Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10 and Rule 13)

1. TITLE OF THE INVENTION:
METHOD OF PREPARING A BIODEGRADABLE MEDICAL DIAGNOSTIC CASSETTE

2. APPLICANT:
Meril Life Sciences Pvt. Ltd., an Indian company of the Survey No. 135/139 Bilakhia House, Muktanand Marg, Chala, Vapi-Gujarat 396191, India.

The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION
[001] The present invention relates to a method of preparing a biodegradable medical product. More specifically, the present invention relates to a method of preparing a biodegradable medical diagnostic cassette.
BACKGROUND OF INVENTION
[002] More often than not, medical products like diagnostic/testing kits are intended for single use, i.e., they are used once and then discarded. Generally, the reason being, most medical products should be sterile for safe use.
[003] Most of the medical products are made from plastic like high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene, etc. Naturally, once these plastic-based medical products are discarded, these medical products take an eternity to naturally degrade. Due to their non-degradable nature, these medical products are accumulated in the environment thereby significantly contributing towards the present-day problem of inefficiency in solid waste management (like overflowing landfills).
[004] Further, recycling these medical products requires treatment methods which are expensive and harmful to the environment as the residual fumes and discharge adulterates the surroundings. This, in turn, discourages recycling of the said medical products.
[005] Thus, there arises a need to provide naturally degradable medical products that can overcome the issues related to conventional medical products.
SUMMARY OF INVENTION
[006] The present invention relates to a method to prepare a cassette for diagnostic testing kits. The method commences by obtaining a plant raw material. The plant raw material including at least one of cellulose, hemicellulose and lignin. A pre-defined amount of water is added to the plant raw material obtained to yield a pulp. The pulp is then subjected to a first pre-defined temperature for a first pre-defined time period to yield a fibrous material. The first pre-defined temperature ranges from 90 °C to 200 °C. A pre-defined amount of hot water is added to the fibrous material to yield a slurry. The hot water being at a second pre-defined temperature ranging from 140 °C to 180 °C. A pre-defined amount of one or more additives is added to the slurry. The slurry is poured in to a mold. The mold is maintained at a fourth pre-defined temperature and a first pre-defined pressure for a fourth pre-defined time period to yield the cassette. The fourth pre-defined temperature and the first pre-defined pressure ranges from 90 °C to 200 °C and 1.8 MPa to 3 MPa respectively. The cassette is removed from the mold.
[007] The foregoing features and other features as well as the advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[008] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the apportioned drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[009] Fig. 1 depicts an exemplary method 100 to prepare a cassette in accordance with an embodiment of the present invention.
[0010] Fig. 2 depicts an exemplary cassette in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF DRAWINGS
[0011] Prior to describing the invention in detail, definitions of certain words or phrases used throughout this patent document will be defined: the terms "include" and "comprise", as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or; the phrases "coupled with" and "associated therewith", as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have a property of, or the like; Definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases.
[0012] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.
[0013] Although the operations of exemplary embodiments of the disclosed method may be described in a particular, sequential order for convenient presentation, it should be understood that the disclosed embodiments can encompass an order of operations other than the particular, sequential order disclosed. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Further, descriptions and disclosures provided in association with one particular embodiment are not limited to that embodiment, and may be applied to any embodiment disclosed herein. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed system, method, and apparatus can be used in combination with other systems, methods, and apparatuses.
[0014] Furthermore, the described features, advantages, and characteristics of the embodiments may be combined in any suitable manner. One skilled in the relevant art will recognize that the embodiments may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments. These features and advantages of the embodiments will become more fully apparent from the following description and apportioned claims, or may be learned by the practice of embodiments as set forth hereinafter.
[0015] In accordance with the present disclosure, a method to prepare a medical diagnostic cassette (or cassette) is disclosed. The cassette of the present invention is naturally degradable. In other words, the cassette of the present invention is biodegradable.
