Description:FIELD OF THE INVENTION
[0001] The present disclosure relates generally to pharmaceutical formulations of Zaleplon. More specifically, the disclosure is directed to a buccal disc formulation comprising Zaleplon and a mucoadhesive polymer of modified Moringa Oleifera gum. The present disclosure also provides a process of manufacturing the formulation.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Sleep, as well as food and shelter, are a significant necessity for all humans, and in a demanding environment often psychological stresses contribute to inadequate sleep habits that damage biological clocks. Nearly 25% of adults are affected by insomnia and about 10% are chronic. Sleeplessness is categorized into four major types: irregular waking, early morning awakening, low sleep quality and sleep difficulties. Zaleplon (ZLP) is a pyrrazolopyrimidine used for the treatment of insomnia and epilepsy. ZLP has a good sensitivity to the a1 subunit on the GABAA receptor in the brain that stimulates the activity of GABA more selective than benzodiazepines, which is a short term hypnotic for sleep induction (Dooley, M. and Plosker, G.L., 2000. Zaleplon. Drugs, 60(2), pp.413-445).
[0004] It has two major problems from pharmaceutical point of view one is low bioavailability and the other is poor aqueous solubility. ZLP is often affected by comprehensive hepatic metabolism first pass that leaves only 30% of systemic and short removal half-life (1 h) available (Drover, D.R., 2004. Comparative pharmacokinetics and pharmacodynamics of short-acting hypnosedatives. Clinical pharmacokinetics, 43(4), pp.227-238). The production of drugs that suffer from substantial first-pass metabolism in a more bioavailable form has faced an emerging challenge since the birth of pharmaceutical field.
[0005] In recent years, there has been a significant rise in interest in the advancement of novel intra-oral drug delivery systems. The distribution by buccal delivery was always an appealing alternative, since it provides a pathway to system circulation which overcomes the destructive metabolism of traditional oral routes and leads to improved bioavailability (Di Benedetto A, Gigante I, Colucci S, Grano M. Periodontal disease: linking the primary inflammation to bone loss. Clinical and Developmental Immunology. (2013); 23). Extension of their release limits regular dosage for medicines with limited half-life, and for ZLP that means avoiding an early morning wake without mid night dose. In pediatric and geriatric patients, this route of administration is particularly appropriate, as people sometimes fail to swallow conventional solid oral doses. In addition to this, the oral route is very useful for ineffective medications, for those that disturb the gastrointestinal tract or cause nausea and vomiting.
[0006] Thus, there is a need in the art to devise buccal drug delivery systems for improving the bioavailability and overcoming poor solubility of Zaleplon.

OBJECTS OF THE INVENTION
[0007] An object of the present disclosure is to provide a buccal drug delivery system for Zaleplon.
[0008] Another object of the present disclosure is to provide a buccal disc formulation of Zaleplon using a mucoadhesive polymer of modified Moringa Oleifera gum.
[0009] An object of the present disclosure is to provide a buccal disc formulation with improved swelling, drug release and bio-adhesion to buccal cavity.
[0010] Yet another object of the present disclosure is to provide a process for manufacturing the buccal disc formulation.

