7,8 ] , amylose [ 9 ] , inulin [ 10 ] , guar gum [ 11,12 ] , locust bean gum [ 13 ] , khaya gum [ 14 ] , chitosan [ 15,16 ] , xanthan gum [ 1,13 ] and others.
The present work was done by utilizing the cheap, of course and copiously available cluster bean gum ( GG ) , xanthan gum ( XG ) and chitosan ( CHN ) for colon targeted bringing of secnidazole. Guar gum is a natural non-ionic polyose derived from seeds of Cyamopsis tetragonolobus. Guar gum is reported as a colon-specific drug bearer in the signifier of a matrix tablets [ 11 ] . Xanthan gum is high molecular weight excess vascular hetero polyose produced by agitation with gram negative bacteria Xanthomonas campestris. Xanthan gum is reported for colon specific drug bringing in the signifier of compaction coated tablets [ 1,13 ] . Chitosan is a natural polymer obtained by alkalic deacetylation of chitin, is non-toxic, biocompatible and biodegradable. Chitosan could be assuring for colonic bringing if its solubility is reduced in stomachic acerb conditions. This could be accomplished by uniting with non-water-soluble polymers [ 15 ] .
MATERIALS AND METHODS
Secnidazole was obtained as gift sample from Magnus Pharma Pvt. Ltd, Nepal. Sodium amylum glycollate was obtained as gift sample from Wockhardt research Centre, Aurangabad. Guar gum and microcrystalline cellulose were purchased from SD all right chemicals, Mumbai. Xanthan gum and Chitosan ( Mw 45 kDa, 87 % DD ) were purchased from Himedia laboratories Ltd, Mumbai. All other chemicals used were of analytical class.
Preparation of fast disintegrating nucleus tablets:
The nucleus tablets of secnidazole were prepared by direct compaction technique utilizing the composing given in Table 1. Secniazole, Na amylum glycolate, micro crystalline cellulose, Mg stearate and talc were exhaustively mixed in a polybag and passed through sieve no # 80 ( 179 µm ) to guarantee complete commixture. Sodium amylum glycolate was added to obtain a fast disintegrating tablet. The mixture was compressed in to tablet on a individual station tablet pluging machine ( M/s Cadmach, India ) utilizing 9.5 millimeter unit of ammunition, flat-faced and apparent clouts.
Preparation of compaction coated tablets:
The composing of compaction surfacing stuff is shown in Table 2. All the ingredients of each coat preparation were weighed accurately and assorted in a polybag. 40 % weight of entire weight ( 250 milligram ) of surfacing mixture was placed in the die pit of individual station tablet pluging machine, the nucleus tablet was placed on it at Centre, staying 60 % of surfacing mixture was added to the dice pit and tablets were compressed utilizing 12.6 mm level clouts. The entire weight of the compaction coated tablet was about 400 milligrams.
Evaluation of tablets:
Thickness and Diameter:
The thickness and diameter of the tablets was determined by utilizing dial thickness setup and Vernier callipers severally. Five tablets from each preparation were used and mean values were noted.
Tablet hardness of all the preparations was determined by utilizing Monsanto hardness examiner. Five tablets from each preparation were used and mean values were recorded.
Both nucleus and compaction coated tablets from all preparations were subjected for crumbliness trial utilizing friabilator. Ten tablets were weighed ( W0 ) and placed inside the Roche friabilator. The instrument was operated for 4 mins at 25 revolutions per minute. The ensuing tablets after 100 falls from a tallness of six inches were collected ; weighed ( Wt ) and per centum loss was calculated utilizing following equations.
Wo – W T
Percent crumbliness = — — — — — — — — * 100
Weight fluctuation trial:
The weight fluctuation surveies of the prepared preparations was performed as per the standard process following Indian pharmacopoeia [ 16 ] . The sample mean and standard divergence of each batch of tablets were reported.
