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7.3 Global Market Analysis
The market size of oral solid dosage forms administered orally was evaluated to be
US$ 679.53 billion in 2022, and the gross income is expected to surge at cross
annual growth rate of 7.10% from 2023 to 2029, reaching nearly US$ 1098.34 bil-
lion. The vital market companies producing oral solid dosage forms are Takeda
Pharmaceutical Company Limited, Merck & Co., Corealis Pharma Inc., Astellas
Pharma Inc., Corden Pharma International, Bayer AG, AbbVie Inc., Thermo Fisher
Scientic Inc., Lonza, Catalent Inc., Alcami Corporation, Halo Pharmaceutical Inc.,
Arnet Pharmaceutical, Jubilant Life Sciences, Pzer Inc., Piramal Enterprises Ltd.,
and many more. The tablet division is governing the world market with a stake of
55.6% in 2022.
The oral solid dosage forms market analysis report provides a complete outlook
throughout the globe with unique importance in North America, Europe, Asia
Pacic, Latin America, the Middle East, and Africa. North America region had the
leading market share in the oral solid dosage form market in 2021. Asia Pacic
held the second position which was followed by the other provinces (Oral Solid
Dosage Pharmaceutical Formulation Market—Global 2023). Tablets are modied
from time to time to improve its applicability, popularity, patient’s compliance, and
protability. Several kinds of tablets that are available in the market are listed below.
7.4 Types ofTablets
Tablets have been modied several times to cater needs of patients, which led to the
existence of a huge collection of varieties of tablets available for commercialization.
Traditional tablets are basically mono-layered tablets with basic constituents like
active pharmaceutical ingredients (APIs), diluents, binders, disintegrants, and lubri-
cants (Waterman etal. 2009). Bilayer tablets are intended to avoid chemical incom-
patibility by physically separating the two active substances. Further, two-layered
tablets prompt two diverse release kinetics, with one layer for immediate release
and the second for controlled release (Patel etal. 2007). As two or more incompat-
ible active agents need to be managed concurrently, multilayered tablets can be
prepared. Therefore numerous granulated preparations are formulated which
undergo compression and produced a single tablet with either double or additional
layers of variable colors generating a unique appearance (Abebe etal. 2014).
With time, the art of formulation of tablets headed in the direction of specialized
tablets. Specialized tablets can overcome the limitations of normal tablets as the
consistent drug levels in the blood can be achieved, adverse effects can be mini-
mized, and inappropriate physicochemical properties of the API, like low absorp-
tion and solubility, presystemic metabolism, and narrow therapeutic index, can be
tackled. Specialized tablets can be classied broadly in two ways: organ-targeted
tablets and drug-release prole-specic tablets (Advankar etal. 2019). Apart from
this, several types of tablets come under the category of miscellaneous like matrix
S. Tarannum and K. Jain
179
system; reservoir system; chewable, orodispersible, and effervescent tablets; loz-
enges; osmotic tablets; and many more.
7.4.1 Organ-Targeted Tablets
Organ-targeted tablets are specically designed for a particular organ or for localized
action and make sure that other body parts remain unexposed to the drug. Common
organ-specic tablets include buccal tablets, sublingual tablets, oating tablets,
enteric-coated tablets, vaginal tablets, rectal tablets, dental cones, implantable tab-
lets, and ocular tablets (Orlu etal. 2006). Some of these are shown in Fig.7.1.
7.4.2 Modified Release Tablets
The pharmaceutical companies have explored several approaches like modied
drug delivery that involves timed, sustained, delayed, as well as programmed-
release systems, to satisfy particular market requirements. The principle of modied
release indicates certain modications in the release prole like faster, delayed, sus-
tained, controlled, or targeted. As per the regulatory bodies, modied release prepa-
rations need to be efcacious, safe, and with minimum side effects. The high crests
and low troughs in the plasma drug concentration curve should be negligible with
the main focus on reducing the dosing administration frequency, which will eventu-
ally improve the patient’s understanding of medication (Şengel etal. 2006).
Fig. 7.1 Organ-specic tablets
7 Formulation Evaluation andDevelopment ofSpecialized Tablets
180
Modied release formulations are fabricated in such a manner that their rate or
site of release of therapeutics is controlled, unlike the immediate release formula-
tions. This thoughtful alteration is attained by implementing changes in the formu-
lation and production approaches. Modied release formulations are administered
by different routes like oral, intramuscular, subcutaneous, etc. The modied release
version of any medicament is made if the need for a more precise formulation is
well analyzed (like patient compliance or safety). The report submitted for market-
ing approval needs to give a thorough explanation of the physical structure of the
modied release substitute and the release principle; the reason for the selection of
the specic dosage form in terms of indication and posology; and the reason for the
selection of the quantity of API per unit of the dosage form (European Medicines
Agency 2014).
