“FORMULATION DEVELOPMENT AND EVALUATION OF GASTRORETENTIVE FLOATING FILMS OF LAFUTIDINE”

ABSTRACT The present invention was aimed to formulate and evaluate Lafutidine gastro retentive films. The films were prepared by solvent casting technique using different film forming polymers like HPMC and Ethyl cellulose. PEG 400 used as a plastsizer. The prepared films were evaluated for number of parameters like Physical appearance, Weight variation, Thickness, Folding endurance, Tensile strength, unfolding behavior, floating properties, drug content and In vitro drug release studies. From the trial batches the best release for gastroretentive film was shown by formulation T5 (Ethyl cellulose and PEG 400). Formulation T5 exhibited good appearance, better mechanical strength with acceptable flexibility. Also, formulation T5 was given more than 90 % drug released after 12 hr and 97.56 % Drug content. For optimization of formulation, 3 factorial design was applied by taking Ethyl cellulose and PEG 400 as an independent variables. Drug release at 8 hour and folding endurance selected as dependent variables. Based on drug release study, L8 batch found most satisfactory in all formulation and the effect of Ethyl cellulose and PEG 400 found significant. L8 batch found stable during stability study.


Gastro retentive Dosage Form (GRDF): (1, 2)
A few troubles are looked in structuring continued discharge and controlled discharge frameworks for better assimilation and upgraded bioavailability. One of such troubles is the failure to restrict the measurement frame in the coveted region of the gastrointestinal tract. Gastro retentive frameworks can stay in the gastric locale for a few hours and consequently fundamentally drag out the gastric living arrangement time of medications.
GRDF can be utilized as bearers for medications with alleged ingestion windows. These substances for example antiviral, antifungal and anti-infection operators (sulphonamides, quinolones, penicillins, cephalosporins, aminoglycosides, antibiotic medications and so on.), are ingested just from unmistakable locales of the GI mucosa.

Basic Gastrointestinal Tract Anatomy and Physiology (3)
The basic comprehension of the life systems and physiological attributes of the human gastrointestinal tract is fundamental for the effective regulation of the gastrointestinal travel time of a medication conveyance framework to guarantee maximal gastrointestinal ingestion of medications.  Improvement of bioavailability and remedial adequacy of the medications and conceivable decrease of portion e.g. Furosemide  Maintenance of steady restorative levels over a drawn out period and accordingly decrease in change in helpful levels limiting the danger of opposition particularly if there should be an occurrence of anti-microbials. E.g. b-lactam antibiotics(penicillins and cephalosporins)  For drugs with generally short half life, continued discharge may result in a flip-flounder pharmacokinetics and furthermore empower lessened recurrence of dosing with enhanced patient Compliance.  They additionally have leverage over their ordinary framework as it tends to be utilized to conquer the difficulties of the gastric maintenance time (GRT) and additionally the gastric purging time (GET). As these frameworks are relied upon to stay light on the gastric liquid without influencing the inherent rate of utilizing on the grounds that their mass thickness is lower than that of the gastric liquids.  Gastro retentive medication conveyance can create drags out and supports arrival of medications from measurements frames which benefit neighborhood treatment in the stomach and small digestive tract. Thus they are helpful in the treatment of disarranges identified with stomach and small digestive system.  The controlled, moderate conveyance of medication shape gastro retentive measurement frame gives adequate neighborhood activity at the unhealthy site, in this way limiting or wiping out fundamental presentation of medications. This site-particular medication conveyance diminishes unfortunate Effects of reactions.  Gastro retentive dose frames limit the change of medication fixations and impacts. Subsequently, focus subordinate unfavorable impacts that are related with pinnacle fixations can be displayed. This element is of exceptional significance for medication with a restricted restorative record.  Gastro retentive medication conveyance can limit the counter movement of the body prompting higher medication effectiveness.  Reduction of vacillation in medication focus makes it conceivable to acquire enhanced selectivity in receptor initiation.

Limitations of gastro retentive delivery systems :-(8)
 Require a larger amount of liquids in the stomach.  Not appropriate for Drugs that Have dissolvability issues in gastric liquid. e.g. phenytoin  Cause G.I bothering. e.g. NSAIDS.  Are flimsy in acidic condition.

