Gel Tablets Research Articles

Rheology and Extrusion Printing of κ-Carrageenan/Olive Oil Emulsion Gel Tablets with Varying Surface Area to Volume Ratios for Release of Vitamin C and Curcumin.

In this work, κ-carrageenan and olive oil at different oil to κ-carrageenan ratios (OCR) are homogenized to create emulsion gels. Interestingly, confocal imaging shows that the oil droplets are stabilized in the κ-carrageenan-structured gel matrix without using any surfactants. Rheological studies show that the oil droplets enhanced the oscillatory yield stress and the maximum printable height of the emulsion gels. The creation of the emulsion gels with an OCR of 1:9-3:7 led to an improvement in the structural integrity of extrusion printed structures. The emulsion gel with an OCR of 3:7 efficiently encapsulates vitamin C in the aqueous phase and curcumin in the hydrophobic oil phase, enabling the extrusion 3D printing of tablets with varying surface area to volume (SA/V) ratios. The release of vitamin C and curcumin is influenced by the preparation method of printing versus casting and the SA/V ratio of the tablets. The hollow cylinder with the highest SA/V ratio was observed to have the highest vitamin C release, whereas for curcumin, the printed tablets had a higher release compared to the cast tablet. Additionally, through rheo-dissolution experiments, we observe a lower modulus and higher vitamin C release from the 3D-printed disc versus the higher modulus and lower vitamin C release from the cast disc tablet.

Dissolvable shower gel tablets with enhanced skin benefits.

The excessive use of plastic packaging, even though it is possible to recycle it, is one of the main causes of global warming. In this study, dissolvable shower gel tablets for multiple uses have been developed in order to reduce the use of fresh plastic packaging. The appropriate ratio of two surfactants, cocoyl glutamic acid (CGA) and sodium coco sulphate (SCS), was optimized using design of experiments. Additionally, skin hydration of the emollient either omega oil or glycerine was taken into account when determining its concentration. After that, powdered shower gel formulations were made and tested for their properties, including cleaning power, and foamability. On 30 humanvolunteers, the effects of reconstituted shower gel on skin redness, cleaning effectiveness and overall satisfaction were evaluated. The study found that, when cleaning power and foam height were taken into account, the proper surfactant ratio was 7.5:0 (SCS:CGA). The 5% glycerine shower gel formula demonstrated significantly greater skin hydration than other formulas. The in vivo study's findings demonstrated that there was no statistically significant difference between selected formulas (5% glycerine and 2.5% omega oil) in terms of cleaning ability. Comparing both formulas to the control, neither showed any skin redness. Additionally, it was discovered that the developed products were much more effective at cleaning and easier to use when washing for the volunteers than regular liquid soap. Overall satisfaction and the moisturizing feel were not significantly different among all products. The formula with 7.5% SCS and 5% glycerine is said to be the best one for both cleaning ability and moisturizing effect. These findings suggest that dissolvable shower gel tablets with enhanced skin benefits could offer a promising innovation in the personal care industry.

Nutmeg Essential Oil, Red Clover, and Liquorice Extracts Microencapsulation Method Selection for the Release of Active Compounds from Gel Tablets of Different Bases.

The current study presents the most suitable method for encapsulating nutmeg essential oil with liquorice and red clover. Two widely used methods, spray-drying and freeze-drying, were employed to find the most suitable for essential oil volatile compounds' protection. Results showed that freeze-dried capsules (LM) had a higher yield (85.34%) compared to the exact formulation of spray-dried microcapsules (SDM)-45.12%. All the antioxidant and total phenolic compounds' results obtained with the LM sample were significantly higher compared with SDM. LM microcapsules were incorporated in two different bases with no additional sugar (gelatin and pectin) for targeted release. Pectin tablets had firmer and harder texture properties, while gelatin tablets had a more elastic texture. There was a significant impact on texture changes caused by microcapsules. Microencapsulated essential oil with extracts can be used alone or in a gel base (pectin or gelatin, depending on user preferences). It could be an effective product to protect the active volatile compounds and regulate the release of active compounds and give a pleasant taste.

