Design and testing in vitro of a bioadhesive and floating drug delivery system for oral application

Model-Informed drug development of gastroretentive release systems for sildenafil citrate

Gastroretentive drug delivery systems (GRDDS) are modified-release dosage forms designed to prolong their residence time in the upper gastrointestinal tract, where some drugs are preferentially absorbed, and increase the drug bioavailability. This work aimed the development of a novel GRDDS containing 60 mg of sildenafil citrate, and the evaluation of the feasibility of the proposed formulation for use in the treatment of pulmonary arterial hypertension (PAH), for once a day administration, by using in silico pharmacokinetic (PK) modeling and simulations using GastroPlus^TM. The Model-Informed Drug Development (MIDD) approach was used in formulation design and pharmacokinetic exposure prospecting. A 2² factorial design with a central point was used for optimization of the formulation, which was produced by direct compression and characterized by some tests, including buoyancy test, assay, impurities, and in vitro dissolution. A compartmental PK model was built using the GatroPlus^TM software for virtual bioequivalence of the proposed formulations in comparison with the defined target release profile provided by an immediate release (IR) tablet formulation containing 20 mg of sildenafil administered three times a day (TID). The results of the factorial design showed a direct correlation between the dissolution rate and the amount of hydroxypropyl methyl cellulose (HPMC) in the formulations. By comparing the PK parameters predicted by the virtual bioequivalence, the formulations F1, F2, F3 and F5 failed on bioequivalence. The F4 showed bioequivalence to the reference and was considered the viable formulation to substitute the IR. Thus, GRDDS could be a promising alternative for controlling the release of drugs with a pH-dependent solubility and narrow absorption window, specifically in the gastric environment, and an interesting way to reduce dose frequency and increase the drug bioavailability. The MIDD approach increases the level of information about the pharmaceutical product and guide the drug development for more assertive ways.

Design and Development of Gastro-retentive Drug Delivery System for Trazodone Hydrochloride: a Promising Alternative to Innovator's Controlled-Release Tablet

Trazodone hydrochloride (TZN) is a serotonin reuptake inhibitor that treats a major depressive disorder. It exhibits a short plasma half-life of 4.1 h and shows pH-dependent solubility. Above its pKa (6.74), solubility of TZN is very low, affecting its dissolution in the lower part of GIT. Hence, the present work aimed to develop gastro-retentive floating tablet of TZN. Central composite design was employed to optimize the formulation. Formulation variables like the concentration of HPMC-K100M, Polyox WSR 303 Leo, and sodium bicarbonate were evaluated for the responses like floating lag time and drug release. X-ray imaging study was performed on rabbits to determine the in vivo gastric retention of the optimized formulation. The accelerated stability study was conducted on optimized tablets as per ICH guidelines. Floating lag time and f₂ value of the optimized formulation were found to be 2.51±0.02 min and 62.79, respectively. X-ray imaging studies in rabbits determined the in vivo gastro retention time. After 12 h of administration, tablet remained in the gastric region, indicating better retentive power. Accelerated stability studies showed sufficient formulation stability even after 3 months of storage. All these studies depict that the floating gastro-retentive system could be used as an alternative to the innovator formulation.

Design, statistical optimization of Nizatidine floating tablets using natural polymer

Background

The present research was aimed in developing gastroretentive tablets of Nizatidine, in order to increase the bioavailability of the drug. Nizatidine belongs to BCS class 3 and thus formulating into gastroretentive tablets helps to achieve a better therapeutic effect. There were no reports available on the use of Mimosa gum in the design of gastroretentive drug delivery systems. Response surface methodology was employed to optimize the formulation with suitable experimental design. The goal of the response surface methodology was to obtain a regression model and to find a suitable approximation for the true functional relationship between the response and the set of independent variables. Hence, the statistical approach like full factorial design was utilized to obtain optimized formulation with a smaller number of experiments.

Results

DSC study justified no interaction of the drug with excipients. The floating lag time was observed to be less than 20 s, total floating time was in the range of 8–24 h, hardness ranges from 4 to 5 kg/cm2, and friability was less than 1%. Dissolution data indicated that the higher viscosity of Mimosa (2%) delayed the drug release for extended period of time up to 23 h when compared to lower viscosity Mimosa (1%), which controlled the release of the drug up to 12 h only. The ‘n’ values of all the prepared formulations were found to be 0.59 to 0.81 indicating that the release mechanism followed anomalous (non-Fickian) diffusion. The optimal values of independent test variables were obtained from the overlay plots. The optimized formulation of Mimosa gum (2%) (M2%opt) contained 170 mg of polymer and 25.5 mg (15%) of sodium bicarbonate. Similarly, the optimized formulation of Mimosa (1%) (M1%opt) contained 255 mg of polymer and 34 mg (10%) of sodium bicarbonate.

Conclusion

The results clearly indicated that the optimized formulations followed zero-order release kinetics with diffusion mechanism as per the predicted theoretical release rate confirming the suitability of the predicted theoretical release profile.

