INTRODUCTION^1,2:

The concept of Fast Dissolving Drug Delivery System emerged from the desire to provide patient with conventional mean of taking their medication. Difficulty in swallowing (Dysphasia) is a common problem of all age groups, especially elderly and pediatrics. Mouth dissolving films are prepared by many techniques, mainly solvent casting method. Hydralazine hydochloride (1-hydrazinylphthalazine) is a direct smooth muscle relaxant used to treat hypertension by acting as a vasodilator.

Hydralazine increases cyclic guanosine monophosphate (cGMP) levels, increasing the activity of protein kinase G (PKG) muscle. This results in blood vessel relaxation. It has an elimination half‐life is 2-4 hrs. It is soluble in water (1g/125ml), slightly soluble in methanol (1g/500ml), soluble in 6.8 phosphate buffer (1g/MT 1000ml). The objective of this study was to formulate Hydralazine hydrochloride fast dissolving sublingual film using solvent casting method and to clarify the effect of superdisintegrant like pvpk-30 on the disintegrating and dissolution properties of film. The oral route is the most preferable route for administration of dosage forms from the view of patient compliance. One such new drug delivery route is the mouth Dissolving Films i.e. FDSF’s. Such film can be prepared by using hydrophilic polymers that can gets rapidly dissolve in the buccal cavity. Fast dissolving oral drug delivery systems are the system which disintegrates or dissolves within 1 min when placed in the mouth without use of any kind of liquid. As these dosage forms are meant to be administered through oral cavity, so it’s important to study the oral structure. The surface of buccal cavity consists of stratified squamous epithelium which is separated from the underlying tissue of lamina propria and submucosa by basement membrane. The interesting thing is that the permeability of buccal mucosa is more than that of the skin, but less than that of intestine. It is also studied that the permeability of the buccal mucosa is approximately 4–4000 times greater than that of the skin. Hence the buccal delivery or oral delivery serves as an excellent platform for absorption of molecules that have poor dermal penetration. Oral transmucosal drug delivery systems are generally meant to deliver the drug either for: Immediate release of drug for quick action. Pulsatile release of drug with fast appearance of drug into systemic circulation and simultaneous maintenance of drug concentration within therapeutic range or Controlled release of drug for long period of time.

MATERIALS AND METHODS:

Hydralazine hydrochloride was Gifted from IPCA pharmaceuticals and PEG-400 (LR), PVA (LR) and PVP-K30 (LR) Are purchased from Reliance Cellulose, Evonik, Kolkata

Preformulation study:^2-4

Preformulation testing is the first step in rational development of dosage forms of a drug substance. Preformulation study is the process of optimizing the delivery of drug through determination of physicochemical properties of the new compound that could affect drug performance and development of an efficacious, stable and safe dosage form. It gives the information needed to define the nature of the drug substance and provide a framework for the drug combination with pharmaceutical excipients in the dosage form. Hence, Preformulation studies were performed for the obtained sample of drug for identification and compatibility studies.

Identification of drug:

Organoleptic properties of drug:^5,7

The sample of Hydralazine Hydrochloride was studied for organoleptic properties such as colour, odour, and appearance

Melting point:⁵

It includes drug characterization. Capillary fusion method was used to determine the melting point of Hydralazine hydrochloride. The determined melting point of Hydralazine hydrochloride was 273°C which is identical to the theoretical value which is 270-273° C.

Solubility ⁵

The solubility of Hydralazine Hydrochloride was checked in different solvents like Water , methanol, 6.8 Phosphate buffer etc.

Fourier transform infra-red (FTIR) analysis:

Infra-red spectroscopic analysis was performed by Fourier Transform Infrared Spectrophotometer ECO-ATR (BRUKER), with a resolution of 8cm-1, in the range of 4000-500 cm-1, using Diomand disc

Compatibility study

Fourier transform infra-red (ftir) analysis:^5,6

Compatibility study was carried out by using Fourier transform infrared spectrophotometer (Bruker). FTIR study was carried on pure drug, PVP+PVA+Drug. Physical mixture of drug and polymers were prepared and samples were kept for 1 month at 400C. The infrared absorption spectrum of Hydralazine Hydrochloride and physical mixture of drug and polymers was recorded.