[0016] The cassette of the present invention may be used as diagnostic testing kits including but not limited to Antigen assay kits, RT-PCR kits, Malaria detection kits, human Chorionic Gonadotropin (hCG) detection kits, etc. Generally, diagnostic testing kit is a term coined to describe one time and easy to use diagnostic kits that are deployed to perform quick antigen-antibody screenings. Additionally or optionally, the method described in the present invention may be used to prepare various medical products (such as medical bottles/containers, band-aid containers, a dental floss containers, swab containers, syringes, inhalers, droppers, tampons, etc.), food packaging, paper, fibreboards, etc.
[0017] The method of the present invention utilizes fibrous residues of plant raw material (for example, sugarcane bagasse) along with water soluble synthetic linear polymers (additives) as raw materials. The said raw materials are then processed by pulp molding (a type of injection molding technique) to form the cassette of the present invention.
[0018] The resultant cassette from the method of the present invention has a smooth texture and increased strength. The cassette is completely degraded in 60-90 days when the cassette is subjected to moisture, soil, and microbes (naturally present in soil). The cassette is compatible with various analyte solution(s) used in the diagnostic testing kits and the like. In other words, the cassette provides an inert substrate for the antigen-antibody screenings (described above). The cassette is stored inside an inert environment (sealed away from moisture) thus, rendering the cassette to have a good shelf life of at least 3-4 years. The cassette can maintain its integrity for up to 4-5 hours after the cassette is subjected to moisture (for example, when the cassette is used for testing antigen/antibody).
[0019] Fig. 1 depicts an exemplary method 100 to prepare a cassette of the present invention. The method 100 commences at step 101 by obtaining at least one plant raw material. The plant raw material includes, without limitation, Cellulose, Hemicellulose, Lignin, or a combination thereof. In an exemplary embodiment, the plant raw material includes sugarcane bagasse.
[0020] Sugarcane bagasse corresponds to a fibrous residue that is obtained after juice (or liquid) is extracted from the sugarcane (or cane stalk). The sugarcane bagasse includes a combination of Cellulose, Hemicellulose, Lignin, water, and relatively small quantities of soluble solids (like sugars) and carbohydrates (like ash). Usually, sugarcane bagasse is discarded by the food industry as waste. Hence, the method 100 of the present invention advantageously recycles a naturally occurring resource (which is available abundantly) to form the cassette of the present invention.
[0021] At step 103, the plant raw material may be converted to a pulp by adding a pre-defined amount of water to the plant raw material. In an exemplary embodiment, for every kilogram of sugarcane bagasse, 60 liters of water is added to yield the pulp. Converting the plant raw material to the pulp makes it easier to process the plant raw material in subsequent steps of the method 100.
[0022] At step 105, the pulp may be subjected to physical agitation. In an exemplary embodiment, the pulp is subjected to physical agitation by stirring the pulp. In an alternate embodiment, the pulp is subjected to physical agitation by beating the pulp with a long metal rod. Other form(s) of physical agitation is within the scope of the teachings of the present invention. Subjecting the pulp to physical agitation loosens the plant raw material and enhances its availability for further processing.
[0023] Additionally or optionally, the pulp is allowed to rest for a pre-defined amount of time. In an exemplary embodiment, the pulp is allowed to rest for 24 hours.
[0024] At step 107, the pulp is processed to form a fibrous material. In an exemplary embodiment, the pulp is processed to form paper. The pulp may be subjected to a first pre-defined temperature for a first pre-defined time period and shaped using a molding technique to transform the pulp into the fibrous material. The first pre-defined temperature may range from 90°C to 200°C. The first pre-defined time may range from 140 minutes to 180 minutes. The molding technique may be selected from at least one of thermoforming pulp molding, dry press method, etc. In an exemplary embodiment, the pulp is heated at 160°C for 150 minutes and molded by dry press method to yield the fibrous material.
[0025] At step 109, the fibrous material may be allowed to rest for a second pre-defined time period. The second pre-defined time period may range from at least 24 hours to few days. In an exemplary embodiment, the fibrous material is allowed to rest for 30 hours. Allowing the fibrous material to rest helps to combine a plurality of short fibers of the fibrous material resulting in good strength and low tearing properties.
[0026] The resultant fibrous material from step 109 is rendered dry. The fibrous material of the present invention is competent enough to replace hardwood pulp.