Formulation and Evaluation of Moisture Protective Tablet Compression Coat Using Natural Polymers

This study aims to formulate and evaluate moisture protective coat for tablets using natural polymers of Fenugreek seeds and okra fruits in different concentrations compared with synthetic moisture protective coat. Ethanolic extracts of fenugreek and okra were treated with acetone as solvent for isolation of the mucilage, which is then dried and powders obtained identified and tested for polysaccharides using Molisch's reagent, Barofoead, KOH, Fehling reagent. The physicochemical tests including pH, viscosity, moisture content, percentage yield and swelling index were also carried out. Two formulations of 150 mg Silica gel tablets weighing 300mg and 500mg using PVP, magnesium stearate and Microcrystalline cellulose (MCC) as excipients were prepared and the powder mixture of flow ability was evaluated by measuring Carr's index, Hausener ratio and Angle of repose. The compressed tablets were evaluated according to USP monograph by testing the physical test of both tablets. Two coating materials were prepared and evaluated using natural polymers in different concentration 5%w/w and 10%w/w. The coated tablets with natural and synthetic polymers were compared by observing weight and moisture change of tablets pre and after stability study for 2 weeks in stress conditions at temperature (500 C) and RH 75 %. All the identification tests were positive indicating the presence of polysaccharides. Also, the physicochemical parameters tested were within the acceptable limits. Both fenugreek and okra mucilage's as polymers in low concentration 5%w/w revealed much better results regardless of weight of tablets. Coat defects were observed in tablets coated with 10%w/w of the polymers. The standard film coating polymer showed better moisture protection as moisture content about 4%. coating materials were successfully prepared and evaluated as moisture protective coat of silica gel tablets. Optimum coating formulations were found at 5%w/w concentration for mucilage's of both fenugreek and okra.

Development of Innovative Chewable Gel Tablets Containing Nutmeg Essential Oil Microcapsules and Their Physical Properties Evaluation.

Chewable gel tablets are a dosed pharmaceutical form, which can have an active substance, pharmacological effect, or value of nutrition. The texture of these tablets is soft, springy, flexible, and elastic—this is influenced by the chosen ingredients. The aim of this study was to prepare chewable gel tablets with nutmeg essential oil-loaded microcapsules and determine the volatile compounds released from this pharmaceutical form. Gel tablets were prepared by using gelatin as basis, nutmeg essential oil as active compound, and natural ingredients: thyme-sugar syrup, thyme extract, and citric acid as taste and color additives. Texture properties were measured by a texture analyzer. The release of volatile compounds from nutmeg essential oil and gel tablets were analyzed by headspace-gas chromatography with mass spectroscopy in control and artificial saliva conditions in vitro. Nutmeg essential oil microcapsules had influence on the gel tablet’s physical properties (p < 0.05, by comparing tablets without glycerol and relative sample with glycerol); glycerol protects the tablets from the formation of sugar crystals on top and keeps good physical parameters (p < 0.05). A total of 12 volatile compounds were identified in nutmeg essential oil, and the six compounds with the highest amounts were selected as controls. Gel tablets prolong the release time of volatile compounds and reduce the amount of the compounds compared to the microcapsules (p < 0.05).

The Effect of Myristica fragrans on Texture Properties and Shelf-Life of Innovative Chewable Gel Tablets.

Chewable gel tablets are an underdeveloped subject, even though there are many simple chewable tablets and gummy candies in the food and pharmaceutical industries. Chewable gel tablets are not as sweet, they can have an active substance, pharmacological effect, and a value of nutrition. The aim of this study was to prepare gelatin-based chewable tablets with Myristica fragrans as a preservative and to determine the shelf-life variability depending on storage conditions, and to evaluate texture changes. Firmness and springiness of gel tablets were measured by a texture analyzer and compared between different storage conditions and the shelf-life of tablets was established by mold growing time. Chewable gel tablets were prepared by using silicone form. Mold was most likely to grow on tablets that have been packaged in squeezable bags (after 14 days 60% of all formulations had a mold, p < 0.05). The most stable tablets (over 180 days) were in sealed boxes and contained nutmeg essential oil or its solution, or ethanolic nutmeg extract. The gel tablets’ firmness increased about 4 times when they were stored in opened plastic boxes and their springiness decreased about 1.65 times after 28 days in the mentioned conditions, p < 0.05. Nutmeg hydrolat had the highest influence on texture variation (p < 0.05).