Differential scanning calorimetry

The powdered sample (3 mg) was hermetically sealed in aluminum pans and heated at a constant rate of 10 °C/min, over a temperature range of 30–300 °C with nitrogen. Flow rate of 30 ml/min. Thermogram of the sample was obtained using differential scanning calorimetry (DSC-60, Shimadzu, Japan). Thermal analysis data was recorded with Shimadzu software programs.

Evaluation of hydralazine hydrochloride sublingual film

Mechanical Properties^{: 8,9}

Mechanical properties of the films were evaluated using TexturePro CT V1.4 build 17 analyzer equipment by Brookfield Engineering Labs, Inc. equipped with a 50 N load cell. Films are held between two clamps positioned between 3 cm. During measurement the strips were pulled at the rate of 0.3mm/sec. The force and elongation are measured when film breaks. Two mechanical properties namely tensile strength and % elongation were calculated.

Tensile strength: ^8,9,10

Tensile strength is the maximum stress applied to a point at which the strip specimen breaks. Tensile testing of the film was determined with digital tensile tester, which consists of two load cell grips. The lower one is fixed and upper one is movable. The test film of specific size was fixed between cell grips and force was gradually applied till the film breaks.

Fig no-1.texturepro CT V1.4 build 17 analyzer equipment (INTRON TENSILE TESTER)

Tensile strength is calculated by Formula at break

Percent Elongation^{: 8,9,10}

It is calculated by the distance travelled by pointer before the break of the film on the graph paper. When stress is applied, a film strip sample stretches and this is referred to as strain. Strain is basically the deformation of film strip divided by original dimension of the sample. Generally elongation of strip increases as the plasticizer content increases. It is calculated as

Thickness of the Film: ^11,12,13

The thickness of the drug loaded films was measured with the help of micrometer screw gauge at different strategic locations like four corners and center of the each film. Mean SD was calculated. The standard range for film thickness should not be less than 5 %. This is essential to assure uniformity in the thickness of the ﬁlm as this was directly related to the accuracy of dose.

Weight variation of the film:^14,15,16

Weight variation is studied by individually weighing 10 randomly selected filmstrips using Shimadzu, Japan balance and calculating the average weight. It should not deviate significantly from average weight. According to specifications given in I.P.2007 for 30 mg film standard deviation should not be more than 10 %.

Folding endurance: ^17,18,19

It is measured manually for the prepared oral film. A film was repeatedly folded at the same place till until it breaks. The number of times the film could be folded at the same place without breaking gave the value of folding endurance. This test was performed on three films of each formulation and mean ±SD was calculated.

Surface pH: ^19,20,21

The film formulation has to be kept in the oral cavity, pH of the saliva ranging from 5.5-7.5. So, to dissolve and solubilize the drug in saliva present in the oral cavity the pH of film should keep near to neutral. Since acidic or alkaline pH may leads to irritation to the buccal mucosa. The surface pH of the film was calculated in order to investigate any side effects in vivo. A combined pH electrode was used for this purpose. The film preparation to be tested was placed in nesseler cylinder and was slightly moistened with 0.5 ml distilled water introduced drop wise. The pH is measured by bringing the electrode in contact with the surface of the oral film and allowing equilibrating for 1 min. The study performed on three films of each formulation and mean ±SD was calculated.

Ex-vivo Mucoadhesive strength of sublingual film:^10,11

Mucoadhesion was evaluated using a texture analyzer (CEB Texture Analyzer, Make- Brookfield Engineering Labs, Inc., Model no.Texture Pro CT V1.4 Build 17). Goat buccal mucosa was utilized as the model membrane for mucoadhesive strength determination of various formulations. A patch was carefully attached to a 10-mm cylindrical probe (TA probe) by a double face tape. The upper platform was moved downward manually near to the mucosa surface and then the polymer sample was brought toward the mucosa at a constant speed of 0.5 mm/s until a predetermined compressive force of 1 N was applied for 60 s. The probe was then removed at 5 mm/s to a distance of 15 mm and maximum detachment force (kg) was determined for each Sample. For each new sample, a different mucosa sample was used (Peh and Wong 1999)

Fig no-2 Modified balance for bioadhesive study

A: Modified balance, B: Weighing pan, C: Weight , D:Sublingual film, E: Buccal mucosa F:polypropylene cylinder.