` Mr. Hir R. Mehta et al, Journal of Pharmaceutical and Biological Science Archive
19 | P a g e  Drugs planned for particular discharge in the colon e.g. 5-amino salicylic corrosive and corticosteroids and so forth.  The drifting frameworks in patients with achlorhydria can be faulty in if there should arise an occurrence of swellable framework.  Retention of high thickness frameworks in the antrum part under the moving floods of the stomach is sketchy.  The bodily fluid on the dividers of the stomach is in a condition of consistent restoration, coming about a capricious adherence.


Limited acid solubility e.g. phenytoin etc.  Instability in the gastric environment e.g. erythromycin etc.  Selective release in the colon e.g. 5-amino salicylic acid, corticosteroids etc.

Approaches to gastric retention or mechanistic aspects of GRDFS: -(10) a) Floating Systems:
Floating Drug Delivery Systems (FDDS) have a mass thickness lower than gastric liquids and along these lines stay light in the stomach for a drawn out timeframe, without influencing the gastric purging rate. While the framework is gliding on the gastric substance, the medication is discharged gradually at a coveted rate from the framework.

b) High Density Systems:
These frameworks with a thickness of around 3 g/cm3 are held in the rugae of the stomach and are fit for withstanding its peristaltic developments. A thickness of 2.6-2.8 g/cm3 goes about as an edge an incentive after which such frameworks can be held in the lower some portion of the stomach.

c) Bio/Muco-adhesive Systems:
Bio/muco-glue frameworks are those which tie to the gastric epithelial cell surface or mucin and fill in as potential methods for expanding the GRT of medication conveyance framework (DDS) in the stomach, by expanding the closeness and term of contact of medication with the natural film.

d) Swelling and Expanding Systems:
These are the measurements frames, which subsequent to gulping; swell to a degree that keeps their exit from the pylorus. These frameworks might be named as "plug type framework", since they show the propensity to remain logged at the pyloric sphincter if that surpass a distance across of around 12-18 mm in their extended state. Expandable gastroretentive measurements shapes (GRDFs) have been intended for as far back as 3 decades. They were initially made for conceivable veterinary utilize, yet later the structure was altered for improved medication treatment in people. These GRDFs are effortlessly gulped and achieve an altogether bigger size in the stomach because of swelling or unfurling forms that drag out their gastric maintenance time (GRT). After medication discharge, their measurements are limited with resulting departure from the stomach. In any case, the dose shape must be little enough to be gulped, and should not cause gastric check either separately or by gathering. Hence, their setups are required to build up an expandable framework to delay gastric maintenance time (GRT): 1. A little arrangement for oral admission, 2. An extended gastro retentive frame, and 3. A last little frame empowering clearing following medication discharge from the gadget.
In this manner, gastro retentivity is enhanced by the blend of considerable measurement with high unbending nature of dose shape to withstand peristalsis and mechanical contractility of the stomach. Unfoldable and swellable frameworks have been examined and as of late attempted to build up a powerful gastroretentive medication conveyance. Unfoldable frameworks are made of biodegradable polymers. Expandable frameworks have a few downsides like problematical stockpiling of much effortlessly hydrolysable, biodegradable polymers moderately fleeting mechanical shape memory for the unfurling framework most hard to industrialize and not savvy. Once more, perpetual maintenance of inflexible, substantial single-unit expandable medication conveyance dose structures may cause brief impediment, intestinal grip and gastropathy.

e) Incorporation of Passage Delaying Food Agents
Nourishment excipients like unsaturated fats e.g. salts of myristic corrosive change and alter the example of the stomach to a sustained state, in this manner diminishing gastric purging rate and allowing impressive prolongation of discharge. The postponement in the gastric exhausting after suppers wealthy in fat is to a great extent caused by immersed unsaturated fats with chain length of C10-C14.

f) Ion-Exchange Resins
Particle trade pitches are stacked with bicarbonate and an adversely charged medication is bound to the gum. The resultant dabs were then epitomized in a semi-penetrable layer to defeat the ` Mr. Hir R. Mehta et al, Journal of Pharmaceutical and Biological Science Archive 21 | P a g e quick loss of carbon dioxide. Upon landing in the acidic condition of the stomach, a trade of chloride and bicarbonate particles occurs. Because of this response carbon dioxide was discharged and caught in the film along these lines conveying dots towards the highest point of gastric substance and creating a drifting layer of sap dabs rather than the uncoated dabs, which will sink rapidly.