SUMMARY OF THE INVENTION
[0011] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in Detailed Description section. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
[0012] The present disclosure relates to buccal delivery systems comprising Zaleplon that improves its systemic circulation by avoiding gastrointestinal and hepatic metabolism.
[0013] In an aspect, the present disclosure provides a buccal disc formulation comprising Zaleplon and mucoadhesive polymer of Moringa Oleifera gum.
[0014] In an embodiment, the buccal disc formulation comprises Zaleplon and modified Moringa Oleifera gum; wherein the modified Moringa Oleifera gum is a graft-polymer of Moringa Oleifera gum and acrylamide.
[0015] In an embodiment, the Moringa Oleifera gum is modified by microwave-assisted graft co-polymerization reaction.
[0016] In another embodiment, the formulation further comprises one or more pharmaceutically acceptable excipients. The pharmaceutically acceptable excipients may be selected from lubricant, fillers, binder, stabilizer, flavoring agent or combinations thereof.
[0017] In an aspect, the present disclosure provides a medicament comprising the buccal disc formulation comprising Zaleplon and modified Moringa Oleifera gum.
[0018] In another aspect, the present disclosure provides a bi-layered chrono-patch for pulsating release of Zaleplon comprising at least one layer of buccal disc formulation comprising Zaleplon and modified Moringa Oleifera gum, wherein the modified Moringa Oleifera gum is a graft-polymer of Moringa Oleifera gum and acrylamide. Preferably the buccal disc formulation may be a lyophilized buccal disc formulation.
[0019] In another aspect, the present disclosure provides a process of manufacturing a buccal disc formulation comprising Zaleplon and modified Moringa Oleifera gum, wherein the modified Moringa Oleifera gum is a graft-polymer of Moringa Oleifera gum and acrylamide.
[0020] In an embodiment, the process of manufacturing buccal disc formulation comprising Zaleplon and modified Moringa Oleifera gum, comprises the steps of: (a) mixing Moringa Oleifera gum with acrylamide and a catalytic amount of a free radical initiator; (b) irradiating the mixture of step (a) with a microwave irradiation in a periodic heating-cooling cycle to give the modified Moringa Oleifera gum; (c) mixing the modified Moringa Oleifera gum with Zaleplon and optionally one or more pharmaceutically acceptable excipients to give a mixture; and (d) compressing the mixture to give the buccal disc formulation.
[0021] Other aspects of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learnt by the practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The following drawings form part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.
Figure 1 provides the Fourier Transform Infrared Spectrum (FTIR) of Zaleplon.
Figure 2 provides the Differential Scanning Calorimeter (DSC) curve of Zaleplon.
Figure 3 provides the X-ray diffraction (X-RD) diffractogram of Zaleplon.
Figure 4 provides pictorially the Scanning Electron Microscopy (SEM) images of: (a) shape of drug Zaleplon and (b) the surface of drug Zaleplon.
Figure 5 provides the absorbance versus concentration (µg/mL) calibration curve of Zaleplon in phosphate buffer at pH 6.8.
Figure 6 provides FTIR spectrum of native Moringa Oleifera gum.
Figure 7 provides FTIR spectrum of grafted polymer or modified Moringa Oleifera gum prepared as per an embodiment of the present disclosure.
Figure 8 provides the DSC curve of native Moringa Oleifera gum.
Figure 9 provides the DSC curve of grafted polymer or modified Moringa Oleifera gum prepared as per an embodiment of the present disclosure.
Figure 10 provides the X-RD diffractograms of: (a) native Moringa Oleifera gum; (b) modified Moringa Oleifera gum prepared as per an embodiment of the present disclosure; (c) drug (Zaleplon) and native Moringa Oleifera gum; and (d) drug and modified Moringa Oleifera gum prepared as per an embodiment of the present disclosure.
Figure 11 provides the SEM images of Moringa Oleifera gum showing: (a) shape and (b) surface of native Moringa Oleifera gum; shape (c) and surface (d) of modified Moringa Oleifera gum prepared as per an embodiment of the present disclosure; and shape (e) and surface (f) of the buccal disc formulation prepared as per an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION
[0023] The following is a detailed description of embodiments of the disclosure. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0024] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0025] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0026] In some embodiments, numbers have been used for quantifying weights, percentages, ratios, and so forth, to describe and claim certain embodiments of the invention and are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0027] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0028] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0029] Unless the context requires otherwise, throughout the specification which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense that is as “including, but not limited to.”
[0030] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein.
[0031] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0032] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified.
[0033] The description that follows, and the embodiments described therein, is provided by way of illustration of an example, or examples, of particular embodiments of the principles and aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure.
[0034] It should also be appreciated that the present disclosure can be implemented in numerous ways, including as a system, a method or a device. In this specification, these implementations, or any other form that the invention may take, may be referred to as processes. In general, the order of the steps of the disclosed processes may be altered within the scope of the invention.
[0035] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
[0036] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
[0037] As described herein, the term ‘effective amount’ refers to the amount of the composition required to bring about a change or improvement in a subject without side effects or overdosing.
[0038] The term, "subject" as used herein refers to an animal, preferably a mammal, and most preferably a human. The term "mammal" used herein refers to warm-blooded vertebrate animals of the class 'mammalia' , including humans, characterized by a covering of hair on the skin and, in the female, milk-producing mammary glands for nourishing the young, the term mammal includes animals such as cat, dog, rabbit, bear, fox, wolf, monkey, deer, mouse, pig and human.
[0039] The terms ‘Moringa Oleifera gum’ and ‘Moringa Oleifera’ have been used interchangeably throughout the present disclosure.
[0040] The terms ‘modified Moringa gum’ and ‘graft polymer Moringa gum’ have been used interchangeably throughout the present disclosure.
[0041] As used herein, the term ‘modified Moringa gum’ refers to a graft co-polymer of Moringa gum and acrylamide obtained by microwave assisted graft co-polymerization reaction.
[0042] In an embodiment, the present disclosure provides a buccal disc formulation comprising Zaleplon.
[0043] In an embodiment, the buccal disc formulation comprises Zaleplon and modified Moringa Oleifera gum, wherein the modified Moringa Oleifera gum is a graft-polymer of Moringa Oleifera gum and acrylamide.
[0044] In an embodiment, the formulation comprises Zaleplon in a range of about 6%w/w to about 7%w/w, preferably about 6%w/w to about 6.25%w/w of the formulation.
[0045] In an embodiment, the formulation comprises modified Moringa Oleifera gum in a range of about 37%w/w to about 40%w/w, preferably about 37%w/w to about 38%w/w of the formulation.
[0046] In an embodiment, the Moringa Oleifera gum may be extracted from the stem or bark of Moringa Oleifera tree. Alternatively, the Moringa Oleifera gum may be commercially obtained.
[0047] In an embodiment, the Moringa Oleifera gum is modified by grafting with acrylamide using microwave-assisted irradiation.
[0048] Graft polymer synthesis of the present disclosure is a microwave-initiated hybrid traditional synthesis process that is based on a free radical mechanism using radical microwave synergy to create free radical sites of the Moringa gum backbone with the free radical initiator. As the link is much more polar (as the bond of an OH), in the presence of micro-wave irradiation, it quickly breaks up into a free radical site on Moringa's backbone. Moringa Oleifera gum is essentially a polysaccharide that includes galactose (25.9 percent), rhamnose (5.6 percent) and traces of uronic acid in hydroxyl pending groups. Without being bound to theory, it is believed that with microwave irradiation, the hanging polysaccharide hydroxy groups rotate which result in dielectric heating, which increases the rate of reaction at these groups. Furthermore, the Gibb’s energy of reactivation is also decreased by the microwave irradiation leading to higher reaction times. In order to provide the free radical initiator in the reaction, free radicals that abstract hydrogen atoms from polysaccharide (gum) molecules that generate macro radicals are employed. These free radicals react with acrylamide for free radicals of acrylamide, resulting in a number of free, initiated chain reactions, which give the final products gum-g-poly(acrylamide) and poly-homo-polymer (acrylamide), i.e., the modified Moringa Oleifera gum.
