Oral drug delivery remains the preferred route for administration of various drugs. Recent developments in the technology have prompted scientists to develop orally disintegrating tablets (ODTs) with improved patient compliance and convenience. ODTs are solid unit dosage forms, which disintegrate or dissolve rapidly in the mouth without chewing and water. Orally disintegrating tablets provide an advantage particularly for pediatric and geriatric populations who have difficulty in swallowing conventional tablets and capsules. This review describes the various formulation aspects, disintegrants employed and technologies developed for ODTs, along with various excipients, evaluation tests, marketed formulations, and drugs explored in this field.

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Solubility is an essential factor for drug effectiveness, independent of the route of administration. Poorly soluble drugs are often a challenging task for formulators in the industry. Conventional approaches for enhancement of solubility have limited applicability, especially when the drugs are poorly soluble simultaneously in aqueous and in non-aqueous media. Nanosuspension technology can be used to improve the stability as well as the bioavailability of poorly soluble drugs. Nanosuspensions are biphasic systems consisting of pure drug particles dispersed in an aqueous vehicle, stabilized by surfactants. These are simple to prepare and are more advantageous than other approaches. Techniques such as wet milling, high-pressure homogenization, emulsification-solvent evaporation and super critical fluid have been used in the preparation of nanosuspensions. It has the advantage of delivery by various routes, including oral, parenteral, pulmonary and ocular routes. The present article reviews the current methods used to prepare nanosuspensions and their application in drug delivery.

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Glass transition temperature (Tg) is an important tool used to modify physical properties of drug and polymer molecules. Tg is shown by certain crystalline as well as amorphous solids. During the process of heating, some solid gets melted and if quench cooled, instead of crystallizing, gets converted to amorphous solid form appearing as that of glass. This glass formation is seen because of the dynamic arrest of molecules forming a disordered state at Tg. The molecules/atoms in glassy state are subject to only vibration and not translational and rotational motion. Mainly, at Tg, conversion of glassy (vitrified, amorphous) solid to rubbery (viscous liquid) takes place. Numerous factors like structural change in molecules, cooling rate and incorporation of additives alter the Tg. Techniques like differential scanning calorimetry, elastic modulus, broad-line NMR are used to measure the Tg of substances. The change in Tg has been carried out to improve dissolution and bioavailability, processing and handling qualities of the material.

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Tetracycline is a broad spectrum antimicrobial agent, which is formulated into films and evaluated for the treatment of periodontitis. Chitosan films containing tetracycline in three different concentrations (10, 20, and 30% w/w to the weight of polymer) were prepared by the solution casting method, using 1% v/v acetic acid solution. The prepared films were evaluated for various properties such as weight variation, tensile strength, stability studies, in-vitro release, and mass balance studies. Further films were cross-linked in order to extend the drug release. Average weight and thickness among the different films was uniform. Tensile strength was maximum for plain films and minimum for films containing the highest percentage of the drug or cross-linked films. The stability studies did not show any significant changes. Static dissolution studies showed a burst release initially followed by a progressive fall in the release of the drug, and also showed extended release when cross-linking was attempted. The in-vitro release kinetics of tetracycline followed the zero order pattern. The fact that the mass balance studies done after in-vitro dissolution did not deviate by more than 3% from the experimental drug content, confirms that the drug is in free form rather than bound to the polymer.

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The objective of the present work is to envisage and develop hollow calcium pectinate beads for floating pulsatile release of aceclofenac intended for chronopharmacotherapy. Floating pulsatile concept was applied to increase the gastric residence of the dosage form having lag phase followed by a burst release. The method used for the development of the beads was a simple process of acid-base reaction during ionotropic cross linking. The floating beads obtained were porous, hollow with a bulk density <1 and had an F _t50 of 14-24h. The floating beads showed a two-phase release pattern with initial lag phase during floating in an acidic medium followed by rapid pulse in phosphate buffer. The approach indicates the use of hollow calcium pectinate microparticles as a promising floating pulsatile drug delivery system for site- and time-specific release of drug acting as per chronotherapy of disease.