Fabrication of novel casein gel with controlled release property via acidification, spray drying and tableting approach

In this work, casein has been acidified at a pH of 1.0, forming a shampoo/lotion-like gel. It has been further processed by spray drying and tableting for controlled-release applications. The engineered casein gel shows higher moisture contents and lower Tg/dehydration temperatures compared with the non-gelled casein, based on the DSC and FTIR analysis. Casein is sensitive to thermal exposure (DSC), and no significant change in the casein was observed during acidification (FTIR). The particle size of the spray-dried casein gel increased as the spray-drying temperature decreased. The particles that were spray-dried at high temperatures were more likely to have wrinkled surfaces (raisin-like). For the microencapsulation of ascorbic acid (vitamin C), the spray-dried powders had lower moisture contents and higher Tg/dehydration temperatures as the spray-drying temperature was increased. By increasing the inlet temperature (100-190 °C), the retention of ascorbic acid decreased (80-60%) while the yield increased (0-70%). The DMA analysis showed that the casein gel tablet was elastic, and its stiffness was measured to be 0.8 N/mm. For controlled release, the casein gel tablet gave a slow release of ascorbic acid for 24 h at pH of 2 or 12 h at pH of 7.4. High compression pressure (320 MPa) resulted in slightly slower release than a compression pressure of 80 MPa.

Controlled release of caffeine from tablets of spray-dried casein gels

The controlled release of caffeine from the casein gel tablets has been achieved over release periods lasting from a few minutes to over a few days. A novel casein gel has been acidified at pH of 1.0 as the insoluble controlled-release matrix and spray-dried with coffee for microencapsulation. The optimal inlet temperature of spray drying for the casein-coffee mixtures has been found to be 150 °C. The elastic casein-coffee tablets have been engineered without denaturing the components (as indicated by DSC and FTIR analysis). Pressure-controlled release has been achieved for the casein-coffee tablets prepared by compression at 8 (with lactose excipient), 80 and 160 MPa. The corresponding releases of over 80% caffeine are about 24, 12 and 3–6 h, respectively. By changing the coffee/casein ratio from 10 to 100%, the release time of 80% caffeine can be controlled from 24 to 0.5 h. The spray-dried casein-coffee particles shown in the SEM images are similar in size (about 10 μm) and shape (raisin-like). No significant interactions between the casein and coffee components have been observed by FTIR analysis.

Dynamics of a camphoric acid boat at the air–water interface

We report experiments on an agarose gel tablet loaded with camphoric acid (c-boat) spontaneously set into motion by surface tension gradients on the water surface. We observe three distinct modes of c-boat motion: harmonic mode where the c-boat speed oscillates sinusoidally in time, a steady mode where the c-boat maintains constant speed, and an intermittent mode where the c-boat maintains near-zero speed between sudden jumps in speed. Whereas all three modes have been separately reported before in different systems, controlled release of Camphoric Acid (CA) from the agarose gel matrix allowed the observation of all the three modes in the same system. These three modes are a result of a competition between the driving (surface tension gradients) and drag forces acting on the c-boat. Moreover we suggest that there exist two time scales corresponding to spreading of CA and boat motion and the mismatch of these two time scales give rise to the three modes in boat motion. We reproduced all the modes of motion by varying the air–water interfacial tension using Sodium Dodecyl Sulfate (SDS).

Design and optimization of novel in situ gel of mercaptopurine for sustained drug delivery

Mercaptopurine is a purine antagonist, belonging to the class of antimetabolites. Its oral absorption is erratic and variable throughout GIT, with bioavailability of 5-37% and belongs to Biopharmaceutical Classification System (BCS) class IV. The focus of the present study was to improve solubility of mercaptopurine and to release the drug uniformly throughout the GIT by formulating into a novel in situ gel tablet. By in vitro swelling studies, xanthan gum was selected as the best gelling polymer and the tablets were prepared by direct compression. Sodium chloride was used as a release modifier to improve the release of drug from the tablet. A 32 full factorial design was applied to optimize the percentage of xanthan gum and sodium chloride to get desired swelling index and release profile. Tablets were evaluated for weight variation, hardness, friability, disintegration time, drug content, in vitro swelling studies and in vitro dissolution studies. The best optimized formulation showed good swelling index and extended the release up to 12 h, where as conventional tablet released the drug within 45 min. The results indicate that mercaptopurine loaded in situ gel tablet could be effective in sustaining drug release for a prolonged period of time throughout the GIT, which can possibly improve the oral bioavailability.