Development and Optimization of Microballoons Assisted Floating Tablets of Baclofen

The objective of the present study was to develop microballoons aided gastro-retentive floating tablets of baclofen, a skeletal muscle relaxant with a low elimination half-life of ~ 3.5 h. Baclofen floating tablet was prepared to offer convenience by designing a tablet that would float in the stomach for a prolonged period and allow controlled drug release to enable once-a-day administration. Ethylcellulose microballoons (ECMBs) prepared by pseudo emulsion solvent diffusion method were employed as floating aid. The ECMBs were spherical with a size of 446.71 µm and a circularity index of 0.995. Buoyancy of 98.90 percent and good flowability reflected by an angle of repose of 23° suggested the feasibility of preparing floating tablets by direct compression. Directly compressed baclofen floating tablets comprised ECMBs, HPMC-K15M, and hydroxyl ethylcellulose as independent variables in the Box-Behnken design, however, performance characteristics of tablets such as in vitro drug release, floating lag time, and swelling index were selected as the dependent variables. Among the variables, ECMBs played a critical role in ensuring buoyancy. However, HPMC-K15M significantly influenced in vitro drug release. The optimized batch displayed Hickson-Crowell kinetics and exhibited a similar drug release profile as a marketed once-a-day formulation (f₂, 91.03). Furthermore, optimized tablets showed a swelling index of > 300, floating lag time < 3 s, and total floating time > 24 h. Microballoons assisted floating tablets exhibited great promise for assured gastric retention of tablets.

DoE-Based Design of a Simple but Efficient Preparation Method for a Non-Effervescent Gastro-Retentive Floating Tablet Containing Metformin HCl

A sustained-release non-effervescent floating matrix tablet was prepared using a simple and efficient direct compression of spray-dried granules containing metformin hydrochloride and cetyl alcohol with hydroxypropyl methylcellulose K15M (HPMC K15M). The design of experiments was employed to explore the optimal composition of the tablet. The similarity factor was employed to evaluate the equivalence in dissolution profiles between the test tablets and Glucophage XR as a reference. Bootstrap analysis was used to eliminate the formulations for which the dissolution profile was potentially inequivalent to that of the reference. The optimized tablet consisting of 150 mg of cetyl alcohol and 17% HPMC K15M showed a dissolution profile comparable with that of the reference with a similarity factor of 52.41, exhibited a floating lag time of less than 3 s in buffer media, remained floating for 24 h, and reduced the tablet weight by about 20% compared to that of the reference. The current study sheds light on the potential use of non-effervescent gastro-retentive extended-release tablets for high-dose drugs using a simple and efficient direct compression method, and as a potential alternative treatment for Glucophage XR. This study also highlights the importance of a systematic approach to formulation optimization and the evaluation of the dissolution profile.

Design, development and optimization of sustained release floating, bioadhesive and swellable matrix tablet of ranitidine hydrochloride

Ranitidine HCl, a selective, competitive histamine H₂-receptor antagonist with a short biological half-life, low bioavailability and narrow absorption window, is an ideal candidate for gastro-retentive drug delivery system (GRDDS). Controlled release with an optimum retentive formulation in the upper stomach would be an ideal formulation for this drug. The aim of the present study was therefore to develop, formulate and optimize floating, bioadhesive, and swellable matrix tablets of ranitidine HCl. The matrix tablets were prepared using a combination of hydroxypropyl methylcellulose (HPMC) and sodium carboxymethyl cellulose (NaCMC) as release retarding polymers, sodium bicarbonate (NaHCO₃) as gas generating agent and microcrystalline cellulose (MCC) as direct compression diluent. Central composite design (CCD) was used to optimize the formulation and a total of thirteen formulations were prepared. Concentration of HPMC/NaCMC (3:1) (X₁) and NaHCO₃ (X₂) were selected as independent variables; and floating lag time (Y₁), bioadhesive strength (Y₂), swelling index at 12 h (Y₃), cumulative drug release at 1 h (Y₄), time to 50% drug release (t_50%) (Y₅) and cumulative drug release at 12 h (Y₆) were taken as the response variables. The optimized batch showed floating lag time of 5.09 sec, bioadhesive strength of 29.69 g, swelling index of 315.04% at 12 h, t_50% of 3.86 h and drug release of 24.21% and 93.65% at 1h and 12 h, respectively, with anomalous release mechanism. The results indicate that sustained release matrix tablet of ranitidine HCl with combined floating, bioadhesive and swelling gastro-retentive properties can be considered as a strategy to overcome the low bioavailability and in vivo variation associated with the conventional ranitidine HCl tablet.

Relevancy of Nizatidine’s Release from Floating Tablets with Viscosity of Various Cellulose Ethers

Nizatidine is a gastroprotective drug with a short biological half-life and narrow absorption window. This study aimed at developing floating tablets of nizatidine using various HPMC viscosity grades, namely K4M, E4M, K15 and K200M. Directly compressed tablets revealed an excellent uniformity in hardness, thickness and weight and nizatidine was evenly distributed within the matrix floating tablets. Buoyancy study revealed floating lag time as low as 18–38 s, and tablets remain buoyant for upto 24 h. However, the later depended upon viscosity grade of HPMC and that the higher the viscosity, the less was the total floating time. In vitro dissolution indicated viscosity dependent nizatidine release from the floating tablets. HPMC K4M and E4M based floating tablets released almost 100% drug in 12 h, whilst higher viscosity polymers such as K15 and K200M only released 81.88% and 75.81% drug, respectively. The drug release followed non-Fickian diffusion from tablets formulated with K4M, K15 and K200M, whilst super case II transport was observed with E4M based tablets. More interestingly, K4M and E4M polymers have similar viscosity yet exhibited different drug release mechanism. This was attributed to the difference in degree of substitution of methoxyl- and hydroxypropoxyl- groups on polymer backbone.