1. Formulation of Modied Release Tablets
Modied release dosage forms are of diverse types. These are (a) prolonged
release; (b) delayed release; (c) multiphasic release; (d) biphasic release; (e)
pulsatile release; (f) multiple-unit, (g) single-unit, e.g., osmotic tablet, and (h)
intramuscular/subcutaneous depot formulations; (i) transdermal drug delivery
systems; and so on.
Hydrogels like cross-linked polyvinyl alcohol (PVA), cross-linked polyvinyl
pyrrolidone (PVP), and polyethylene oxide (PEO); hydrophilic polymers like
polyvinylpyrrolidone (PVP) and hydroxypropyl methylcellulose (HPMC); bio-
polymers like polylactic acid (PLA) and polyglycolic acid (PGA); mucoadhe-
sive polymers like polyacrylic acid, tragacanth, methylcellulose, and pectin;
nonbiodegradable polymers like cellulose acetate and ethyl cellulose; and natu-
ral polysaccharides like guar gum, karaya gum, and locust bean gum are the
common excipients which can modify the release prole of incorporated active
agents leading to the fabrication of various kinds of modied release dosage
forms available in the market (Murugesan etal. 2019; Zarate etal. 2010). For
observing the tablet production quality, quantitative evaluations and assessments
of tablet’s physicochemical as well as bioavailability properties must be made.
2. Evaluation of Modied Release Tablets
The evaluation of modied release tablets is similar to conventional tablets.
Thickness, hardness, friability, content uniformity, weight variation, swelling
index, and dissolution studies are carried out for the proper evaluation of the
prepared modied release tablets (Wen etal. 2021). Tablet’s hardness is usually
studied as the force needed for carrying out the disruption of the tablet in a par-
ticular axis. Hardness index is used which establishes a relation between hard-
ness and weight to break the tablet so that a numerical value can be generated
which can be utilized for relating tablets with their ease of getting broken. The
dissolution process is conducted using apparatus 2 to investigate the release of a
modied release tablet at various pH levels that mimic the pH conditions
throughout the gastrointestinal tract. The medium is maintained at a constant
temperature of 37°C±0.5°C and stirred at a speed of 50rpm. The release is
S. Tarannum and K. Jain
181
carried out at pH 1.2, 4.5, 7, and more alkaline pH, respectively, using 2M HCl
and 2M NaOH.The time points for sampling are 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
11, and 12h. At every time point, 2mL of the sample is extracted, resulting in a
further dilution to 20mL, and subsequently evaluated using a spectrophotome-
ter. After each sample is extracted, it is substituted with a new dissolving media.
The dissolution of tablet is performed in triplicate, and the average of these val-
ues is calculated. The evaluation of drug-release pattern involves the investiga-
tion of kinetics and mechanisms using several model-dependent approaches
(such as zero and rst models, Higuchi, Hixson-Crowell, and Korsmeyer-Peppas
models) and model-independent approaches (such as mean dissolution time
determination), as previously indicated.
Many researchers formulated modied release tablets of different drugs and
evaluated them to analyze their performance. Some instances of the formulation
development of modied release tablets are given. Mahapatra etal. (2015) devel-
oped delayed release tablets of zolpidem tartrate via the biphasic delivery system
process, using sodium starch glycolate as a super disintegrant in instant-release
fragment and HPMC as a delayed release matrix in the central part. Tablets were
directly compressed with active agents present in both the central part and in the
coat. Optimized formulations follow Fick’s law of diffusion and exhibited simi-
lar release proles as mentioned in the United States Pharmacopeia guidelines
for extended-release dosage forms of zolpidem tartrate. Accelerated stability
tests were carried out on the optimized formulation which ensures that it can
tolerate the typical stressful circumstances of humidity and temperature
(Mahapatra et al. 2015). Gaikwad et al. (2020) formulated modied release
affordable tablets of capecitabine with no use of coating practices. The tablets
were developed by the wet granulation process. Hydroxypropyl cellulose (HPC)
was employed which acts as an extended-release matrix agent, and sodium algi-
nate (SA) gave the sustained-release effect and exhibited mild gelling properties.