[0049] In an embodiment, the free radical initiator is ceric ammonium nitrate.
[0050] In an embodiment, the free radical initiator may be employed in a catalytic amount based on the amount of Moringa Oleifera gum and acrylamide employed. In a preferred embodiment, the free radical initiator may be employed in a range of about 1% w/w to about 10% w/w of the Moringa Oleifera gum.
[0051] In another embodiment, the formulation further comprises one or more pharmaceutically acceptable excipients. The pharmaceutically acceptable excipients may be selected from lubricant, fillers, binder, stabilizer, flavoring agent or combinations thereof.
[0052] In a preferred embodiment, the excipients may be selected from lactose, dicalcium phosphate, cellulose, microcrystalline cellulose, hydroxypropyl methylcellulose, polyethylene glycol 4000, talc, magnesium stearate, or combinations thereof.
[0053] In an embodiment, the formulation comprises excipient in a range of about 40%w/w to about 60%w/w of the formulation.
[0054] In an embodiment, the formulation provides a self-nanoemulsifying drug delivery system.
[0055] The formulation of the present disclosure is a buccal disc that controls the amount of drug being released. The modified Moringa Oleifera gum acts as mucoadhesive polymer and a drug release modifier that alters the physicochemical properties of the drug.
[0056] In an embodiment, the composition may be applied to the buccal mucosal membrane.
[0057] The formulation of the present disclosure has improved mucoadhesive strength in the buccal cavity, flow properties and swelling index compared to formulations comprising native Moringa Oleifera gum. The formulation provides higher ex-vivo bio-adhesion time at the buccal cavity and greater controlled release effect for the drug through the length of the day.
[0058] In an embodiment, the formulation may have mucoadhesion for a period of about 10 hrs to about 12.5 hrs.
[0059] The formulation overcomes the drawbacks of other known oral dosage forms by avoiding hepatic and gastrointestinal metabolism.
[0060] In an embodiment, the present disclosure provides a medicament comprising the buccal disc formulation comprising Zaleplon and modified Moringa Oleifera gum.
[0061] In another embodiment, the present disclosure provides a bi-layered chrono-patch for pulsating release of Zaleplon comprising at least one layer of buccal disc formulation comprising Zaleplon and modified Moringa Oleifera gum, wherein the modified Moringa Oleifera gum is a graft-polymer of Moringa Oleifera gum and acrylamide. Preferably the buccal disc formulation may be a lyophilized buccal disc formulation.
[0062] In another embodiment, the present disclosure provides a process of manufacturing a buccal disc formulation comprising Zaleplon and modified Moringa Oleifera gum, wherein the modified Moringa Oleifera gum is a graft-polymer of Moringa Oleifera gum and acrylamide.
[0063] In an embodiment, the process of manufacturing a buccal disc formulation comprising Zaleplon and modified Moringa Oleifera gum, comprises the steps of: (a) mixing Moringa Oleifera gum with acrylamide and a catalytic amount of a free radical initiator; (b) irradiating the mixture of step (a) with a microwave irradiation in a periodic heating-cooling cycle to give the modified Moringa Oleifera gum; (c) mixing the modified Moringa Oleifera gum with Zaleplon and optionally one or more pharmaceutically acceptable excipients to give a mixture; and (d) compressing the mixture to give the buccal disc formulation.
[0064] In an embodiment, the free radical initiator is ceric ammonium nitrate.
[0065] In an embodiment, the catalytic amount of free radical initiator depends on the amount of Moringa Oleifera gum and acrylamide. In a preferred embodiment, the free radical initiator may be employed in a range of about 1% w/w to about 10% w/w of the Moringa Oleifera gum.
[0066] In an embodiment, the microwave may have a power in a range of about 600W to about 1200W, preferably the microwave may be set at a power of about 800W.
[0067] For the periodic heating-cooling cycle the microwave is regularly stopped in a single boiling set (ca. 65°C) and cooled in cold water followed by irradiation again. This process may be repeated till a gel-like mass is obtained or in absence of gelling, for about 3-4 minutes.
[0068] In an embodiment, the modified Moringa Oleifera gum obtained may be gel like in consistency.
[0069] In an embodiment, the present disclosure provides a method of treatment of epilepsy or sleep associated disorders by administering a therapeutically effective amount of the buccal disc formulation to the subject.
[0070] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
EXAMPLES
[0071] The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed methods and compositions, the exemplary methods, devices and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such methods and conditions may vary.
[0072] Materials: Zaleplon was purchased from Unichem Laboratories Ltd., Goa, India. Moringa Oleifera gum was purchased from Yarrow Chem Products, Mumbai, India. Acrylamide and Ceric Ammonium Nitrate were obtained from V S Corporation, Chandigarh, India. Ethanol, di- calcium Phosphate, PEG-4000, Lactose, HPMC K15, microcrystalline cellulose, magnesium stearate, acetone and methanol were obtained from Loba Chemie Pvt. Ltd., Mumbai, India.
[0073] Statistical Data Analysis: The t-test was used for the interpretation by using ANOVA (Sigma Stat 3.5 Software). Statistically important was the gap below likelihood level 0.05.
[0074] Example 1: Characterization of Zaleplon
[0075] The purchased Zaleplon was characterized before forming the formulation:
[0076] a) FTIR spectroscopy: The FTIR spectrum was related to the pure drug. The infrared (IR) spectrum of the drug (Figure 1) indicates distinctly the peaks of the different functional groups found in the drug. The IR spectrum shows typical ranges for C-H extending vibration of 3087.7 cm-1, and 2933.7 cm-1. The bands of stretch vibrations -C=N (Alcohol) with 1614.4 cm-1 and 1223.5 cm-1 for C-N also display characteristic bands. It depicts the -C=C- (aromatic) stretch bands at 1576.3 cm-1. Zaleplon displays high uptake peaks of 2232.7 cm-1 and 1651 cm-1 suggesting cyanide involvement and carbonyl amide group. The ranges of IR peaks obtained were also seen in pure drug (Zaleplon). The melting point was determined by capillary fusion method and was found to be 157? compared to the literature value of 157-159?.
[0077] b) DSC Study: A few mg fine sample powder was placed into the regular aluminum bowl and heated at the speed of 10°C/min within 40-350°C temperatures in an inert nitrogen atmosphere (50 mL/min) and was thereafter analyzed. The DSC curve was sharp at 188.33°C, while a little plateau was observed at 45.73°C (refer Figure 2).
[0078] c) X-ray diffractometer: Powder XRD experiments were used to characterize the drug in solid state. A 0-80° (2 lbs) diffraction angle with scanning velocity of 0.005 min-1 at room temperature was used for the diffraction pattern. The sharp peaks of the diffractogram may be found in 2 lines = 10, 14, 16, 18, 21, 22, 25, 26 and 29, which are clearly illustrated in their crystalline existence (Figure 3). This reveals that the drug in crystalline shape has decreased to amorphous.
[0079] d) Scanning electron microscopy (SEM): SEM was used to study the drug’s surface morphology (ZEISS, EVO 18 and China). The powder mixture was placed on a double carbon tape that was mounted on a sample holder and sputtered under high vacuum with a thin film of gold. At varying magnifications, photo micrograms were taken at 20 kV accelerating voltage. Figure 4 provides the SEM images of pure drug with its shape (Figure 4a) and surface (Figure 4b).
[0080] e) Drug analysis: The U.V. spectroscopic approach in phosphate buffers of pH 6.8 was used for Zaleplon's study.
(i) Zaleplon ?max estimation by using U.V. Spectrophotometer:
[0081] Zaleplon was prepared in phosphate buffer of pH 6.8 and Tmax was scanned from 200-400nm using a visible spectrophotometer. According to published literature the scanned graph was reached at 254nm and this confirmed that the drug was Zaleplon. The parameters set for dissolution are provided in Table 1 below:
Table 1: Parameters for dissolution of Zaleplon in phosphate buffer
Medium As Specified
Volume 900 mL
Apparatus USP-1 (Basket Type)
RPM 100 r.p.m
Temperature 37o C ± 0.5 oC
Time Points As Specified

