INTRODUCTION:

Any pharmaceutical formulation contains two ingredients- active pharmaceutical ingredient and excipients. Excipients help in the manufacturing of dosage form and it also improves physicochemical parameters of the dosage form. Polymers play an important role as excipients in any dosage form [1]. The advances in drug delivery have simultaneous urged the discovery of novel excipients which are safe and fulfill specific functions and directly or indirectly influence the rate and extent of release or absorption [2]. A large number of plant-based pharmaceutical excipients are available today. Many researchers have explored the usefulness of plant-based materials as pharmaceutical excipients. Synthetic polymers are toxic, expensive, have environment related issues, need long development time for synthesis and are freely available in comparison to naturally available polymers. However the use of natural polymers for pharmaceutical applications is attractive because they are economical, readily available, non-toxic and capable of chemical modifications, potentially biodegradable and with few exceptions and also biocompatible. The fact for increase in importance of natural plant based material is that plant resources are renewable and if cultivated or harvested in a sustainable manner, they can provide a 6 constant supply of raw materials [3]. However, substances from plant origin also pose several potential challenges such as being synthesized in small quantities and in mixtures that are structurally complex, which may differ according to the location of the plants as well as other variables such as the season. This may result in a slow and expensive isolation and purification process. Another issue that has become increasingly important is that of intellectual property rights. The plant based polymers have been studied for their application in different pharmaceutical dosage forms like matrix controlled system, film coating agents, buccal films, microspheres, nanoparticles, viscous liquid formulations like ophthalmic solutions, suspensions and implants. These have also been utilized as viscosity enhancers, stabilisers, disintegrants, solubilisers, emulsifiers, suspending agents, gelling agents, bioadhesives and binders [4].

Natural polymers are basically polysaccharides so they are biocompatible and without any side effects. Starch is a polysaccharide, produced by all green plants as an energy store and especially present in seeds and underground organs. A number of starches are recognized for pharmaceutical use. These include maize (Zea mays), rice (Oryza sativa), wheat (Triticum aestivum), and potato (olanum tuberosum). It is comprised of two polymers, namely amylose and amylopectin [5].

The rising demand for new drug delivery systems, greater understanding of the functional benefits of excipients, growing pharmaceutical industry, and patent expiries of several blockbuster drugs are positively impacting the overall growth of the market. The global pharmaceutical excipients market is projected to reach USD 8.1 Billion in 2021 at a CAGR of 6.1% in the forecast period 2016 to 2021 [6].

The global Pharmaceutical Starch market size is projected to reach USD 1581.3 million by 2026, from USD 1051.3 million in 2020, at a CAGR of 7.0% during 2021-2026.The India starch and starch derivative market is projected to grow at a CAGR of 5.1% during the forecast period 2020-2025. The market is majorly driven by the abundant availability of raw materials from which starch is derived. The major raw material for the Indian starch and starch derivative market is maize. Other raw materials used are rice, potato and tapioca. India is one of the primary consumers and producers of rice worldwide. North-east India, including Assam, is seen as a point of convergence of the start of the rice and is provided with especially rich rice good assortment. Among those, Assam Bora rice (Oryza sativa L, Japonica assortment), a social occasion of glutinous rice of Assam, portrayed by high amylopectin content, is promptly accessible. Starch obtained from glutinous rice is used in pharmaceutical industries for various purposes [7].

If the current vigorous investigations on the use of natural polymeric materials are sustained and maintained, it is probable that there would be a breakthrough that will overcome some of the disadvantages of this class of potential pharmaceutical excipients that would change the landscape of the preferred pharmaceutical excipient for drug delivery in the future.

History:

Starch has been used for many centuries. An Egyptian papyrus paper dating from 3500 BCE was apparently treated with a starch adhesive. Cato gave a procedure for starch production in some detail in a Roman treatise. In the Middle Ages the manufacture of wheat starch became an important industry in Holland, and Dutch starch was considered to be of high quality [8]. An early form of starch modification practiced in this period involved the starch being slightly hydrolyzed by vinegar. The nineteenth century witnessed an enormous expansion of the starch industry, due largely to demands of the textile, color printing, and paper industries, and to the discovery that starch can be readily converted into a gum-like product known as dextrin. In 1900, the United Starch Company and the National Starch Manufacturing Company joined forces to form the National Starch Company of New Jersey. Starch in its native form is a versatile product, and the raw material for production of many modifications, sweeteners, and ethanol. Starting in the 1930s, carbohydrate chemists have developed numerous products that have greatly expanded starch use and utility [9]. The major starch sources are tuber, such as potatoes and cassava, and cereals. Cereals are crops that have served as staple foods for millions of people throughout the world for many centuries. Wheat, rice, corn (maize), rye, oats, barley are common cereals. These crops contain starch of as one their major component, which has made them good sources of starch that could be used as pharmaceutical excipients [10]. Starch is one of the most widely used excipients in the food and pharmaceutical industries where they are used as fillers, glidants, thickeners, binders, disintegrants as well as gelling, bulking, and water retention agents. Commercial starches are obtained from cereals (corn and wheat) and from tubers and roots (particularly potato and cassava) and they dominate the world markets for starches in the food and pharmaceutical industries. A survey of the literature shows that the usefulness of starches from various botanical sources as pharmaceutical excipients has formed a subject of interesting study for close to four decades [11]. Rice (Oryza sativa) is the second largest cereal crop and is a staple food in all areas of Asia. Unlike wheat, which is generally raised on large farms and harvested mechanically, rice is usually grown on small paddies and harvested by hand. Among various varieties of rice developed on the planet, waxy rice is profoundly esteemed all through Asia and has more extensive acknowledgment in Europe. Upper east India, especially Assam, is a rich wellspring of a hereditary decent variety of rice. Among these, glutinous rice (normally known as Bora rice in Assam) is a significant class inside the classification of waxy rice and considered as delicate rice because of its delicate cooking consistency. This gathering of rice with low amylose content (all the more precisely named as apparent amylose content, AAC), considered as the claim to fame rice, is under development by the farmers from days of yore. Assam Bora rice locally known as Bora Chaval is generally circulated throughout Assam. Bora rice was presented in Assam from Thailand or Myanmar by Thai-Ahoms [12] and is utilized as food source and arrangement of dishes on religious occasions (Bihu) and creation of extraordinary rice lager in regional Assam. During the Ahom supremacy in Assam, Bora rice with egg was used in constructing buildings only because of its sticky quality. From last two decades Assam bora rice is one of the focal point for research in pharmaceutical utility. Bora rice and its starch is utilized as characteristic polymer for drug delivery and preferred as mucoadhesive matrix in controlled release drug delivery system since it is exceptionally clingy and has splendid gelling property.

Types of bora rice:

Rice is developed in a wide scope of agro-environmental circumstances in Assam from the slope inclines of Karbi Anglong to dry season influenced upland and downpour took care of swamp to exceptionally profound water conditions. The varieties of bora rice with some of their characteristic properties found in the northeastern part of India are enlisted in table 1.

Geographical source:

There are around 41 conventional glutinous rice assortments, classed as Birain, Bora, and Chokuwa gathering, in Assam from two assorted agro-climatic zones prevailing in the Brahmaputra valley and the Barak sub-basin of North-East India [14].

Cultivation and collection of Assam Bora Rice:

There are four expansive divisions of rice cultivars developed in Assam – Sali (winter rice), Ahu (harvest time), Boro (summer), and Bao (deepwater rice), with different attributes, for example, tenacity, high starch content, waxy and fragrant. Sali (winter rice) developed during June/July - Nov/December. These are additionally delegated Sali, Joha, Bora, and Chokuwa dependent on grain qualities. The varieties of bora rice along with their place of cultivation are listed in table 2. Bora assortments likewise called Birain is clingy which are utilized for making different sorts of breakfast nourishments including delicate rice and Chokuwa rice [15]. Starch isolated from the fruit of Assam Bora rice (Oryza sativa, family Gramineae) is pharmaceutically used especially in controlled drug delivery and colon targeted drug delivery system.

Isolation of bora rice starch

The yield of starch from Assam Bora rice is generally around 83.5% on the grain mass premise. The wet milling method is mostly used to isolate starch granules from rice flour with some modifications [16]. The steps of isolation are depicted in figure 1.

Figure 1: Method of isolation of bora rice starch

Physical properties of bora rice:

Bora rice is also known as sticky rice or glutinous rice is a short-grain, Asian varietal that is used in many cuisines for its characteristic sticky texture and also possesses a good gelling property [17]. There is limited information on the structure and physicochemical properties of Assam Bora rice starch. Properties are normal to their biological origin. These properties are listed in table 2.