Swelling Index :¹¹

For the determination of swelling index the preweighed three patches of 2×2cm2 of each formulation were placed in in a petridish and 50 ml of phosphate buffer, pH 6.8 was added.. The percent swelling For the determination of swelling index the. After particular interval patches was removed and wiped with tissue paper and weighed. Formula of Swelling Index

S.I = W2-W1/ W1 ×100

Where-S.I. - swelling index

Percent moisture absorption study:¹¹

The percentage moisture loss was carried out to check integrity of the film at dry conditions. film from each batch were weighed and kept in a desiccators containing anhydrous calcium chloride. After three days, the patches were taken out and reweighed. The percentage moisture loss. The percentage moisture absorption was calculated by.

%Moisture = (Final weight-Initial weight) X 100

absorption Initial weight

Uniformity of Content: ^11,12

The films were tested for content uniformity. Films of size 4cm2 is placed in 100 ml volumetric flask and dissolved in methanol, ume is made up to 100 ml with methanol (100µg/ml). Samples were suitably diluted by using methanol. The absorbance of the solution was measured at 264.0 nm in UV spectrophotometer. The acceptance value (AV) of the formulation should

In-vitro disintegration time:^11,12

In vitro disintegration time was determined visually in a glass dish of 25 ml distilled water with swirling every 10 seconds. The test was performed in triplicate for each formulation. The disintegration time is the time when the film breaks or disintegrates. All the films were subjected to disintegration test and results obtained. In Indian pharmacopoeia limits for disintegration is 1-3 min for fast dissolving dosage forms.

In-vitro drug release study: ¹²

The in vitro dissolution study was carried out in freshly prepared deionised simulated saliva solution pH 6.8 phosphate buffer using USP paddle apparatus at 37±0.5oC. Percent drug release was calculated for each formulation. Samples were withdrawn at every 1 min time interval within 5 min dissolution study. Samples were diluted by 6.8 phosphate buffer solution and analysed by UV-Visible spectrophotometer.

Kinetics of drug release:¹³

The drug release of optimized formulation was fitted to zero order kinetics, first order kinetics, Higuchi model, Hixson-Crowell, Korsmeyer-Peppas model to ascertain the kinetic modeling of drug release and the model with the higher correlation coefficient i.e. higher R² was considered to be the best fit model (Deshmane et al. 2009, Alanazi et al. 2007)

Differential Scanning Calorimetry:

The formulation was hermetically sealed in aluminium pans and heated at a constant rate of 10 °C/min, over a temperature range of 30–300 °C with nitrogen flow rate of 30 ml/min. Thermogram of the sample was obtained using differential scanning calorimetry (DSC- 60, Shimadzu, Japan). Thermal analysis data was recorded with Shimadzu software program

Optimization study:¹⁸

Study is carried using design expert software 9.0.3.1 version. Statistics are apply to the results obtained from general factorial design in which two independent variables varied namely polyvinyl alcohol (X1) and polyvinyl pyrrolidone K-30 (X2) and their effect is recorded on dependent variable namely % drug release (Y1). Evaluation and interpretation of research findings are almost important and the p-value serves a valuable purpose in these findings.

Morphology study:

These surface morphology of the films was studied using scanning electron microscopy (SEM), at a definite magnification. For this purpose JOEL JSM-6390 Scanning Electron Microscope was used. The external morphology of the formulation F6 was analyzed using SEM to determine the drug distribution within the film.

Stability studies: ^18,19

The standard test conditions for stability study were Given in table no-2

Test Conditions
Duration of study:	90 days
Temperature conditions:	25± 2°C
Relative humidity conditions:	60± 5%
Frequency of testing the samples:	30, 60 and 90 days.

The Optimized formulation 6 was evaluated mainly for its physical characteristics at the predetermined intervals of 30day, 60day and after 90 days like appearance (colour changes), pH, drug content and disintegration time.

RESULT AND DISCUSSION:

PREFORMULATION STUDY:

Organoleptic Property:

A white crystalline powder, almost odorless powder complying with the description that is found in the literature.