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Oral sustained release gastroretentive dosage forms offer many advantages for drugs having absorption from the upper gastrointestinal tract and improve the bioavailability of medications that are characterized by the narrow absorption window. A new gastroretentive sustained release delivery system using the novel effervescent system was developed with floating, swellable, and bioadhesive properties. Various release retarding polymers like psyllium husk, HPMC K15M, and a swelling agent crosspovidone in different combinations were tried and optimized to get the release profile for 12hours. The formulations were evaluated for physicochemical characteristics, in vitro drug release profile, swelling characteristics, floating capacity, and in vitro bioadhesive property. i0 n vitro drug release followed the Higuchi kinetics and the release mechanism was found to be of a non-Fickian type. The swelling properties were increased with increasing crosspovidone concentration and contributed to the drug release from the tablet matrix. In this study, an attempt has been made to explore novel effervescent agents such as citroglycine and disodium glycine carbonate for achieving the desired floating time.

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The objective of the present study is to prepare sustained-release methotrexate microspheres of bovine serum albumin in different ratios by the emulsion cross-linking method. The prepared microspheres were subjected to various physicochemical evaluation and in vitro release studies. The drug release from microspheres of 1:6 ratio is the most constant and prolonged drug release is diffusion followed by erosion. The characteristics of the prepared microspheres are conducive to the formulation of the sustained release drug delivery system.

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The purpose of this study was to construct a microemulsion-based hydrogel formulation for the transdermal delivery of dexamethasone. Almond oil, olive oil, linseed oil, and nutmeg oil were screened as the oil phase. A microemulsion-based system was chosen due to its good solubilizing capacity and skin permeation capabilities. The pseudoternary phase diagrams for microemulsion regions were constructed using various oils, egg lecithin as the surfactant, isopropyl alcohol (IPA) as the cosurfactant, and distilled water as the aqueous phase. Microemulsion gel formulations were prepared using Carbopol and filled into a reservoir-type transdermal system. The ability of various microemulsion formulations to deliver dexamethasone through the rat skin was evaluated in vitro using Keshary Chien diffusion cells. In order to enhance permeation, the skin was treated with an abrading gel (apricot seed powder in hydrogel base). The in vitro permeation data showed that microemulsions increased the permeation rate of dexamethasone compared with the control. The optimum formulation consisting of 0.1% dexamethasone, 10% olive oil, 70% egg lecithin:IPA (2:1), and water showed a permeation rate of 54.9 µg/cm ² /h. The studied microemulsion-based hydrogel was stable toward centrifugation test and was nonirritating to the skin. The pharmacodynamic studies indicated that microemulsion based on nutmeg oil demonstrated a significantly ( P < 0.05) higher anti-inflammatory potential. The nutmeg oil-based transdermal microemulsion gel system demonstrated 73.6% inhibition in rat paw edema. Thus, microemulsion-based transdermal systems are a promising formulation for dermal delivery of dexamethasone.

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The present work was designed to develop suitable transdermal matrix patches of tramadol hydrochloride, a non-steroidal anti-inflammatory drug, using hydroxy propyl methyl cellulose (HPMC), Eudragit RL-100 and Eudragit RS-100 with triethyl citrate as a plasticizer and dimethyl sulfoxide (DMSO) as a penetration enhancer. Different batches developed using Eudragit RL-100 : HPMC and Eudragit RS-100 : HPMC in ratio of 2 : 8, 4 : 6, 6 : 4, and 8 : 2. Drug - excipients interaction study was further carried out using Fourier transform infrared (FTIR) spectroscopic technique. Physical evaluation was performed such as moisture content, moisture uptake, tensile strength, flatness, and folding endurance. In vitro diffusion studies were performed using cellulose acetate membrane (pore size 0.45 µ ) in a Franz's diffusion cell. The concentration of diffused drug was measured using UV-visible spectrophotometer (Jasco V-530) at l_max 275 nm. The batch containing Eudragit RL-100 : HPMC (8 : 2) showed 79.65% release within 12 h and batch containing Eudragit RL-100 : HPMC (2 : 8) showed only 58.30% release in 12 h. This is because that the Eudragit produce crystallization free patch.