Fast Dissolving Tablets of Aloe Vera Gel

Purpose: The objective of this work was to prepare and evaluate fast dissolving tablets of the nutraceutical, freeze dried Aloe vera gel. Methods: Fast dissolving tablets of the nutraceutical, freeze-dried Aloe vera gel, were prepared by dry granulation method. The tablets were evaluated for crushing strength, disintegration time, wetting time, friability, drug content and drug release. A 32 full factorial design was applied to investigate the combined effect of two formulation variables - amounts of microcrystalline cellulose and mannitol. Results: The results of multiple regression analysis revealed that in order to obtain a fast dissolving tablet of the Aloe vera gel, an optimum concentration of mannitol and a higher content of microcrystalline cellulose should be used. A response surface plot was also provided to graphically represent the effect of the independent variables on the disintegration time and wetting time. The validity of the generated mathematical model was tested by preparing a check point batch. Conclusion: This investigation has demonstrated that satisfactory fast dissolving Aloe vera gel tablets can be formulated. It also showed the potential of experimental design in understanding the effect of formulation variables on the quality of fast dissolving tablets. Keywords: Aloe vera, Fast dissolving tablet, Factorial design, Mathematical model, Mannitol, Microcrystalline celluloseTropical Journal of Pharmaceutical Research Vol. 8 (1) 2009: pp. 63-70

Adsorption of Dimethyl(1,5-cyclooctadiene)platinum on Porous Supports in Supercritical Carbon Dioxide

The adsorption of dimethyl(1,5-cyclooctadiene)platinum on porous supports in supercritical carbon dioxide was investigated. Silica gel tablets and a monolithic material were used as the solid support. An experimental method was developed for the investigation of adsorption kinetics where the substance was allowed to dissolve in the supercritical fluid before coming in contact with the solid support. Online UV spectroscopy was used to observe the decrease in bulk concentration in the supercritical solution. Adsorption experiments were carried out at 333 and 353 K at a constant pressure of 15 MPa. Additionally, the solubility of the platinum compound at the experimental conditions was determined. The influence of concentration, temperature, and support material on the adsorption was investigated.

An Adjusted Pharmacokinetic Equation for Predicting Drug Levels In Vivo Based on In Vitro Square Root of Time Release Kinetics

An adjusted pharmacokinetic equation that predicts in vivo plasma drug profiles for controlled release (CR) dosage forms having square root of time drug release kinetics has been derived. The CR hydrogel tablets containing hydroxypropyl methylcellulose (HPMC) were formulated with theophylline and Fast Flo® lactose, to produce tablets with HPMC K100MP content of 30% w/w. Plasma profiles in vivo were determined from four male beagle dogs. Tablet gel strength (Γ) was measured as previously reported. Results show drug release in vitro follows square root of time kinetics for the formulation in all media (purified H2O, 0.1 N HCl, and pH 6.8 phosphate buffer). The Γ values were not significantly different (p>0.05) among the tablets in different dissolution media, with absolute values in DI H2O of 6600 erg/cm3, which is above the minimum threshold value of Γ (≈6000 erg/cm3) needed for acceptable in vitro/in vivo correlation. Comparison of predicted and observed plasma profiles in vivo, using the adjusted square root pharmacokinetic equation, showed a better fit of the overall pattern and absolute values of the in vivo data as compared to equations that assume first- or zero-order drug release from the HPMC based tablets. The adjusted square root pharmacokinetic equation can serve as a valuable aid in the design of formulations to yield a desired plasma profile in vivo and provides supporting evidence to the mechanism of drug release in vitro.