Determination of drug content:
One tablet from each preparations of compaction coated and the nucleus tablets were powdered and transferred in to 100 milliliters volumetric flask. Initially 50 milliliter of phosphate buffer ( pH 7.4 ) was added and allowed to revolve in a rotary shaker for 24 H ; the concluding volume was made up with phosphate buffer ( pH 7.4 ) . The solution was filtered appropriately and sum of secnidazole nowadays in the solution was estimated by utilizing UV- spectrophotometer ( UV 1601, Shimadzu, Japan ) at 320 nanometers against a suited space.
One tablet from each preparation was indiscriminately selected, weighed separately ( W1 ) and placed individually in a wire basket which was placed in a 100 milliliter beaker incorporating 0.1 N HCl for first 2 H and subsequently pH 7.4 ( 24 H ) . After 2, 4, 6, 8 and 24 H the tablets were removed from wire basket and extra H2O was removed utilizing filter paper. The conceited tablets were reweighed ( W2 ) and swelling index of each tablet was calculated utilizing the below equation.
( W2- W1 )
% Swelling Index = — — — — — — — – * 100
Preparation of 2 % rat caecal content:
Male wistar rats weighing 150-200 gram maintained on a normal diet were used for the survey. Rats were asphyxiated utilizing C dioxide. The venters were opened, ceci were traced, ligated at both terminals, dissected instantly and transferred in to phosphate buffer ( pH 7.4 ) antecedently bubbled with CO2. The caecal bags were opened and the contents were separately weighed pooled and so suspended in a phosphate buffer to supply 2 % ( w/v ) dilution, all of these operations were performed under changeless supply of CO2 ambiance.
In vitro drug release survey:
Dissolution experiments were carried out in a USP basket type setup at 100 revolutions per minute at 37±1 & A ; deg ; C. Drug release surveies were conducted in 900 milliliter of 0.1N HCl for the initial 2 H, followed by phosphate buffer ( pH 7.4 ) up to 24 h. Samples of 10 milliliters were withdrawn at preset clip intervals and were replaced with fresh disintegration medium to keep sink conditions. Samples withdrawn were filtered and assayed spectrophotometrically at 277 nanometers and 320 nanometer in SGF and SIF severally.
In order to measure the susceptibleness of cluster bean gum and xanthan gum, being acted upon by colonic bacteriums, drug release surveies were besides carried out in presence of rat caecal content because of the similarity with human enteric vegetation. In vitro drug release surveies in the presence of rat caecal contents were same as mentioned above except that rat caecal content ( 2 % w/v ) was added merely to phosphate buffer ( pH 7.4 ) , to imitate colonic status.
In vitro release informations were fit to first order, zero order and higuchi equations to analyze the dynamicss of drug release from the tablets. Further, in vitro release consequences were fit to the undermentioned Koresmeyer-Peppas equation, to analyze drug release mechanism.
Mt/M? = Ktn
Where Mt/M? is the fraction of drug released at clip T, K is kinetic changeless and ‘n ‘ is release advocate that characterize the drug conveyance.
Stability of the preparations was assessed by hive awaying preparations F1, F5 and F11 at 40 & A ; deg ; C/75 % RH for 6 months. At the terminal of survey period, preparations were observed for physical alteration, drug content and in vitro drug release.
The disintegration informations, performed with and without rat caecal content was statistically analysed utilizing pupils t-test. A value of P & A ; lt ; 0.05 was considered statistically important.
RESULTS AND DISCUSSION
The present survey was aimed at developing unwritten colon targeted preparations for Secnidazole utilizing different polyoses. Further, it was aimed to place the most suited polyose either entirely or in combinations for colonic bringing of secnidazole based on microbic debasement. Ideally, the drug bringing system targeted to colon should stay integral in the tummy and let go of the drug in the colonic part. Hence efforts were made to explicate the compaction coated tablets utilizing guar gum, xanthan gum, chitosan, either entirely or in combination.