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The present research work investigates enhancement of dissolution profile of meloxicam using solid dispersion (SD) with various polymers. The work also describes the formulation of dispersible tablet (DT) and effervescent tablet of meloxicam. PEG 6000, PEG 8000, PEG 20000, Lutrol F-127, and β -cyclodextrin were selected for the preparation of SD. The SDs were prepared by melting and solvent evaporation methods. Dissolution studies were performed for plain meloxicam, SDs, and tablet formulations. Infrared spectroscopy and differential scanning calorimetry were performed to identify the physicochemical interaction between drug and carriers. Dispersible tablets and effervescent tablets were compared with tablet containing plane drug for dissolution profile. Dissolution of DT improved significantly in SD product (<95% in 1 min).

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Pulsatile drug delivery system is the most interesting time- and site-specific system. This system is designed for chronopharmacotherapy which is based on circadian rhythm. The principle rationale for the use of pulsatile release is for the drugs where a constant drug release, i.e., a zero-order release is not desired. Pulsatile drug delivery system is defined as the rapid and transient release of certain amount of molecules within a short time period immediately after a predetermined off-release period, i.e., lag time. Various systems like capsular systems, osmotic systems, pulsatile system based on the use of soluble or erodible polymer coating, use of rupturable membranes and pulsatile system based on membrane permeability are summarized in this article. These systems are beneficial for the drugs having chronopharmacological behavior where night time dosing is required and for the drugs having high first-pass effect and having specific site of absorption in gastrointestinal tract.

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Nateglinide (NTG) is available as tablet dosage form in 60 mg and 120 mg strength. In the present study, two simple, reproducible and efficient UV spectrophotometric methods for the estimation of this drug in bulk and pharmaceutical dosage forms have been developed. In method I, methanol-AR was used as solvent, while in method II, Methanol-AR + 10% V/V 3N NaOH was used as reference solvent. In method I, nateglinide shows λ_max at 216 nm, which is then shifted to 225.4 nm on increasing the basicity of the reference solvent in method II. The linearity for nateglinide was observed to be statistically in the range of 10-100 μg/ml in method I and 100-1000 μg/ml in method II. Both the methods were validated using ANOVA. The recovery studies confirmed the accuracy of the proposed methods.

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The present study involves preparation and evaluation of floating microspheres using famotidine (FM) as a model drug for prolongation of the gastric retention time. The microspheres were prepared by the solvent evaporation method using different polymers, i.e. acrycoat S100 and cellulose acetate. The size or average diameter (d _avg ) and surface morphology of the prepared microspheres were recognized and characterized by the optical and scanning electron microscopic methods, respectively. In vitro drug release studies were performed and the drug release kinetics were evaluated using the linear regression method. Effects of the stirring rate during preparation, polymer concentration on the size of the microspheres and drug release were also observed. The prepared microspheres exhibited prolonged drug release (18 h) and remained buoyant for more than 12 h. The mean particle size increased and the drug release rate decreased at a higher polymer concentration. No significant effect of the stirring rate during preparation on drug release was observed. In vitro studies demonstrated a diffusion-controlled drug release from the microspheres. The objective of the present study was to develop floating microspheres of FM in order to achieve an extended retention in the upper gastrointestinal tract, which may result in enhanced absorption and thereby improved bioavailability. The prepared microspheres were evaluated for particle size, in vitro release and buoyancy and incorporation efficiency. The effect of various formulation variables on the size and drug release was investigated. In vitro drug release studies were performed and the drug release kinetics were evaluated using the linear regression method. FM was obtained as a gift sample from Intas Pharmaceuticals, Ahmedabad, India. Polyvinyl alcohol was obtained from S.D. Fine Chemicals Ltd., Mumbai, India. Dichloromethane, acrycoat S100, cellulose acetate and Tween 80 were obtained from Central Drug House (P) Ltd., Delhi, India. All other chemicals/reagents used were of analytical grade. A UV/visible spectrophotometer was used for drug analysis. Experimental results were expressed as mean ΁ SD. Chi-square test and one-way analysis of variance (ANOVA) were applied to check significant differences in drug release from different formulations. Differences were considered to be statistically significant at P = 3.23, DF = 1, i.e. P < 0.05. The prepared floating microspheres exhibited prolonged drug release, i.e. <18 h, and the floating time was <12 h in 0.1 N HCl. The mean particle size of the prepared floating microspheres increased but the drug release rate from the microspheric-coated layer decreased as the polymer concentration increased. No significant effect of the stirring rate during preparation on drug release was observed. In vitro data obtained for floating microspheres of FM showed excellent floatability, good buoyancy and prolonged drug release. Microspheres of different size and drug content could be obtained by varying the formulation variables. Diffusion was found to be the main release mechanism. Thus, the prepared floating microspheres may prove to be potential candidates for multiple-unit delivery devices adaptable to any intragastric condition.

