EXPLORING THE POTENTIAL OF 3D PRINTING IN PHARMACEUTICAL DEVELOPMENT

Pharmaceuticals have been transformed by additive manufacturing, often known as three-dimensional printing (3DP) a disruptive technology. The concept of additive manufacturing is examined, with a focus on its potential for quick prototyping, cost savings, and development of customized medicines. In the pharmaceutical industry 3DP is used to develop numerous dosage forms and drug delivery systems including oral films, controlled-release tablets and transdermal patches. It also makes it possible to produce specialized medical prosthetics, implants and gadgets. The applications of various 3DP types such as material extrusion, material jetting, binder jet printing and powder-based procedures like selective laser sintering, are thoroughly covered. This review assesses the compatibility of the common 3DP materials for pharmaceutical applications including hydroxypropyl methylcellulose, hydroxypropyl cellulose, Carbopol and Eudragit. This review article forecasts 3DP prospects and shortcomings. The technology's continued development and use in the pharmaceutical industry and other industries will depend on overcoming regulatory challenges, creating standardized procedures and optimizing material alternatives. By tackling these issues 3DP has a great deal of potential to revolutionize personalized medicine, medical device production and variety of other industries ultimately leading to better patient outcomes and healthcare solutions. Types and principles, materials, applications, scalability, regulatory compliance and potential future challenges are discussed in this review paper.


INTRODUCTION
Three-dimensional printing (3DP) or additive manufacturing is a novel technique wherein the binding materials are deposited in layers to obtain 3D printed object [1].3D printers work like inkjet printers, where powder is slowly put on layer by layer to obtain a 3D printed image.Computer-aided design (CAD) software is employed in the fabrication of objects with various shapes and sizes.Signal is transferred to 3D printer by CAD software, which produces solid layers to build up objects [2].Additive manufacturing helps in rapid prototyping, easily modifying product at design level, manufacturing small objects and cost reduction [3].
Producing personalized medicine has been gaining more relevance due to the development of 3DP.These are safe and efficacious, cost effective and improve patient compliance.Personalized medicines will provide aid to pediatric, geriatric and dysphagic patients [4].Available dosage forms (oral liquids) of personalized medicine taken by dosing aids like calibrated spoons, droppers or syringes may not provide accurate dosing due to human errors.Additive manufacturing helps develop personalized medicines which avoid human errors [5].
Application of 3DP in pharmaceutical industry is growing, it is employed in fabrication of various pharmaceutical products like orodispersible films, controlled release tablets, polypills, gastro-floating tablets, self-emulsifying drug delivery systems, microneedles and transdermal patches [6].Various medical prosthetics, implants and devices for individual patient needs are manufactured by 3D printing technology [7].In mid 1980s, stereolithography apparatus was first invented and patented by Charles Hull.In this process UV light polymerizes the resins to obtain the desired object.In 1988, the first commercial SLA printer was produced by 3D systems [8].In 1989 S. Scott and Lisa Crump patented fused deposition modelling (FDM), wherein a metal wire or plastic filament were heated in the nozzle and then extruded [9].Later Carl Deckard, an undergraduate student at Texas University invented Selective Laser Sintering (SLS) technique.The first SLS printer was produced in the year 1992 [10].Spritam® (levetiracetam) the first commercial 3D tablet was approved by the USFDA in August 2015 [11].

Material extrusion
It is the least expensive and frequently used type of 3D printing.It is classified into two types: fused deposition modelling and semisolid extrusion [12,13].The pre-printing material is extruded in a continuous stream through a nozzle in both techniques.To obtain a particular geometry the nozzle or platform (or a combination of the two) is moved in the x, y, and z directions [14].[15].Fused deposition modelling utilizes a heated extrusion nozzle [16].In FDM, thermoplastic polymers in form of a filament are extruded through the printer head at a specific temperature at definite directions and the semi-molten material is deposited on the build plate to form the layers [17,18].The process of FDM can be divided into three stages: (i) molten material extrusion (ii) material layer deposition and (iii) layer solidification [19].Generally, the initial printing step involves creating the outer layer and subsequently the internal structures are constructed layer by layer.To fill the internal space, an extruded polymer called "infill" is used with the extent of filling determined as needed [20,21].