Table 2: Physical properties of bora rice starch

Parameter	Remark
Color	White
Odor	Odorless
Taste	Tasteless
Solubility	Soluble in cold water
Flow property	Poor flow property
Total ash value	0.491 – 0.500%
Acid insoluble ash	0.200 – 0.205%
Sulphated ash	0.25-0.27%
Acidity	0.60-0.65
True density	1.5-1.8g/ml
Loss on drying	10.8-12.5%
Hydration capacity	4.8-5.0
Viscosity (0.5% Assam Bora rice starch in 1 M KOH)	Relative – 7.1 to 7.8 Specific – 6.1 to 6.8 Inherent – 3.9 to 4.2

Identification test of starch:

After isolation of starch granules from bora rice flour; it is subjected to identification test. This is done by dissolving starch powder in water followed by boiling and cooling. Addition of iodine solution to the mucilage obtained if turns into dark blue or purple color confirms the presence of starch. The same is enlisted in figure 2.

Figure 2: Identification test of bora rice starch

Chemical constituents of bora rice:

Starch is delivered in plants and is a blend of straight amylose (poly-α-1,4-Dglucopyranoside) and amylopectin (poly-α-1,4-Dglucopyranoside and α-1,6-D-glucopyranoside). Rice for the most part contains two kinds of starch segments Amylose and Amylopectin. There are varieties in the evident amylose and amylopectin content in those glutinous rice assortments. The Bora rice artificially can be described by the absence of amylose content and the most noteworthy measure of amylopectin. Amylopectin is a profoundly fanned particle, comprising of three sorts of branch chains.

The chemical structure of amylopectin is shown in figure 3. A chains are those connected to different chains (B-or C-) by their diminishing closures through α-D-(1→6) linkages, yet they have not extended themselves. B-affixes are those connected to another B-chain or a C-chain, however, B-chains are fanned by A-chains or other B-chains at O-6 of a glucosyl unit. Each amylopectin particle has just a single C-chain, which conveys the sole lessening end of the molecule. The digestive enzymes can act just on the expanded bit of amylopectin. The hydrolytic response of amylopectin with β-amylase results in just half of the maltose arrangement demonstrating blocked destinations in the structure of amylopectin [18]. The rice variety containing a high measure of amylopectin (Bora rice) has adhesive properties and along these lines can be used alone or in a mix with plant adhesive to a reasonable extent for improvement of lattice-type drug delivery system [19].

Figure 3: Structure of amylopectin (a chief chemical constituent of Assam bora rice)

Modifications of bora rice starch:

Starch is seldomly spent in its total structure and frequently utilized by industry in its regular structure. Most regular starches are confined in their straight case since they are shaky with regard to changes in temperature, pH, and shear forces. Regular starches express an affinity for breaking down and rot. Characteristic starches are much of the time improved to create explicit properties, for example, solvency, surface, bond, and resilience to the warming temperatures utilized in industries. Chemical modifications of starch, including hydrolysis, are useful techniques to improve the properties of Assam bora rice starch. Alterations of starch comprise of physical, chemical, and enzymatic techniques. Physical techniques contain the utilization of heat and moisture, and chemical alterations include the presentation of functional groups into the starch particles utilizing derivatization reactions like, etherification, esterification, crosslinking or include breakdown responses such as hydrolysis and oxidation [20]. On the basis of literature; some of the modifications purpose of bora rice are discussed below-

Thermal and chemical modification of Assam bora rice:

Sharma H.K. et. al. 2011, modified Assam bora rice flour (ABRF) by thermal and chemical treatment and improves its possibility as a directly compressible excipient. Tablets were prepared using atorvastatin calcium (ATV Ca) as a model drug using treated, untreated ABRF, and accorded with tablets prepared with microcrystalline cellulose. The untreated and thermally treated tablets did not show obligatory hardness deprived of the binding agent but spray-dried and acid-modified ABRF measures showed very decent hardness without the binding agent, which tells that acid-modified and spray dried ABRF can be utilized as the directly compressible agent [21].