Solubility:

Table 3: Solubility Profile of Hydralazine Hydrochloride

Sr. No.	Solvent	Solubility
1.	Water	Soluble
2.	Alcohol	Slightly soluble
3.	Ether	Soluble
4.	Methanol	Soluble
5.	Hydrochloric acid ( 0.1N)	Soluble
6.	Phosphate buffer pH 6.8	Soluble

Infra-Red Spectrum:

The Infra-Red spectrum of Hydralazine Hydrochloride is shown in Figure 2.

Fig No: 3 FTIR of Hydralazine Hydrochloride

The FTIR spectra of pure Hydralazine Hydrochloride showed the peaks at wave numbers (cm-1) which correspond to the functional groups present in the structure of the drug The FTIR spectrum of Hydralazine Hydrochloride exhibited characteristic signals shown in Table 3. The absorption bands shown by Hydralazine Hydrochloride are characteristic of the groups present in its molecular structure. The presence of absorption bands corresponding to the functional groups present in the structure of Hydralazine Hydrochloride and the absence of any well-defined unaccountable peak is a confirmation of the purity of the drug sample.

Compatibility Study

Fourier Transform Infrared Spectroscopy:

Overlay FT-IR spectra of physical mixture of drug with PVA, and PVP K-30, showed matching peaks with the pure drug spectra. The characteristic peaks of drug were also seen in the spectra of drug in combination with polymers (figure 4) which indicate compatibility of drug with polymers.

Fig No 4 : FTIR of mixture of Hydralazine Hydrochloride

Differential scanning calorimetry:

The DSC spectrum of Sublingual Film of Hydralazine Hydrochloride containing drug is shown in figure. 23. showed Sublingual Film of Hydralazine Hydrochloride endothermic sharp peak at 272⁰C. Studies shows that heat of solution is low which indicates that low energy is needed to solubilize the drug when administered as a Sublingual Film of Hydralazine Hydrochloride. A study also showed that drug is totally embedded within the polymer matrix of the film which indicates that stability of drug would be good

Fig No.5. DSC Spectra of Sublingual Film of Hydralazine Hydrochloride

Tensile strength:

Mechanical properties of the Sublingual film are evaluated using Texture Pro CT V1.4 Build 17 equipment equipped with a 50 N load cell. During measurement the strips were pulled at the rate of 2mm/sec. From the results it clears that when the concentration of the polymer increases, the tensile strength of the sublingual film also increases. The formulation F6 shows the maximum tensile strength. Presence of PEG 400 as a plasticizer imparts the flexibility to the Polymers. Tensile strength measures the ability of the Sublingual film to withstand rupture. The Formulation F6 shows the maximum strength 1.3650 ±0.0122, shown in Table 23 This might be due to formation of strong hydrogen bonds between polymer and plasticizer thereby imparting flexibility to withstand rupture, but formulation F3 also shows comparable tensile strength as compared to F7 formulation

Percentage elongation of the sublingual film:

The film of 03 inch X 10 mm was taken for the studies. Percentage elongation was found to be increased as increase in concentration of polymer in the film. Percent elongation of a single film varies from 26.08±0.200 to39.52±0.4606%

Thickness of the sublingual film:

The thickness of the drug loaded films F-1 to F-9 formulations was measured with the help of micrometer screw gauge at different strategic locations like four corners and center of the each films. Mean SD was calculated. Thickness should be controlled within a ± 5 % variation of standard value. Thickness of a single film varies from 0.13±0.0308 to 0.19±0.0360 mm.

Weight variation of sublingual film:

The weight of each sublingual film was taken on Electronic analytical balance and the weight variation was calculated as mean SD and percent deviation. Weight variation varies from 28.42±0.4304 to 31.12±0.0871.Results shows that all the film passed weight variation test as the variation is within the pharmacopoeia limits of ±10%

Folding endurance of the sublingual film:

The number of times the film fold until it breaks was reported. The studies reflex the influence of concentration of PVA in the formulation. As the concentration of PVA is increased, folding endurance is also increased. Formulation F2, F3 and F6 shows the largest folding endurance. The results indicate that concentration of PVA has significant impact on folding endurance of the film, and to maintain the same, concentration of PVP K- 30 should be kept to minimum

Surface pH:

The film formulations have to be kept in the oral cavity, pH of saliva ranging from 5.5-7.5. So, to dissolve and solubilize the drug in the saliva present in the oral cavity the pH of the film should keep near to neutral. If it is acidic it can leads to irritation of the buccal mucosa. Surface pH of the formulation does not show considerable variation in pH. Surface pH of all sublingual film are reported in Table 28.