Oral Drug Delivery: Conventional to Long Acting New-Age Designs

The Oral route of administration forms the heartwood of the ever-growing tree of drug delivery technology. It is one of the most preferred dosage forms among patients and controlled release community. Despite the high patient compliance, the deliveries of anti-cancerous drugs, vaccines, proteins, etc. via the oral route are limited and have recorded a very low bioavailability. The oral administration must overcome the physiological barriers (low solubility, permeation and early degradation) to achieve efficient and sustained delivery. This review aims at highlighting the conventional and modern-age strategies that address some of these physiological barriers. The modern age designs include the 3D printed devices and formulations. The superiority of 3D dosage forms over conventional cargos is summarized with a focus on long-acting designs. The innovations in Pharmaceutical organizations (Lyndra, Assertio and Intec) that have taken giant steps towards commercialization of long-acting vehicles are discussed. The recent advancements made in the arena of oral peptide delivery are also highlighted. The review represents a comprehensive journey from Nano-formulations to micro-fabricated oral implants aiming at specific patient-centric designs.

Gellan gum based gastroretentive tablets for bioavailability enhancement of cilnidipine in human volunteers

Cilnidipine, a fourth-generation both L-and N-type calcium channel blocker (CCB) is safe and effective in lowering blood-pressure without reflex tachycardia compared to other dihydropyridine CCBs. However, its low solubility coupled with extensive first-pass metabolism results in very low oral bioavailability. Thus the study aimed to improve oral bioavailability of Cilnidipine by increasing its gastrointestinal transit-time and mucoadhesion. Gastroretentive tablets were prepared by direct-compression technique using gellan gum as hydrogel forming polymer and sodium bicarbonate as gas-generating agent. Statistical optimization was carried out by design approach which showed that gellan gum has significant impact on floating lag time, mucoadhesive strength, % drug release at 1 h and time to release 90% of drug. Drug release study revealed that optimized tablets prolonged drug release for 12 h and followed anomalous-diffusion indicating drug release is by coupling of both diffusion and erosion mechanism. Intragastric behaviour of formulation in human volunteers revealed that radio-opaque tablets remain buoyant in stomach for more than 6 h with sufficient mucoadhesion. Comparative pharmacokinetic profiling in human subjects revealed that relative bioavailability of Cilnidipine GR tablets was enhanced compared to reference tablets. Thus concluded that gastroretentive tablets to be promising strategy for improved oral bioavailability of Cilnidipine for effective treatment of hypertension.

Silk industry waste protein: isolation, purification and fabrication of electrospun silk protein nanofibers as a possible nanocarrier for floating drug delivery

Amongst assorted regio-selective and targeted oral drug delivery strategies accepted for the gastro-retentive drug delivery system (GRDDS), the floating drug delivery system (FDDS) holds a major share as clinically accepted formulations. The major objective of the present investigation was to explore the silk industry waste protein, silk fibroin (SF) as a possible electrospun nanocarrier for the FDDS. In a nutshell, electrospinning (ES) is one of the flexible and astonishing strategies for the fabrication of porous electrospun nanofibers (NFs), which offers the potential to amend the floating profile, dissolution rate, solubility, and release patterns of the drug, etc as per compendial requirements. Looking at the prospects of floating SF-NFs preparation, we have isolated and lyophilized the SF from industrial waste cocoons and prepared drug-loaded SF single polymer nanofibers (SPN). Lafutidine (LF) being a good candidate for GRDDS selected as a model drug, which is an excellent proton pump inhibitor, mainly used in the treatment of gastric ulcers. Finally, the obtained LF loaded SF-NFs (LF-SF-NFs) were successfully analyzed for physicochemical characteristics, porosity, swelling index, antioxidant activity, mucoadhesion strength, floating properties, enzymatic degradation, and accelerated stability study, etc. Further, these LF-SF-NFs were evaluated for percent drug content, weight variation, in-vitro dissolution in 0.1 N hydrochloric acid (HCl, pH:1.2) and fasted state simulated gastric fluid (FSSGF), and accelerated stability study. It has shown significant floating time >18 h, about 99% ± 0.58% floating buoyancy with sustained release up to 24 h. LF-SF-NFs showed good compatibility, entrapment efficiency, antioxidant activity, mucoadhesion strength, enzymatic degradation, and long term stability. Soon, the essential floating and drug release profiles can claim single polymer (SF) based electrospun protein NFs as a possible novel oral nanocarrier for FDDS.

Preparation and in vitro Characterisation of Solid Dispersion Floating Tablet by Effervescent Control Release Technique with Improved Floating Capabilities

In this research, an effort has been done for the development of effervescent controlled release floating tablet (ECRFT) from solid dispersions (SDs) of diclofenac sodium (DS) for upsurge the solubility and dissolution rate. ECRFT of DS was prepared by using SDs of DS and its SDs prepared with PEG as carrier using thermal method (simple fusion). SDs of DS was formulated in many ratios (1:1, 1:2, 1:3 and 1:4). Prepared SDs were optimised for its solubility, % drug content and % dissolution studies. Tablets were formulated by using optimised SDs products and all formulation was evaluated for various parameters. A clear rise in dissolution rate was detected with entirely SD, amid that the optimised SD (SD4) was considered for ECRFT. Among all the tablet formulations, its F3 formulation was better in all the terms of pre-compression and post-compression parameters. It had all the qualities of a good ECRFT, based on this F3 formulation was selected as the best formulation. Data of in vitro release were fitted in several kinetics models to explain release mechanism. The F3 formulation shows zero order release. From this study, we can conclude that ECRFT containing SDs of DS can be successfully used for achieving better therapeutic objective.