(ii) Preparation of the standard phosphate buffer curve of Zaleplon at pH 6.8:
[0082] 100 gms of Zaleplon was dissolved in a 100mL phosphate buffer of pH 6.8 to obtain a 1000µg/mL stock solution. Different concentrations of 1mL to 10mL solutions were prepared. The samples were then analyzed with a UV spectrophotometer (AU-2701 Systronic, Mumbai, India) at 254 nm. The µg/mL values in X-axis displayed a graph of concentration and Y-axis absorption values in Figure 5. The R2 and pitch values were 0.9958 and 0.0634. The test was conducted and the uniform curve from both readings was collected.
Table 2: Calibration Data of Zaleplon in Phosphate Buffer pH 6.8
Concentration (µg/mL) Absorbance
1 0.128
2 0.188
3 0.257
4 0.306
5 0.359
6 0.422
7 0.484
8 0.563
9 0.627
10 0.713

[0083] Example 2: Preparation of modified Moringa Oleifera gum by grafting technique
[0084] 1gm of native Moringa Oleifera gum was dissolved in 40mL of distilled water. 5mL of acrylamide was dissolved in 10mL of distilled water and then added to the Moringa Oleifera gum solution. The solutions were mixed well and transferred to a reaction vessel (250 mL beaker). A catalytic amount of Ceric Ammonium Nitrate (0.1 gms) was added to the reaction vessel and the vessel was then placed on a microwave turntable and heated with microwave irradiation power of 800W. The radiation was paused regularly in a single boiling set (~65°C) and was cooled by placing it in cold water. This cycle of heating-cooling was repeated for up to 3 minutes (in absence of gelling) or until a gel like mass was left. The contents of the reaction vessel were cooled and kept undisturbed to complete the grafting reaction. The obtained gel-like mass was poured into an excess of acetone (30%), resulting in precipitation of the graft-polymer of modified Moringa Oleifera gum. This was then dried (40°C), pulverized and sieved before storage. The percentage grafting efficiency (%GE) of this microwave assisted synthesized grafted polymer Moringa Oleifera gum was evaluated as:
% GE = [(Wt. of graft polymer - Wt. of polysaccharide)/ Wt. of monomer] × 100
wherein the monomer is acrylamide and polysaccharide is Moringa Oleifera gum.
Various copolymer grades were synthesized by differing concentrations of ceric ammonium nitrate (CAN) and acrylamide (monomer). In the concentration of gum-1gm Moringa Oleifera, 0.1gm Ceric Ammonium nitrate and 5gm of acrylamide were found to have the optimum measured parameters, giving a grafted co-polymer with a percent grafting efficiency of 65%.
[0085] Characterization of native Moringa gum and modified Moringa gum
[0086] The physicochemical characteristics of native Moringa gum and graft polymer Moringa gum (modified Moringa gum) were determined by the procedures provided below and the results are presented in Table 3.
[0087] a) Swelling index: 1 gm of Moringa gum was blended with 96 percent ethanol (sufficient to damp the gum) and then 25 mL of purified water was added into a graduated cylindrical cylinder, shaken for an hour and 10 minutes thereafter permitted to stand for 5 hours. Evaluated the volume of the enlarged gum. Swelling index was represented as 1 g of the drug after swelling, as a volume in mL.