Consequences of drug content, hardness, thickness, diameter and crumbliness of nucleus tablets and all compaction coated preparations are shown in Table 3. All the preparations showed a hardness value in the scope of 5.67±0.15 to 6.23±0.15 kg/cm2 ; it indicates that the hardness is depending on the measure and type of polyose used in the tablet. The hardness of nucleus tablets of secnidazole was found to be 2.8±0.01 kg/cm2. The per centum crumbliness of all preparations was found in the scope of 0.86±0.04 to 0.98±0.03 % ; bespeaking that the crumbliness is within the acceptable bounds. In instance of nucleus tablets the per centum crumbliness was more and it was found to be 3.06±0.12 % , because nucleus tablets holding lower hardness and fast decomposition features. The consequences of weight fluctuation of tablets for all preparations was found in the scope of 396.67±3.51 to 402.33±2.08 milligrams and in instance of nucleus tablets it was found to be 152.67±3.51 milligram ; bespeaking that the weight fluctuation is within the acceptable bounds. The per centum drug content both for nucleus tablets and compaction coated tablets of all preparations was found in the scope of 98.39±0.58 to 101.17±1.18 % . The decomposition clip was measured for nucleus tablet and it was found to disintegrate within 60 sec.
Swelling survey was performed for all preparations for 24 Hs in two different buffer media. Swelling surveies was done for first 2 H in 0.1N HCl ( pH 1.2 ) and later in phosphate buffer ( pH 7.4 ) . The swelling behaviour was dependent upon the polymer or combination of the polymers used for surfacing the nucleus tablet. In instance of the preparations F1 ( GG ) , F2 ( XG ) and F3 ( CHN ) , the swelling index after 24 Hs were 478.09±14.02 % , 1089.01±9.07 % and 149.33±11.91 % , severally ( Table 4 ) . In instance of combination of guar gum and chitosan the swelling index for the preparation F4, F5, F6 and F7 at 0.1N HCl after 2 Hs were 243.33±4.95 % , 168.12±4.87 % , 154.2±29.16 % and 140.15±10.23 % , severally, and at pH 7.4 after 24 Hs were 388.79±8.11 % , 394.05±14.96 % , 422.62±21.55 % and 470.01±13.44 % , severally. The information indicates that as chitosan proportion in the coating bed additions, the swelling index besides increases in stomachic status ( 0.1N HCl ) , but it decreases in colonic conditions ( pH 7.4 ) . In instance of combination of xanthan gum and chitosan, the swelling index for the preparation F8, F9, F10 and F11 at 0.1N HCl after 2 Hs were 262.53±6.06 % , 150.42±6.30 % , 141.46±4.35 % and 127.52±5.59 % , severally, and at pH 7.4 after 24 Hs were 737.65±8.45 % , 850.19±2.94 % , 959.44±12.24 % and 1009.18±10.75 % , severally. At the terminal of 24 H, preparation F11 with higher proportion of xanthan gum has shown highest swelling. This is potentially because of high swelling ability of xanthan gum, as the concentration of xanthan gum was increased swelling index was besides increased. In instance of combination of all three polymers, the swelling index for the preparation F12, F13, F14 and F15 after 24 Hs were 386.47±7.27 % , 416.04±10.43 % , 576.68±5.57 % and 472.10±7.03 % , severally. The information indicates that the preparation F14 incorporating equal proportion of cluster bean gum and xanthan gum ( each at 75 milligram ) was more conceited compared with other preparations.
It was observed that as the proportion of cluster bean gum and xanthan gum was increased, the per centum swelling index increased due to hydrophilic nature of the polymer. As the sum of polymer increased sum of H2O soaking up was besides increased, ensuing in high swelling index.
In vitro release surveies:
In instance of preparations with individual polymer, the sum of drug released from the preparation F1 ( GG ) and F2 ( XG ) after 8 Hs were 38.39±1.23 % and 32.29±0.1 % severally, and after 24 Hs were 87.59±0.92 % and 87.07±0.91 % , severally ( fig. 1 ) . Although, at the terminal of 8 H higher sum of drug was released from preparation incorporating guar gum ( F1 ) , at the terminal of 24 H there was no important difference in sum of secnidazole released. This is likely because xanthan gum requires more clip ( ? 50 H ) to wholly swell compared to guar gum ( 24 H ) [ 1 ] . Formulation F3 incorporating chitosan entirely was non possible to aim the drug for colonic part, as 99.13±0.79 % drug was released in stomachic status ( 0.1N HCl ) itself.