[0027] At step 111, the fibrous material may be liquified to form a slurry by adding a pre-defined amount of hot water. The hot water may have a second pre-defined temperature ranging from 140 °C to 180 °C. In an exemplary embodiment, hot water having a temperature of 160 °C is added to fibrous material by mixing at a rapid speed to yield the slurry. In an exemplary embodiment, 60 liters of hot water is added for every kilogram of fibrous material. The step of liquefying the fibrous material to form the slurry helps the plurality of short fibers to achieve stronger binding when the slurry is mixed with one of more additives (described below).
[0028] At step 113, the slurry may be allowed to rest for a third pre-defined time period. The third pre-defined time period ranges from 2 hours to 3 hours. In an exemplary embodiment, the slurry is allowed to rest for 3 hours. Allowing the slurry to rest helps in physical binding of the fiber matrix (including the short fibers).
[0029] At step 115, a pre-defined amount of one or more additives may be uniformly added to the slurry. In an exemplary embodiment, 25% (v/v) additive(s) is added to the slurry. The one or more additives may be selected from Tert-Butyl Acrylamides (TBAA), Polyacrylamide (PAM) and/or copolymer of the acrylamide-2-methylpropane sulfonic acid with other water-soluble monomers. The one or more additives provides better bonding between the fibers of the slurry such that the water retention time of the cassette (without any disfiguration) of the present invention is enhanced.
[0030] TBAA includes a plurality of water based monomers and co-polymers (in a liquid emulsion) including but not limited to are poly(N-tert-butyl acrylamide), poly(N-acryloylmorpholine), etc. TBAA is mainly used to enhance moisture resistance, heat sealing properties, and strength of cellulosic fibers (i.e., their binding properties). TBAA is further used as a retention aid that enhances the flocculating tendency of the fibers, contaminants and other additives. TBAA performs well under ambient conditions of humidity and temperature. Further, TBAA is non-toxic, non-hazardous and non-flammable.
[0031] PAM is a water-soluble polymer compound with active amide groups and double bonds on the main chain. PAM acts as dry strengthening and reinforcing agent. Further, PAM helps in retention and fiber dispersant. When PAM is added to the slurry, the fibers and fillers present in the slurry flocculate quickly, and the finer fibers and fillers in the slurry adhere to the surface of the longer fibers so that the slurry is easily dehydrated (described below) and the retention of the fine fibers and the fillers is improved.
[0032] The copolymer of the acrylamide-2-methylpropane sulfonic acid with other water-soluble monomers is used to improve binding of fillers and fine particles present in the slurry thereby enhancing the strength of the cassette. It further increases the water retention time of the cassette.
[0033] Furthermore, the one or more additives provide water resistance and improved shelf life (preservation) of the cassette thereby making the cassette easy to use and dispose in an eco-friendly manner (described below).
[0034] At step 117, the slurry may be filtered. The slurry may contain lumps or solid waste (including large unwanted particulate matter) that may hinder subsequent steps of the method 100. Hence, the slurry is subjected to a filtration process to remove any unwanted lumps and solid waste, etc. The filtration process may include but not limited to cross flow micro-filtration, vacuum suck filtration, sieve filtration, etc. In an exemplary embodiment, the slurry is filtered by vacuum filtration. The step of filtering the slurry removes unwanted particulate matter from the slurry thus, making it uniform/homogenous for further processing. This step of filtering the slurry also helps the plurality of fibers to bind strongly.
[0035] The slurry includes a predefined composition having the plurality of fibers and the one or more additives. The plurality of fibers in the slurry may constitute 70% to 75% (w/v) of the slurry. And, the one or more additives in the slurry may constitute 25% to 30% (w/v) of the slurry.
[0036] At step 119, a mold (not shown) is pre-heated up to a third pre-defined temperature. The third pre-defined temperature may range from 150 °C to 250 °C. In an exemplary embodiment, the mold is pre-heated to a temperature of 200 °C.
[0037] The mold may be made of a material including but not limited to high-speed steel, stainless steel, etc. In an exemplary embodiment, the mold is made of stainless steel. The mold may be used to shape the slurry into the cassette. In an exemplary embodiment, the mold may include a top part, a bottom part and a void there between. The void between the top part and the bottom part of the mold corresponds to a shape of the cassette. Therefore, the void between the top part and the bottom part may be designed depending upon the desired shape of the cassette.