Mucoadhesive strength of sublingual film:

Bioadhesive force means the force with which sublingual film bind to buccal mucosa. Greater mucoadhesion is indicative of prolonged residence time of a film. The mucoadhesion force increased significantly as the concentration of mucoadhesion polymers increased. The Detachment force was determined for sublingual film. Results of this test indicate that the variable PVA and PVPK-30 both are having effect on mucoadhesive strength. It shows that mucoadhesive force has increased with the increasing concentration of the PVA. The mucoadhesion strength of all sublingual film are shown below in table no 29.

Swelling Index of sublingual film:

The Swelling Index of each sublingual film was taken weighed on Electronic analytical balance and the Swelling Index was calculated as mean SD. Swelling Index varies from 50.55±2.92 to 95.04±0.7850.

Percentage moisture absorption study of sublingual film:

The percentage moisture absorption was carried out to check integrity of the film at dry conditions. Film from each batch were weighed and kept in a desiccators containing anhydrous calcium chloride. After three days, the Film were taken out and reweighed. The percentage moisture loss, percentage moisture absorption was calculated as mean SD. Percentage Moisture Absorption varies from 3.54±0.7338 to 11.73±1.76.

Uniformity of content:

Drug content of optimized batches were calculated by using sublingual film containing 10 mg of Hydralazine Hydrochloride. Three trials from each formulation are analyzed spectrophotometricaly. The mean value and standard deviation of all the formulations are calculated. The drug content ranging from 90.2±0.040 to 98.75 ±0.0291.The results indicated that in all the formulations the drug content is uniform The studies also show that uniformity of content was within the specifications range 85-115%.

In-vitro Disintegration Test:

In-vitro disintegration time is determined visually in a glass dish of 25 ml distilled water with swirling every 10 seconds. The disintegration is the time when sublingual film breaks or disintegrates. PVP K-30 is incorporated as a super-disintegrates. As the concentration of PVP K-30 increases, the disintegration time decreases. All the sublingual film were subjected to disintegration test and results obtained. In Indian pharmacopoeia limits for disintegration are 1- 3 min.

In-vitro Drug release study:

In-vitro dissolution study shows maximum release i.e. 98.55% for F6 formulation this could be attributed to higher concentration of PVP and Lower concentration of PVA in the formulation. This also resembles to the results of disintegration test.

Table No-4 Evaluation parameter of formulated sublingual film

Batch no	Tensile Strength (kg/mm²)	Elongation at break (%)	Thickness (mm)	Weight variation (mg)	Percent Deviation %	Folding Endurance
F1	1.2261 ± 0.012	27.12 ± 0.070	0.14 ±0.026	29.83±0.332	0.42	170 ± 0.97
F2	1.3075± 0.081	33.01± 0.837	0.16 ±0.015	30.88±0.017	0.21	189 ±1
F3	1.3191 ± 0.042	36.05± 0.355	0.17 ±0.026	31.10±0.107	0.13	193 ± 1.15
F4	1.1958 ± 0.035	26.08± 0.200	0.14 ±0.040	29.38±0.071	1.37	145 ± 1
F5	1.2750 ± 0.189	29.73± 0.568	0.15 ±0.033	30.19±0.052	0.06	188 ± 1.00
F6	1.3650± 0.083	39.52± 0.460	0.19 ±0.036	31.12±0.087	0.11	211 ± 2.04
F7	1.1866± 0.045	26.72± 0.030	0.13 ±0.030	28.42±0.430	0.55	133 ± 1.50
F8	1.2141± 0.061	26.10± 0.856	0.14 ±0.021	29.07±0.522	0.67	153± 1
F9	1.2225± 0.061	27.09± 0.162	0.14 ±0.020	30.05±0.050	0.05	170 ±0.5774