In instance of combination of guar gum and chitosan, the sum of drug released from the preparation F5, F6 and F7 at 0.1N HCl after 2 Hs were 5.86±0.25 % , 5.86±0.07 % and 5.14±0.17 % , severally, and at pH 7.4 after 8 Hs were 41.61±0.16 % , 41.79±0.45 % and 42.60±0.31 % , severally, and after 24 Hs were 97.89±0.62 % , 94.59±0.93 % and 93.57±1.24 % , severally ( fig. 2 ) . It is apparent from fig. 2, that the preparation F4 incorporating chitosan is more than 50 milligram in surfacing stuff resulted is 98.43±1.35 % drug release in stomachic status ( 0.1N HCl ) itself ; so the preparation F4 was considered as non suited for colonic bringing. From the release data it indicates that the preparation F5 incorporating 50 mg chitosan releases less sum of drug in fake tummy status and higher sum of drug release in fake colonic status.
In instance of combination of xanthan gum and chitosan, the sum of drug released from the preparation F9, F10 and F11 at 0.1N HCl after 2 Hs were 4.17±0.11 % , 3.95±0.15 % and 3.51±0.15 % , severally, and at pH 7.4 after 8 Hs were 37.42±0.60 % , 38.03±0.59 % and 32.13±1.36 % , severally, and after 24 Hs were 96.25±1.81 % , 92.83±1.20 % and 91.25±2.72 % , severally ( fig. 3 ) . The release informations indicates that the preparation F9 incorporating 50 mg chitosan in surfacing stuff gives higher drug release in colonic status compared to other preparations. If the proportion of chitosan is more than 50 milligram, as in instance of F8, 97.45±0.61 % of drug is released in stomachic status ( 0.1N HCl ) itself, doing it unsuitable for the coveted colonic bringing systems.
In instance of combination of cluster bean gum, xanthan gum and chitosan, the chitosan measure ( 50 milligram ) was same for all the preparation because the preparation which incorporating 50 milligram of chitosan resulted in coveted release profile. The sum of drug released from the preparation F12, F13, F14 and F15 at 0.1N HCl after 2 Hs were 3.49±0.05 % , 4.12±0.07 % , 3.06±0.29 % and 4.56±0.15 % , severally, and at pH 7.4 after 8 Hs were 31.57±0.45 % , 37.83±1.13 % , 39.69±0.14 % and 35.34±0.32 % , severally. At the terminal of 24 H the same set of preparations gave 95.95±1.37 % , 98.83±0.06 % , 99.95±0.28 % and 98.56±0.78 % drug release, severally ( fig. 4 ) . The prepared preparations incorporating mixture of all three polymers ( F12-F15 ) was besides found to supply coveted release profile of drug. As smaller sum of drug release was seen in stomachic environment ( 0.1N HCl ) in comparing to simulated colonic fluid.
On the footing of drug release informations, preparation F5, F9 and F14 were selected to carryout disintegration surveies in the presence of rat caecal contents ( 2 % w/v ) . There was a important difference ( P & A ; lt ; 0.05 ) in the drug release when compared to that of the release surveies performed in the absence of rat caecal content. The rat caecal content in the release survey was considered to mime the human colonic environment as it contains microflora which releases many glycosidase and degrade the polyose polymers [ 14 ] .
When the in vitro disintegration surveies were carried out in the presence of rat caecal content medium, the cumulative per centum drug released from the preparation F5, F9 and F14 after 8 H were found to be 58.62±0.42 % , 54.48±0.24 % and 60.42±0.16 % , severally, and without rat caecal content were found to be 41.61±0.16 % , 37.42±0.60 % and 39.69±0.14 % , severally ( fig. 5 ) .
In all three preparations about 100 % of drug was released after 24 H in presence of rat caecal content. Hence, in presence of rat caecal affair, drug was faster from preparations compared to dissolution medium without rat caecal content. This indicates that the drug release from preparations is chiefly due to the presence of enzymes released by microorganisms of rat caecal contents. Rat caecal affair 2 % w/v was used in the survey for the simple ground that the microbic burden in the colon is 1011-1012 CFU/ml [ 14 ] .