Physical modification of glutinous rice starch by ball milling method:

May T.S. et. al. 2020, investigated that, to examine physicochemical properties and possible utilization of glutinous rice starch as a mucoadhesive polymer, a planetary ball milling strategy was utilized as an adjustment method. To achieve modified glutinous rice starch (MGRS), a planetary ball mill furnished with the 250-mL container and four 30-mm width zirconium oxide balls was utilized. XRD and ATR-FTIR results showed a decrease in the crystallinity of starch after ball milling. Examination of mucoadhesive properties utilizing Texture Analyzer with porcine mucosa showed that MGRS tablets displayed more noteworthy mucoadhesive capacities contrasted with hydroxypropyl methylcellulose tablets, however more fragile than those of sodium carboxymethylcellulose tablets. Tablets made of 15-min-processed MGRS had practically identical tableting, expanding, and mucoadhesiveness, yet lower disintegration contrasted with 45-min-processed MGRS. Definitively, ball processing treatment could effectively prompt the mucoadhesive properties of glutinous rice starch and extend its application as a mucoadhesive polymer [22].

Alcohol- acid hydrolysis of Assam bora rice starch:

Chemical modifications of starch, including hydrolysis, are useful techniques to improve the properties of Assam bora rice starch. "Alcohol acid hydrolysis" of starch implies an alteration of starch within the sight of acids in alcohol. To attain the alcohol- acid hydrolysis of Assam bora rice starch (ABRS), Gope S. et. al. 2016, extricated the starch from glutinous rice by the alkali extraction strategy. Subsequently, the 1-butanol-hydrochloric acid alteration of ABRS was done. The progressions in Physico-chemical and morphological properties of ABRS during hydrolysis was examined. The study revealed that there was a noteworthy increment in water dissolvability of starch because of modification; in any case, expanding and sedimentation esteem decline after modification, The examination of microstructure uncovered that the hydrolysis changed the morphology of starch granules. The hydrolysis was influenced by the surface properties and granule size of rice starch and recommended that 1-butanol–HCl hydrolysis of ABRS can be a favored method of modification [23].

Etherification of Assam bora rice starch:

Mohapatra S. et. al. 2018, uncovered that the modification of ABRS with carboxymethyl by the etherification technique improves its functionality. This chemical modification method helps ABRS to explore as a carrier for hydrophilic drugs. The blend of carboxymethyl Assam Bora rice starch (CM-ABRS) depends on Williamson’s ether synthesis. The iso-propanolic slurry of ABRS was treated with 8N alkali in presence of etherifying agent, chloroacetic acid at 65°C with ideal mixing of about ~2000 rpm. The yield product obtained after 3 hrs. of non-stop reaction was neutralized with 50% (v/v) glacial acetic acid. It was further purified by filtration followed by washing with 85% (v/v) ethanol until the pH of the liquid was neutral. The degree of substitution of synthesized CM-ABRS was determined by the acid-base titration method, where excess NaOH present in a sample (25 mL) was back titrated with 0.05M of HCl in the presence of phenolphthalein indicator. Carboxymethyl Assam Bora rice starch coated superparamagnetic iron oxide nanoparticles (CM-ABRS SPIONs) were synthesized and characterized. The study revealed that the hydrophilic nature of CM-ABRS helps to encapsulate hydrophilic drugs easily. Investigated from a simulation study of magnetic drug targeting, it was found that CM-ABRS SPIONs were profitable agents for various therapeutic as well as theranostic in vivo applications [24].

Modification of starch with chitosan:

It is realized that a solitary film framing polymer probably won't have satisfactory mucoadhesiveness, drug delivery, and medication penetrability. The utilization of mixes to shape composite materials speaks to a reasonable system to defeat the downsides of every polymer and give the predominant properties. Also, basic changes in polymer proportions may bring about a wide scope of physicochemical properties and consequently may give various examples of medication conveyance. It has been accounted for that the mixing of starch with CS could adjust the hydrophobic nature and mechanical properties of the resultant films. Ahmad Z. N. et. al. 2013, manufactured the MGRS: CS composite films utilizing a solvent casting method. The prepared films were stacked with Lidocaine hydrochloride (LDHC), model hydrophilic medication, and characterized for physicochemical, mechanical, swelling, mucoadhesiveness, release, and penetrability properties. The fabrication and characterization of ball-milling modified glutinous rice starch (MGRS): chitosan (CS) composite films were illustrated. The impact of CS proportions (2:1, 1:1, 1:2 MGRS: CS) on the film properties was explored. ATR-FTIR, XRD, mucoadhesive examination, drug release study was exhibited and they concluded that the MGRS: CS composite could be valuable for buccal delivery of the hydrophilic drug [25].