Table No-5 Evaluation parameter of formulated sublingual film

Batch no	Surface pH	Mucoadhesive force N	Swelling Index (mg)	Moisture Absorption (mg)	% Drug content	Disintegration time (sec)
F1	6.34 ±0.0212	0.171	68.49 ±1.0014	5.97 ±2.76	98.75 ±0.0291	53.11 ±0.1529
F2	6.72 ±0.0222	0.189	83.86 ±0.351	7.61 ±0.4335	96.83 ±0.020	57.05±0.055
F3	6.8 ±0.0141	0.190	87.87 ±0.7238	9.06 ±1.23	97.94±0.02	58.12± 0.00029
F4	6.21 ±0.0212	0.164	59.68 ±3.62	4.14 ±1.4	91.36 ±0.0150	49.92±0.371
F5	6.73 ±0.0158	0.182	73.35 ±0.8183	6.52 ±0.2367	95.07 ±0.01224	56.95± 0.0670
F6	6.84 ±0.0474	0.21	95.04±0.7850	11.73±1.27	98.75 ±0.0291	59.03± 0.038
F7	6.17 ±0.0173	0.152	50.55±2.92	3.54 ±0.7338	90.2±0.040	40.13±0.1311
F8	6.29 ±0.0122	0.165	62.53±0.6710	5.08 ±1.70	93.12±0.0261	50.01±0.0982
F9	6.49 ±0.026	0.180	69.92±0.9271	6.26 ±0.3901	94.58±0.0353	54.09±0.10

Table No.6. In-vitro drug release study of all formulations

TIME IN MIN	% CUMULATIVE DRUG RELEASE ± S.D
TIME IN MIN	F1	F2	F3	F4	F5	F6	F7	F8	F9
1	57.34± 0.010	67.464 ±	66.62 ±	64.09 ±	58.33±	77.70±	48.66 ±	64.31±	63.39±
	57.34± 0.010	0.01	0.0010	0.008	0.0017	0.010	0.0024	0.0124	0.001
2	62.17 ±	76.291±	71.36±	77.86±	62.49±	81.50±	59.64±	68.59±	68.56±
	0.0144	0.0013	0.0006	0.0077	0.0003	0.002	0.002	0.0014	0.002
3	67.36±	79.96±	83.79±	80.75±	65.71±	86.89±	74.58±	75.39±	73.67±
	0.0036	0.0003	0.0099	0.0066	0.0025	0.001	0.0027	0.0028	0.002
4	71.17±	84.59±	87.29±	84.57±	75.80±	92.75±	79.08±	81.57±	78.10±
	0.006	0.0009	0.001	0.0009	0.0003	0.0001	0.0025	0.0018	0.002
5	89.59±	90.34±	93.34±	85.87±	88.68±	98.55±	83.87±	86.56±	87.85±
	0.002	0.0051	0.0101	0.004	0.0006	0.032	0.0046	0.0027	0.004

Fig No.6.Comparative Evaluation of In-vitro drug release study of sublingual film of Hydralazine Hydrochloride

Optimization:

Statistics was applied to the results obtained from general factorial design in which two independent variables varied namely Polyvinyl alcohol (X1) and Polyvinyl Pyrrolidone (X2) and their effect is recorded on dependent variable namely % drug release (Y1).Evaluation and interpretation of research findings are almost important and the p-value serves a valuable purpose in these findings. Table 7, shows ANOVA for the dependent variable % drug release. The values of X1 and X2 were found to be significant at p < 0.05, hence confirmed the significant effect of both the variables on the selected responses. Variable caused significant change in the responses. From this data optimum concentration of polyvinyl pyrrolidone 20 mg and polyvinyl alcohol 30 mg was found.

Table No.7 ANOVA for % Drug release (Y1).

Source

Degree of

Freedom

F value

P-value

Inference

Model

6.78

0.0289

Significant

A-PVA

8.80

0.0250

B-PVP K -30

4.75

0.0721

std.dev. = 2.81

R-Squared = 0.6931

The Variance Inflation Factor (VIF) measured how much the variance of that model coefficient was inflated by the lack of orthogonality in the design and was calculated for % drug release. It was found to be near to one which indicating good estimation of the coefficient. Similarly Ri-squared was near to zero which led to good model. The values of Prob>F were less than 0.0500, which indicated model terms were significant.

