INTRODUCTION:

Irritable bowel syndrome (IBS) includes disturbed pattern of defecation followed by abdominal pains and discomfort¹. It is non-life threatening disorder but for some patients it represents a chronic condition with significant physical and psychosexual morbidity.

Some time patient may have disturbance in intestinal motility². It is affecting 15% of general adult population and proper diagnosis is difficult due to variability of symptoms amongst the individuals and difficulty in quantifying the symptoms. Spiegel et al (2010) suggested that better implementation of guidelines should be warranted to minimize variation in diagnosis of IBS and to improve the cost effectiveness of care³ The various categories of drugs are used in IBS such as antispasmodics to relieve abdominal pain, anti-diarrhoeal and bulking agent for disturbed bowel habit and antidepressants for treating affective disorders. Alverine citrate, a spasmolytic agent is used in the treatment of irritable bowel syndrome for many years⁴. It has a specific action on the smooth muscle of alimentary tract uterus, without affecting heart, blood vessels or tracheal muscles at therapeutic doses. Its exact mechanisms of action are still not clear, due to the lack of information of its effects on isolated smooth muscle in vitro. On oral administration, it is rapidly converted to its primary active metabolite which is then reconverted to two secondary metabolites. It is eliminated by active renal secretion. It is slightly soluble in water and has short plasma half-life, 1 to 6 h⁵.

Oral administration of ALV suffers from various disadvantages such as headache, feeling dizziness, itching, skin rash and rare hepatotoxicity⁶. Further, it is not administered by parenteral route due to pain and safety issues. Therefore, rectal administration of medicaments is preferable due to the advantages that include: a) improved enzymatic drug stability b) higher drug content c) constant and static environment of rectum d) avoidance of overdosing e) improved patient compliance f) avoidance of first pass effect in the gastrointestinal tract and liver.Conventional solid suppositories have variousdisadvantages such as patient feels a discomfort due to its solid nature^7,8. Such suppositories may reach to the colon and undergo the first pass effect. Also, sometimes the medicaments may leak out from the suppositories⁹.

Design of mucoadhesive microspheres of ALV is better alternative to overcome the above mentioned disadvantages of suppositories. Microspheres are used to produce local effect, reduce the side effects and improve therapeutic response of drug¹⁰. Such microspheres distribute drug uniformly in the rectum thus ensuring more uniform drug absorption and reducing patient-to-patient variability. Chitosan, a natural cationic polysaccharide derived from chitin, is a copolymer of glucosamine and N-acetyl glucosamine units¹¹. It can form a gel matrix with counter-ions such as glutaraldehyde. It has satisfactory mucoadhesive property and good application potential. It also has favorable biological properties such as biodegradability, biocompatibility and non-toxicity and improves the fluidity of powder mixtures. Drug diffusion from chitosan microspheres may be controlled by cross linking with a dialdehyde such as glutaraldehyde¹².If such mucoadhesive microspheres containing chitosan loaded with alverine citrate are developed, drug will adhere to the rectal mucosa and will absorb from lower hemorrhoidal veins and may increase the bioavailability¹⁰. Therefore, present investigation aims to formulate mucoadhesive microspheres of ALV for rectal delivery that may be useful to relieve the symptoms of IBS.

MATERIALS AND METHODS:

ALV was obtained as a gift sample from Indoco Pharma, Goa. Cocoa butter (CB) was purchased from Rajesh Chemicals Pvt Ltd., Mumbai, India. Poloxomer 407 was gifted by BASF, Mumbai, India. Span 85, glutaraldehyde, liquid paraffin (heavy and light) and acetic acid were purchased from Loba Chemie, Mumbai. Chitosan was purchased from Mahatani Chitosan Pvt, Ltd., Veral, India. All other chemicals and reagents used were of analytical grade and used as received.

