Polypropylene Foam Powder Research Articles

Optimization of non-effervescent riboflavin gastroretentive floating tablets using mixture design

Gastroretentive Floating Drug Delivery Systems (GRFDDS) are long-acting oral dosage forms that float on gastric juice and remain in the stomach for an elongated period gradually delivering drug substances to the upper part of the gastrointestinal system. This study aims to develop and enhance the bioavailability and stomach retention of non-effervescent riboflavin floating tablets by using a variety of polymers. In this investigation, both pre-compression evaluation and post-compression of all the tablet materials were performed according to USP specifications. In vitro, buoyancy analyses were carried out to achieve minimum floating lag time and maximum floating duration. The tablet employed direct compression methods using HPMC K17, Carbopol 940p, and polypropylene foam powder. In vitro, buoyancy studies were performed to achieve minimum floating lag time and maximum floating duration. Tablets were evaluated for physicochemical properties according to USP specifications. An optimized tablet with a floating lag time of 0.77 minutes and a floating time of 48.74 minutes was developed using Design of Experiments (DoE). The results indicated that the optimized formulation, designated as Y, performed the best. It consists of 0.45% polypropylene foam powder, 0.15% HPMC K17, and 0% Carbopol 940p. The developed non-effervescent riboflavin floating tablets have the potential to improve the bioavailability and therapeutic efficacy of riboflavin by enhancing its gastric residence time.

Development of curcumin floating beads with low density materials and solubilizers

Curcumin floating beads with low density materials including polypropylene foam powder, oils and various solubilizers were developed to prolong gastroretention and improve typically insufficient curcumin release, thus providing possible utilization for peptic ulcer treatment. They were prepared by ionotropic gelation and characterized for physical properties, floating properties and drug release. The results revealed that immediately floating beads with prolonged floatation could be successfully prepared using 1% w/w of foam powder. Floating properties and curcumin release were further improved by adding low density oils and solubilizers. Using G-rich alginate as a bead forming polymer provided slower curcumin release than using M-rich alginate. Freeze-drying yielded floating beads with a lower density and more highly porous structure, leading to higher curcumin release compared to oven-drying. The optimum formulation consisted of 1% w/w foam powder, 10% w/w peppermint oil, 10% w/w Cremophor RH40 and 10% w/w ethanol. This study demonstrated robust alginate floating systems with low density materials and solubilizers are promising carriers for stomach-targeted delivery of curcumin.

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 12h with zero floating lag time. The release of valsartan from optimized formulation NF-2 showed sustained release up to 12h; 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 12h. Consequently, all the findings and outcomes have showed that developed valsartan matrix tablets could be effectively used for floating drug delivery system.

Formulation and Evaluation of Gastroretentive Floating Matrix Tablets of Atorvastatin Calcium

The present work focuses on the development of hydrodynamically balanced delivery system of Atorvastatin as a single-unit floating Tablet which, after oral administration should have the ability to prolong gastric residence time with the desired in vitro release profile for the localized action in the stomach. Fourier transform Infrared spectroscopy and DSC study confirmed the absence of any drug/polymers/excipients interactions. Floating effervescent tablets were formulated by various materials like. hydroxypropyl methylcellulose (HPMC) K4M, K15M, psyllium husk, swelling agent as crospovidone and micro crystalline cellulose and gas generating agent like sodium bicarbonate and citric acid and evaluated for floating properties, swelling characteristics and drug release studies. Floating non effervescent tablets were prepared by polypropylene foam powder and different matrix forming polymers like HPMC K4M, Carbopol 934P xanthan gum and sodium alginate. The Tablets were prepared by wet granulation method and the polymer in varying ratios. The prepared floating tablets were evaluated for hardness, weight variation, thickness, friability, drug content uniformity, buoyancy lag time, total floating time, water uptake (swelling index) and in-vitro dissolution studies Incorporation of gas-generating agent together with polymer improved drug release, besides optimal floating. The formulation was optimized on the basis of in vitro buoyancy and in vitro release in 0.1N HCl. By fitting the data into zero-order, first-order, and Higuchi models, we concluded that the mechanism of release of Atorvastatin from the floating tablet was anomalous diffusion transport and follows zero order kinetics, as the correlation coefficient (R value) was higher for zero-order release. Stability studies revealed that formulations were stable when stored at different temperatures and the values were within permissible limits.