From the above two disintegration informations ( in the presence and in the absence of rat caecal content ) important alterations in the release behaviour was observed. From the informations it can be concluded that polysaccharides entirely neither can be used efficaciously for aiming the drug to the colon nor for prolonging the release of drug. Hence combination of assorted polyoses for compaction coating is ideal for aiming the drug to colon.
In position of the possible public-service corporation of F5, F9 and F14 preparations for aiming of secnidazole to colon, stableness surveies were carried out at 40 & A ; deg ; C/75 % RH for 6 months to measure their long term stableness. After storage, the preparations were observed for physical alteration and were subjected to assay of drug content and in vitro disintegration surveies. At the terminal of storage period ( 40EsC/75 % RH for 6 months ) , there was no alteration either in physical visual aspect or in drug content. When the disintegration survey was conducted in the fake physiological environment as described in old subdivisions, no important difference ( P & A ; gt ; 0.05 ) was observed in the secnidazole release from F5, F9 and F14 in comparing to that released from the same preparations before storage.
To cognize the mechanism of drug release from the preparations, the informations were treated harmonizing to first order, zero order and Higuchi equations. All preparations except F3, F4 and F8 showed the one-dimensionality with regard to zero order ( R2=0.9634-0.9901 ) as compared to first order ( R2=0.8858-0.9515 ) ( Table 5 ) . Formulation F3, F4 and F8 did non showed one-dimensionality with regard to first order equation ( R2=0.9467-0.9655 ) . In presence of 2 % w/v rat caecal content as a disintegration medium, the preparation F5, F9 and F14 showed one-dimensionality with regard to first order equation ( R2=0.9528-0.9683 ) ( Table 6 ) . Higuchi equation arrested development values for all preparations with and without rat caecal contents ranges from degree Fahrenheit ( R2=0.8236-0.9342 ) . Hence to corroborate exactly the domination mechanism ; the information was plotted harmonizing to Koresmeyer-Peppas equation.
The ‘n ‘ value ( diffusional advocate ) indicated the mechanism of drug release. For tablet systems, if n & A ; lt ; 0.45 it suggests the Fickian diffusion ; if 0.46 & A ; lt ; n & A ; lt ; 0.89, it suggests the anomalous ( non-Fickian ) conveyance, for n= 0.89, the zero-order release is possible and if n & A ; gt ; 0.89, a ace case-?†?† conveyance is operative. In order to foretell and correlate the release behaviour of drugs from the tablet, it is necessary to suit them in to let go of dynamicss profiles ( Fickian, anomalous or super-case ?†?† ) . This will ease the apprehension of manner of drug release such as whether the release is because of lone diffusion or lone eroding or caused by both diffusion and eroding. The ‘n ‘ values were calculated for all preparations. Except F3, F4 and F8, ‘n ‘ values were found in the scope of 1.10-1.61, bespeaking a ace case-?†?† conveyance. These observations confirmed that both diffusion and eroding is dominant mechanism for drug release. The ‘n ‘ values for preparation F3, F4 and F8 were found in the scope of 0.481-0.492, bespeaking anomalous conveyance and these observations confirmed that the eroding is dominant mechanism for drug release. Hence natural polymer like cluster bean gum, xanthan gum is ideal for site specificity particularly in combination with chitosan to aim the drug to colon.
The present probe was performed to develop the colon targeted drug bringing systems of secnidazole for an effectual and safe therapy of amebiasis. The disintegration informations obtained from the assorted preparation developed demonstrates that secnidazole release rate is dependent upon the nature and proportion of polyoses used as a bearer. Among the assorted preparations, it appears that compaction surfacing with a mixture of cluster bean gum and xanthan gum with chitosan ( 50 milligram ) in 250 milligram coat or combination of guar gum and xanthan gum at equal proportion ( each at 75 milligram ) combined with chitosan ( 50 milligram ) in 250 milligram coat are most likely to supply targeted bringing of secnidazole to the colon. It can be concluded that a individual polyose can non be used for aiming the drug to the colon expeditiously.