Characterization using differential scanning calorimetry (DSC) and powder
X-ray diffraction (PXRD) highlighted the retention of crystallinity of capecitabine
within the optimized tablet. The selected formulation delayed the release up till
24h (Gaikwad etal. 2020). Nagasamy etal. (2021) developed sustained-release
tablets of isradipine, comprised of HPMC using the wet granulation method. Its
invitro as well as invivo characterization was matched with the normal immedi-
ate release tablet as a primary evaluation. Tablets having 15% (w/w) HPMC
showed a sustained release for 24h. The release pattern of isradipine followed
the Fickian diffusion abiding the rst-order reaction. The absorption was signi-
cantly greater than the typical tablets, which exhibited immediate drug release.
In vivo studies performed on rabbits indicated that the isradipine absorption rate
from the formulated tablets was better than the immediate release tablets
(Nagasamy Venkatesh etal. 2021). Some types of tablets do not t in either the
category organ-specic or modied release tablets. These tablets (chewable,
effervescent, and orodispersible) are discussed in the miscellaneous part in the
upcoming section.
7 Formulation Evaluation andDevelopment ofSpecialized Tablets
182
7.4.3 Miscellaneous
7.4.3.1 Chewable Tablets
Chewable tablets are subjected to be masticated in between the teeth and the rate of
release of API depends on the number of chews. These tablets are prescribed mostly
for kids, elders, and patients with dysphagia. These are basically desirable for local
action as compared to systemic action. Wet granulation or direct compression tech-
niques are well established for the manufacturing of chewable tablets. Additionally,
therapeutics in micronized and submicronized forms are used to improve the
absorptivity of less soluble therapeutics (El-Gazayerly etal. 2004).
As per the USP, chewable tablets are divided into two types: chewable tablets
which are (1) masticated for easy administration, for example, Nicorette gum (nico-
tine) and Aspergum (aspirin) and (2) those that need to be masticated before gulping
down in order to circumvent choking or to make sure the release of the API, for
example, niclosamide tablets. Chewable tablets are preferred for the APIs whose
therapeutic dose is adequately large, and thereby, they cannot be administered as an
intact tablet because of the large size. Chewable tablets are also proven to have bet-
ter bioavailability as chewing tablets prior to swallowing improves the dissolution
of the medication. Similarly, because of the pleasant taste and mouthfeel, the com-
pliance of pediatric patients improves (Suzuki etal. 2004).
However chewable tablets have a few limitations like their hygroscopic nature
and compromising mechanical strength which necessitates their vigilant handling.
Moreover, continued mastication sometimes causes pain in the facial muscles.
Bowel congestion occurs when patients ingest intact or partially chewed tablets,
whereas dental injury or denture fracture can arise from tablets that are excessively
hard. Further, a few constituents, like sorbitol, are responsible for atulence and
diarrhea, while certain avoring agents can cause mouth ulcers (Dahiya etal. 2015).
But these side effects are very rare and can be avoided easily.
1. Formulation of Chewable Tablets
The main components of chewable tablets are therapeutic agents, diluents,
sweetening agents, avors, and colorants. The major difculty that arises in the
formulation of these tablets is taste masking as numerous medicines identied
up to now are bitter in taste. Accordingly, taste-masking substances, certain a-
vors, and sweetening agents are used. Flavor masking comprises the inclusion of
avors, acids, and sweetening agents (Elder etal. 2016). Taste masking using
granulation, solid dispersion, molecular complexes, inclusion complexes, ion
exchange, microencapsulation, preparation of distinct salts/derivatives, spray
cooling, and spray coating are also employed (Pardhi and Jain 2021). During the
chewable tablet formulation, the API’s taste is examined foremostly followed by
the usage of respective sweeteners as the optimum quantity of sweetness is
essential for sapidity. Moreover, the bitter taste is concealed with the use of suit-
able avoring agents (Sohi etal. 2004) as shown in Fig.7.2.
S. Tarannum and K. Jain
183
2. Evaluation of Chewable Tablets
Essential quality parameters for chewable tablets consist of hardness, disinte-
gration, and dissolution, along with all factors that may affect bioavailability as
well as bioequivalence of active agents. The size, thickness, friability, and taste
of the tablet mainly decide the acceptance of the tablet by the patients. The ef-
ciency of a chewable tablet does not depend on one quality characteristic. Rather,
the prime focus must be to incorporate the appropriate blending of the men-
tioned parameters so that the chewable tablets show optimum efciency for its
expected use (SahabUddin etal. 2016).