Development of Floating Tablets of Metformin HCl by Thermoplastic Granulation. Part II: In Vitro Evaluation of the Combined Effect of Acacia Gum/HPMC on Biopharmaceutical Performances

Purpose: The aim of this study was to evaluate the combined effect, acacia gum(AG)/ hydroxypropylmethylcellulose (HPMC), on biopharmaceutical performances of floating tablets of metformin hydrochloride (MTH) prepared by thermoplastic granulation using stearic acid. Methods: We have prepared the matrixes using AG/HPMC as a polymer combination. This combination of polymers which represents 15% of the total mass of tablet was used at various ratios 3:1, 1:1, 1:3, with two viscosity grade of HPMC (k15M and k100M). The developed matrixes have been evaluated for their pharmacotechnical and biopharmaceutical properties. Results: In addition to the satisfactory physical characteristics of matrixes, it was revealed that the Fc3 and Fc6 formulations with AG/HPMC k15M and AG/HPMC k100M respectively, at ratio, 1:3 were considered the most performance. These formulations have shown swelling, fast flotation, 360 and 480 seconds respectively, and remained floating on the surface of the medium for more than 24 hours, with the matrix integrity, while F1, containing only AG, did not show swelling and did not float. In addition, extendedin vitro release (>8 hours) with decreased dissolved MTH rates was demonstrated for Fc3 and Fc6 matrixes, 95% and 91% respectively, compared to F1 where MTH dissolution was complete after 2 hours. The drug release from the highest-performance matrixes (Fc3 and Fc6) was found to follow Korsmeyer-Peppas's model. The mechanism drug release was controlled by diffusion and erosion. Conclusion: The AG/HPMC combination was suitable as a polymer matrix to improve the in vitro biopharmaceutical properties of MTH compared to AG.

Improved bioavailability of Azelnidipine gastro retentive tablets-optimization and in-vivo assessment

Azelnidipine, dihydropyridine based calcium channel blocker has been used for treating ischemic heart disease and cardiac remodeling after myocardial infarction but it is having a low bioavailability due to its poor solubility. The present study is to investigate the formulation and evaluation of floating tablets of Azelnidipine for controlled release and to increase bioavailability by increasing the gastrointestinal transit time and mucoadhesion of drug. The gastro retentive tablets were prepared by direct compression method using different concentrations of combination of Polyoxyethylene oxide WSR 303 as hydrophilic polymer and Potassium bicarbonate as gas generating agent. Main effects of the formulation variables were evaluated quantitatively using design approach showing that both independent variables have significant effects on floating lag time, % drug release at 1 h (D1 h) and time required to release 90% of the drug (t90). The statistically optimized formulation (F3) released 95.11 ± 1.43% drug for 12 h followed K-Peppas drug release kinetics indicating release of drug by diffusion and erosion mechanism. Evaluation of the optimized formulation in vivo in human volunteers showed that the GFT was buoyant in gastric fluid and that its gastric residence time was enhanced. Pharmacokinetics studies carried out revealed significant (P < 0.05) equivalent Cmax, longer Tmax and higher AUC values for the optimized formula compared to the marketed oral product. From the results obtained it can be concluded that Azelnidipine Gastro retentive tablets with enhanced bioavailability and better release pattern is suitable for more effective treatment compared to marketed conventional tablets.

Formulation, Optimization, and In vivo Evaluation of Gastroretentive Drug Delivery System of Nifedipine for the Treatment of Preeclampsia

The study aimed to develop gastroretentive drug delivery system of nifedipine, its optimization, and in vivo evaluation. Bilayered tablet of nifedipine was prepared using central composite design with 3 factors, 5 responses, and 15 experimental trials. Response surface methodology along with numerical and graphical optimization was used to select the best formulation. Scanning electron microscopy study of optimized tablet at different time interval was carried out which showed formation of porous structure on the tablet surface. In vivo studies for optimized formulation were carried out on 10 healthy human volunteers and obtained pharmacokinetic parameters were compared with the marketed formulation, "Nicardia XL." Optimized formulation containing 3.083 mg HPMC K15M, 29.859 mg HPMC E15LV, and 3.541 mg Carbopol 974P releases the drug in a desired manner and remain buoyant for more than 12 h in human stomach. Both the formulations were found to have similar in vitro release profile (f1 4.5089 and f2 55.8274) and also were found to be bioequivalent. Finally, the stability study of the optimized formulation proved the integrity of the optimized formulation. Hence, the data suggest gastroretention as a promising approach to enhance bioavailability of nifedipine.