Analytical parameters of bora rice starch

On the basis of literature; the analytical parameters like FTIR, DSC, XRD and SEM of bora rice are discussed below-

Differential scanning calorimetry (DSC):

Abdul B. A. et. al. 2017, assessed DSC thermogram of the bora rice starch utilizing a differential scanning calorimeter (Perkin Elmer 4000). The DSC bend of bora rice starch shows an endothermic peak at 76.18˚c with a heat of fusion 114.72 J/g [26]. In bora rice starch; the To, Tp, and Tetemperature were found to be 64 ⁰C, 68 ⁰C, and 78 ⁰C respectively. The gelatinization temperature (Hgel) was found to be 36.1 cal/g and was almost similar to the other waxy rice starch. This high Hgelreveals the stronger crystalline nature of Assam Bora rice starch, because high energy is required to melt the crystallinity of starch granules. The DSC thermogram of bora rice starch is shown in figure 4.

Figure 4: DSC thermogram of bora rice starch

Fourier transform infra-red spectroscopy (FTIR):

Sharma H. et. al. 2013, investigated Infrared absorption spectroscopy of bora rice starch and provided information about the functional group present in the compound. The most distinct peaks of bora rice starch in the range of 4000–400 cm⁻¹are showed in figure 5 and interpreted in table 3 [27].

Table 3: Interpretation of FTIR Spectra of bora rice starch

Characteristic peaks	Wave Number(cm^-1)
Hydroxyl (-OH) groups	3301.18
C-H Stretching	2930.92
C-OC stretching	1151.21
C-C stretching	1001.43
OH stretching	3360
CH₂ bend	1420
Ring vibration	925-930

Figure 5: FTIR spectra of bora rice starch

Scanning electron microscopy (SEM):

Mohammad Z. A. et. al. 2009, have taken Scanning electron micrographs (SEM) of the starches with a scanning electron microscope (Hitachi S-300N, electron Microscope). They concluded that starch from Assam bora rice is spherical to polygonal in shape and some granules were of irregular shape. The surface of starch is relatively smooth with some evidence of crack and indentations [28].The SEM image is shown in shown in figure 6.

Figure 6: Scanning electron micrographs of Assamborarice starch

X-ray diffraction pattern:

Vasanthan T. et. al. 1999, exhibited type of diffraction pattern of Bora rice starch with maximum X-ray diffraction peak at 17.3200 (2q) and 24.0400(2q). The crystallinity level of starch from Assam bora rice was significantly high i.e. 37.09%. This is significantly higher than potato starch. The starch granules were found to be semi-crystalline and crystallinity has been assigned to the well-ordered structure of amylopectin molecules inside the granules since the crystallinity level of starch granules is reported to be influenced by amylopectin [29]. The diffractogram is shown in figure 7.

Figure 7:X-ray diffraction pattern of Assam Borarice starch

Advantages of Assam bora rice starch:

Some of the advantages of ABRS as compared to other starches on the basis of literature review are as follows-

· It is novel, cost effective, natural, bio-polymeric matrixing agent in fabricating modulated release drug delivery system [30].

· It has potential use in the formulation of matrix and compression coated tablets for colon targeting [31].

· ABRS exhibited good flow property, useful in minimizing the problems of lamination and capping as compared to other modified starch. Therefore, used as direct compression excipient [32].

· It would be more useful when high tensile strength of tablet is desired even when compared to commercial modified starch excipient such as starch 1500® [25].

· It can be used in the formulation of amine drugs due to its very low moisture content which reduces the chance of Maillard reaction [25].

Applications of bora rice in drug delivery:

Medication conveyance innovation is one of the boondocks zones of research in the field of science and innovation. Extensive consideration is centered around the improvement of controlled drug delivery systems offering the benefits of better therapeutic efficacy and simpler to consent to than the traditional regimens requiring frequent dosing [33]. Various more current polymers have been researched in this field yet just a couple of them have discovered modern applications. The biocompatibility and cost are the two significant restricting elements for industrial use in practice. Utilization of regular and adjusted normal polymers in the drug delivery keeps on being a zone of escalated research notwithstanding the coming of a few new synthetic polymers. Natural polymers principally stay alluring for various reasons as they are conservative, promptly accessible, fit for changes, and in this way possibly degradable and perfect because of their natural origin [34].