Hardness: Chewable tablets need to have a hardness in a range so that they
can resist the harshness of production, packaging, transportation, and distribu-
tion and at the same time can be masticated in no time by the subjected patients
(Gupta etal. 2015).
Disintegration: For chewable tablets, disintegration time has to be short to
avoid intestinal blockage in case a tablet is masticated in an improper manner by
the patient. Generally, the incorporation of a suitable disintegrant based on its
type, quality, and quantity enables quick disintegration of the tablet (FDA 2018).
Dissolution: Absorption of active agents from chewable tablets is based on
the release of the same from the intact tablets; thus, invitro dissolution study of
chewable tablets must adhere to the dissolution testing fundamentals of typical
immediate release tablets. The APIs of the chewable tablets must be effectively
released into solution from the dosage form. From the characterization point of
view of chewable tablet in the course of development, invitro dissolution studies
need to be performed on entire tablets in minimum four media, that is, water and
aqueous buffer solutions at pH4.5, 6.8, and 1.2, respectively, with well-known
dissolution approaches by means of USP apparatus type 1 (basket), type 2 (pad-
dle), or type 3 (reciprocating cylinder).
(a) Performance in Simulated Physiological Media
The invitro approaches using simulated physiological media like saliva
as well as gastric uids are likely to mimic the invivo performance of tab-
lets, specically the ones prepared with low-soluble APIs (Dressman etal.
1998; Markopoulos etal. 2015).
Fig. 7.2 Flavor groups for different types of taste
7 Formulation Evaluation andDevelopment ofSpecialized Tablets
184
Certainly, chewable tablets need to be assessed with dissolution media
like simulated fasted as well as fed state gastric and intestinal uids with
enzymes. Hardness testing is carried out after a transitory exposure (30s) to
approximately 1mL of simulated salivary uid, and the result can be useful
for establishing the hardness requirement.
(b) In Vitro Bioequivalence Data Usability and Post-approval Concerns
The solubility and permeability of the APIs basically decide the position
of the drug in the Biopharmaceutics Classication System (BCS). The BCS
class of the active agents mainly determines whether the invitro gures will
sufce the bioequivalence or not for chewable tablets (U.S.Department of
Health and Human Services etal. 2023). Changes in the chemistry, manu-
facturing, and controls after approval of the chewable tablets must be made
in accordance with the principles instructed in the Scale-up and Post-
Approval Changes Immediate Release (SUPAC IR) guidelines
(U.S.Department of Health and Human Services et al. 2023). Numerous
drugs in the dosage form of chewable tablets are available in the market like
carbamazepine, Motrin, Alka-Seltzer, montelukast, etc. with a protable
business. Some of the recent developments in the eld of chewable tablets
are discussed in the below subsections (Gaikwad 2023).
3. Formulation Development of Chewable Tablets
Many researchers formulated chewable tablets of different drugs and evalu-
ated them to analyze their performance. Some instances of the formulation
development of chewable tablets are given. Dille etal. (2018) produced a gela-
tin-based, soft chewable formulation of APIs (ibuprofen, acetaminophen,
meloxicam) as a substitute for conventional tablets for dysphagia patients. Soft-
chewy tablets displayed better stability for all three therapeutics (till 24months);
the chewable tablet of ibuprofen showed similar dissolution as that of normal
tablet along with better resistance to microbial growth. The rheology of the ibu-
profen/gelatin tablet was highly comparable to the true gelatin gel, even though
the formulation has greater storage and young moduli as well as melting point
(Dille etal. 2018). Kimaro etal. (2019) formulated a novel generic albendazole
chewable tablet with a better dissolution prole. They carried out the optimiza-
tion with the help of the wet granulation process. The formed product was simi-
lar to the innovator tablet available in the market on the basis of quality
considerations and thereby can be marketed as a generic product in the local
market with the due support of the pharmaceutical industry in manufacturing
(Kimaro etal. 2019).
Yoo etal. (2022) developed a new chewable chocolate-based tablet of trama-
dol for children. Tramadol is a bitter opioid analgesic, used for the treatment of
postsurgical pain in children. Still, in several countries, no approved tramadol
formulation is accessible for children. The relative bioavailability of this chew-
able tablet was 1.25-fold greater as compared to tramadol hydrochloride oral
liquid, and its acceptability was better in children due to its taste when analyzed
by the children, parents, and nurses as well (Yoo et al. 2022). Karaoglu et al.