g) Osmotic Regulated Systems
It is contained an osmotic weight controlled medication conveyance gadget and an inflatable drifting help in a bio-erodible container. In the stomach the case rapidly deteriorates to discharge the intra-gastric osmotically controlled medication conveyance gadget. The inflatable backings inside structures a deformable empty polymeric pack that contains a fluid that gasify at body temperature to expand the sack. The osmotic controlled medication conveyance gadget comprises of two components-sedate repository compartment and osmotically dynamic compartment.

h) pH-Independent formulation
Most medications are either powerless acids or feeble nuts and bolts and henceforth pH subordinate discharge is seen in body liquids. Anyway supports can be added to such details to help in keeping up a consistent miniaturized scale natural pH to acquire pH autonomous medication discharge.

g) Multiple-unit dosage forms
The motivation behind planning numerous unit dose shape is to build up a solid definition that has every one of the upsides of a solitary unit frame and furthermore is without the previously mentioned detriments of single-unit details. Microspheres have high stacking limit and numerous polymers have been utilized, for example, egg whites, gelatine, polymethecrylate, polyacrylamine. Round polymeric microsponges likewise alluded to as "microballoons" have been readied.

Peptic Ulcer (11)
Peptic ulcers are sores that develop in the lining of the stomach, lower esophagus, or small intestine. They're usually formed as a result of inflammation caused by the bacteria H. pylori, as well as from erosion from stomach acids. Peptic ulcers are a fairly common health problem.

There are three types of peptic ulcers:
 Gastric ulcers: ulcers that develop inside the stomach  Esophageal ulcers: ulcers that develop inside the esophagus  Duodenal ulcers: ulcers that develop in the upper section of the small intestines, called the duodenum

Causes of peptic ulcers:
Different factors can cause the lining of the stomach, the esophagus, and the small intestine to break down. These include:


Helicobacter pylori (H. pylori), a type of bacteria that can cause a stomach infection and inflammation  frequent use of aspirin (Bayer), ibuprofen (Advil), and other anti-inflammatory drugs (risk associated with this behavior increases in women and people over the age of 60)  smoking  drinking too much alcohol

Absorption
After oral administration, Lafutidine is rapidly absorbed in the GIT.

Metabolism
It has been reported that CYP3A4 is mainly (CYP2D6 is partially) associated with the metabolism of 23anthan2323a.

Excretion
Lafutidine is mostly excreted in urine as drug metabolites and as unchanged drug, to some extent.

Mechanism of action
Lafutidine has multimodal mechanism of action. Lafutidine not only suppresses gastric acid secretion, but also has cytoprotective properties by the virtue of its property to induce the collagen synthesis in the gastric mucosa.

Applications in Pharmaceutical Formulation or Technology
: In spite of the fact that povidone is utilized as a part of an assortment of pharmaceutical plans, it is basically utilized as a part of strong measurement shapes. In tableting, povidone arrangements are utilized as covers in wet-granulation forms. Povidone is additionally added to powder mixes in the dry shape and granulated in situ by the option of water, liquor, or hydroalcoholic arrangements. Povidone is utilized as a solubilizer in oral and parenteral plans, and has been appeared to upgrade disintegration of ineffectively solvent medications from strong dose frames.

Appearance
Ethylcellulose is a tasteless, free-flowing, white to light tan-colored powder.

White to tan
Odour Odorless

Solubility
Ethylcellulose is practically insoluble in glycerin, propylene glycol, and water.

Use
Propylene glycol is generally utilized as a plasticizer in watery film-covering plans. Propylene glycol is likewise utilized as a part of beauty care products and in the nourishment business as a transporter for emulsifiers and as a vehicle for flavors in inclination to ethanol, since its absence of instability gives a more uniform flavor. : Sodium bicarbonate is generally used in pharmaceutical formulations as a source of carbon dioxide in effervescent tablets and granules. It is also widely used to produce or maintain an alkaline pH in a preparation. In effervescent tablets and granules, sodium bicarbonate is usually formulated with citric and/or tartaric acid METHOD:

Organoleptic property:
This includes recording of colour and odour of the drug using descriptive terminology.