Semi-solid extrusion 3D printing
Extrusion-based semi-solid extrusion (SSE) printing is another important type of 3DP technique that could be very useful for soft materials [22].Semisolid extrusion printers can print a range of materials using pneumatic or mechanical extrusion forces instead of relying solely on heat [23].To create a three-dimensional object a syringe-based tool-head nozzle is used to extrude a combination of semi-solid materials [24].These initial materials are typically pastes or gels those are created by carefully mixing solvents and components in specific quantities to achieve the desired viscosity for printing [25,44].The fluid must have the right viscosity to ensure a smooth extrusion.

Material jetting
The material jetting technique resembles to that of inkjet printers.The print head and platform are actuated to move in the x, y and zaxis.The material must be cross-linkable upon delivery for successful printing.Cross-linking processes not only includes semisolid extrusion but also involve photo, thermal, ionic and pHdependent effects [26].One of the most significant advantages of this approach is that it can print multiple materials at the same time, even materials with differing properties [27].

Inkjet printing method
Inkjet printing refers to the technique that use pattern generating devices to digitally control and place small liquid drops on a substrate [28].In pharmaceuticals appropriate drug blends and excipients (known as ink) are deposited in small drops layer by layer on a suitable substrate [29].Various types of inkjet printer are available, which are outlined below:

Continuous inkjet printer (CIP)
Continuous inkjet printers eject a stream of liquid droplets on a substrate continuously.Continuous inkjet printing involves the creation of a pressure wave within the ink flow.This wave disrupts the ink into consistently sized droplets through nozzle vibration, after which the droplets are expelled from the nozzle.This approach results in ink wastage due to the continuous expulsion of droplets.The benefits of this printing process include high-speed continuous droplet creation which prevents nozzle clogging [30].

Drop-on-demand inkjet printer
Drop on demand inject printing method is quite simple provides excellent precision in affordable cost.In continuous inkjet printer's droplets are expelled by external pressure, whereas in drop-ondemand inkjet printers droplets acquire their kinetic energy from nearby sources situated within the printhead [31].Drop-on-demand inkjet printer further classified in thermal inkjet and piezoelectric printer based on printhead type [32].

Thermal inkjet printer (TIJ)
Thermal energy is used as the trigger mechanism to release droplets in TIJ, which then exit the nozzle.The print heads have resistors that are in direct contact with the fluid (ink) and produce heat when an electric current is applied to them.This heat causes a bubble to form within the volatile fluid, which then expands and ejects a small volume of fluid out of the nozzle, generating a droplet [29,31].

Piezoelectric inkjet printer (PIJ)
This technology utilizes a piezoelectric element or actuator that undergoes a shape transformation when subjected to an electric voltage [33].This creates pressure, which causes the fluid (ink) to be ejected from the nozzle.The nozzle is reloaded with fluid and ready to be activated once the element has returned to its original shape.
The key benefits of this technology include its ability to operate at room temperature while using less volatile and more biocompatible fluids [34].

Binder jet printing
It is also known as the drop-on-powder method which is an application of inkjet printing technology.A printer nozzle containing the binder fluid is designed to move along an x-y axis and jet the liquid onto the loose powder bed.Printhead of jet printer could be thermal or piezoelectric.The liquid drips moisten the powder, which causing the layer to harden and solidify [18].Subsequently, the manufacturing platform moves downward along the z-axis while the powder supply platform rises.A roller is then used to transport a powder layer from the bed to the top of the previously bound layer.This method is performed several times until the 3D product is completed [18,33].