[0038] At step 121, the slurry may be poured within the mold.
[0039] At step 123, the slurry may be processed by maintaining the mold at a fourth pre-defined temperature and a first pre-defined pressure for a fourth pre-defined time period. The fourth pre-defined temperature may range from 90 °C to 200 °C. The first pre-defined pressure may range from 1.8 MPa to 3 MPa. The fourth pre-defined time period may range from 20 minutes to 40 minutes. In an exemplary embodiment, the mold is maintained at a temperature and pressure of 150 °C and 2.5 MPa respectively for 30 minutes. Maintaining the mold at the pre-defined temperature and the pre-defined pressure helps to evaporate any excess water from the slurry. Further, the pre-defined temperature and the pre-defined pressure of the mold makes the fiber of the slurry to strongly bond with each other yielding the cassette having smooth texture and excellent stiffness.
[0040] At step 125, the cassette may be cooled and then removed from the mold. In an exemplary embodiment, the cassette is cooled to room temperature.
[0041] At step 127, additionally or optionally, the cassette may be cut to a pre-defined shape depending upon the user requirements. The cassette may be cut automatically or manually. In an exemplary embodiment, the cassette is cut automatically by the mold.
[0042] At step 129, the cassette(s) may be assembled together as per user requirements. In an exemplary embodiment, the cassette is assembled together with a testing strips/solutions (not shown), etc.
[0043] At step 131, the cassette may be subject to packaging and sterilization. The cassette may be packed using but not limited to Tyvek pouch, triple laminated aluminum pouch, etc. to seal away moisture from the cassette. Thereafter, the cassette may be sterilized using but not limited to Gamma radiation, Argon gas, Ethylene oxide gas, etc. In an exemplary embodiment, the cassette is packed inside triple laminated aluminum pouch and sterilized by Ethylene oxide gas. The packed cassette has a good shelf life of at least 3-4 years.
[0044] The cassette of the present invention, upon subjecting to moisture, soil and microbes (naturally present in the soil), begins to degrade. Cellulose present in the cassette is degraded to Cello-dextrin, Cellobiose and Glucose. Hemi-cellulose present in the cassette is degraded to multiple sugars including but not limited to Arabinose, Mannose, Galactose, Glucose, and Xylose. Similarly, Lignin present in the cassette breaks down into aryl and biaryl compounds such as b-aryl ethers which are further mineralized. The breakdown of the cassette of the present invention is partly influenced by one or more enzymes produced by one or more bacteria or fungi (naturally present in the soil) thereby making disposal of the cassette of the present invention eco-friendly.
[0045] Example 1: Preparation of the cassette by method 100 of the present invention
[0046] The plant raw material i.e., sugarcane bagasse was obtained. The plant raw material was converted to pulp by adding 60 liters of water per kilogram of the plant raw material. Thereafter, the pulp was subjected to physical agitation by stirring the pulp and then allowed to rest for 24 hours. Further, the pulp was processed to form the fibrous material by heating the pulp at 160°C for 30 minutes. The fibrous material, so obtained, was allowed to rest for 30 hours.
[0047] Sixty liters of hot water was added to per kilogram of the fibrous material and then allowed to rest for 3 hours to form the slurry. The slurry, as obtained, was mixed with additives (25% v/v) including Tert-butyl polyacrylamide, Polyacrylamide with co-polymer acrylamide-2-methylpropane sulfonic acid with other water-soluble monomer. The mixture containing the slurry and the additives was vacuum filtered.
[0048] The mold having a pre-defined shape as per the requirements of the user (and/or medical product) was pre-heated to a temperature of 200 °C. The filtered slurry was poured within the pre-heated mold. The mold was then maintained at 200°C temperature and 2.5 MPa pressure for 30 minutes. The mold was cooled to room temperature and the cassette was recovered from the mold. An exploded view of the said cassette is depicted in Fig. 2.
[0049] The cassette was assembled (with a testing strip for immunochromatographic test) and packed inside a triple laminated aluminum pouch. The said pouch was subjected to sterilization by Ethylene oxide gas. The cassette was found to have smooth textures and increased strength.
