Melt solidification technique: Incorporation of higher wax content in ibuprofen beads

The purpose of this study was to achieve incorporation of a higher amount of wax during the preparation of ibuprofen beads by a melt solidification technique for better integrity and prolonged drug release by using a combination of waxes. A mixture of cetyl alcohol (CA) and palmitic acid (PA) was used to improve the matrix integrity and drug release. The effect of variables such as CA, PA, and speed of agitation were studied using 3³ factorial design. Yield, crushing strength, and drug release were analyzed using response surface methodology. The in vitro dissolution test did not show any significant improvement in the drug release. Scanning electron microscopy (SEM) showed that beads were spherical with a smooth surface, but after dissolution became rough and porous. Differential scanning calorimetry (DSC) studies showed that different solidification and erosion properties of waxes are responsible for the inability of waxes to retard drug release even at higher concentration.     

Design of innovated lipid-based floating beads loaded with an antispasmodic drug: in-vitro and in-vivo evaluation

Context: Drotaverine hydrochloride (DRT) is used to treat gastrointestinal spasms accompanied with diarrhoea. Hence, the drug suffers from brief residence in the highly moving intestine during diarrhoea which leads to poor bioavailability and frequent dosing.

Objective: This study aimed to extend DRT residence in the stomach.

Methods: Calcium alginate floating beads were prepared using sodium alginate, isopropylmyristate (oil), and Gelucire® 43/01 (lipid) adopting emulsion gelation technique. The beads were evaluated for their floating ability, DRT entrapment efficiency and in-vitro release. Gelucire® 43/01 /oil-based beads of the selected formula were coated using ethylcellulose and different plasticizers as polyethylene glycol 400 and triethyl citrate to retard the drug release. The coated beads were re-characterized. Finally, the best formulae were investigated for their in-vivo floating ability in dogs besides their delivery to the systemic circulation compared to drug powder in human volunteers.

Results: Incorporation of Gelucire® 43/01 to oil-based beads enhanced the in-vitro performance of the beads. Coated beads prepared using drug:sodium alginate ratio of 1:3 (w/w), 20% (w/v) isopropylmyristate, 20% (w/v) Gelucire® 43/01 showed promising in-vitro performance. The beads floated for 12?h in the dogs’ stomach and produced three-fold increase of the total amount of DRT absorbed within 24?h compared to that of DRT powder.

Conclusions: Gelucire® 43/01 /isopropylmyristate-based calcium alginate floating beads coated with ethylcellulose using either PEG 400 or TEC as plasticizers proved to be a successful dosage form in extending DRT release.     

Effect of Drug Loading Method on Drug Content and Drug Release from Calcium Pectinate Gel Beads

Drug-loaded calcium pectinate gel (CaPG) beads were prepared by either mixing, absorption, or swelling method. The effects of drug loading method as well as the drug loading factors (i.e., drug concentration, soaking time in drug solution, type of solvent) on drug content and drug release were investigated. The amount of drug uptake (i.e., drug content) into CaPG beads increased as the initial drug concentration increased and varied depending on the loading method. The in vitro release studies in 0.1 N hydrochloric acid (HCl) and pH 6.8 buffer indicated that the drug loading method affected drug release and release parameter, time for 50% of drug release (T ₅₀). The mixing method provided a faster drug release and lower T ₅₀ than the absorption method and swelling method, respectively. This is probably due to higher drug content in CaPG beads. The increased concentration of drug in soaking solution and soaking time resulted in higher drug content and thus faster drug release (lower in T ₅₀ values). When using 0.1 N HCl as solvent for soaking instead of water, the drug release was slower owing to the increase in molecular tortuosity of CaPG beads. The drug release was also affected by pH of the release medium in which drug release in 0.1 N HCl was faster than in pH 6.8 buffer.     

Statistical Approach for Assessing the Influence of Calcium Silicate and HPMC on the Formulation of Novel Alfuzosin Hydrochloride Mucoadhesive-Floating Beads as Gastroretentive Drug Delivery Systems