Fig. 9: Schematic of binder jet printing [22]
Selective laser sintering Selective laser sintering works similarly to binder jetting however, instead of a binder, a laser is used to sinter powder particles together [36].The spreading platform, powder bed and laser system are the three primary components of a SLS system [37].This method is useful because it is a one-step rapid manufacturing procedure that does not require use of any solvent.Since is use laser precision, it also produces high-resolution objects [38].

Fig. 10: Schematic of selective laser sintering [22]
Selective laser melting A specific rapid prototyping, additive manufacturing (AM) or 3D printing process called selective laser melting (SLM) aims to melt and fuse metallic powders using a high power-density laser.SLM uses a powerful laser beam to create 3D parts, such as SLA, which uses a UV laser.The laser beam melts and combines different metallic particles together while printing [39].A building platform is covered with metal powder which has been heated nearly to its melting point and spread using a roller.The cross-section of the 3D object is drawn into the powder material using a laser after which the chosen particles are fully combined to obtain 100% density.In this manner, the melting happens when the grain viscosity decreases with an interfacial connection between the grains but not when the temperature melts completely.Grain viscosity in 3D printing refers to the flow behavior and thickness of the material being used for printing, often associated with granular or particulate materials like powders.2D cross-section made up of layers with thicknesses of 20 to 100 microns.An even layer of metallic powder is then applied using a recoater to construct the part and each layer is fused separately in a precisely regulated inert environment.Once the printing process is finished any leftover powder is cleared away.
During the procedure laser is utilized to shape the powder layers and the object is created using with laser energy [40].

Stencil printing
Wickstrom and colleagues have introduced a novel printing technique that has not yet been employed in pharmaceutical manufacturing.The objective of their investigation was to determine whether drug-loaded polymer inks could be produced to develop pliable pharmaceutical products that have consistent content and mass.They used a prototype stencil printer and polyester as the stencil material to print discs containing Haloperidol (HAL) [41].

Digital light processing (DLP)
Digital light processing is a 3D printing technique that shares similarities with SLA, but instead of using a laser beam, it employs UV light from a projector to solidify each layer of a resin-based material.Madzarevic et al. utilized this technology to produce ibuprofen tablets through DLP 3D printing [42].

Embedded 3D printing
Embedded 3D printing (e-3DP) is a new type of additive manufacturing (AM) in which a viscoelastic ink is deposited into a reservoir that solidifies using a deposition nozzle that follows a predetermined path.Rycerz et al. demonstrated one of the initial applications of e-3DP in the pharmaceutical domain by producing dual drug-loaded chewable oral dosage forms.The team suspended paracetamol and ibuprofen in a locust gum solution and then embedded them in a gelatine-based matrix material to create the final product [43].• Amphiphilic nature.
[58, 59] Polylactic acid (PLA) • Synthetic polymer that is insoluble and biodegradable [60] Polyvinylpyrrolidone (PVP) • PVP dissolves in water and organic solvents.[61] Applications and scalability aspects 3DP is the process utilized to manufacture 3D products layers after layers using digital designs.The 3DP is regarded as a versatile tool for producing numerous products quickly.3DP makes possible creation of custom drug dosages and formulations which makes personalized treatment of each patient possible [62].The technology may also be used to fabricate customized medical devices such as prosthetics, hearing aids and orthotics, which can raise the standard of living and improve the quality of life for patients.
3DP, also known as additive manufacturing, has emerged as a promising technology in various fields, including pharmaceutics.Some of the applications of 3DP in pharmaceutical dosage form designing are as follows

Solid oral dosage forms (SODFs)
SODFs are the most suitable choice for drug administration due to their convenience in handling and manufacturing, as well as their high patient compliance [63].The conventional manufacturing processes of SODFs are characterized by a multitude of steps, lengthy durations, high costs and a lack of customization to meet individual requirements.Furthermore, these methods are primarily focused on large-scale bulk production [64].3DP is a cutting-edge and emerging technology that has the potential to address these challenges.By utilizing three-dimensional printing, it becomes possible to create personalized shapes for SODFs, incorporate many drugs into a single dosage form and manufacture medication tailored to individual patients, resulting in improved safety, convenience and adherence [65].