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Glipizide is a poorly water-soluble (BCS class II) antidiabetic drug. Due to the poor water solubility of this drug, its bioavailability is dissolution rate-limited. The purpose of this study was is to increase the solubility of Glipizide (GZ) in aqueous media by solid dispersion (SDs) technique with Poloxamer (PXM) 188 and Poloxamer (PXM) 407 by using the kneading method. The GZ-PXM solid dispersion system was characterized by dDifferential scanning calorimetry (DSC), X-ray powder diffraction (XRD) analysis, Fourier transform-infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM), and in vitro dissolution studies. No chemical interaction was found between GZ and PXM 188 or PXM 407. The results from DSC, XRD and SEM studies show that PXM 188 or PXM 407 inhibits the crystallization of GZ. The SDs prepared in this study were found to have better dissolution rates in comparisoncompared to intact GZ and physical mixture of PXM 188 or PXM 407 and GZ. It was found that the optimum weight ratio for drug: Carrier is 1:5 for PXM 188 and 1:6 for PXM 407.

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Poly (D, L-lactide-co-glycolide) (PLGA) is approved by the Food and Drug Administration for drug delivery use. The polymeric nanoparticles based on PLGA and its co-polymer are designed for controlled and targeted drug delivery. Also, PLGA and its co-polymer are important in designing nanoparticles with desired characteristics such as biocompatibility, biodegradation, particle size, surface properties, drug release and targetability. This review focuses on the polymer literature, methods for preparation of nanoparticles and recent studies on the nanoparticles based on PLGA and its co-polymer for the conventional and targeted delivery of drugs by various routes.

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Ambroxol hydrochloride (HCL) is a potent mucolytic capable of inducing bronchial secretion. It is used in the treatment of asthma, bronchitis, and cough. But it is a very bitter drug and slightly soluble in water. Thus, in the work under taken, an attempt was made to mask the taste and to formulate into a oro-dispersible tablet by complexation with ion exchange resins, which also acts as super disintegrating agents. Since, these tablets can be swallowed in the form of dispersion, it is suitable dosage form for pediatric and geriatric patients. Cation exchange resins like Indion-204 and Indion-234 were utilized for the sorption of drug. Drug-resinates were prepared in drug to resin ratio of 1:5 and 1:6. The prepared tablets were evaluated for general appearance, content uniformity, hardness, friability, taste evaluation, mouth feel, wetting time, in vitro and in vivo disintegration time, and in vitro dissolution studies. Tablets with both the resins have shown quick disintegrating features, i.e., within 20 s, which is very characteristic of oro-dispersible tablets. Also, the dispersion not showing any bitter taste, indicate the capability of ion exchange resins used, both as taste masking and super disintegrating agents. Almost more than 90 percent of drug was released from both the formulations within 1 h. Further formulations were subjected to stability testing for 3 months at temperatures 25±5ºC/60±5%RH and 40±5ºC/75±5%RH. Both tablets have shown no appreciable changes with respect to taste, disintegration, and dissolution profiles.

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Nasal drug delivery system offers lucrative way of drug delivery of both topical and systemic therapies. The high permeability, high vasculature and low enzymatic environment of nasal cavity are well suitable for systemic delivery of drug molecules via nose. The noninvasiveness and self administrative nature of nasal delivery also attracts the formulation scientists to deliver protein and peptide compounds. Despite of all the advantages of nasal drug delivery, the bioavailability of nasally administered products, especially for protein and peptide molecules, is affected by many barriers such as physiological barriers, physicochemical barriers, and formulation barriers. This review will focus on the various bioavailability barriers in nasal drug delivery and the strategies to improve the bioavailability of nasal dosage forms.