Utilizing bora rice as a pharmaceutical excipient is conceivably fascinating as it is a typical staple and can be named 'GRAS' (Generally regarded as safe), which is important for any new excipient to be utilized in pharmaceutical for an administrative purpose [35]. The characteristic materials have been broadly utilized in the field of medication conveyance since this can be a potential promoting instrument in the 'herbal blast around the world', the present-day shopper searches for the natural fixings in the food, medication, and beautifiers as they accept that anything natural will be more secure and without reactions when contrasted with their synthetic counterparts [36]. Some of the formulations of drug using bora rice starch as excipient are listed in table 4.

As directly compressible agents:

Sharma H.K. et. al. 2011, investigated that ABRS can likewise be executed as a directly compressible agent and possible binder in an assortment of tablet formulations. Atrovastatin calcium was utilized as a model medication for the preparation of tablets to investigate the chance of ABRF as a legitimately compressible specialist. Tablets were prepared with untreated ABRF, thermally treated ABRF, acid altered ABRF, and spray dried ABRF and compared with tablets prepared with microcrystalline cellulose. It was examined that untreated and thermally treated ABRF didn't show needed hardness without a binding agent, in any case, acid modified and spray dried ABRF can be utilized as a directly compressible agent [21].

Similarly, different varieties of ABRF were investigated by Ahmad Z.M. et. al. 2012, for mechanical and compaction properties and compared with official starch 1500®. The ABRFs were evaluated for their compression properties, toughness, and Young’s modulus. Heckel and Kawakita's analysis was used to study mechanical properties and compression characteristics. Results demonstrated the potential use of ABRF as a directly compressible agent for tablets as compared to starch 1500® [32].

In another investigation by Bhattacharya A. et. al., 2010, tablets containing Ketotifen Fumarate as a model drug were prepared using ABRS. The tablets were assessed for tensile strength, friability, drug content, disintegration and dissolution profiles and revealed that ABRS has special filler- binder property and is a promising agent for preparation of tablets by direct compression [37].

In one more investigation, by Rajak P. et. al. 2014, Paracetamol tablets prepared with ABRS were evaluated for their relevant properties as a binder in different concentrations. A comparative study was done with tablets prepared using official gelatin powder. The tablets were evaluated for hardness, friability, uniformity in weight, disintegration, and dissolution profiles. Results got demonstrated that Assam Bora rice starch proceeded in the same class as gelatin as a binder in paracetamol tablets and utilized as a promising binding agent for tablet formulation [38].

As plasma volume expander:

Assam Bora rice starch was portrayed by polymer examination by Bhattacharya A. et. al., 2010, for use as plasma volume expander. The justification for picking Assam Bora rice starch as plasma volume expander was that it comprises of amylopectin which is fundamentally the same as in structure to glycogen, and its similarity with physiological tissues, other than being unaffected by the presence of amylase. Characterization includes FTIR, degree of branching by H1 NMR, osmotic pressure by inward estimation technique, foundation of Mark-Houwink relationship and assurance of Molecular weight –viscosity relationship. It was researched that ABRS can be conceivably used as plasma volume expander [39].

In development of targeted drug delivery system:

Ahmad Z.M et. al. 2012, created a novel colon targeted compression covered tablet for site-specific delivery of 5- FU with ABRS. The center tablet was prepared utilizing microcrystalline cellulose and spray dried lactose by direct compression strategy and afterward coated with ABRS which acted as a drug carrier for focused delivery. The study presumed that Assam bora rice starch can be used as a medication transporter for a successful colon targeted delivery system for drugs effective in large intestinal ailments [31].

Another study for delivery of 5-FU to colon by Ahmad Z.M. et. al.,2012, investigated that ABRS can be used as a biocompatible mucoadhesive polymer for the preparation of mucoadhesive microspheres (MAMs) by double emulsion solvent evaporation method for targeted drug delivery [40].

The research was conducted by Sarangi M.K. et. al., with Naproxen (NA) containing beads formulated by using a blend of ABRS and sodium alginate polymer by an ionotropic gelation technique. From the result, it was concluded that the optimized formulation proved the colon targeting of beads in intact form [41].

Correspondingly, Ahmad Z.M. et.al., 2012, the colon targeted Irinotecan HCl stacked microspheres which were set up by double emulsion solvent evaporation technique with ABRS. The microspheres were described for their micromeritics properties, loading proficiency, in vitro, and in vivo drug release studies. The study suggested the moderate and broadened release of ITC-HCl over longer timeframes with diminished systemic side-effects [42].