Tablets
The most prevalent SODFs produced by 3D printing are tablets.With the aid of 3DP, it is simple to create and modify tablets for various shapes, release profiles and special doses, including combinations of different medications [66].

Immediate-and modified-release tablets
3DP has made it possible to manufacture formulations that dissolve quickly in mouth [67,68].Modified-release tablets include delayed-release, controlled-release, sustained-release and targeted-release.The overall surface area of conventional modified tablets decreases during the gastrointestinal tract's absorption process, causing a non-constant drug release.3DP may solve this problem with manufacturing tablets with complex geometries that provide the formation of both those with individualized release profiles and those with continuous sustained-release dissolving profiles [69].

Orally disintegrating tablets (ODTs)
ODTs are oral delivery systems that can dissolve within seconds without the need for additional liquid.Patients with dysphagia and patients who have trouble swallowing may find ODTs especially beneficial.3DP avoids the heavy compression pressures needed in the conventional manufacturing process, so the fabricated final structure is significantly more porous and disintegrates more quickly.Spritam is an example of an additive manufacturing (AM) application in a pharmaceutical and fabricated using a technique called binder jetting, which dissolves within 2-27 seconds [74].
Another investigation by Tian et al. utilized the same technique to prepared oro-dispersible warfarin tablets [75].This study showed that increasing lattice density resulted into sinking of tablet that increased drug release rate [77].

Polypills
The fabrication of multi-API tablets (polypills) is another advantage of 3DP.Patients with various illnesses who need to take a variety of medications throughout the day may gain benefit from it [78].The first study on 3DP polypills to be published in the literature is that of Khaled et al.The team created polypills containing glipizide, captopril and nifedipine utilizing extrusion-based 3D printer.The polypill was developed to treat diabetics with hypertension [79].

Capsules
Capsules are dosage forms that contain shell around the medication.The cap and body of 3D printed capsules and capsule devices can be created separately and then filled and assembled or they can be produced and filled in one manufacturing process [80].Melocchi et al. were the first to study the 3D printing potential for use in capsule production.The team utilized a swellable HPC-made capsular device prepared for oral pulsatile release via FDM printing [81].

Orodispersible films
Orodispersible films (ODFs) are thin polymer films that stick to the tongue or palate before quickly dissolving or disintegrating.It is usually prepared by casting methods.Current investigations of their 3D printing preparation have also been made.Öblom et al. compared traditional oral powders in sachets (OPS) with Warfarin ODFs prepared by 3DP using semisolid extrusion and inkjet printing.In comparison to OPSs, the 3D-printed ODFs had higher drug concentration and more consistent unit doses [81].

Tablets for certain patient groups
The creation of tablets for certain patient groups, including pediatrics, dysphagic and blind patients is another important use of 3DP.Children's solid oral dose forms are often created by modifying adult formulas.But it could result in serious pharmaceutical errors.A method to prevent these possible errors may be 3DP [82].Namely, Pediatrics patients get option to select the form and color of their choice.By using FDM Scouters et al. created candy-like SODFs that contained indomethacin.The formulations were successful in minimizing the bad taste of indomethacin and ensuring its rapid release [83].

Implants
An implant is a dosage type that helps patients who need long-term medication therapy and contains active components in a sustainedrelease matrix.3D printed Implants include spine implants, shoulder joints (glenoid replacement, hip implants) and implants for the OMF area oral and maxillofacial surgery.Recently, A 3DP based multidrug implant was developed by Wu et al. (2016).Tobramycin and Levofloxacin were implanted as APIs [84].

Transdermal microneedle (MN) patches
It is a type of transdermal drug delivery containing tiny needles on a matrix.By using 3DP technology, microneedles can be fabricated with more complex and advanced geometries as opposed to those that are limited to being made using traditional microfabrication processes.AM technologies, particularly SLA and DLP, offer alternative method for MN fabrication.To imitate a specific area of the human facial shape, Lim et al. created MN patches containing various curves with the help of DLP printer [85].It was shown that curved MNs dispersed pressure uniformly which require for absorption that offered greater dermal absorption and delivered drug effectively.