Flow Properties a) Loose bulk density
Weigh accurately drug (M), which was previously passed through 20 # sieve and transferred in 50 ml graduated cylinder. Carefully level the powder without compacting, and read the unsettled apparent volume (V 0 ). Calculate the apparent bulk density in gm/ml by the following formula:

Bulk density = weight of powder / Bulk volume b) Tapped bulk density
Weigh accurately drug, which was previously passed through 20 # sieve and transfer in 50 ml graduated cylinder. Then tap the cylinder for 100 times manually and measure the tapped volume (V 1 ) to the nearest graduated units, repeat the tapping an additional 100 times and measure the tapped volume (V 2 ) to the nearest graduated units. If the difference between the two volumes is less than 2% then final the volume (V 2 ).Calculate the tapped bulk density in gm/ml by the following formula:

Tapped density = weight of powder / Tapped volume c) Carr's index
The Compressibility Index of the powder blend was determined by Carr's compressibility index. It is a simple test to evaluate the BD and TD of a powder and the rate at which it packed down. The formula for Carr's Index is as below:

Carr's index (%) = [(TD-BD) x100] / TD d) Hausner's ratio
The Hausner's ratio is a number that is correlated to the flow ability of a powder or granular material.

e) Angle of repose
The angle of repose of API powder was determined by the funnel method. The accurately weight powder blend were taken in the funnel. The height of the funnel was adjusted in such a way the tip of the funnel just touched the apex of the powder blend. The powder blend was allowed to flow through the funnel freely on to the surface. The diameter of the powder cone was measured and angle of repose was calculated using the following equation.

tan ф = h/r
Where, h and r are the height and radius of the powder cone respectively.

Compatibility Studies by FT-IR:-
To investigate any possible interactions between the drug and Excipients used, the FT-IR spectra of pure Lafutidine and its physical mixture (final formulation) with different Excipients were carried out using thermo FTIR spectrophotometer. The samples were prepared as KBr (potassium bromide) disks compressed under a pressure of 150 lbs. The wave number range is selected in between 500 -3500cm -1 .

Identification of drug by DSC:-
Assessment of possible incompatibilities between an active drug substance and its physical mixture (final formulation) an important part of the Preformulation stage during the development of dosage forms. Differential Scanning Calorimeter allows the fast evaluation of possible incompatibilities, because it shows changes in the appearance, shift of melting endotherms and exotherms, and/or variations in the corresponding enthalpies of reaction.

Standard calibration curve
Accurately weighed 100 mg of Lafutidine was dissolved in 100 ml of the freshly prepared pH 1.2, 0.1 N HCl to obtain the working standard (i.e. stock solution) of 1000 μg /ml. Aliquots of 1 ml to 6 ml from the above stock solution representing 10 to 60 μg/ml of drug were prepared and transferred to 10 ml volumetric flask. The Volume was adjusted to 10 ml with pH 1.2. Absorbance of the above solutions were taken at 286 nm against the blank solution prepared in the same manner without adding the drug. A graph of absorbance vs. concentration was plotted. The solubility of drug to be determined by taking 10 ml of various medium and then cumulative addition of drug was carried out in order to make saturated drug solution, maintained at 37 °C ± 0.5 °C in a water bath and continually shaken in to mechanical shaker up to 24 h. Samples were withdrawn, filtered through a filter paper suitably diluted and assayed by UV spectrophotometer.

Dose Calculation
For sustained release dosage form, Dose calculation for 12 hrs calculated by below equation;

Method of Preparation:-
The Lafutidine film was prepared by using solvent casting method with various polymers. The amount of Lafutidine in the film was 19 mg in 4X2 cm 2 film piece. An appropriate amount of Lafutidine and sodium bicarbonate was dissolved in a suitable amount of solvent methanol and added to the polymer solution slowly with continuous stirring with magnetic stirrer, when drugpolymer mixture mixed homogeneously then added proper amount of plasticizer with continuous stirring and the resulting solution poured in a Petri dish. Then dried the film and remove film from Petri dish and evaluate it.  Initially feasibility trial was planned by taking different film forming polymers. PEG 400 selected as a plastsizer. Solvent system selected based on solubility of drug and polymers. Drug was easily soluble in methanol so drug dissolve in methanol and polymer solution prepared in Dichloromethane.
Based on trial batches results, factorial design was applied to optimize the final polymer and plastsizer composition.