where, v1 = the initial volume of material before hydration and v2= the final volume of hydrated material.
[0088] In comparison with grafted polymer, pure Moringa gum has low swelling index at pH 6.8. On the contrary, graft polymer Moringa gum swells more than native gum and begins to erode more quickly.
[0089] b) Total ash: The ash concentration was obtained after combustion in a furnace at 450°C to measure the remaining residue. The ash was boiled for 5 minutes using 25 ml of 2M hydrochloric acid solution, and the insoluble material was filtered, cleaned and ignited by hot water and the resulting weight was established. It was measured as the proportion of insoluble acid ash.
[0090] c) Angle of Repose: The static rest angle "REAT" was calculated by a set funnel and standing cone system. A funnel was tightened on a flat plane with its tip 2 cm over graphical paper. The powders were slowly pumped into the funnel before the cone apex reached the edge of the funnel. Determined the median diameters of the base of the powder cones and measured the tangent of the rest angle using the equation:

where, ? = Angle of repose, h= Height of granules and r = radius of granules.
[0091] d) Bulk and Tap densities: An amount of 2 gm was put in a 10 ml measuring cylinder for each of the powder samples, and the volume, Vb, was observed without tapping each of the samples. The filled volume Vt was read after 100 taps on the table. The bulk and tap densities were determined by the following equations according to the ratio of weight and volume (Vb and Vt respectively):


where, M = weight of powder, Vb = volume occupied by powder without tapping and Vt = volume occupied by powder after tapping.
[0092] e) Hausner’s ratio: Hausner's ratio is an indirect powder flow facility. It was determined according to the equation of the specimens

[0093] f) Carr’s compressibility index: Carr's compressibility index specified the compression index of the powder blend. It is a straightforward measure for the measurement of the powder bulk density and tapped density and the rate at which it is packed. It was determined by:

Table 3: Physicochemical characterization of native Moringa gum and Modified Moringa gum
Parameters Native Moringa gum Modified Moringa gum
Angle of repose (?) 37.20 ± 2.22 29.60 ± 2.15
Bulk densities (g/ml) 0.42 ± 0.01 0.45 ± 0.01
Tapped densities (g/ml) 0.51 ± 0.02 0.53 ± 0.02
Hausner’s ratio 1.21 ± 0.14 1.17 ± 0.11
Compressibility index (%) 17.64 ± 0.35 15.09 ± 0.27
Swelling index 78.43 94.57
Total ash content (% w/w) 1.10 ± 0.12 0.96 ± 0.05