Dose dispensing aids
Recently, AM has proven to be an effective technique for creating samples of pharmaceutical distributing equipment that is suitable for customized medication.Niese et al. created samples of pharmaceutical distributing equipment for a drug containing film which promotes variable dose with individualized treatment.

Drug eluting devices
Drug eluting dosage form enables the continuous release of a medicinal substances over a significantly long time.The shape, components and dose options for drug-eluting products are constrained.3DP facilitate this by altering dose, dosage form shape and medication release profile.

Acellular models
Models have long been used as a tool to improve learning.With the use of AM technology, we can go one step further and create customized 3D printing models, enabling a more customized approach and more patient-centric treatment.For example, Spence et al. prepared various devices to transport large flow for nasalcannula (HFNC) treatment.

Cellular models
3D printed cellular models are physiologically more relevant than conventionally manufactured cellular models.They more accurately represent tissue microenvironments, cell-to-cell communications and biological events which occur in vivo.

Opportunities
In the pharmaceutical industry, 3DP has several potential opportunities.Some of them are as follows:

Personalized medicine
3DP technology can be used to create customised dosage forms for each patient based on their specific physiological characteristics.This might result in more efficient medical interventions and better patient outcomes [86].

On-demand manufacturing
3DP makes it possible to quickly produce medications and medical equipment when needed, eliminating the need for mass production and storage facilities [87].

Improved drug delivery
By using 3DP it is possible to design medication delivery systems with accurate dosing and release characteristics.This aid in more effective drug release control, fewer side effects and higher patient compliance [88].

Production of complicated structures
Using conventional manufacturing methods it is difficult or impossible to build complicated structures such as scaffolds for tissue engineering or drug delivery systems [89].

Quicker drug development
3DP enables the quick creation of small batches of pharmaceuticals for testing and evaluation, which helps speed up the medication development process.New drug development and approval could proceed quickly as a result [90].

Rapid prototype development
3DP makes it possible to quickly and affordably prototype new medication formulations and medical devices, which makes the creation of pharmaceutical goods more effective [91].

Manufacturing effectiveness
Pharmaceutical businesses can streamline their processes by using 3DP to cut the time and costs involved with conventional drug manufacturing [92].

Challenges
The pharmaceutical sector has identified 3DP commonly referred to as additive manufacturing as a viable technology.It makes it possible to produce medical equipment, drug delivery systems, and personalised medications quickly, accurately and flexibly.However, there are a number of challenges that must be resolved.

Printing resolution
For 3DP, printing resolution is a key component.It is the measure of the layer thickness, typically expressed in microns, determining the level of detail and smoothness in the finished printed object.It establishes the degree of accuracy and precision.To achieve precise dosage and drug release in the pharmaceutical industry the printing resolution must be good enough [93].

Material choice
It is crucial to choose the right materials for 3D printing in the pharmaceutical industry.The materials should have appropriate mechanical qualities, be stable, and be biocompatible.There are few suitable materials readily available and creating new materials for 3DP is difficult [94].

Regulatory approval
A major obstacle to pharmaceutical 3DP is regulatory approval.To assure the safety and effectiveness of 3DP products the regulatory authorities need thorough testing and validation [95].

Quality control
It is necessary to guarantee product uniformity and safety.But because of the complexity of the production process, the unpredictability of the materials and the absence of standardized testing procedures, quality control for 3DP medications is difficult [96].

Intellectual property
Concerns about intellectual property rights are raised by the 3DP of medications.Legal problems may arise from the unlicensed printing of patented medicines or medical equipment [97].