Preparation of mucoadhesive microspheres of alverine citrate:

Mucoadhesive microspheres of ALV were prepared at various drug: polymer ratios by simple emulsification methodusing glutaraldehyde as a crosslinking agent¹³. In brief, ALV (750mg) was dispersedin 30ml aqueous acetic acid (2%w/v) solution containing varying concentrations of chitosan (0.5 to 2%w/v). Dispersed aqueous phase was added to continuous phase (75 ml) consisting of n-hexane containing Span 80 (0.5%w/v) with continuous stirring at 2000 rpm using mechanical stirrer (Remi Equipments, Mumbai, India) to form a water in oil (w/o) emulsion. After emulsification, a measured quantity of aqueous glutaraldehyde (previously 1.852 ml glutaraldehyde 25% v/v diluted up to 10 ml) was added drop wise at different time intervals (15, 30, 45, 60 and 75 minutes) and stirred for 2.5h. Microspheres were separated by filtration under vacuum and washed with petroleum ether (60°C-80°C) followed by distilled water to remove the adhered n- hexane and glutaraldehyde. The microspheres were then dried at room temperature and stored in a desiccator.

Table1: Formulation of Alverine citrate loaded chitosan microspheres

Formulation code	ALV (mg)	Chitosan (%w/v)	Glutaraldehyde 25% v/v (ml )	Span 80, 0.5%w/v (ml)	n-hexane (ml)	Stirring speed (rpm)
AM1	750	0.5	1.85	0.37	75	2000
AM2	750	1.0	1.85	0.37	75	2000
AM3	750	1.5	1.85	0.37	75	2000
AM4	750	2.0	1.85	0.37	75	2000
AM5	750	2.0	1.85	0.37	75	3000

Evaluation of microspheres:

Attenuated total reflectance-fourier transform infrared (ATR-FTIR) spectroscopy:

The ATR-FTIR spectra of chitosan, ALV citrate, physical mixture of drug and chitosan and optimized formulation were obtained using ATR-FTIR spectrophotometer (Shimadzu, Miracle 10, IR Affinity, Japan). The samples to be analyzed were placed ontothe ATR and spectra were recorded in the range of 600–4000 cm⁻¹at an average of 25 scans and resolution of 4 cm⁻¹.

Differential scanning Calorimetry (DSC) studies:

Thermal analysis by differential scanning calorimetry (DSC) was carried out for the plain drug, pectin polymer, physical mixture and the optimized formulation using Model-SDT Q600 V20.9 Build 20 with a computerized data station. Samples were placed in an aluminum pan and heated at arate of 10°C/min in the temperature range of 30–300°C. The thermal analysis was performed under nitrogen atmosphere.

Particle size and shape of microspheres:

The particle size of microspheres was determined using optical microscope¹⁰. The average particle size was determined by using Ed-mondson’s equation,

Dmean=∑nd/∑n (1)

Where, n is the number of microspheres observed and d is mean of size range.

Surface morphology of the microspheres was studied using scanning electron microscopy (SEM), (JSM-6360, JEOL Ltd., Tokyo, Japan). Microspheres were sprinkled on to double sided tape, sputter coated with platinum and examined under the microscope at 15Kv.

Percentage yield:

The percentage yield of microspheres was calculated as the weight percentage of the final product after drying with respect to the initial quantity of drug, chitosan and glutaraldehyde used for preparation¹⁴.

Percentage drug encapsulation:

Accuratelyweighed hundred milligrams of microspheres were dispersed in100 ml of phosphate buffer pH7.4 in volumetric flask and shaken vigorously for 24 h using rotary shaker (Bio-Technics, India)¹⁵. Supernatant was filtered, diluted suitably and analyzed using Spectrophotometer (UV 1800, Shimadzu, Japan). Entrapment efficiency was measured by using following formula:

% Drug entrapment=[Practical content/Theoretical content] x 100 (2)

Equilibrium swelling degree:

The swelling degree of microspheres (ESW) was determined by swellinghundred milligramsof dried microspheres in 4ml phosphate buffer pH 7.4 in a measuring cylinder for 24h. The following equation was used for computing the swelling degree¹⁶.

Esw=We-Wo/Wo×100 (3)

Where, Esw is the percent swelling of microspheres at equilibrium, We is the weight of microspheres at equilibrium swelling and Wo is the initial weight of microspheres.