Formulation and Evaluation of Gastro-retentive Floating Multi-particulate System of Metoprolol Tartarate

Purpose: To develop a floating multiparticulate unit system for metoprolol tartarate, using a porous carrier, with an outcome for delayed gastric emptying.Methods: Dried microparticles of metoprolol tartarate were prepared by solvent evaporation using Eudragit® RS-PO, polypropylene foam powder, and dichloromethane as release-rate modifying polymer, floating aid and solvent respectively. The surface topography of the particles was assessed by SEM while the physical state of the drug within the developed system was characterised by DSC and XRD. Drug release was investigated by in vitro dissolution test. Tc99m sulfur colloid radio-labelled microparticle formulation was administered to fasting rabbits and their transit behavior was monitored using gamma scintigraphy. The anterior and posterior images recorded were computed to determine the geometric mean counts, enabling quantitative estimation of gastric emptying rate.Results: Dried free-flowing, white coloured microparticles were obtained. They were highly porous and also irregular in shape. The drug in the microparticles was partly amorphous, showing a decrease in crystallinity. In vitro drug release from the particles followed a biphasic pattern with zero-order kinetics. The microparticulate system exhibited good floating ability with t1/2 of 300 min over the duration of the in vivo study (6 h).Conclusion: The developed microparticles showed suitable release properties, were free-flowing and exhibited good floating ability in rabbit stomach. Therefore, the formulation is capable of being further processed into tablet and/or capsule dosage forms for oral administration as a gastro-retentive controlled delivery system.Keywords: Metprolol tartarate, Gastro-retention, Eudragit polymer, Polypropylene foam powder, Gamma scintigraphy, Microparticulate system, Zero order release.

Preparation and Evaluation of Gastroretentive Floating Tablets of Acyclovir

The present study performed by preparation and evaluation of floating tablets of Acyclovir as model drug for prolongation of gastric residence time. Floating effervescent tablets were formulated by various materials like hydroxypropyl methylcellulose K 4M, K 15M, psyllium husk, swelling agent as crospovidone and microcrystalline cellulose and gas generating agent like sodium bicarbonate and citric acid and evaluated for floating properties, swelling characteristics and in vitro drug release studies. Floating noneffervescent tablets were prepared by polypropylene foam powder and different matrix forming polymers like HPMC K 4M, Carbopol 934P, xanthan gum and sodium alginate. In vitro drug release studies were performed and drug release kinetics evaluated using the linear regression method was found to follow both the Higuchi and the Korsmeyer and Peppas equation. The drug release mechanism was found fickian type in most of the formulations.

Preparation and Evaluation of Gastroretentive Floating Tablets of Silymarin

The present study performed by preparation and evaluation of floating tablets of Silymarin as model drug for prolongation of gastric residence time. Floating effervescent tablets were formulated by various materials like hydroxypropyl methylcellulose (HPMC) K 4M, K 15M, psyllium husk, swelling agent as crospovidone and microcrystalline cellulose and gas generating agent like sodium bicarbonate and citric acid and evaluated for floating properties, swelling characteristics and in vitro drug release studies. Floating noneffervescent tablets were prepared by polypropylene foam powder and different matrix forming polymers like HPMC K 4M, Carbopol 934P, xanthan gum and sodium alginate. In vitro drug release studies were performed and drug release kinetics evaluated using the linear regression method was found to follow both the Higuchi and the Korsemeyer and Peppas equation. The drug release mechanism was found fickian type in most of the formulations. The developed floating tablets of Silymarin may be used in clinic for prolonged drug release for at least 24 h, thereby improving the bioavailability and patient compliance.