Cost-effectiveness
Cost effectiveness is still an issue with 3DP in the pharmaceutical industry.Cost effectiveness of 3DP depends on factors like material costs, equipment, design complexity and production volume.
Equipment and materials for 3DP are highly expensive and economies of scale have not yet been attained [98].

Sterilisation
To avoid contamination and guarantee the safety of the final product, sterilisation is an essential step in the manufacturing of pharmaceuticals.Specific sterilisation procedures can be necessary for 3DP items which could have an impact on their mechanical and structural qualities [99].

Scalability
Because 3DP in the pharmaceutical industry is still in its infancy, it may be difficult to scale up manufacturing to fulfil the demand for personalised medications at a large scale [100].

Printing software
Modelling, slicing, printing and post processing are the four basic processes in 3DP.In printing process, the computer is first used to create a printing model and slice it to specify the printing route of each layer and then the formulation with a complicated structure is manufactured in accordance with the prefabricated model.The modelling and slicing software must thus be continuously upgraded to match higher printing requirements as the complexity of the desired structure rises [94].

Printability
A material's ability to be printed using a particular 3DP process is known as printability.It may be difficult to create the intended product since some pharmaceutical materials may not be compatible with specific 3DP procedures [101].

Post-processing
In order to give 3DP objects the desired qualities, post-processing may be necessary such as cleaning, polishing or coating.The choice of appropriate post-processing processes is crucial for maintaining product quality although post-processing can be time-consuming [102].

Design optimisation
In 3DP design optimisation is essential to ensuring the usefulness, safety and effectiveness of the final product.However, it could be challenging to produce pharmaceutical items for 3DP with optimized features due to the complexity of the production process and the nature of the material [103].

Uniformity
To achieve consistent dosing and efficacy 3D-printed items must be uniform.Due to variances in the printing process, it might be difficult to produce medications using 3D printing with consistency [103].

Regulatory aspects
As 3DP technology has developed, it has given the pharmaceutical sector new opportunities.However, when using 3DP technology in pharmaceuticals there are a number of regulatory aspects that must be taken into account due to the complexity of pharmaceutical products.

Adherence to GMPs
Good Manufacturing Practices (GMPs) are a set of rules that guarantee pharmaceutical products are consistently created and monitored in accordance with quality standards.GMP compliance must be achieved while using 3DP in the pharmaceutical industry to maintain the product's quality and safety [104].

Validation
To ensure that the finished product complies with the necessary requirements, 3D printing procedures must be validated.This includes verifying the raw components, the printing technique and the final product.

Intellectual property
There are questions about intellectual property rights raised by the use of 3DP technology in pharmaceuticals [105].As a result, regulatory authorities demand that patent rules and regulations be strictly followed.

Material safety
It is important to determine the safety and compatibility of 3D printing materials with pharmaceutical items.This includes figuring out how the substance and the active pharmaceutical ingredients (APIs) might interact.

Labelling and packaging
The labelling and packaging specifications for pharmaceutical products made using 3DP are the same as those for goods made using more traditional manufacturing methods.This includes the demand for accurate dosage, strength and expiration date labelling.
Currently, there are no specific global guidelines governing 3D printing in pharmaceuticals [106].However, many regulatory bodies have issued guidance on using 3D printing in medical devices and drugs.In addition to regulatory organizations, many nations also have their own laws governing the usage of 3D printing in the pharmaceutical industry.Depending on the nation these laws may have standards for GMP compliance, validation, material safety and packaging.A few examples are given below:

United States
In 2015, Spritam (levetiracetam), a medication used to treat epilepsy received Food and Drug Administration (FDA) approval.[107] Since then, several other 3D-printed medications have received approval, including medication for Parkinson's disease produced by GlaxoSmithKline.The FDA released guidelines for the 3D printing of medical devices in 2017, offers suggestions for design, production and testing.This draft guidance is broadly organized into two topic areas such as Design and Manufacturing Considerations and Device Testing Considerations [117].The FDA released drafted guidance also offers suggestions for labelling and premarket filings [107].