[0094] Dry modified Moringa gum powder exhibits better flow characteristics, and swelling index that make it ideal for direct tablet compression.
[0095] g) Infrared spectral analysis: The samples were tritured using KBr agate and morter with an IR (IR Hydraulic Press CAP-15T, PCI Analytics, Mumbai, India) pressing at an output of 75 kg/cm2 per 30 s. At 75kg/cm2, the mixture was compressed into discs. FT-IR (IR affinity I, Shimadzu) in range 4000-400cm-1 were registered using the Fourier transformed infraround (FT-IR) disc spectrum.
[0096] Pure gum: The infrared (IR) spectrum specifically indicates the peaks of the gum’s functional groups. The IR-Spectrum has standard vibration levels of the N-H at 3418.7 cm-1 and C-H at 2925 cm-1 stretching vibration, respectively. It also shows typical bands of –C-O (alcohol) stretch vibration of 1062.8cm-1. It displays the -C=C- (aromatic) extending bands at 1619cm-1. The IR pure gum (Moringa gum) spectrum is presented in Figure 6.
[0097] Modified gum: The infrared (IR) spectrum of the compound specifically indicates the peaks of the gum functional groups. The IR continuum shows typical bands of the stretching vibrations of the 3427.5 cm-1 N-H and 2924.6 cm-1 C-H stretch vibration. The pulse of –C-O (alcoholic) at 1063.3 cm-1 is also characteristic in chains. It displays -C=C- (aromatic) stretching bands at 1671.2 cm-1. The IR variety of gum obtained from grafted Moringa is presented in Figure 7. The grafted Moringa gum FT-IR spectra demonstrated difference in amplitude and change of peaks caused by hydroxyl groups' involvement in chemical reactions. The grafting of Moringa gum is verified with the inclusion of a 1671.2 cm-1 absorption band because of the >C=O amide stretching vibration and a 1063 cm-1 absorbing band due to alcohol stretching.
[0098] h) Differential scanning calorimeter analysis: Moringa gum and grafted Moringa gum thermograms were obtained with a differential calorimeter scanner (Q10, TA systems, USA). A small amount of fine powdered sample was shifted into regular aluminum pan and heated at a rate of 40 to 350°C at 10°C/min. The inert nitrogen atmosphere (50 ml/min) analysis was carried out.
[0099] The thermal curve of native Moringa gum reveals the flat low peak but not too sharp at 72.59°C, 135.49°C and 273.04°C (refer Figure 8). The modified Moringa gum's thermal curve revealed slight plateau at 94.86°C (refer Figure 9). The move to lower values with lower fusion heat in the endothermal transition temperature suggests that the modified Moringa gum is more amorphous than the native Moringa gum.
[00100] i) X-ray Diffractometry: For the solid characterization of Moringa gum and grafted Moringa gum, powder XRD experiments were used. The diffractometer configuration was traced from 0-80° (2 pounds) with a 0.05 min - 1.1 scanning speed at room temperature by using X-ray diffractometers (Miniflex II, Rigaku, Japan). Two combinations were prepared with the drug (Zaleplon).
[00101] In [Figures 10(a-d)], X-RDs of pure gum, modified gum, Zaleplon drug + pure gum, and Zaleplon drug + modified gum are provided. A sharp peak of 2? = 26 and 27 can be seen for pure Moringa gum, while 2? = 18, 19, and 20 can be observed with the modified Moringa gum. The peaks are detected at 2? = 10, 12, 14, 16, 17, 18, 19, 20, 21, 21, 23, 24, 27 and 29 for drug and modified gum but the highs are less extreme.
[00102] j) Scanning electron microscopy: The Moringa gum and Grafted Moringa gum surface morphology was analyzed by SEM (ZEISS, EVO 18 and China). The powdered sample was fixed on a double adhesive carbon tape set on a holder and covered in a thin, high-vacuum gold film. At various magnifications, the photomicrographs had a 20 kV acceleration voltage. A combination was prepared including the drug (Zaleplon) with the modified Moringa gum.
[00103] The gum particles were seen to be polyhedral [refer Figure 11(a)]. The pure gum surface [refer Figure 11(b)] was not flat. Comparatively, the modified gum retains the polyhedral shape [Figure 11(c)] but reveals smoother surfaces that reflect the decrease in crystallinity in grafting, as seen in [Figure 11(d)]. Due to the inclusion of drug in the matrix of the modified Moringa gum [Figure 11(f)] the final formulation was seen to be less smooth.
[00104] Example 3: Formulations of Zaleplon loaded-buccal discs of Moringa gum and grafted Moringa gum
[00105] Six separate batches of buccal CDs were formulated with differing amounts of gums and lactose. Moringa gum, or grafted Moringa gum, were briefly fused into the hydraulic IR compressed (Hydraulic Presses, CAP-15T) at a pressure of 50 kg/cm2: Zaleplon, (10 mG), PEG-4000 (25 mg), lactose, Di-calcium phosphate (45 mg), HPMC K15M (15 mg), Microcrystalline cellulose (45 mg), Magnesium-stearate, and Talc at a pressure of 1.5. Table 4 below provides the compositions of the formulations prepared.
Table 4: Composition of different formulations of Zaleplon loaded buccal Discs
Ingredients MF1
(mg) MF2
(mg) MF3
(mg) MF4
(mg) MF5
(mg) MF6
(mg)
Zaleplon 10 10 10 10 10 10
Grafted Moringa gum 60 - 60 - 60 -
Moringa gum - 60 - 60 - 60
Lactose 45 45 - - - -
Di-Calcium Phosphate - - 45 45 -
MCC - - - - 45 45
HPMC 15 15 15 15 15 15
PEG-4000 25 25 25 25 25 25
Talc 1.5 1.5 1.5 1.5 1.5 1.5
Magnesium Stearate 3.5 3.5 3.5 3.5 3.5 3.5
Total 160 160 160 160 160 160

[00106] Example 4: Evaluation of Formulations
[00107] The formulations prepared in Table 4 were evaluated further for the following properties before and after compression.
[00108] a) Weight Variation Test: Ten discs were independently picked and weighed. The average weight and default weight were then computed. When two discs vary from normal weight, the test is passed.
[00109] b) Hardness: Durability or crushing power was determined by using the Monsanto disc stiffness test to split a disc in a diametric compression. It is expressed in kg/cm2.
[00110] c) Friability of the disc: In a disc-friability measuring unit (Remi Equipment, Mumbai, India), the pre-weighed (W1) sample of ten oral discs were mounted. The drum was rotated for 4 min at 25 rpm and the disc was weighted (W2). The following equation is used for calculating the friability:

where, W1 = pre- weighed sample of buccal discs and W2= re-weighed sample of Buccal discs.
[00111] d) Thickness: Ten randomly chosen oral discs were tested by the digital vernier caliper, values were registered as mean ±SD.
[00112] e) Percentage Drug Content: Dissolved 1 disc (equivalent to 10 mg drug) in methanol and maintained in ultrasonicator for 20 minutes for determination of the drug quality. With purified water, the volume was set to 100 ml. The solution was purified using Whatmann's filter paper No. 41, diluted correctly, and UV spectrophotometer was used to measure its absorption by 254 nm. The drug quality percentage was determined with the calibration curve of Example 1.
[00113] f) Mucoadhesive strength: Texture analyzer was used to calculate the strength of the discs formed by recording the strength required to separate the discs from the gastric mucous membrane of the freshly excised goat. In short, the goat stomach mucosal tissues were harvested and used directly from the nearby slaughterhouse. The test discs were attached to the cylinder sample with a cyanoacrylate adhesive tape (diameter 10 mm). For research discs and molecular tissues, the cylindrical probe (with the panel attached) was reduced (speed 0.5 mm/sec maintained). A force (1N) was applied for a given time on the sensor at that point (60 sec). At 0.5 mm/sec the sensor was then pushed upside down (15 mm distance). The mucoadhesive strength was achieved i.e. the maximum strength necessary to separate the discs from the mucosal surface.
[00114] g) Muco-adhesion Time: The time was determined by adhering to the gastric mucosa of goat formulated discs. The stomach tissue was first pasted onto a diaphragm with a cyanoacrylate tape (glass). A decrease (pH 6.8) was dumped at the surface of the test discs to make the disc moist to bind with mucosal tissue. A beaker of medium pH buffer was loaded and a temperature of 37 ± 0.5°C preserved. The slide was stored inside the beaker using the pasted disc on the mucosal tissue. The stirrer was allowed to spin inside the beaker (50 rpm) and the amount of time the discs took for separation from the stomach tissue of the goat was registered as time of mucosal adhesion.
[00115] Pre-compression parameters: Pre-compression parameters are provided in Table 5. Hausner’s ratio was found to be <1.13 which means the strong flow characteristics of all powder mixtures, i.e. MF1-MF6. The powder blend MF1-MF6 compressibility index was found to be 6-12, suggesting strong flow characteristics. The resting angle of repose for both formulations was located in 25-30?, indicating strong flow properties of all formulation blends.
Table 5: Pre-compression parameters of Zaleplon buccal discs using Moringa gum
Formulation Code Bulk Density (g/cm3) Tapped Density (g/cm3) Hausner’s Ratio Carr’s Compressibility Index (%) Angle of Repose (

MF1 0.420 0.478 1.13 12.1 29.5
MF2 0.490 0.522 1.06 6.1 25.7
MF3 0.448 0.487 1.08 8.0 26.4
MF4 0.434 0.477 1.09 9.0 28.2
MF5 0.462 0.494 1.06 6.4 25.9
MF6 0.439 0.483 1.10 9.1 30.2

[00116] Post-compression parameters: The post-compression parameters for the formulations are provided in Table 6 below.

Table 6: Post-compression parameters of Zaleplon buccal discs using
modified Moringa gum
Formul-ation Code Weight Variatio-n (mg) Tablet Thickness (mm) Hardness (kg/cm2) Friabilit-y (%) Drug Content
(%) Mucoadhe-sive strength Mucoadhesi-on time
MF1 159.8 3.2 4 0.89 98.29 ± 1.02 12.52 ± 1.52 2.51 ± 0.30
MF2 160.6 3.1 4.2 0.78 101.43 ± 2.80 22.76 ± 1.86 6.12 ± 0.55
MF3 160.1 3.0 4.12 0.72 99.81 ± 1.81 55.15 ± 3.55 12.21 ± 0.91
MF4 158.9 3.0 4.4 0.86 99.17 ± 2.02 29.44 ± 2.52 9.21 ± 0.80
MF5 156.0 3.2 3.8 0.91 102.10 ± 1.45 16.98 ± 1.42 4.18 ± 0.35
MF6 160.3 3.0 4.1 0.68 99.46 ± 2.40 28.45 ± 1.81 8.25 ± 0.55

[00117] h) In vitro swelling percentage in (pH 6.8): After measuring weight, individual discs were soaked up in buffer of pH 6.8. The discs (swollen) were separated and dried superficially by blotting paper after the required time (2, 4, 6, 8, 12 and 24 h). Furthermore, the physical observation of the swollen discs was documented by calculating the diameter of the discs with graphic paper on the petri platter. The swelling percentage (SP) was determined by the following formula:

where, wf is final weight of sample after swelling and wi is initial weight of the sample. The swelling percentage for the buccal disc formulations has been provided in Table 7. There was proportional weight gain and swelling.

Table 7: Swelling percentage of Zaleplon Buccal Disc in (pH 6.8)
Percentage weight gained(%)
Time (h) MF1 MF2 MF3 MF4 MF5 MF6
2 25.22 ± 1.34 29.14 ± 1.42 45.22 ± 1.98 48.98±1.65 40.76 ± 1.47 42.45 ± 1.09
4 37.54 ± 1.80 41.39 ± 2.11 59.87 ± 1.86 63.62±1.99 55.11 ± 1.21 57.75 ± 2.91
6 49.23 ± 2.13 52.51 ± 2.56 69.12 ±1.85 74.23±1.86 64.98 ± 2.32 66.34 ± 2.65
8 59.12 ± 2.45 61.29 ± 2.37 76.65 ± 2.42 80.41±2.77 69.25 ± 2.76 72.05 ± 2.51
12 - - 85.12± 2.21 83.52±2.95 - -