The Effect of Formulation Composition and Dissolution Parameters on the Gel Strength of Controlled Release Hydrogel Tablets

The impact of hydrogel polymers and dissolution media on tablet gel strength, Γ, of controlled release (CR) hydrogel tablets was investigated. CR tablets containing either hydroxypropyl methylcellulose (HPMC), hydroxypropyl cellulose (HPC), or carbomer were formulated with theophylline and Fast Flo® lactose, to produce tablets with a polymer content of 8, 15, and 30% w/w. Γ was measured using a previously reported method. The drug dissolution profiles were similar, irrespective of polymer type or dissolution media (DI water, 0.1 N HCl, and pH 6.8 phosphate buffer), at the same % w/w level of polymer. Γ, however, showed large and significant differences (p≤0.05) between tablets containing different polymers and between different dissolution media. Γ values were HPMC K100MP > HPC HXF > carbomer 971P (same % w/w) with absolute Γ values at 30% w/w in DI water of 6600, 4600, and 1600 ergs/cm3, respectively. Γ for HPMC based tablets was independent of changes in dissolution media, while the Γ values for HPC tablets were 18% lower in acid and buffer than in DI water. Of the polymers tested, carbomer based tablets had the lowest Γ values in all dissolution media and an unexpected 58% lower Γ in buffer compared with DI water or acid. Γ provides a quantitative measure of the effect of formulation and dissolution parameter changes on tablet gel layer strength, under in vitro stress conditions that may parallel in vivo tablet performance, but which cannot be deduced from a comparison of dissolution profiles or polymer viscosity.

A Novel Method for Measuring Gel Strength of Controlled Release Hydrogel Tablets Using a Cone/Plate Rheometer

A novel method for measuring gel strength of hydrogel controlled release (CR) tablets is presented. CR tablets containing hydroxypropyl methylcellulose (HPMC) were fixed to a glass plate, placed in a dissolution apparatus, and subjected to dissolution conditions corresponding to 50% drug release. Tablets were then removed from the dissolution apparatus without disturbing the swollen (gel) layer. Tablet gel strength (Γ) was determined by shearing the external gelled layer of the tablet by a cone/plate rheometer recording E, energy/volume, as a function of rotational speed of the cone, RPM. The RPM is increased to the point ofy “Shear Failure,” RPMsf, i.e., until there is no further increase in E. Plots of, E vs. RPM were fit to a bi-exponential equation, where ε is the zero RPM intercept of the plot. Γ is calculated from Γ = ERPMsf - ε. Γ varepsilon is defined as the minimum energy input/unit volume needed to cause shear failure of the tablet gel layer. Mean Γ for tablets containing 50% theophylline and different ratios of HPMC to Fast Flo lactose were determined. Tablets containing 30%, 15%, and 8% HPMC K100MP have Γ means of 6600, 4700, and 1500ergs/cm3, and percent relative standard deviations of 9, 13, 33%,respectively. Tablets made entirely of HPMC K100MP (no theophylline or lactose) have an Γ of 15500 ergs/cm3. Γ values are significantly different (p < 0.0001) between the various formulations. Γ values also show a strong inverse correlation with the cumulative percent of drug released in vitro. Results obtained demonstrate the application of this novel method for measuring gel strength of different CR hydrogel tablets and usingthis strength to characterize drug diffusion in vitro.

高齢者向け経口製剤の検討クエン酸ナトリウム添加ゼラチン乾燥ゲル錠の物理的性質に及ぼす添加剤の影響

Influence of additives on friability, water absorption profiles and disintegration time of dried gel tablets prepared from gelatin-addedsodium citrate was investigated for preparation of dried gel tablets having high strength, fast water absorption rate and rapid disintegration as an oral preparation for elderly patients, pour kinds of Avice® (PH101, PH301, PH-F20, RC-591NF), polyethylene glycol and poyvinylpyrrolidone were used as additives.For the additives used friability decreased with an increase in the amount of additives. The apparent water absorption rate increased with the increase in the amount of PH301. Disintegration time was shortened at the mixing ratio of 15%(w/w) in PH301 and RC-951NF. These results suggested that the addition of 15% PH301 to dried gel powders is effective. In dried gel tablets to which PH301 was added at a mixing ratio of 15%, friability increased with the decrease in compression pressure but the apparent water absorption rate and disintegration time were scarcely affected by the compression pressure.