In another investigation, by Ramteke K.H. et. al. 2014, Glipizide containing microspheres were prepared by the ionotropic gelation procedure utilizing a mix of pectin and bora rice polymers with zinc acetate as a cross-linking agent for colon focused conveyance framework. Microspheres were characterized for particle size, swelling index, drug entrapment efficiency, and percent drug release. It was concluded from the examination that bora rice end up being a possible polysaccharide for colon targeted drug delivery systems [43].

As biopolymeric polymer:

The investigation by Sachan N.K. et. al., 2012, visualizes drug utility of Assam Bora rice as biopolymeric excipient in drug conveyance. The sustained delivery potential from the proposed lattice spine was explored through in vitro dissolution investigations of microbeads arranged by an ionotropic gelation strategy utilizing the mixes of pregelatinized Bora rice alongside sodium alginate, according to SUPAC-MR rules. The arranged beads were described for surface morphology, drug- polymer compatibility, mucoadhesion and other pharmacotechnical boundaries. The results of studies have shown that Assam Bora rice holds the guarantee of being utilized as a drug release modulator in the medication transporter frameworks [44].

In development of drug delivery devices:

Sachan N.K et. al., 2009, created hydrogel microbeads by an ionotropic gelation strategy utilizing the mixes of pregelatinized bora rice alongside sodium alginate. Information got from in vitro discharge examines were fitted to different kinetic equations to discover the kinetics and mechanism of medication discharge from manufactured microbeads. It was concluded from the study that Assam Bora rice starch can be a promising alternative for mucoadhesive controlled medication conveyance frameworks as a natural excipient [45].

In another investigation by Sachan N.K. et. al., 2006, Metformin hydrogel microbeads were developed by micro orifice ionic-gelation technique using a combination of ABRS and sodium alginate. The created beads were assessed for particle size, swelling index, mucoadhesiveness, entrapment efficiency, and drug release. Results revealed that the utilization of bora rice is not only limited to sustained delivery yet besides display brilliant mucoadhesive properties [46].

Matrixing agent for controlled release drug delivery system:

The utility of Assam glutinous rice as natural biopolymeric network for microfabricated controlled DDS was explored by Sachan N.K et. al., 2011. Ibuprofen stacked Microcarriers were developed utilizing the mixes of ABRS and sodium alginate biopolymer by ionic gelation technique. The microcarriers were evaluated for particle size analysis, entrapment efficiency, mucoadhesivity, swelling, surface topography and drug release kinetics and in vitrodissolution testing. Results from examination uncovered that bora rice is a possibly valuable characteristic material for making controlled delivery framework [30].

Similarly, the oral mucoadhesive gel of irinotecan utilizing a mix of Assam bora rice starch and Carbopol 934 for the therapy of mouth cancer was grown effectively and assessed by Abdul B. A. et. al., 2017, for different parameters. The in-vitro study demonstrated a further extent of controlled drug release from the starch-based gels than carbopol based gels after 6 hrs investigation in phosphate buffer pH 6.8. Because of this investigation, it very well may be reasoned that the current examination uncovered the achievability of the Assam bora rice starch as a likely mucoadhesive operator to be utilized in a controlled drug delivery system [26].

CONCLUSION AND FUTURE DIRECTION:

India has a long history of rice development. North-east India, including Assam, is the main point of cultivation of rice. Assam Bora rice (Oryza sativa L, Japonica assortment) family Gramineae, is glutinous rice of Assam essentially contains amylopectin as a central substance constituent and known as sticky rice. Starch secluded from Assam Bora rice has uncovered that physicochemical properties are very like rice starches. Amylose content was practically insignificant. The shape of the Assam Bora rice starch is polygonal to spherical with a moderately smooth surface. An FTIR spectrum is practically similar to the standard FTIR for starch. The pharmaceutical utility of Assam Bora rice, portrayed by extremely high amylopectin content, is proposed and analyzed as biopolymeric polymers in drug delivery system is a well matrixing operator for control release drug delivery system. The way to deal with use Bora rice flour as release controlling polymer in the sedate conveyance is possibly intriguing because the rice is a typical staple and is bio-perfect, promptly accessible, and perhaps named ‘Generally Regarded As Safe' (GRAS). Hence, the remarkable property of Bora rice can be used for the advancement of drug delivery devices. Comparative conventional food can likewise be tended to for use as pharmaceuticals which would offer some benefit expansion to these natural materials and would likewise affect the economy of the particular regions. In future; bora rice starch as excipient could be utilized for controlled/sustained/prolonged release of drugs with poor physical and chemical properties. Also, till date there is no single patent reported on bora rice starch this opens newer avenues to explore the potential benefits of bora rice starch polymer for commercial utility. One more important area where the application of bora rice starch is still awaited is nano sized colloidal, vesicular and particular carrier system. Based on above literature; use of bora rice for nanotechnology could contribute to additive or synergistic effect for delivery of water insoluble drugs thereby improving the physico-chemical properties and modifying the pharmacokinetics and pharmacodynamics of drug.