The linear model obtained from the regression analysis used to build a 3-D graph’s in which the responses were represented by curvature surface as a function of independent variables. The relationship between the response and independent variables can be directly visualized from the response surface plots.The response surface plots were generated using Design Expert 7.0.0.0. Software presented in figure. 33. to observe the effects of independent variables on the response studied % drug release.

From response surface 3 level factorial design was chosen using linear design mode. The range was set from minimum 83.87 to maximum 98.55 The 9 run was performed for the response % Drug release and model was found to be linear.

Fig. No 7: Surface Response plot showing effect of polyvinyl alcohol And polyvinyl Pyrrolidone K-30 on Release

Fig No. 8: The contour plot showing effect of polyvinyl alcohol and polyvinyl pyrrolidone K-30 on Release

Perturbation Plot

Fig no-9 perturbation plot

Kinetics of drug release

Determination of best fit model for dissolution

First Order kinetics of optimized formulation From the results of R² (table 36 and fig. 38), Zero order, Higuhci, Korsmayer-peppas models were found to be best fit. This indicates that drug diffuse from the Film in Immediate manner with erosion of polymer matrix

Table 8: R² values and slope values for applied values

S. No.	Models	R²values	Slope value
1	Zero order	0.994	0.5295
2	First order	0.997	0.0263
3	Higuchi	0.9643	1.963
4	Korsemayer-Peppas	0.9249	0.1499

Fig no-10 zero order kinetic of formulation f6 batch

Fig no-11 First order kinetic of formulation f6 batch

Fig no-12 Higuchi model of formulation f6 batch

Fig no-13 korsemeyer-peppas equation of formulation f6 batch

The classical First order release order curve was found to be linear .the curve plotted according to Zero order and Higuchi model were also found to be linear, for the korsemayer - peppas release curve R²was found to be ≥0.75 for all 9 formulations .and value was found to be ≥0.14which indicates that all the formulations show anomalous (Non-Fickian release: swelleable matrix) The drug release occurs probably by Erosion dissolution. from the above table it is seen that the best fit model for formulation in first order kinetic such type of model is applicable when fast dissolving mechanism are seen

Scanning Electron Microscopy (SEM):

Fig No. 14. SEM Photograph at x 500

Surface of the Sublingual film was found to be uniform but with some particulate spots this may be because of improper drying of the sublingual film. But this problem can be overcome by increase in concentration of PVP or by changing in drying cycle

Stability studies:

Table No. 9 Stability data for F6 formulation

SR. NO	OBSERVATION	BERFOR STABILITY TESTING	AFTER STABILITY TESTING
1.	Drug content	98.75%	98.15%
2.	Visual appearance (Colour changes)	Light yellow	Light yellow
3.	pH	6.8	6.8
4.	Disintegration time	59 Sec	58 Sec

Optimized formulation F6 at 40^oC, 75% RH ± 5 % was found to be stable up to 90 days. There was no significant change in drug content, visual appearance i.e. change in colour. All Formulations stored at elevated temperature showed slight change in pH and disintegration time, other parameters were found to be unchanged.

CONCLUSION:

Finally it is concluded that the drug release from the sublingual film was increased by using the increased concentration of superdisintegrant thus assisting in faster disintegration in the buccal cavity. As the drug is having low solubility, fast disintegration may lead to more drug availability for dissolution, resulting in faster absorption in systemic circulation. Increased systemic availability of drug may lead to quick onset of action, which is a prerequisite for hypertension patient optimized formulation fulfils all necessary attributes required for sublingual film and can become a promising alternative to present marketed tablet.

REFERENCES:

1. K.D. Tripathi, Antihypertensive drugs, essentials of pharmacology, Ed ” Jaypee medical publications,6^th ed:pp 512-528.

2. WHO guideline Global health risks: mortality and burden of disease attributable to selected major risks, 2009.

3. Talseth T. Clinical pharmacokinetics of hydralazine. Clin Pharmacokinetic 1977; 2: 317. 46

4. Rowe R C., Sheskey P.J., Owen S., Hand book of pharmaceutical excipient, Pharmaceutical Press; 5^th ed:pp.517-522; 592-593; 611-616.