Development of Valsartan Floating Matrix Tablets Using Low Density Polypropylene Foam Powder: In vitro and In vivo Evaluation

The main purpose of the study was to develop valsartan floating tablets (VFT) via non-effervescent technique using low density polypropylene foam powder, carbopol, and xanthan gum by direct compression. Before compression, the particulate powdered mixture was evaluated for pre-compression parameters. The prepared valsartan tablets were evaluated for post-compression parameters, swelling index, floating lag time, in vitro buoyancy studies, and in vitro and in vivo X-ray imaging studies in albino rabbits. The result of all formulations for pre- and post-compression parameters were within the limits of USP. FTIR and DSC studies revealed no interaction between the drug and polymers used. The prepared floating tablets had good swelling and floating capabilities for more than 12 h with zero floating lag time. The release of valsartan from optimized formulation NF-2 showed sustained release up to 12 h; which was found to be non-Fickian release. Moreover, the X-ray imaging of optimized formulation (NF-2) revealed that tablet was constantly floating in the stomach region of the rabbit, thereby indicating improved gastric retention time for more than 12 h. Consequently, all the findings and outcomes have showed that developed valsartan matrix tablets could be effectively used for floating drug delivery system.

Micromotors for drug delivery in vivo: The road ahead

Autonomously propelled/externally guided micromotors overcome current drug delivery challenges by providing (a) higher drug loading capacity, (b) localized delivery (less toxicity), (c) enhanced tissue penetration and (d) active maneuvering in vivo. These microscale drug delivery systems can exploit biological fluids, as well as exogenous stimuli, like light-NIR, ultrasound and magnetic fields (or a combination of these), towards propulsion/drug release. Ability of these wireless drug carriers towards localized targeting and controlled drug release, makes them a lucrative candidate for drug administration in complex microenvironments (like solid tumors or gastrointestinal tract). In this report, we discuss these microscale drug delivery systems for their therapeutic benefits under in vivo setting and provide a design-application rationale towards greater clinical significance. Also, a proof-of-concept depicting 'microbots-in-a-capsule' towards oral drug delivery has been discussed.

Development and Evaluation of Compression Coating Gastro-Floating Tablet of Alfuzosin Hydrochloride for Zero-Order Controlled Release

Alfuzosin hydrochloride is an appropriate candidate drug to prepare a gastro-retention controlled release dosage form since it demonstrates a narrow absorption window in the proximal section of the gastrointestinal tract with a short half-life. The purpose of the present study was to develop and optimize a gastro-floating tablet of alfuzosin hydrochloride by using the compression coating method for controlling drug release in a controlled manner. The floating tablets were developed utilizing hydroxypropyl methylcellulose and carbomer as matrix materials. The impact of formulation factors on buoyancy property and in vitro drug release of the floating tablet was investigated. The "similarity factor" (f₂) was used as the indicator for the optimization of the formulations. Furthermore, in vivo pharmacokinetic study in rabbits and correlation of in vitro/in vivo study were also performed. It was found that the optimized formulation F9 could float immediately less than 2 min and remain lastingly buoyant over 24 h and follow zero-order release kinetics well. In comparison with the commercially available prolonged release tablets XATRAL® XL, the prepared floating tablet exhibited similar pharmacokinetic parameters (C_max, T_max, t_1/2, and AUC_0 - t) and plasma concentration versus time profile. Moreover, it indicated from the correlation of in vitro/in vivo study that the floating tablets exhibited a good correlation of in vitro/in vivo. In summary, the compression coating gastro-floating tablets might be a promising drug delivery system for alfuzosin hydrochloride to control drug release.

Pharmaceutical Applications of Cellulose Ethers and Cellulose Ether Esters

Cellulose ethers have proven to be highly useful natural-based polymers, finding application in areas including food, personal care products, oil field chemicals, construction, paper, adhesives, and textiles. They have particular value in pharmaceutical applications due to characteristics including high glass transition temperatures, high chemical and photochemical stability, solubility, limited crystallinity, hydrogen bonding capability, and low toxicity. With regard to toxicity, cellulose ethers have essentially no ability to permeate through gastrointestinal enterocytes and many are already in formulations approved by the U.S. Food and Drug Administration. We review pharmaceutical applications of these valuable polymers from a structure-property-function perspective, discussing each important commercial cellulose ether class; carboxymethyl cellulose, methyl cellulose, hydroxypropylcellulose, hydroxypropyl methyl cellulose, and ethyl cellulose, and cellulose ether esters including hydroxypropyl methyl cellulose acetate succinate and carboxymethyl cellulose acetate butyrate. We also summarize their syntheses, basic material properties, and key pharmaceutical applications.

Preparation and investigation of novel gastro-floating tablets with 3D extrusion-based printing

Three dimensional (3D) extrusion-based printing is a paste-based rapid prototyping process, which is capable of building complex 3D structures. The aim of this study was to explore the feasibility of 3D extrusion-based printing as a pharmaceutical manufacture technique for the fabrication of gastro-floating tablets. Novel low-density lattice internal structure gastro-floating tablets of dipyridamole were developed to prolong the gastric residence time in order to improve drug release rate and consequently, improve bioavailability and therapeutic efficacy. Excipients commonly employed in the pharmaceutical study could be efficiently applied in the room temperature 3D extrusion-based printing process. The tablets were designed with three kinds of infill percentage and prepared by hydroxypropyl methylcellulose (HPMC K4M) and hydroxypropyl methylcellulose (HPMC E15) as hydrophilic matrices and microcrystalline cellulose (MCC PH101) as extrusion molding agent. In vitro evaluation of the 3D printed gastro-floating tablets was performed by determining mechanical properties, content uniformity, and weight variation. Furthermore, re-floating ability, floating duration time, and drug release behavior were also evaluated. Dissolution profiles revealed the relationship between infill percentage and drug release behavior. The results of this study revealed the potential of 3D extrusion-based printing to fabricate gastro-floating tablets with more than 8h floating process with traditional pharmaceutical excipients and lattice internal structure design.