Ex vivo bioadhesion:

The ex vivo bioadhesion of microspheres was determined by following a previously reported method with certain modification¹⁷. In brief, fifty milligrams of microspheres (50mg) were placed on rectal mucous membrane of wistar rats (2cm²) and kept for 20 min in a humidity temperature control cabinet (Remi Instruments, Mumbai, India) at 75% relative humidity and temperature of 25±2^o C to allow hydration of the microspheres. This was followed by through washing of the mucosal lumen with isotonic phosphate buffer pH 7.4. The washings were then dried at 60^oC in a hot air oven and weighed. Percent bioadhesion was determined by following formula.

% Bioadhesion=(W_o-W_d/W_o) × 100 (4)

Where, W_o is weight of applied microspheres and W_d is weight of detached microspheres.

In vitro release studies:

The dissolution study was performed using USP-XXIII type dissolution apparatus using 900 ml phosphate buffer pH 7.4. The speed of rotation was controlled at to 100±2 rpm. Microspheres equivalent to 80 mg drug were dispersed in dissolution medium.Aliquots of 5 ml dissolution medium were taken at different time intervals and sink condition was maintained. The absorbance was taken with the help of spectrophotometrically (UV 1800, Shimadzu, Japan) at λmax 258 nm.

Preparation of ALV suppositories:

Initially the displacement value of the chitosan microspheres containing alverine citrate was calculated in the bases.Six different batches (see Table 2) of suppositories weighing one gram each containing optimized batch of microspheres equivalent to 80mg of alverine citrate were prepared by hot meltor fusion method using different suppository bases¹⁸ such as cocoa butter, PEG 2000, PEG 4000 and combinations of PEG 4000 and PEG 2000 in different ratios like 1:0.5, 1:1 and 1:1.5. The prepared suppositories were wrapped in aluminum foil, kept in refrigerator and were used for further investigation.

Evaluation of solid suppository:

Appearance:

Suppositorieswere cut longitudinally and the surfaces wereexamined with naked eye.

Weight variation test:

Twenty suppositories were weighed individually and the averageweight was determined¹⁹. The individual weights werecompared with the average weight for determination of weight variation. As per IP specifications, no suppository should deviatefrom averageweight by more than 5% except two that maydeviate by not more than 10%.

Table 2: Formulation of optimized microspheres loaded suppository

Batch code	A	B	C	D	E	F
Alverine citrate(%)	0.8	0.8	0.8	0.8	0.8	0.8
Cocoa butter (g)	qs	-	-	-	-	-
PEG 2000 (g)	-	qs	-	-	-	-
PEG 4000 (g)	-	-	qs	-	-	-
PEG 4000:2000 (1:0.5) (g)	-	-	-	qs	-	-
PEG 4000:2000 (1:1) (g)	-	-	-	-	qs	-
PEG 4000:2000 (1:1.5) (g)	-	-	-	-	-	qs

q.s.-quantity sufficient

Hardness test:

Hardness was determined at room temperature (25°C) using a hardness tester (Electrolab, India).

Drug content:

Individual suppository was soaked in 900ml water for 30 min and broken with spatula⁸. The dispersion was vortexed for 5min and diluted to 50ml with distilled water. Diluted dispersion was placed in ultrasonic water bath for 30 min. Aliquots were equilibrated for 2 days and filtered through whatmann filter paper and analyzed spectroscopically (UV 1800, Shimadzu, Japan) at 258 nm.For cocoa buttersuppositories, the suppository was heated in 500ml distilled waterat 50°C for 5 min. The aqueous layer was separated out using separating funnel, then diluted to 50 ml with distilled water and placed in an ultrasonic water bath for 30 min. The aliquots were equilibrated for 2 days. Aliquots were filtered through whatmann filter and assayed. The determination was carried out in triplicate.