5. Indian Pharmacopoeia , A publication of the I.P. commission, Ministry of Health & Family Welfare Government of India, 6th edition; Published by I.P commission, Ghaziabad ,2014: vol 2,pp 1897-1899

6. USP-NF, the official compendia of standards, Asian edition, 2008:vol 2,pp 2488-2490.

7. British pharmacopoeia , Published by British Pharmacopoeia Commission,2009 vol- II, pp:1172-73.

8. Singh S., Jain S., Muthu M. S., Tiwari S., Tilak R., Preparation and evaluation of buccal bioadhesive films containing clotrimazole; AAPS Pharm sci , 2008 ; 9(2) : pp:660- 66.

9. Nitesh S.C., Tomar A., et. al., Formulation and Evaluation of Fast Dissolving Oral Film of Dicyclomine as potential route of buccal delivery; International Journal of Drug Development and research, 4(2) :2012: 408-417.

10. Salunkhe S.D., Sathe B.S., Jain P., Patil R.N., Formulation and Evaluation of Fast Dissolving Oral thin film of Ropinirole HCl; International Journal of Chemistry and Pharmaceutical Sciences,1(5) :2015: 351-361

11. VA. Deore, RS Kumar and PS Gide ,Development and statistical optimization of Mucoadhesion Buccal Patches of Indomethacin In –vitro and Ex- vitro evaluation International Jornal of Advances In Pharmacy Biology And Chemistry, 2013 Apr-June: 2(2):415-416

12. Nagaveni Somepalli , Chandra Shekhar Moru, Formulation And Evaluation of Buccal films of salbutamol sulphate ,Mintage Journal Of Pharmaceutical And Medical Sciences ,2013

13. Upendra C Galgatte, Sunil S Khanchandan, Investigation of Different Polymer Plasticizers And Superdisintegrating Agents Alone And In Combination For Use In The Formulation Of Fast Dissolving Oral Films; International Journal of PharmaTech Reaserch - 2013 , 5(4)

14. Samanthula Kumara Swamy et al , devolpment and in vitro evaluation of bioadhesive buccal tablets of Hydralazine Hydrochloride International journal of pharmacy education and research , Apr-June; 1(2):2014:8-16

15. Geetika Sharma et al ,formulation ,Evaluation And Optimization of Mouth Dissolving Tablet of Hydralazine Hydrochloride Using Novel Co-Processing Technique, International Journal of Scientific Progress And Research , 2015: 12(1)

16. Amol pachade et al , Devlopment and evaluation of mucoadhesive film of Acyclovir in Oral environment – along with model study of chloehexidine ,Scholars research library , 2013 ; 5(6) :60-66

17. Rowe R.C., Sheskey P.J., Quinn M.E., Handbook of Pharmaceutical excipients, Pharmaceutical Press; 6^th ed :pp 517-522; 564-565; 581-585

18. Banker G.S., Rhodes C.T., Modern pharmaceutics, vol 121, 4th edition, revised and expanded, Marcel Dekker, New York, Basel, Chpt.18.

19. ICH Harmonised Tripartite Guideline, International Conference on Harmonisation Stability testing of new drug substances and products Q1A (R2) and Evaluation for stability data Q1E, current step version, 6 February 2003.

20. USP-NF 2008, the official compendia of standards, Asian edition, vol 2, 2488-2490.

21. Hypertension Available at: http://en.wikipedia.org/wiki/Hypertension(Last accessed on March 2014)

Received on 29.06.2016 Modified on 08.07.2016

Research J. Pharm. and Tech 2016; 9(10):1681-1690.

DOI: 10.5958/0974-360X.2016.00339.5

Ingredients (mg)	F1	F2	F3	F4	F5	F6	F7	F8	F9
Hydralazine Hydrochloride	180	180	180	180	180	180	180	180	180
PVP	150	150	150	200	200	200	250	250	250
PVA	200	250	300	200	250	300	200	250	300
PEG-400	0.18	0.18	0.18	0.18	0.18	0.18	0.18	0.18	0.18
Sod. Saccharin	40	40	40	40	40	40	40	40	40
Water.	q.s.	q.s.	q.s.	q.s.	q.s.	q.s.	q.s.	q.s.	q.s.