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In this study, a significant effect of different polymers on improving the solubility, dissolution rate, and physicochemical properties of carbamazepine (CBZ) has been demonstareted by emulsion solvent diffusion technique, with ethanol-chloroform-water as the solvent system. The hydrophilic polymers like polyethylene glycol, chitosan, and hydrophobic polymer Eudragit RSPO were used in the recrystallization process. The pure drug CBZ and the prepared spherical crystals of CBZ with different polymers were characterized in terms of morphology (microscopical photograph), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), drug contents, solubility, dissolution rate, crushing strength, wettability, flowability, and packability. The FTIR spectra of the prepared spherical crystals showed that changes in the chemical nature occur and do not present great fingerprint difference. The XRD also revealed a characteristic decrease in crystallinity. The solubility and dissolution studies demonstrated a marked increase in solubility and dissolution rate in comparison with the pure drug. The prepared spherical crystals with different polymers exhibited excellent physicochemical properties like flowability, packability, and wettability compared with the pure drug. The spherical crystals with polyethylene glycol and chitosan showed higher crushing strength when compared with the hydrophobic polymer (Eudragit RSPO).

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The aim of the current study was to design oral controlled release (CR) theophylline anhydrous bioadhesive tablets and to optimize the drug release profile and in vitro bioadhesion strength. Different types of natural hydrophilic polymers such as xanthun gum, locust bean gum, guar gum, karaya gum, and their combinations were used to formulate matrix tablets. Tablets of anhydrous theophylline were prepared by the direct compression method and were subjected to in vitro drug dissolution for 12 hours using the USP dissolution apparatus basket type at a speed of 100 rpm and temperature of 37 ± 0.5°C using gastric fluid (pH 1.2). The bioadhesive strength of the tablets was measured as the force of detachment against the porcine gastric mucosa. The in vitro release study as well as the retention time of the bioadhesive tablets on the mucous membrane were investigated to develop a bioadhesive polymer-based CR delivery system and to evaluate the performance of such a delivery device. The combination of karaya gum:guar gum (6:4) tablet showed a greater bioadhesive strength as compared with a single gum and other gum combination tablets. Karaya gum:guar gum-loaded tablets were not discharged from the mucous membrane and were dissolved in the gastric fluid. An increase in the gum concentration increases the drug release profile beyond 12 hours whereas there is no significant effect of gum concentration on the bioadhesive strength of the tablet.

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The present investigation was aimed to evaluating the possibility of using different polymeric grades of hydroxy propyl methyl cellulose (6cps, 15cps, and K4M) for the development of transdermal drug delivery systems of nicorandil, an antianginal drug. Prepared matrix-type patches were evaluated for their physicochemical characterization followed by in vitro evaluation. Selected formulations were subjected for their ex vivo studies on porcine ear skin.

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With the discovery of insulin in 1922, identification and commercialization of potential protein and peptide drugs have been increased. Since then, research and development to improve the means of delivering protein therapeutics to patients has begun. The research efforts have followed two basic pathways: One path focused on noninvasive means of delivering proteins to the body and the second path has been primarily aimed at increasing the biological half-life of the therapeutic molecules. The search for approaches that provide formulations that are stable, bioavailable, readily manufacturable, and acceptable to the patient, has led to major advances in the development of nasal and controlled release technology, applicable to every protein or peptide. In several limited cases, sustained delivery of peptides and proteins has employed the use of polymeric carriers. More successes have been achieved by chemical modification using amino acid substitutions, protein pegylation or glycosylation to improve the pharmacodynamic properties of certain macromolecules and various delivery systems have been developed like the prolease technology, nano-particulate and microparticulate delivery systems, and the mucoadhesive delivery of peptides. The needle and syringe remain the primary means of protein delivery. Major hurdles remain in order to overcome the combined natural barriers of drug permeability, drug stability, pharmacokinetics, and pharmacodynamics of protein therapeutics. In our present review we have tried to compile some recent advances in protein and peptide drug delivery systems.

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The biopharmaceutical classification system (BCS) is a new concept in the field of pharmaceutical science and technology. This is a valuable tool for the formulation scientists, for the selection and design of the formulation of any drug substance. The recent developments have also enabled us to predict the solubility and permeability characteristics of the drug molecule in the early development stages so that the necessary structural changes can be made to the molecule in order to optimize the pharmacokinetic parameters. The BCS has also got a place in various guidance documents of regulatory importance. This article reviews the criteria for classifying drugs according to the BCS and discusses further potential applications of the BCS, including the developments of new drugs and controlled release products.