Porous carriers for controlled/modulated drug delivery.

Considerable research efforts have been directed in recent years towards the development of porous carriers as controlled drug delivery matrices because of possessing several features such as stable uniform porous structure, high surface area, tunable pore size and well-defined surface properties. Owing to wide range of useful properties porous carriers have been used in pharmaceuticals for many purposes including development of floating drug delivery systems, sustained drug delivery systems. Various types of pores like open, closed, transport and blind pores in the porous solid allow them to adsorb drugs and release them in a more reproducible and predictable manner. Pharmaceutically exploited porous adsorbents includes, silica (mesoporous), ethylene vinyl acetate (macroporous), polypropylene foam powder (microporous), titanium dioxide (nanoporous). When porous polymeric drug delivery system is placed in contact with appropriate dissolution medium, release of drug to medium must be preceded by the drug dissolution in the water filled pores or from surface and by diffusion through the water filled channels. The porous carriers are used to improve the oral bioavailability of poorly water soluble drugs, to increase the dissolution of relatively insoluble powders and conversion of crystalline state to amorphous state.

Release mechanisms behind polysaccharides-based famotidine controlled release matrix tablets.

Polysaccharides, which have been explored to possess gelling properties and a wide margin of safety, were used to formulate single-unit floating matrix tablets by a direct compression technique. This work has the aim to allow continuous slow release of famotidine above its site of absorption. The floating approach was achieved by the use of the low density polypropylene foam powder. Polysaccharides (kappa-carrageenan, gellan gum, xyloglucan, and pectin) and blends of polysaccharides (kappa-carrageenan and gellan gum) and cellulose ethers (hydroxypropylmethyl cellulose, hydroxypropylcellulose, sodium carboxymethyl cellulose) were tried to modulate the release characteristics. The prepared floating tablets were evaluated for their floating behavior, matrix integrity, swelling studies, in vitro drug release studies, and kinetic analysis of the release data. The differential scanning calorimetry and Fourier transform infrared spectroscopy studies revealed that changing the polymer matrix system by formulation of polymers blends resulted in formation of molecular interactions which may have implications on drug release characteristics. This was obvious from the retardation in drug release and change in its mechanistics.

Multiple unit gastroretentive drug delivery systems: A new preparation method for low density microparticles

The aim of this study was to develop a new preparation method for low density foam-based, floating microparticles and to demonstrate the systems' performance in vitro. Major advantages of the novel preparation technique include: (i) short processing times, (ii) no exposure of the ingredients to high temperatures, (iii) the possibility to avoid toxic organic solvents, and (iv) high encapsulation efficiencies close to 100%. Floating microparticles consisting of polypropylene foam powder, model drug [chlorpheniramine maleate (CPM), diltiazem HCl, theophylline or verapamil HCl] and polymer [Eudragit RS or polymethyl methacrylate (PMMA)] were prepared by soaking the microporous foam carrier with an organic solution of drug and polymer and subsequent drying. The effects of various formulation and processing parameters on the resulting in vitro floating behaviour, internal and external particle morphology, drug loading, in vitro drug release and physical state of the incorporated drug were studied. Good in vitro floating behaviour was observed in most cases and a broad variety of drug release patterns could be achieved by varying the drug loading and type of polymer. Interestingly, PMMA-based microparticles showed incomplete drug release with verapamil HCl. This restriction could be overcome by forming the free base of the drug prior to microparticle preparation. In contrast to the salt, the free base acted as a plasticizer for PMMA, resulting in sufficiently high diffusion coefficients and, consequently, complete drug release. The low density microparticles were compressed into rapidly disintegrating tablets in order to provide an administrable oral dosage form.

Multiple unit gastroretentive drug delivery systems: a new preparation method for low density microparticles.