CONFLICT OF INTEREST:

The author declares no conflict of interest.

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Received on 12.07.2020 Modified on 10.09.2020

Research J. Pharm. and Tech. 2020; 13(12):6266-6275.

DOI: 10.5958/0974-360X.2020.01091.4

Sr. No.	Type of bora rice	Characteristics
1.	Jangoni Bora	The cropping period is six months. Grows well on medium land. Grows both on sandy to clay type soil. Plant height medium. Yield 8-12 mon per bigha. The grain color is red and the rice color is yellowish. The grain is round with sticky grains.
2.	Swagmoni Bora	Grows well on medium to low land and on black to sandy soil. Crop duration is around 180 days with medium plant height. Yield is around 10 mon per bigha. The grain color is brownish yellow and the rice color is whitish. The grain type is long. Rice is sticky when cooked.
3.	Kola Bora	Grows well on low land with black and sandy soil. Crop duration is around 180 days. The plant height is tall. The yield goes up to 500 kg. perbigha. It cannot tolerate floods or drought. Grain color is black. The straw from this variety is soft. Rice cooks quickly with sticky rice.
4.	Bokul Bora	Grows well on medium land with clay type soil. Also seen to be grown on sandy loam soil. Crop duration is around 150-155 days. Plant height is medium. Yield per bigha varies from 8-12 mon.The grain is brownish yellow and long and large grain type. The rice color is yellowish. The rice cooks quickly with sticky rice.
5.	Makhon Bora	Grows on medium to low land with black to sandy soil. Crop duration is around 180 days. Plant height is a tall type. The yield goes up to 18-20 mon per bigha. The average yield is around 15-16 mon per bigha. The grain type is brownish yellow and the rice color is reddish. Gets cooked quickly with sticky grains.
6.	Ghew Bora	Grows on Medium land with clay type of soil. The maturity period is around 160 days. The plant height is tall. The average yield is 7-8 mon per bigha. The grain is long and the color is red. Rice color is also reddish.
7.	Helosi Bora	Grows on medium land with clay type of soil. Crop duration is 150 days. Plant height is medium. The average yield is 8-10 mon per bigha. The grain type is fat and the color is red. The Rice color is white. Rice is sticky on cooking.
8.	Fapori bora	Grows on medium land. The maturity period is 5 months. Plant height is medium. The average yield is around 2380 kg per acre. This variety can tolerate floods or drought. The rice has an aroma and grain type is fat and round. This rice is used for special festivals and ceremonies.
9.	Man bora	Grows well on medium land on clay type soil. Maturity period is 6 months. The plant height is tall. The average yield is 8-9 mon per bigha. It cannot tolerate floods or drought. The straw from this variety is soft. The grain type is slim. Rice cooks quickly and sticky grains.
10.	Pakhi Bora	Grows on medium land and red soil. Crop duration is around 180 days. Plant height is medium. The average yield is around 12 mon per bigha. The grain is peculiar with having a “wing” kind of covering around it and hence the name “pakhi” bora which in Assamese means wing.Grain is fat and rounded and is red. The color of the “wing” is yellow. Rice is small and white. On cooking produces sticky rice.

Sr. No	Formulation	Drug	Polymer	Method	Reference
1.	Micro-carrier	Ibuprofen	Bora rice starch sodium alginate	ionotropic gelation	30
2.	Microbeads	Metformin Hydrochloride	Bora rice starch sodium alginate	ionotropic gelation	46
3.	Tablets	KetotifenFumarate	Bora rice starch	Compaction	37
4.	Mucoadhesive gel	Irinotecan	Bora rice starch Carbopol 934	-	26
5.	Microspheres	Glipizide	Bora rice starch Pectin	ionotropic gelation	43