 3 2 Factorial Design for Optimization of Lafutidine Gastroretentive film
Factorial design is suitable for exploring quadratic response surface and constructing second order polynomial models. The design consists of replicated center points and the set of points lying at the midpoint of the multidimensional cube that defines the region of interest.
This study investigated utility of a 2-factor, 3-level factorial design and optimization process for films prepared by solvent casting technique. Amounts of Ethyl Cellulose (X1) and PEG 400 (X2) were selected as the independent variables whereas total Y8 % (amount of drug release after 8 h) and folding endurance were selected as dependent variables. Below table showed the composition and experimental runs as per factorial designs. 10 10 10 10 10 10 10 10 10 DCM (ml) 10 10 10 10 10 10 10 10 10

 Physical appearance and surface texture of films
This parameter was checked simply by visual inspection of films and evaluation of texture by feel or touch.

 Thickness
Three films of each formulation were taken and the film thickness was measured by using vernier caliper at different strategic locations (3 locations). Mean thickness of each was calculated.

 Folding endurance
Three films of each formulation of 4 cm × 2 cm were cut by using sharp blade. Folding endurance was determined by repeatedly folding a small strip of film at the same place till it break. The number of times, the film could be folded at the same place without breaking gives the value of folding endurance. The mean value of three readings was calculated.

 Weight Variation
Three films of every formulation were selected randomly and individual weight of each 4 cm × 2 cm film was noted on digital balance. The average weight was calculated.

 Drug content
Accurately size 4 cm×2 cm of the films were taken and dissolved in 100 ml of 0.1 N HCl solutions in 100 ml volumetric flask then whole solution was sonicated. After sonication and subsequent filtration, suitable dilutions were made with 0.1 N HCl solutions. The prepared solutions were analyzed by using UV spectrophotometer.

 Surface pH
The film to be tested was placed in a test tube and was moistened with 1.0 ml of distilled water and kept for 30 seconds. The pH was noted after bringing the electrode of the pH meter in contact with the surface of the formulation.

 Swelling index
Swelling of films was examined for triplicate in 0.1N HCl. After recording the initial weight of a film (W1), it was immersed in medium of temperature 37 ± 1 0 C for 720 min and weighed again (W2). Swelling index (%) = (W2-W1)/W1 x 100.

 Tensile strength
The tensile strength of the film was evaluated by using the tensilometer. It consists of two load cell grip, the lower one was fixed and upper one was movable. Film strips with dimension 4×2 cm 2 were fixed between these cell grips and force was gradually applied till the film break. The tensile strength was taken directly from the dial reading in kg.
It is calculated by following equation:

Tensile strength= F/A
Where, F=Break force,

 In-vitro unfolding behavior
The capsules were taken for In-vitro unfolding behavior study in 900 ml 0.1N HCl at 37 ± 0.5 ºC using the dissolution USPXXIII Apparatus1 basket (Electrolab) at 50 rpm. Baskets were removed after 5, 15,30,60,90,120,240,480 and 720 min and the films were examined for their unfolding behavior.

 Floating characteristics
Three floating films from each formulation were put in flask containing 250 ml of 0.1 N HCl (pH 1.2). The time taken by the film to come from bottom to top was taken as floating lag time and the duration of time for which the film constantly floated on the surface was noted as total floating time.

 In -vitro drug release study
The in vitro drug release study of gastroretentive mucoadhesive film in capsule was carried out in the dissolution USPXXIII Apparatus I basket (Electrolab) 900 ml 0.1 N HCl was used as a dissolution medium. Temperature was maintained at 37±0.5°C and basket was rotated at the speed of 50 rpm. Drug release was monitored for 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 hrs. 5 ml of samples was withdrawn at each time intervals and sink condition was maintained by replacing an equal amount of fresh dissolution medium. Samples were filtered and analyzed by UV spectrophotometer.