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A reservoir-type transdermal patch for the delivery of ketorolac was studied. The low permeability of the skin is the rate-limiting step for delivery of most of the drugs. Studies were carried out to investigate the effect of pH, alcohols, and chemical permeation enhancers on the in vitro permeation of ketorolac. The reservoir core of the transdermal patch was filled with the hydrogel of a nonionic polymer, methocel K ₁₅ M (hydroxyl propyl methylcellulose, HPMC) formulated at an optimized pH of 5.4. Enhanced in vitro permeation was achieved after the incorporation of the alcohols. Higher enhancement was produced by short-chain alcohols like ethanol and isopropyl alcohol (IPA). Propylene glycol (PG) along with other alcohols, viz. n-propanol, n-butanol, and n-pentanol, lagged behind. An exponential rise in permeation was observed in flux with an increase in the concentration of IPA. At 25%w/w IPA concentration, the observed ketorolac flux was 18.04mg/cm ² /h. Terpene containing eucalyptus oil was studied to determine its permeation enhancement capability. The increase in the concentration of eucalyptus oil enhanced the drug permeation and a maximum flux of 66.38 and 90.56mg/cm ² /h was achieved at 10 and 15%w/w concentrations. The anti-inflammatory potential of the transdermal formulation was evaluated on a carrageenan-induced paw edema model, with 41.67% inhibition at 6 h. The skin irritation potential was evaluated by the Drazie test and the formulations prepared were found to be safe. The reservoir-type transdermal patch for the delivery of ketorolac appeared to be feasible for delivering ketorolac across the skin.

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The objective of the present study was to microencapsulate the anti-inflammatory drug (aceclofenac) to provide controlled release and minimizing or eliminating local side effect by avoiding the drug release in the upper gastrointestinal track. The drug was targeted to the colon and their aligned area for their local effect. Aceclofenac was microencapsulated with Eudragit (S 100, RL 100, and RS 100), using an O/W emulsion-solvent evaporation technique. Aceclofenac microspheres were subjected to micromeritic properties including angle of repose, bulk density, tapped density, Carr's index, Hausner's ratio, and particle size determination. Microspheres were subjected to drug loading, in vitro drug release as well as for scanning electron microscopy. The prepared microspheres were white, free-flowing, and almost spherical in shape. The drug-loaded microspheres show 60-82% drug entrapment, angle of repose was in the range of 16.13 ± 0.621-24 ± 0.590, bulk and tapped densities respectively were in the range of 0.311 ± 0.006-0.562 ± 0.012 and 0.373 ± 0.01-0.735 ± 0.02, Carr's index ranges from 14.04 ± 0.026 to 27.25 ± 1.405, Hausner's ratio was 1.14 ± 0.026-1.37 ± 0.03, and particle size was in the range of 79.7016-144.840 µm. In vitro drug release studies were carried out up to 24 h in three different pH media, i.e., 0.1 N HCl (pH 1.2), phosphate buffer (pH 6.8), and phosphate buffer (pH 7.4). The drug-polymer concentration of dispersed phase influences the particle size and drug release properties. All the formulations at higher pH were followed by the Matrix-Higuchi model.

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Size reduction is a process of reducing large solid unit masses into small unit masses, coarse particles or fine particles. Size reduction process is also termed as comminution or diminution or pulverizations . In addition to the standard adjustments of the milling process (i.e., speed, screen size, design of rotor, load), special techniques of milling may be useful including special atmosphere, temperature control, sonocrystallization, supercritical fluid process. etc. Moreover, some advance technologies of size reduction including Micron Technologies, Gran-U-Lizer™ Technology, Jet-O-Mizer™ and Microfluidics® have been popular. Various application of size reduction concept covers oral delivery of poorly soluble drugs, micronization, nanotechnology (micro- and nano suspensions), etc. This systemic review highlights advantages and disadvantages, mechanisms, theories, techniques, advances, and pharmaceutical applications of size reduction technology.

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