The In vitro/vivo Evaluation of Prepared Gastric Floating Tablets of Berberine Hydrochloride

Currently available antiulcer drugs suffered from serious side effects which limited their uses and prompted the need for a safe and efficient new antiulcer agent. The objective of this project work was to retain the drug in the stomach for better antiulcer activity and less side effects. Hence, the aim of our present work was to prepare a gastric floating tablet of Berberine hydrochloride (Ber) with suitable in vitro/vivo properties. In this study, different Ber gastric floating tablets were prepared by simple direct compression using various amounts of HPMCK15M and Carbopol 971PNF combined with other tablet excipients. The properties of the tablets including hardness, buoyancy, swelling ability, in vitro drug release, and in vivo pharmacokinetic study were evaluated. The obtained results disclosed that hardness, floating, swelling, and in vitro drug release of the Ber tablets depended mainly on the ratio of polymer combinations. Moreover, among six formulations, F3 exhibited desirable floating, swelling, and extended drug release. In addition, in vivo pharmacokinetic study suggested that prepared gastric floating tablets had significantly sustained-releasing effects compared with market tablets. Therefore, the developed gastric floating tablets of Ber could be an alternative dosage form for treatment of gastrointestinal disease.

Development and gamma scintigraphy evaluation of gastro retentive calcium ion-based oral formulation: an innovative approach for the management of gastro-esophageal reflux disease (GERD)

Calcium chloride is an essential calcium channel agonist which plays an important role in the contraction of muscles by triggering calcium channel. First time hypothesized about its role in the treatment of GER (gastro-esophageal reflux) and vomiting disorder due to its local action. There are two objectives covered in this study as first, the development and optimization of floating formulation of calcium chloride and another objective was to evaluate optimized formulation through gamma scintigraphy in human subjects. Gastro retentive formulation of calcium chloride was prepared by direct compression method. Thirteen tablet formulations were designed with the help of sodium chloride, HPMC-K4M, and carbopol-934 along with effervescing agent sodium bicarbonate and citric acid. Formulation (F8) fitted best for Korsmeyer-Peppas equation with an R² value of 0.993. The optimized formulation was radiolabelled with ^99mTc-99 m pertechnetate for its evaluation by gamma scintigraphy. Gastric retention (6 h) was evaluated by gamma scintigraphy in healthy human subjects and efficacy of present formulation confirmed in GER positive human subjects. Gamma scintigraphy results indicated its usefulness in order to manage GERD. Stability studies of the developed formulation were carried out as per ICH guidelines for region IV and found out to be stable for 24 months.

Risk-based approach for systematic development of gastroretentive drug delivery system

The research envisioned was the development of diltiazem hydrochloride effervescent floating matrix tablet using a risk-based approach. Preliminarily, the in vitro drug release profile was derived which theoretically simulated the in vivo condition after oral administration. Considering this as a rationale, the formulation development was initiated with defining the quality target product profile (QTPP) and critical quality attributes (CQAs). The preliminary studies were conducted to screen material attributes and process parameters followed by their risk assessment studies to select the plausible factors affecting the drug product CQAs, i.e., floating lag time and drug release profile. A 3(2) full factorial design was used to estimate the effect of the amount of swelling polymer (X 1) and gas-generating agent (X 2) on percent drug release (Q t1h and Q t8h) and floating lag time. Response and interaction plots were generated to examine the variables. Selection of an optimized formulation was done using desirability function and further validated. The model diagnostic plots represent the absence of outliers. The optimized formula obtained by the software was further validated, and the result of drug release and floating lag time was close to the predicted values. In a clear and concise way, the current investigations report the successful development of an effervescent floating matrix tablet for twice daily administration of diltiazem hydrochloride.

Design and development of controlled release floating matrix tablet of Nicorandil using hydrophilic cellulose and pH-independent acrylic polymer: in-vitro and in-vivo evaluations

OBJECTIVES

The purpose of the study was to develop a floating matrix tablet of Nicorandil using blends of hydrophilic cellulose and pH-independent acrylic polymer to improve the therapeutic effectiveness of the drug in cardiovascular disease.

METHODS

Nicorandil tablets were prepared by direct compression and evaluated for drug-excipients compatibility, in-vitro buoyancy and in-vivo γ-scintigraphy study. The selected formulation (FT5) was also evaluated for stability study and the in-vivo absorption in rabbits to compare the pharmacokinetic parameters with the commercially available immediate release tablet of Nicorandil.

RESULTS

DSC and FT-IR studies confirmed the absence of incompatibility and were found stable at refrigerator temperature (2-8°C) and at 25ºC/60% RH. The in-vivo γ-scintigraphy studies revealed that the system was floated for a period of 6 -7 h in the stomach and in-vivo absorption study showed a significant difference (p < 0.05) in the pharmacokinetic parameters (AUC increased by 3 fold and MRT by 2.5 fold) as compared to the marketed formulation.

CONCLUSION

In conclusion, the developed Nicorandil floating matrix tablet improved the pharmacokinetics parameters (AUC and MRT) in rabbit plasma with expected lowering in side effects potential.