The aim of this study was to develop a new preparation method for low density foam-based, floating microparticles and to demonstrate the systems' performance in vitro. Major advantages of the novel preparation technique include: (i) short processing times, (ii) no exposure of the ingredients to high temperatures, (iii) the possibility to avoid toxic organic solvents, and (iv) high encapsulation efficiencies close to 100%. Floating microparticles consisting of polypropylene foam powder, model drug [chlorpheniramine maleate (CPM), diltiazem HCl, theophylline or verapamil HCl] and polymer [Eudragit RS or polymethyl methacrylate (PMMA)] were prepared by soaking the microporous foam carrier with an organic solution of drug and polymer and subsequent drying. The effects of various formulation and processing parameters on the resulting in vitro floating behaviour, internal and external particle morphology, drug loading, in vitro drug release and physical state of the incorporated drug were studied. Good in vitro floating behaviour was observed in most cases and a broad variety of drug release patterns could be achieved by varying the drug loading and type of polymer. Interestingly, PMMA-based microparticles showed incomplete drug release with verapamil HCl. This restriction could be overcome by forming the free base of the drug prior to microparticle preparation. In contrast to the salt, the free base acted as a plasticizer for PMMA, resulting in sufficiently high diffusion coefficients and, consequently, complete drug release. The low density microparticles were compressed into rapidly disintegrating tablets in order to provide an administrable oral dosage form.

Floating matrix tablets based on low density foam powder: effects of formulation and processing parameters on drug release

The aim of this study was to develop and physicochemically characterize single unit, floating controlled drug delivery systems consisting of (i) polypropylene foam powder, (ii) matrix-forming polymer(s), (iii) drug, and (iv) filler (optional). The highly porous foam powder provided low density and, thus, excellent in vitro floating behavior of the tablets. All foam powder-containing tablets remained floating for at least 8 h in 0.1 N HCl at 37 °C. Different types of matrix-forming polymers were studied: hydroxypropyl methylcellulose (HPMC), polyacrylates, sodium alginate, corn starch, carrageenan, gum guar and gum arabic. The tablets eroded upon contact with the release medium, and the relative importance of drug diffusion, polymer swelling and tablet erosion for the resulting release patterns varied significantly with the type of matrix former. The release rate could effectively be modified by varying the “matrix-forming polymer/foam powder” ratio, the initial drug loading, the tablet geometry (radius and height), the type of matrix-forming polymer, the use of polymer blends and the addition of water-soluble or water-insoluble fillers (such as lactose or microcrystalline cellulose). The floating behavior of the low density drug delivery systems could successfully be combined with accurate control of the drug release patterns.

Floating microparticles based on low density foam powder

The aim of this study was to develop a novel multiparticulate gastroretentive drug delivery system and to demonstrate its performance in vitro. Floating microparticles consisting of (i) polypropylene foam powder; (ii) verapamil HCl as model drug; and (iii) Eudragit RS, ethylcellulose (EC) or polymethyl methacrylate (PMMA) as polymers were prepared with an O/W solvent evaporation method. The effect of various formulation and processing parameters on the internal and external particle morphology, drug loading, in vitro floating behavior, in vitro drug release kinetics, particle size distribution and physical state of the incorporated drug was studied. The microparticles were irregular in shape and highly porous. The drug encapsulation efficiency was high and almost independent of the theoretical loading. Encapsulation efficiencies close to 100% could be achieved by varying either the ratio ‘amount of ingredients: volume of the organic phase’ or the relative amount of polymer. In all cases, good in vitro floating behavior was observed. The release rate increased with increasing drug loading and with decreasing polymer amounts. The type of polymer significantly affected the drug release rate, which increased in the following rank order: PMMA<EC<Eudragit RS. A broad spectrum of release patterns could be obtained with the investigated formulations. In contrast, the effect of the volume of the aqueous phase on drug release was not very pronounced. The size of the microparticles was almost independent of the drug loading, but strongly depended on the amount of polymer. The drug was partly dissolved and partly in the amorphous form distributed throughout the system.