Liquefaction/softening time:

A simpleapparatus fabricated in the laboratory was used for determination of liquefaction/softening time²⁰. A stop cock of burette was broken and cut suitablyso that it has a narrow opening on one side and broadopening on another side. The burette was dipped in hot water maintained at 37ºC so that narrow end faces towards hot water. The sample suppository was introducedfrom the top of the burette through broad end and carefullypushed down its length until it reaches narrow end. Aglass rod weighing 30 g and 45 cm in length was theninserted so that it rests over the suppository. The time atwhich glass rod reaches the narrow end after completemelting of suppository represents the liquefaction time.

Melting range test:

Suppository formulation was filled to about 1 cm height in capillary tubes of 10 cm length and dipped in a beaker containing water. The temperature was raised slowly and the temperature at which the mass liquefies was recorded.

In vitro dissolution studies:

In vitro dissolution studies of ALV was carried out in USP-XXIII type dissolution apparatus using 900 ml of phosphate buffer of pH 7.4 at 37±0.5°C²¹. The speed of rotation was maintained at 100 rpm. 5 ml samples were withdrawn periodically at 30 min time intervals and the sink condition was maintained. The samples were analyzed for drug release bymeasuring the absorbance at 254 nm using spectrophotometer (UV 1800, Shimadzu, Japan) after suitable dilution. All the studies were carried out in triplicate.

The kinetics of drug release from the suppositories was determined to fit for zero-order, first-order, Higuchi equation and Korsmeyer–Peppas equation.

RESULTS AND DISCUSSION:

Preparation of mucoadhesive microspheres of alverine citrate:

Mucoadhesive microspheres of ALV were prepared by simple emulsification method using chitosan as a mucoadhesive polymer. The prepared microspheres were evaluated for drug entrapment, mucoadhesion, equilibrium swelling degree and in vitro drug release study.

Evaluation of microspheres:

Particle size and shape of microspheres:

All batches of microspheres showed different size and shapes(table 3). Shape of all the batches was found to be spherical except AM3 and AM4.

Size of all formulated microspheres was found to be in the range of 76.56 to 294.32µm. Batch AM5 showed very small particle size about 76.56 µm due to high stirring speed (2000 rpm) and batch AM4 showed large particle size about 294. 32µm due to high polymer concentration (1:4). Batch to batch variation in the particle size is mainly due to speed of stirring and polymer concentration²². When the speed of stirring was increased particle size was found to be decreased and as the polymer concentration was increased particle size also increased. Particle size was found to be increased with increase in the polymer concentration, chitosan (123.14 to 294. 32µm)²³. Figure 1 shows shape of optimised mincrosphere batch AM5.

Figure1 . Images of scanning electron microscopy of microspheres of optimized batch (AM5)

Percentage yield:

Percentage yield of microspheres was found in the range of 74.23 to 97.62% (table 3). Batch AM4 showed highest percentage yield (97.62%). This may be due to process parameters such as washing, filtration and drying. The percentage yield was found to be increased with increase in the concentration of polymer. On increasing viscosity of organic phase, there may be formation of dense structure of polymer which may have avoided the loss of drug during evaporation²⁴. Batch A5 showed 83.8% yield.

Percentage drug entrapment efficiency:

All the batches of microspheres showed percent drug entrapment efficiency in the range of 41.57 to 98.36% (table 3). The batches AM1 showed lowest drug entrapment efficiency i.e. less than 44%. The various parameters such as drug polymer concentration, stirring speed, emulsifier concentrationand concentration of cross linker may have affected the entrapment efficiency. Based on drug entrapment efficiency 2% chitosan concentration was optimized which exhibited 98.36% drug entrapment efficiency.

It was observed that as the concentration of chitosan increased viscosity of solution increased which may have prevented drug crystals from leaving polymer droplets and thus increasing drug entrapment efficiency. The higher polymer concentration resulted in large size of microspheres which resulted in loss of drug from surface. The loss of drug from surface during washing of microspheres is very less as compared to small microspheres.

Drug entrapment efficiency was found to be increasedas the stirring speed was increased which may be due to fast drug polymer interaction during process. But on addition of the emulsifier at high concentration, the drug entrapment efficiency found to be decreased because of dissolution of drug in the organic phase of the emulsion at higher concentration of span80. The optimized amount of glutaraldehyde favored the cross-linking reaction, and hence spherical free-flowing microspheres were obtained with an increase in entrapment efficiency²⁵.