 Dissolution kinetics
The dissolution profile of formulations was subjected to various models such as Zero order kinetics, First order kinetics, Higuchi, Korsmeyer-Peppas and Hixson-Crowell to assess the kinetics of drug release from prepared gastroretentive mucoadhesive film of Lafutidine.

 Stability Studies
Stability studies were conducted as per ICH Guidelines. The stability study of final formulation was performed by keeping 4×2 cm 2 films at 40 °C temperature and 75% RH for 1 month. Initial and after 1 month parameters (Drug content, folding endurance and drug release study were compared and results were recorded. The above data of API Characterization shows that the API having a poor flow properties. It's a yellowish white crystalline odorless powder. Film formulation does not require flow properties of API because the API has to dissolve in the appropriate solvent and casting of film done.

FTIR Study
FTIR Study of Pure drug Lafutidine and Final Formulation done and results attached in below figure 4 and 5. From the below results it concluded that no any interaction found between drug and Excipients.

Calibration curve of Lafutidine
The calibration curve of Lafutidine was taken to over a concentration range 10-60 µg/ml. (R 2 =0.999) the data for calibration curve is given in table 11 and the calibration curve is shown in fig.8.

Solubility study of Lafutidine
The solubility of drug to be determined by taking 10 ml of various medium and then cumulative addition of drug was carried out in order to make saturated drug solution, maintained at 37 °C ± 0.5 °C in a water bath and continually shaken in to mechanical shaker up to 24 h. Samples were withdrawn, filtered through a filter paper, suitably diluted and assayed by UV spectrophotometer. Results are shown in Table 13. From the above table it concluded that Lafutidine is freely soluble in Acidic medium so Solubility enhancement is not require for drug. Further the development is Gastroretentive type so in 0.1 N HCl solubility is only important which is good enough to dissolve the drug from the dosage form.
Additionally the solubility of drug in methanol was helpful for film preparation by solvent casting method.

Evaluation of the films of trial batches
Various polymers were evaluated for the preparation of gastro retentive films of Lafutidine. The result of prepared batches was shown in below table. The result revealed that the all selected polymers were suitable for the preparation of film.

Physical appearance and surface texture of films
These parameters were checked simply with visual inspection of films and by feel or touch. The observation reveals that the films of batches T1 to T5 were smooth surface, transparent and they were elegant in appearance.

Weight uniformity of films ` Mr. Hir R. Mehta et al, Journal of Pharmaceutical and Biological Science Archive
The weight of the films was determined using digital balance and the weight uniformity of batches T1 to T5 films were given in below table. The films were found uniform in weight.

Thickness of films
The thicknesses of the films were measured using vernier caliper and the average thickness of batches T1 to T5 films were given in below table. The thicknesses of the films prepared were found to be uniform in all the prepared batches.

Folding endurance of films
The folding endurance gives the idea of flexible nature of films. The folding endurance was measured manually, films were folded repeatedly till it broke, and it was considered as the end point. The folding endurance was found more than 200 in all batches and exhibited good physical and mechanical properties. Ethyl Cellulose batch having highest folding endurance 369 as compared to PVPK 30 and HPMC based films.

Surface pH of films
Surface pH of the films was determined by using pH meter. The surface pH of the batch T1 to T5 was found to be in range of 6.5 to 6.7.

Swelling index of films
The swelling index of batch T1 to T5 was found to be in range of 22.4 to 31.9.

Drug content
The film was dissolved in a 0.1 N HCl in a specific volume. Then the solution was filtered through a whatmann filter medium and analyze the drug contain with the UV method. The result was shown in above Table. The drug content in batches T1 to T5 were in the range of 93.3 to 97.6 % and it shows that the drug was uniformly distributed in films during casting.

Unfolding behavior
Prepared films were evaluated for their in vitro unfolding behavior. The films of PVPK 30 and HPMC based were not unfolded up to 1 hour. Films prepared by ethyl cellulose were unfolded within 15 min. Hence this one was one of the most important parameter for optimization of trial batches.