European Union
The European Medicines Agency (EMA) has published a reflection paper on the applications of 3DP in the pharmaceutical sector in 2020, with recommendations on issues related to quality, safety and efficacy [108].Medical devices made using 3DP are likewise subject to the In vitro Diagnostic Regulation (IVDR) and Medical Device Regulation (MDR) of the European Union [109].

International standards organization
The

Australia
Guidelines on the regulation of medical equipment made via 3DP have been published by the Australian Therapeutic Goods Administration (TGA) [109].

Canada
Health Canada Guidelines on Acceptance of Medical Devices Manufactured through Additive Manufacturing or 3D Printing document provides instructions on the manufacture and sale of medical devices made through additive manufacturing or 3DP [109].

Japan
Guidelines on the use of 3DP in pharmaceutical manufacture have been released by the Pharmaceutical and Medical Devices Agency (PMDA) in Japan.These guidelines include suggestions for quality control, safety and efficacy testing and regulatory criteria [110].

India
In India, 3D printing is still a relatively new technology in the pharmaceutical industry, and there are currently no established regulatory standards.The Central Drugs Standard Control Organisation (CDSCO), a division of the Indian Ministry of Health and Family Welfare, is in charge of overseeing 3DP in medical devices.With respect to the registration of medical devices, the CDSCO has published guidelines that provides the specifications for quality management systems and conformity evaluations.Additionally, the CDSCO has developed a legal process for authorising 3DP medical devices.These devices must register with the CDSCO and pass a conformity assessment procedure to validate their safety and efficacy before being supplied in India [111].
Additionally, the Bureau of Indian Standards (BIS) has produced guidelines for material qualities, dimensional accuracy and mechanical features for 3DP in general [112].These rules may be relevant to 3DP in the pharmaceutical business even if they are not particular to the industry.
The regulatory framework for medical devices may apply to 3DP medical devices, including those used for drug delivery, even if there are no regulatory compliances for 3DP in pharmaceuticals in India.
Companies who are interested in designing and producing 3DP medications in India should coordinate closely with the relevant regulatory bodies to make sure that all laws and rules are followed.

CONCLUSION
The potential of Additive manufacturing is tremendous.It has ability to bring revolution in pharmaceutical industry, especially in personalized medicine which will improve patient compliance, reduce side effects, resolve issues related to shelf life.This technology offers flexibility in the development of formulation which is difficult through conventional process.Dosage forms with complex shapes and release profiles can be manufactured.Spritam the first FDA approved commercial tablet has been an aspiration to healthcare industry.
As of now 3DP cannot compete with the conventional drug manufacturing, advancement in future in the printing speed and resolution must be altered which will reduce the energy consumption and the cost of production.For the approval of 3DP dosage forms defining appropriate regulatory guidelines is required.Overcoming these challenges in 3DP technology will help boost the manufacturing of personalized medicines.

Table 2 : Applications of 3D printing on modified-release tablets
[76] the use of 3DP, tablets with prolonged stomach retention (gastrofloating) were effectively produced.Traditional techniques to achieve gastrofloating systems in SODFs, CO2 effervescent systems were used to enable floating or non-effervescent systems that reduce perceived density are used to enable floating.By adjusting the infill density, 3DP makes it simple to modify tablet density[76].Li et al. fabricated a number of lattice-filled dipyridamole tablets.
Additive Manufacturing Technologies was established by American society for Testing and Materials (ASTM) Committee F42 in 2009.With over 150 members attending two days of technical sessions F42 assembles biannually often in the spring and autumn (in the US and abroad respectively).The committee which now has over 725 members, comprises of eight technical subcommittees.All of the standards established by F42 are published in the Annual Book of ASTM Standards, vol.10.04.These norms concentrate on a number of distinct areas, including general norms (such as nomenclature, test techniques, safety), feedstock material norms, application-specific norms (including medicinal uses), process and equipment norms and completed part norms.The standards for 3DP are to the extent feasible based on current standards and where needed updated for 3DP.