Equilibrium swelling degree:

Chitosan microspheres exhibited equilibrium swelling of 1.79 to 2.93. Equilibriumswelling found to be increased with increase in the polymer concentration. This may be due to higher uptake of water at increased concentration of chitosan²⁶. At high concentration of cross linking agent, degree of polymer cross linking increased and diffusion of water into the polymer network may take place at lower rate which in turn, causes an insufficient swelling of polymer²⁷. The equilibrium swelling of chitosan microspheres is as shown in table 4.

Ex vivo bioadhesion:

All themicrosphere formulations showed good bioadhesive property. It was observed that bioadhesion was increased with increasing the polymer concentration, stirring speed and the concentration of glutaraldehyde (cross linking agent). As the polymer concentration increased hydration and swelling of polymer increased. It permits mechanical entanglement by exposing bioadhesive sites for hydrogen bonding and/or electrostatic interaction between the polymer and the mucous network. As the stirring speed was increased, particle size of microspheres was decreased. These small size particles more adhered on mucus membrane than large particles. When glutaraldehyde concentration was increased polymer cross linking network was increased due to interaction of amino group in chitosan molecular chain with aldehyde group of glutaraldehyde and thus bioadhesive strength was decreased due to increase in cross linking of free–NH₂ and–OH groups of chitosan. As a result of this degree of freedom and degree of entanglement was decreased. Sialic acid of mucus binds with the–NH₂ by ionic interaction while–OH group causes hydrogen bonding resulting in mucoadhesion²⁸. The ex vivo bioadhesion studies of microspheres showed bioadhesion in the range of 58.25 to 82.65% as given in table 4.

In vitro release studies:

The drug release profile of all microspheres is shown in the figure 2 which indicated the initial burst release. Initial burst release may be due to dissolution/diffusion of ALV from the superficial regions of chitosan microspheres.Batch AM5 showed the highest initial burst release due to high stirring speed (2500 rpm). Initial burst release was found to be decreased on increasing polymer concentration upto 2% (batches AM1 to AM4). All the batches showed drug release in the range of 63.69 to 94.65% at the end of 10h. All batches except AM1, AM3 and AM4 showed drug release above 80%. The drug release was increased with decreasing the polymer concentration. This may be attributed to formation of dense matrix. The stirring speed also showed the impact on the drug release. As the stirring speed increased, particle size of microspheres (AM5) was decreased and effective surface area was increased so that drug release was increased. When stirring speed was decreased the drug release was found to be decreased. The decrease in stirring speed leads to increase in particle size due to agglomerationof polymer and drug mixture which decreases drug content as well as drug release²⁵.All formulations followed zero order model (table 4). Release exponent (n value) was found in the range of 0.41 to 0.48, thus suggesting Fickian diffusion release mechanism.

Table 4: In vitro drug release studies of different batches of microspheres

Batch	Drug release (%)	‘n’ value	‘r’ value	Beast fit model
AM1	87.95±3.54	0.44	0.999	Zero order
AM2	81.03±3.67	0.48	0.999	Zero order
AM3	72.22±2.13	0.43	0.999	Zero order
AM4	63.69±2.92	0.46	0.999	Zero order
AM5	94.65±3.53	0.41	0.996	Zero order

n: release exponent; r: correlation coefficient

Figure 2 in vitro drug release from microspheres

ATR-FTIR Spectroscopy:

ATR-FTIR spectra of pure ALV (Figure3A) showed characteristic absorbance peaks at 2943.37, 1724.36, 1575.84, 1448.54 and 914.26 cm^-1 indicating aromatic C-H stretching, C=O stretching, C=N stretching, C=C-N=C stretching and OH (bent) stretch respectively. Infrared spectra of chitosan (Figure1B) showed peaks at3201.83cm^-1 (O-H Stretching), 2922.16cm^-1 (C- H stretching), 1585.49cm^-1 (C=N stretching), 1026.13cm-1 (C-O Stretch), 2922.16 (C-H stretching) and 914.26cm^-1(OH (bent) stretch. The IRspectra ofphysical mixtures (Figure1C and 1D) showed presence of all the characteristic peaks of ALV.Microspheres showed characteristic band of–N-H bending vibrations of amino groups of chitosan at 1587.42cm^-1. Peak corresponding to-C-H stretching vibration of ALV and chitosan was observed at 2922.16cm^-1and 2956.58cm^-1 respectively. In addition significant band appeared at, 1587.42cm^-1 due to–C=C ethylinic bond formed between chitosan and glutaraldehyde justifying the crosslinking of chitosan by glutaraldehyde. Absence of characteristic peak of aldehyde group at 1720cm^-1 confirms absence of residual free glutaraldehyde in the microspheres.

Figure3: Overlay of ATR-FTIR spectra of alverine citrate (A), chitosan (B), physical mixture of alverine citrate and chitosan (C), drug loaded microspheres (D), PEG 4000 (E), PEG 2000 (F), optimized formulation of suppository (G)

Differential scanning calorimetry (DSC):

The overlay differential scanning calorimetric (DSC) thermograms of alverine citrate, polymer, physical mixture (ALV and chitosan) and drug loaded microspheres is shown in Figure 4. The DSC of alverine citrate showed an endothermic peak at 105.48ºC, which corresponds to the melting point of alverine citrate101-105ºC. In case of polymer (chitosan) enxothermic peak was observed at 335.53ºC corresponding to degradation of chitosan. The physical mixture of alverine citrate and chitosan showed endothermic peak at 105.48ºC corresponding to the melting point of drug, which suggested lack of interaction between alverine citrate and chitosan. However, the DSC of optimized batch of microsphere showed disappearance of melting peak of alverine citrate, which may be due to molecular dispersion of alverine citrate within the polymeric matrix of chitosan based microspheres.

Formulation of Solid suppository:

Solid suppository of optimized batch of ALV microspheres (AM5) was prepared by fusion methodusing cocoa butter, PEG 2000, PEG 4000 and combination of PEG 2000 and PEG 4000 in different ratios as suppository bases. Homogenous dispersion of the base and microspheres were prepared and poured into suppository mould. After freezing formulated suppositories were evaluated.

Evaluation of Solid Suppository:

Physical examination:

Surface characteristics of suppositories were examined with naked eye. There was absence of pitting, fissuring, fat blooming and sedimentation.

Figure 4: Overlay of DSC thermograms of alverine citrate (A), chitosan (B), physical mixture of alverine citrate and chitosan (C), optimized batch of microsphere (D)

Weight variation, drug content, hardness:

The weight variation of all the suppository formulations found to be within acceptable range (<5%) thus indicating proper calibration of mold (Table 5).The percent deviation from the mean weights of all batcheswas found to be within the prescribed limits (mean weight±5 to 7.5%) as per Indian Pharmacopoeia

Drug content of all batches of suppository formulations found to be in the range of 90.81 to 97.58% thus indicating percentage deviation by not more than 10%²⁹. Hardness of all suppository formulations was found to be within the range of 3.7 to 4.2 kg/cm². This ensures enough mechanical strength of suppositories to withstand mechanical shocks during handling. The results of weight variation, drug content and hardness are shown in table 5.

Liquefaction/softening time and melting range:

The liquefaction time of Alverine citrate suppositories was found to be in the range of 2to 4min at 37⁰C. Chitosan polysaccharide undergoes sol-gel transition at a temperature close to 37⁰C and thus showed short liquefaction time³⁰. All the formulations exhibited meltingrange within 35.11 to 37.83⁰C.