Development and Optimization of Gastro-Retentive Controlled-Release Tablet of Calcium-Disodium Edentate and its In Vivo Gamma Scintigraphic Evaluation

Medical management of heavy metal toxicity, including radioactive ones, is a cause for concern because of their increased use in energy production, healthcare, and mining. Though chelating agents like EDTA and DTPA in parenteral form are available, no suitable oral formulation is there that can trap ingested heavy metal toxicants in the stomach itself, preventing their systemic absorption. The objective of the present study was to develop and optimize gastro-retentive controlled-release tablets of calcium-disodium edentate (Ca-Na2EDTA). Gastro-retentive tablet of Ca-Na2EDTA was prepared by direct compression method. Thirteen tablet formulations were designed using HPMC-K4M, sodium chloride, and carbopol-934 along with effervescing agents sodium bicarbonate and citric acid. Tablet swelling ability, in vitro buoyancy, and drug dissolution studies were conducted in 0.1 N HCl at 37 ± 0.5°C. Ca-Na2EDTA was radiolabeled with technetium-99m for scintigraphy-based in vivo evaluation. Formula F8 (Ca-Na2EDTA 200 mg, carbopol 100 mg, avicel 55 mg, citric acid 30 mg, NaHCO3 70 mg, NaCl 100 mg, and HPMC 95 mg) was found to be optimum in terms of excellent floating properties and sustained drug release. F8 fitted best for Korsmeyer-Peppas equation with an R (2) value of 0.993. Gamma scintigraphy in humans showed mean gastric retention period of 6 h. Stability studies carried out in accordance with ICH guidelines and analyzed at time intervals of 0, 1, 2, 4, and 6 months have indicated insignificant difference in tablet hardness, drug content, total floating duration, or matrix integrity of the optimized formulation. Gastro-retentive, controlled-release tablet of Ca-Na2EDTA was successfully developed using effervescent technique as a potential oral antidote for neutralizing ingested heavy metal toxicity.

Product development studies on sonocrystallized curcumin for the treatment of gastric cancer

Curcumin suffers from the limitation of poor solubility and low dissolution that can lead to limited applications. The investigation was aimed to substantiate the potentiality of melt sonocrystallized gastroretentive tablets of curcumin. Melt sonocrystallized curcumin (MSC CMN) was developed and its therapeutic potential was validated by in vitro cytotoxicity studies against Human oral cancer cell line KB. MSC curcumin was then formulated as floating tablet and evaluated. MSC form of CMN exhibited 2.36-fold and 2.40-fold solubility enhancement in distilled water and phosphate buffer, pH 4.5, respectively, better flow properties and intrinsic dissolution rate (0.242 ± 1.42 and 0.195 ± 1.26 mg/cm2/min) in comparison to its original form. The GI50 value of MSC CMN was found to be less than 10, specifying inhibition of growth more effectively at its least concentration by 50%. The gastroretentive-floating tablet (Formulation F4) displayed controlled drug release (96.22% ± 1.43%) for over 12 h. The present study revealed melt sonocrystallization can be used to produce particles with superior biopharmaceutical properties without the use of organic solvents or the addition of other excipients, and amenable to formulation in to a pharmaceutical dosage form.

Swelling/floating capability and drug release characterizations of gastroretentive drug delivery system based on a combination of hydroxyethyl cellulose and sodium carboxymethyl cellulose

The aim of this study was to characterize the swelling and floating behaviors of gastroretentive drug delivery system (GRDDS) composed of hydroxyethyl cellulose (HEC) and sodium carboxymethyl cellulose (NaCMC) and to optimize HEC/NaCMC GRDDS to incorporate three model drugs with different solubilities (metformin, ciprofloxacin, and esomeprazole). Various ratios of NaCMC to HEC were formulated, and their swelling and floating behaviors were characterized. Influences of media containing various NaCl concentrations on the swelling and floating behaviors and drug solubility were also characterized. Finally, release profiles of the three model drugs from GRDDS formulation (F1-4) and formulation (F1-1) were examined. Results demonstrated when the GRDDS tablets were tested in simulated gastric solution, the degree of swelling at 6 h was decreased for each formulation that contained NaCMC in comparison to those in de-ionized water (DIW). Of note, floating duration was enhanced when in simulated gastric solution compared to DIW. Further, the hydration of tablets was found to be retarded as the NaCl concentration in the medium increased resulting in smaller gel layers and swelling sizes. Dissolution profiles of the three model drugs in media containing various concentrations of NaCl showed that the addition of NaCl to the media affected the solubility of the drugs, and also their gelling behaviors, resulting in different mechanisms for controlling a drug’s release. The release mechanism of the freely water-soluble drug, metformin, was mainly diffusion-controlled, while those of the water-soluble drug, ciprofloxacin, and the slightly water-soluble drug, esomeprazole, were mainly anomalous diffusion. Overall results showed that the developed GRDDS composed of HEC 250HHX and NaCMC of 450 cps possessed proper swelling extents and desired floating periods with sustained-release characteristics.