(2023) designed a standard, effective, and safe masticable tablet (using propolis
S. Tarannum and K. Jain
185
and three plant extracts) with promising inhibition of variants (Wuhan B.1.36
and Omicron BA.1.1) of severe acute respiratory syndrome coronavirus 2
(SARS-CoV-2) as well as additional viral diseases. Green tea, bilberry, and dried
pomegranate peel, along with propolis extracts, were used. Cytotoxic and antivi-
ral effects of every single constituent, and the formulated chewable tablet, were
studied against the SARS-CoV-2 by means of Vero E6 cells with the xCELLi-
gence real-time cell analysis multiple plates system. The antiphlogistic and anal-
gesic effects and mutagenic and antimutagenic properties of the chewable tablet
were also assessed. Chewable formulations of 110 and 55μg/mL concentrations
had antiviral action rates of 101% and 81%, respectively, for the Wuhan variant
and 112% and 35%, consecutively, for the Omicron variant. The blend (plant and
propolis concentrate) was highly efcacious compared to the single extract
(Karaoglu etal. 2023). Al-Madhagi etal. (2023) developed a novel chewable
tablet by combining meclizine and pyridoxine which ensures instant absorption
of therapeutics as well as reduces travel sickness. The chewable tablet was highly
acceptable as it acted in a relatively faster manner, and it was favorable for
patients of any age category (Al-Madhagi etal. 2023).
7.4.3.2 Effervescent Tablets
Effervescent tablets (ETs) produce solutions with the release of carbon dioxide
instantaneously. Basically, these tablets are formulated by compressing the APIs
with a blend of sodium bicarbonate, sodium carbonate, and organic acids like citric
acid, adipic acid, malic acid, ascorbic acid, fumaric acid, maleic acid, succinic acid,
or tartaric acid, thereby fastening the release as well as enhancing the bioavailability
of the incorporated therapeutics (Zheng etal. 2019; Jaipal etal. 2016). Furthermore,
sodium bicarbonate in a dose-dependent manner improves gastric emptying, which
along with fast dissolution accelerates absorption. Mostly, those drugs whose imme-
diate action is required are incorporated within these tablets, so that the dissolution
happens in seconds whenever they come in contact with water which resulted in a
clear and palatable solution (Dubray etal. 2021). Patients who face difculty in
swallowing capsules or tablets, or the ones who want instant relief, generally prefer
ETs. The incorporation of a greater amount of dose than the conventional tablets is
possible with the ETs which is quite acceptable in elderly patients and children as
there is no need for swallowing during the administration.
Nevertheless, some limitations (recurrent sticking, high absorptivity, and tender
nature) of the ETs halt their manufacturing and applicability. Specically, sticking
is very common in tablet manufacturing because the acidic constituent sticks on the
punch tips of the tablets throughout compression (Sendall and Staniforth 2011).
Hence, the surface of the formulated tablet becomes rough and may even undergo
cracking gradually because of continuous compaction runs. All these can lead to the
production of bad-quality tablets with low yield and productivity (Chattoraj etal.
2018; Uchimoto etal. 2013).
7 Formulation Evaluation andDevelopment ofSpecialized Tablets
186
1. Formulation of Effervescent Tablets
API can be incorporated within the effervescent granule, or it can be trans-
formed into the salt form if it has low solubility at the time of dissolution. ETs
are manufactured by blending the active agents or its salt forms with binders,
diluents, as well as lubricants, followed by compaction in the form of tablets.
Highly soluble lubricants are utilized like sodium benzoate, polyethylene glycol,
and adipic acid. Disintegrants are not required in these tablets as the release of in
situ CO
2
accelerates the disintegration process (Clark and Witzel 1978).
Plasticizers are added to improve the rate of effervescence. With the increase in
the plasticizer concentration, the rate of effervescence increases. Additionally,
the effervescence can be changed by adjusting the hydrophilicity of binding
agents used in the hot melt extrusion method. As the concentration of nonpolar
binder increases, the effervescent rate decreases. The rate of effervescence
increases with a minor increase in the concentration of either acid or alkali used
than the condition in which both the components are added in equal amounts.