[0050] The cassette was subjected to the immunochromatographic test by adding an analyte solution over the testing strip (in a dropwise manner). The cassette did not interfere with the test. Any analyte solution that got spilled over the cassette did not affect the integrity of the cassette throughout the duration of the test (which lasted for 4-5 minutes). Furthermore, the cassette was able to maintain its integrity even after the test was over for up to 4-5 hours. Thus, it was observed that the cassette was compatible with various analyte solution(s) used in the testing kits and the like.
[0051] The cassette was safely discarded (subjected to moisture, soil, and microbes) which led to the cassette being completely degraded within 60-90 days.
[0052] The scope of the invention is only limited by the appended patent claims. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used. , Claims:WE CLAIM
1. A method to prepare a cassette for diagnostic testing kits, the method comprising:
a. obtaining a plant raw material, the plant raw material including at least one of cellulose, hemicellulose and lignin;
b. adding a pre-defined amount of water to the plant raw material obtained at step a to yield a pulp;
c. subjecting the pulp obtained at step b to a first pre-defined temperature for a first pre-defined time period to yield a fibrous material, the first pre-defined temperature ranging from 90 °C to 200 °C;
d. adding a pre-defined amount of hot water to the fibrous material obtained at step c to yield a slurry, the hot water being at a second pre-defined temperature ranging from 140 °C to 180 °C;
e. adding a pre-defined amount of one or more additives to the slurry obtained at step d;
f. pouring the slurry obtained at step e to a mold;
g. maintaining the mold at a fourth pre-defined temperature and a first pre-defined pressure for a fourth pre-defined time period to yield a cassette, the fourth pre-defined temperature and the first pre-defined pressure ranging from 90 °C to 200 °C and 1.8 MPa to 3 MPa respectively;
h. removing the cassette obtained at step g from the mold.
2. The method as claimed in claim 1, wherein the step of adding a pre-defined amount of water to the plant raw material includes adding 60 liters of water for each kilogram of plant raw material.
3. The method as claimed in claim 1, wherein after the step of adding the pre-defined amount of water to the plant raw material, the method includes subjecting the pulp to physical agitation.
4. The method as claimed in claim 1, wherein the first pre-defined time period ranges from 140 minutes to 180 minutes.
5. The method as claimed in claim 1, wherein after the step of subjecting the pulp to the first pre-defined temperature for the first pre-defined time period, the method includes allowing the fibrous material to rest for a for a second pre-defined time period ranging from range from at least 24 hours to few days.
6. The method as claimed in claim 1, wherein the step of adding a pre-defined amount of hot water to the fibrous material includes adding 60 liters of hot water for each kilogram of plant raw material.
7. The method as claimed in claim 1, wherein after adding the pre-defined amount of hot water to the fibrous material, the method includes allowing the slurry to rest for a third pre-defined time period ranging from ranging from 2 hours to 3 hours.
8. The method as claimed in claim 1, wherein the one or more additives being selected from at least one of Tert-Butyl Acrylamides (TBAA), Polyacrylamide (PAM) and copolymer of the acrylamide-2-methylpropane sulfonic acid with other water-soluble monomers.
9. The method as claimed in claim 1, wherein after the step of adding one or more additives to the slurry, the method includes filtering the slurry via cross flow micro-filtration, vacuum suck filtration, or sieve filtration.
10. The method as claimed in claim 1, wherein prior to the step of pouring the slurry in the mold, the method includes pre-heating the mold to a third pre-defined temperature ranging from 150 °C to 250 °C.
11. The method as claimed in claim 1, wherein the fourth pre-defined time period ranges from 20 minutes to 40 minutes.
12. The method as claimed in claim 1, wherein prior to the step of removing the cassette from the mold, cooling the mold to room temperature.
13. The method as claimed in claim 1, wherein after the step of removing the cassette from the mold, the method includes:
a. packaging the cassette in at least one of tyvek pouch and triple laminated aluminum pouch; and
b. sterilizing the cassette using at least one of Gamma radiation, Argon gas, Ethylene oxide gas.
14. The method as claimed in claim 1, wherein the method includes assembling the cassette with a testing strip.