Gastroretentive pulsatile release tablets of lercanidipine HCl: development, statistical optimization, and in vitro and in vivo evaluation

The present study was aimed at the development of gastroretentive floating pulsatile release tablets (FPRTs) of lercanidipine HCl to enhance the bioavailability and treat early morning surge in blood pressure. Immediate release core tablets containing lercanidipine HCl were prepared and optimized core tablets were compression-coated using buoyant layer containing polyethylene oxide (PEO) WSR coagulant, sodium bicarbonate, and directly compressible lactose. FPRTs were evaluated for various in vitro physicochemical parameters, drug-excipient compatibility, buoyancy, swelling, and release studies. The optimized FPRTs were tested in vivo in New Zealand white rabbits for buoyancy and pharmacokinetics. DoE optimization of data revealed FPRTs containing PEO (20% w/w) with coat weight 480 mg were promising systems exhibiting good floating behavior and lag time in drug release. Abdominal X-ray imaging of rabbits after oral administration of the tablets, confirmed the floating behavior and lag time. A quadratic model was suggested for release at 7th and 12th h and a linear model was suggested for release lag time. The FPRT formulation improved pharmacokinetic parameters compared to immediate release tablet formulation in terms of extent of absorption in rabbits. As the formulation showed delay in drug release both in vitro and in vivo, nighttime administration could be beneficial to reduce the cardiovascular complications due to early morning surge in blood pressure.

Role of various natural, synthetic and semi-synthetic polymers on drug release kinetics of losartan potassium oral controlled release tablets

OBJECTIVE

The objective of the present work was to formulate and to characterize controlled release matrix tablets of losartan potassium in order to improve bioavailability and to minimize the frequency of administration and increase the patient compliance.

MATERIALS AND METHODS

Losartan potassium controlled release matrix tablets were prepared by direct compression technique by the use of different natural, synthetic and semisynthetic polymers such as gum copal, gum acacia, hydroxypropyl methyl cellulose K100 (HPMC K100), eudragit RL 100 and carboxy methyl ethyl cellulose (CMEC) individually and also in combination. Studies were carried out to study the influence of type of polymer on drug release rate. All the formulations were subjected to physiochemical characterization such as weight variation, hardness, thickness, friability, drug content, and swelling index. In vitro dissolution studies were carried out simulated gastric fluid (pH 1.2) for first 2 h and followed by simulated intestinal fluid (pH 6.8) up to 24 h, and obtained dissolution data were fitted to in vitro release kinetic equations in order to know the order of kinetics and mechanism of drug release.

RESULTS AND DISCUSSION

Results of physiochemical characterization of losartan potassium matrix tablets were within acceptable limits. Formulation containing HPMC K100 and CMEC achieved the desired drug release profile up to 24 h followed zero order kinetics, release pattern dominated by Korsmeyer - Peppas model and mechanism of drug release by nonfickian diffusion. The good correlation obtained from Hixson-Crowell model indicates that changes in surface area of the tablet also influences the drug release.

CONCLUSION

Based on the results, losartan potassium controlled release matrix tablets prepared by employing HPMC K100 and CMEC can attain the desired drug release up to 24 h, which results in maintaining steady state concentration and improving bioavailability.

Gastroretentive inorganic-organic hybrids to improve class IV drug absorption

Therapeutic efficacy of some orally administered molecules is often conditioned by their solubility in physiological fluids as well as their absorption. The last aspect becomes more limitative and conditioning drug plasmatic profiles when the active ingredient is preferentially absorbed in a specific region of the gastrointestinal tract. A case is represented by furosemide (FURO) preferentially absorbed in the stomach, site in which, because of its acidic nature, is poorly soluble. To solve this problem new oral solid formulations have been developed. The inorganic-organic hybrid MgAl-HTlc-FURO has been formulated in tablet in which floating and mucoadhesion properties have been combined. Swellable (Methocel K4, Methocel K15, Methocel K100 M, hydroxypropyl methyl cellulose) or swellable/erodible polymers (Methocel E50 LV, Methocel K100 LV), used to obtain the floating, were combined to Carbopol(®) (971P or 974P) to confer mucoadhesion capacity. Prepared tablets were deeply characterized in terms of hydration capacity, erosion %, buoyancy lag time/floating time and mucoadhesion. The most suitable tablets selected from these preliminary tests, submitted to in vitro release studies, showed a sustained release of FURO. This is useful to maintain the therapeutic concentrations for a long time, in comparison to conventional dosage forms, thanking to the enhancement of formulation residence time in the stomach.

Gastroretentive mucoadhesive tablet of lafutidine for controlled release and enhanced bioavailability

Lafutidine a newly developed histamine H2-receptor antagonist having biological half-life of 1.92 ± 0.94 h due to its selective absorption from upper part of gastrointestinal tract the development of mucoadhesive sustained release drug delivery system is recommended in order to enhance the bioavailability. A mucoadhesive tablets was developed using the natural polymer, sodium alginate, xanthan gum and karaya gum. Mucoadhesion is a complex phenomenon which involves wetting, adsorption and interpenetration of polymer chains. The prepared tablets of various formulations were evaluated for a total mucoadhesion time, buoyancy lag time and percentage drug released. The formulation with xanthan gum showed better results. Thus, it may be useful for prolonged drug release in stomach to improve the bioavailability and reduced dosing frequency. Non-fickians release transport was confirmed as the drug release mechanism from the optimized formulation by Korsmeyer-Peppas. The optimized formulation (B3) showed a mucoadhesive strength >35 g. In vivo study was performed using rabbits by X-ray imaging technique. Radiological evidences suggest that, a formulated tablet was well adhered for >10 h in rabbit's stomach. Optimized lafutidine mucoadhesive tablets showed no significant change in physical appearance, drug content, mucoadhesive properties and in vitro dissolution pattern after storage at 40 °C temperature 75 ± 5% relative humidity for 3 months.