Additionally, the ETs are coated with suitable substances for manipulating the
release prole of active agents at the specic site in gastrointestinal tract
(Rotthäuser etal. 1998). Effervescent granules are formulated at sites where the
relative humidity (RH) is below 40%. These granules are blended in a V-type/
ribbon mixer. Wet granulation is carried out which is followed by the shifting of
granules to the oven. All the needed equipment should be free of traces of water
or moisture so that the effervescent mixture remains stable. Drying is followed
by the sizing of granules, blending them with hydrophilic lubricants, and then at
last compression is performed to collect the tablets. Humidity should be moni-
tored stringently in the production units (18–25°C, 10% RH). Packaging of ETs
should be in such a way that it must protect the tablet from environmental stress
and air entrapment should be minimal as moisture that gets entrapped results in
physicochemical degradation of the tablet (Altomare etal. 1997).
2. Evaluation of Effervescent Tablets
The formulated ETs are evaluated thoroughly so that the standard integrity
can be maintained. Their quality can be controlled and assured to the regulatory
bodies. Most importantly the patient compliance can be managed. Several evalu-
ation tests are performed which are mentioned in brief.
(a) Pre-compression evaluation: These evaluations are done before the com-
pression of tablets takes place. Particle size is measured using the sieve
method. These parameters help in understanding the interparticulate interac-
tions and in turn the ow properties. The ow of powder is crucial in the
process of tableting, as it needs to ow smoothly and evenly into the tablet
dies in order to achieve uniform tablet weight and produce tablets with con-
sistent and replicable characteristics. Bulk density, tapped density, com-
pressibility index, and Hausner’s ratio are determined. The angle of repose
is found using the xed funnel method (Aslani and Sharian 2014).
(b) Post-compressional evaluation: Weight variation, friability, thickness,
hardness, assay, and content uniformity are measured similar to that of con-
ventional tablets. Apart from these, a few evaluation tests specic to ETs are
given in brief.
S. Tarannum and K. Jain
187
pH evaluation: A single tablet is dissolved in water. As the dissolution
ended, the pH of the obtained solution is determined using a pH meter. The
test is performed in triplicate.
Carbon dioxide content: The individual tablet is weighed and solvated
in 1N H
2
SO
4
(100mL) followed by the measurement of weight after dis-
solution. CO
2
content is calculated in milligram. This test is performed on
three tablets.
Effervescent time: A single tablet was taken in a beaker lled with
200mL water and effervescent time is calculated using a timer. The test is
performed in triplicate.
Water content: Ten tablets are weighed before and after insertion in a
desiccator having activated silica gel for 4 h. The water content is deter-
mined using the equation:
Water conten
t
Weight before drying Weight after drying
W
%
()
=
−
eeight before drying
∗
100
Equilibrium moisture content: Three tablets are kept in different desic-
cators having saturated saline solutions, potassium nitrate (RH, 90%),
sodium chloride (RH, 71%), and sodium nitrite (RH, 60%) at 18°C.After 1
and 7days, the equilibrium moisture content in terms of percentage is calcu-
lated using the Karl Fischer titration by means of an automatic titrator.
3. Formulation Development of Effervescent Tablets
Many researchers formulated effervescent tablets of different drugs and eval-
uated them to analyze their performance. Some instances of the formulation
development of effervescent tablets are given. Mohammed etal. (2016) formu-
lated risperidone ETs for simplifying its administration and covering its bitter
taste. The solubility of the active agent was improved by the solid dispersion
method. Optimization was done with water-soluble excipients trehalose, inulin,
pregelatinized starch, carboxymethylcellulose sodium, and Eudragit E100 at dif-
ferent ratios. Rotary evaporation, freeze-drying, and the kneading oven were
employed for evaporating the solvent. The relative bioavailability of risperidone
in the optimized batch was 161.41% with a considerable enhancement in absorp-
tion than the existing marketed normal tablets (Abu Bakr Mohammed etal. 2016).
Zheng etal. (2019) worked on overcoming the shortcomings of ETs (sticking,
high hygroscopicity) so that their production as well as applicability can be
improved. Basically, most of the time recurrent sticking critically damages the
ETs. Hence, the work highlighted the use of polyvinylpyrrolidone (PVP) at vari-
able usage levels, grades, or spray solution concentrations as a coater for the
acidic and alkaline granules of effervescent formulations for combating the
stickiness with the aid of uidized-bed coating method. The conclusions drawn
from the work were that a uniform layer of PVP over the granules solved the
sticking issue and efciently reduced the hygroscopicity and improved the com-
pactness. Further the coating did not affect the disintegration time of the effer-
vescent formulations (Zheng etal. 2019). Dubray etal. (2021) developed the
effervescent formulation of paracetamol which was found to have faster absorp-
7 Formulation Evaluation andDevelopment ofSpecialized Tablets