In vitro Dissolution Studies:

All the suppository formulations of ALV showed drug release within the range of 70.94 to 91.65% at the end of 10h (figure 5). A significant decrease (p<0.05) in ALVrelease was observed from suppositories as compared to microspheres which may be due to low water absorbing property of microspheres. Suppositories containing hydrophilic bases (PEG 2000 and/or PEG 4000) showed maximum drug releasewhereas those containing hydrophobic base (cocoa butter) showed retardation of drug release³¹. This is attributed to the higher solubility of PEG bases in water and dissolution medium. Combination of 4000 PEG and PEG 2000 showed more water solubility than single PEG bases. Therefore, it is concluded that combination of PEG 4000 and PEG 2000 (1:1.5) in the formulation enhanced the drug release.The release kinetics from different suppository formulations is shown in table 6. Dissolution efficiency (DE) of suppository formulations was found in the range of 37.23 to 55.85% while mean dissolution time (MDT) was found to be in the range of 3.90 to 4.75h at the end of 10h. All the formulations followed the zero order kinetic model with release exponent in the range of 0.50–0.75.

Figure 5. in vitro drug release from solid suppositories

3. CONCLUSION:

As per our knowledge, first time sustained release alverine citrate suppositories containing chitosan based mucoadhesive microspheres were prepared using hydrophilic and lipophilic suppositories bases. The prepared microspheres were investigated for particle size analysis, mucoadhesion studies, compatibility studies and release kinetics. Similarly suppositories were also investigated for physical evaluation, release behavior in different bases. For the preparation of microspheres, appropriate concentration of chitosan, stirring speed, concentration of emulsifier, type and concentration of cross linker should be selected and for preparation of suppositories, appropriate base and particle size of microspheres should be selected. The prepared suppositories can avoid the first pass effect, sustain the release of drug and may be useful for the treatment of irritable bowel syndrome (IBS). Thus, prepared suppositories of Alverine citrate will be more promising and useful than conventional suppository.

ACKNOWLEDGEMENTS:

Authors are thankful to President and Vice President of YSPM’s, YTC, Faculty of Pharmacy, Wadhe, Satara for permitting us to carry out the research work.

Conflict of interest statement

The authors declared no conflict of interest

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Received on 06.03.2018 Modified on 29.04.2018

Research J. Pharm. and Tech 2018; 11(7): 3091-3098.

DOI: 10.5958/0974-360X.2018.00568.1

Batch	Particle size (µm)	Particle shape	Yield (%)	DEE (%)	ESD	*Ex vivo* bioadhesion (%)
AM1	123.14±0.99	Spherical	74.23±0.91	43.91±0.28	1.79±0.02	58.25±0.31
AM2	135.43±0.98	Spherical	76.26±0.81	94.62±0.16	2.62±0.06	72.65±0.06
AM3	156.95±0.37	Roughly spherical	97.02±0.35	96.64±0.11	2.85±0.01	74.72±0.04
AM4	294.32±0.57	Roughly Spherical	97.62±0.51	98.36±0.22	2.93±0.03	80.41±0.09
AM5	76.56±0.46	Spherical	83.8±0.50	67.67±0.45	2.27±0.01	82.65±0.04

Batch Code	Weight variation	Drug content (%)	Liquefaction time ( min)	Melting range test (⁰C)	Hardness (Kg)
A	588.5±0.02	91.26	2.36±0.15	35.11±0.2	3.3±0.03
B	574.4±0.08	97.58	4.43±0.32	37.53±0.52	3.8±0.11
C	594.6±0.04	90.81	5.54±0.2	37.83±0.35	4.2±0.07
D	592.5±0.02	92.53	3.13±0.3	37.02±0.86	3.7±0.04
E	593.8±0.06	94.61	2.50±0.15	37.23±0.56	3.8±0.08
F	593.5±0.05	95.54	2.38±0.15	37.44±0.7	3.9±0.05

Batch	Drug release (%)	MDT (h)	DE(%)	‘n’ value	‘r²’ value	Best fit model
A	70.94±2.03	4.75	37.23	0.73	0.989	Zero order
B	77.5±1.34	4.75	40.64	0.74	0.993	Zero order
C	80.65±1.01	4.60	43.48	0.73	0.997	Zero order
D	82.81±1.07	4.43	46.12	0.64	0.997	Zero order
E	86.33±1.63	4.15	50.42	0.56	0.998	Zero order
F	91.65±1.23	3.90	55.85	0.50	0.999	Zero order