[00118] i) In vitro drug dissolution studies: In vitro mixture dissolution and pure compound experiments were conducted with USD dissolution device using the Paddle Stirrer in the Phosphate Buffer 900 mL (pH 6.8) at a stirrer speed of 50 rpm at 37±0.5°C (Type II). 5mL aliquot was removed from the dissolution medium at 1, 2, 4, 6, 8, 10, 12 hours and substituted with the pipette amount of the same buffer quantity. Spectrum photometric at 254 nm is correctly checked and tested. Results from Zaleplon mucoadhesive buccal disc (MF1-MF6) in vitro dissolution analysis are provided in Table 8. The MF3 batch revealed 95.22% w/w drug release in 12 hours.
Table 8 In-vitro drug release data of drug loaded formulation
Time (h) Cumulative % Drug Release
MF1 MF2 MF3 MF4 MF5 MF6
1 39.32 ± 1.23 28.99 ± 1.55 18.66 ± 0.64 12.76 ± 0.95 22.51 ± 0.70 20.99 ± 0.82
2 66.87 ± 1.79 59.23 ± 1.80 28.12 ± 1.34 25.23 ± 1.46 33.55 ± 1.39 30.89 ± 1.40
4 81.12 ± 2.50 77.46 ± 2.72 51.41 ± 1.81 47.09 ± 1.88 59.32 ± 1. 94 57.09 ± 1.90
6 95.87 ± 2.85 93.88 ± 2.90 68.76 ± 2.25 65.54 ± 2.36 77.66 ± 2.50 74.43 ± 2.66
8 95.01 ± 2.85 93.25 ± 2.85 79.87 ± 2. 60 75.91 ± 2.65 95.98 ± 3.25 94.43 ± 3.42
10 - - 85.32 ± 2.95 82.65 ± 3.20 95.16 ± 2.85 93.05 ± 2.85
12 - - 95.22 ± 3.95 94.56 ± 3.41 - -

[00119] j) Stability studies: The purpose of stability tests was to determine the impact on the consistency of the drug material, or of the finished product of temperature, humidity, light and other environmental factors. These findings are used to determine the conditions for packaging, test time and shelf life. Accelerated stability experiments were carried out as stated in the ICH Guidelines. The MF3 formulation was deposited in a stability chamber for a period of one month at 40 ± 2 °C and 75 ± 5 percent relative humidity. After 1 month, spectrophotometers were analyzed for different parameters at 254 nm.
[00120] The findings of rapid stability tests, produced in Table 9, show that the stiffness, drug quality, and total percentage of the drugs released from the tablets stored under the conditions has not changed substantially.
Table 9: Stability data of MF3 batch of Zalelpon Buccal Discs
Evaluation Parameters for F3 Initial 1 month
Hardness (kg/cm2) 4.12 4.02
Drug content (%) 99.81 ± 1.81 98.10 ± 0.13
Cumulative % drug release 95.22 ± 3.95 94.67 ± 0.36

[00121] From the foregoing, it will be appreciated that, although specific embodiments of the invention have been described herein merely for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention and should not be construed so as to limit the scope of the invention or the appended claims in any way.

ADVANTAGES OF THE PRESENT INVENTION
[00122] The present disclosure provides a formulation that improves the bioavailability of the sparsely soluble Zaleplon.
[00123] The present disclosure provides a formulation that is stable, has high swelling index and in vitro drug dissolution capacity.
[00124] The present disclosure provides a formulation comprising a modified Moringa gum that has improved mucoadhesive strength, and mucoadhesive time.

We Claims:

1. A buccal disc formulation comprising Zaleplon and modified Moringa Oleifera gum, wherein the modified Moringa Oleifera gum is a graft-polymer of Moringa Oleifera gum and acrylamide.

2. The formulation as claimed in claim 1, wherein the formulation comprises Zaleplon in a range of 6%w/w to 7%w/w of the formulation.

3. The formulation as claimed in claim 1, wherein the formulation comprises modified Moringa Oleifera gum in a range of 37%w/w to 40%w/w of the formulation.

4. The formulation as claimed in claim 1, wherein the Moringa Oleifera gum is modified by grafting with acrylamide using microwave-assisted graft co-polymerization reaction.

5. The formulation as claimed in claim 4, wherein a free radical initiator for grafting is ceric ammonium nitrate.

6. The formulation as claimed in claim 1, wherein the formulation further comprises one or more pharmaceutically acceptable excipients.

7. The formulation as claimed in claim 6, wherein the pharmaceutically acceptable excipients are selected from lubricant, fillers, binder, stabilizer, flavoring agent or combinations thereof.

8. A bi-layered chrono-patch for pulsating release of Zaleplon comprising at least one layer of buccal disc formulation as claimed in claim 1.

9. A process of manufacturing a buccal disc formulation comprising Zaleplon and modified Moringa Oleifera gum, comprises the steps of: (a) mixing Moringa Oleifera gum with acrylamide and a catalytic amount of free radical initiator; (b) irradiating the mixture of step (a) with a microwave irradiation in a periodic heating-cooling cycle to give the modified Moringa Oleifera gum; (c) mixing the modified Moringa Oleifera gum with Zaleplon and optionally one or more pharmaceutically acceptable excipients to give the mixture; and (d) compressing the mixture to give the buccal disc formulation.