Floating Lag time and Total floating Time
Prepared films were evaluated for their floating behavior. The films of all trial batches float within 1 min hence the amount of sodium bicarbonate was sufficient to float the film. Films prepared by ethyl cellulose were floated up to 12 hour.

In vitro drug release studies
The in-vitro drug release of batches T1 to T5 were shown in Table 17. Drug release study performed for 12 hour. Films of PVPK 30 gives very fast release as compared to other batches. Further the HPMC based films also not retard the drug release more than 6 hours. Ethyl cellulose batch so called T5 batch release drug up to 12 hours and hence the T5 batch selected for further optimization purpose. It may be due to the ethyl cellulose have a water insoluble polymer and hence it retard the drug release up to 12 hours and others were not.
Hence, the amount of Ethyl Cellulose and Amount of PEG 400 selected as an independent variable for further factorial design application.

Evaluation of the films of factorial batches
Lafutidine loaded films of factorial batches were prepared successfully by solvent casting technique employing PEG 400 as plastsizer and ethyl cellulose as film forming polymer. Films were prepared in rectangular shape of 4X2 cm 2 size.
Each of the film was uniform throughout on basis of its weight. The average weight of film was found to be 415 to 607 mg, respectively, for batches L1-L9. Weight of films was increased as the amount of polymer increased.
Thickness of film for each batch was also found to be significantly uniform throughout. The average thickness of film was found to be 0.78 to 0.98 mm, respectively, for batches L1-L9.
The percentage drug content was also found to be uniform. The average % drug content was noted to be 96.8 to 99.1 % respectively, for batches L1-L9.
The Folding Endurance of the prepared films was evaluated and the results revealed that the amount of polymer is directly correlated to the folding endurance. Lower the amount of polymer lesser the folding endurance. The observed folding endurance was 284 to 390 in batch L1 to L9.
Surface pH of all formulations range between 6.5 -7.1. Unfolding time was another important evaluation parameter for films. Lower amount of polymer take longer time to unfold and viceversa. Hence the batches which contain 600 mg of polymer having unfolding time 5 min which was good for the formulation.
Tensile strength of formulations ranges between 0.274 to 0.342 kg/cm 2 . Again this parameter was directly impacted by the amount of plastsizer. Higher amount of plastsizer up to some level helps the films flexibility which improves the strength of films. Hence the batch which contains 0.7 ml of PEG 400 gives high tensile strength value.
Swelling index checked for all batches and results of the swelling index revealed that the higher the amount of polymer, the swelling capacity of films higher. The results show that the L1 batch having 18.3 % swelling and L9 batch have 30.3 % swelling. The sodium bicarbonate present in the matrix of film reacts in the acidic environment of the gastric fluid and generates CO 2 . Thus the generated gas entraps in the matrix of film as micro bubble which imparts buoyancy in the film. Floating lag time for drug loaded floating film was found to be ranging from 49 to 60 s. It was observed that on increasing the ratio of ethyl cellulose the floating lag time also increased. It may be attributed to delayed penetration of 0.1 N HCl in film matrix due to increased thickness of film. Total floating time of film was found up to 12 hour in all formulation, which could be considered for complete release of drug in stomach. The drug release from film was also studied in 900 ml, 0.1 N HCl at 37 °C up to 12 h. It was observed that as the amount of polymer increases in film matrix the release decreases significantly. This may be due to the fact that on increasing the polymer amount the film matrix got thicker and the drug molecules took more time to diffuse from the matrix. The release profile data of all the developed formulations were fitted in kinetic model. The best model was selected on the basis of goodness of fit the values of residual sum of squares (RSS).  Drug release kinetic study of optimized batch performed by fitting the dissolution data in kinetic model and the results showed in below table.  Figure 13: Different release kinetic model plots of formulation L8

Analysis of Factorial Design
The factorial design was applied using Minitab 16 software by free trial version. For analysis purpose following data fitted in to software and 3 2 design selected.

Dependent Factors
Y1=Folding Endurance Y2=% Drug release at 8 hour After fitting of data in Minitab 16, regression analysis was done and the outcome of this analysis showed below.

Stability Study
Stability study of final optimized batch L8 performed for 1 month at 40°C and 75% RH. Initial results and after 1 month results compared and found satisfactory. The batch was found stable during stability. The results were recorded in below table.