Multiparticulate floating drug delivery systems have proven potential as controlled-release gastroretentive drug delivery systems that avoid the "all or none" gastric emptying nature of single-unit floating dosage forms. An objective of the presence investigation was to develop calcium silicate (CaSi)/calcium alginate (Ca-Alg)/hydroxypropyl methylcellulose (HPMC) mucoadhesive-floating beads that provide time- and site-specific drug release of alfuzosin hydrochloride (Alf). Beads were prepared by simultaneous internal and external gelation method utilizing 3(2) factorial design as an experimental design; with two main factors evaluated for their influence on the prepared beads; the concentration of CaSi as floating aid (X (1)) and the percentage of HPMC as viscosity enhancer and mucoadhesive polymer (X (2)), each of them was tested in three levels. Developed formulations were evaluated for yield, entrapment efficiency, particle size, surface topography, and buoyancy. Differential scanning calorimetry, Fourier transform infrared spectroscopy, in vitro drug release, as well as in vitro mucoadhesion using rat stomach mucosal membrane were also conducted. Percentage yield and entrapment efficiency ranged from 57.03% to 78.51% and from 49.78% to 83.26%, respectively. Statistical analysis using ANOVA proved that increasing the concentration of either CaSi or HPMC significantly increased the beads yield. Both CaSi and HPMC concentrations were found to significantly affect Alf release from the beads. Additionally, higher CaSi concentration significantly increased the beads diameter while HPMC concentration showed significant positive effect on the beads mucoadhesive properties. CaSi/Ca-Alg/HPMC beads represent simple floating-mucoadhesive gastroretentive system that could be useful in chronopharmacotherapy of benign prostatic hyperplasia.     

Investigation of factors influencing drug release using calcium alginate polymer

The effects of mixing, the sodium alginate concentration, and calcium chloride concentration on the release of sulphamethoxazole (model drug) impregnated in calcium alginate beads were investigated and evaluated. The release behaviour of the sulphamethoxazole from the calcium alginate beads was studied in a 0.1N HCl aqueous solution at 37v°C. The release rate of the sulphamethoxazole depends heavily on the type of mixers during the formation of the drug-alginate beads. The highest release rate was achieved when four-bladed rectangular agitator was used while the lowest release was achieved when magnetic stirrer was used. The amount of the released sulphamethoxazole varies slightly with the variation of the alginate concentration. The total release of sulphamethoxazole when 1% w/v solution of sodium alginate was used found to be 80% of the total drug content while 72% and 68% of the total drug content for 1.5% and 2% sodium alginate solutions. Three different calcium chloride concentrations were used (i.e., 5%, 10%, and 15% CaCl₂). The effect of the calcium chloride concentration on the release of the sulphamethoxazole is very pronounced.     

Ionotropically emulsion gelled polysaccharides beads: Preparation,in vitro and in vivo evaluation

Floating famotidine loaded mineral oil-entrapped emulsion gel (MOEG) beads were prepared by the emulsion–gelation method. Different polysaccharides (sodium alginate and pectin), oil concentrations (10%, 20% and 30% w/w) and drug:polymer (D:P) ratios (1:1, 2:1 and 3:1) were used and their influence on beads uniformity, drug entrapment efficiency (DEE) and in vitro drug release, was studied. The results clearly indicated that retardation of drug release for 4 h was achieved by the oil hydrophobic diffusional barrier, especially in the presence of the compact network of alginate beads. Calcium alginate beads containing 20% oil and 2:1 D:P ratio, showed an optimum DEE of 88.32%. When evaluated in vivo, this formula displayed superior antiulcer activity (>2) over drug suspension or marketed conventional tablets.     

Stomach-specific drug delivery of 5-fluorouracil using floating alginate beads

A multiple-unit-type oral floating dosage form (FDF) of 5-fluorouracil (5-FU) was developed to prolong gastric residence time, target stomach cancer, and increase drug bioavailability. The floating bead formulations were prepared by dispersing 5-FU together with calcium carbonate into a mixture of sodium alginate and hydroxypropyl methylcellulose solution and then dripping the dispersion into an acidified solution of calcium chloride. Calcium alginate beads were formed, as alginate undergoes ionotropic gelation by calcium ions and carbon dioxide develops from the reaction of carbonate salts with acid. The evolving gas permeated through the alginate matrix, leaving gas bubbles or pores, which provided the beads buoyancy. The prepared beads were evaluated for percent drug loading, drug entrapment efficiency, image, surface topography, buoyancy, and in vitro release. The formulations were optimized for different weight ratios of gas-forming agent and sodium alginate. The beads containing higher amounts of calcium carbonate demonstrated instantaneous, complete, and excellent floating ability over a period of 24 hours. The optimized formulation was subjected to in vivo antitumor studies to check the therapeutic efficacy of the floating dosage forms containing 5-FU against benzo(a)pyrene-induced stomach tumors in albino female mice (Balb/C strain). The multiple-bead FDF was found to reduce the tumor incidence in mice by 74%, while the conventional tablet dosage form reduced this incidence by only 25%. Results indicate that FDF performed significantly better than the simple tablet dosage form. Published: June 22, 2007     

Characterization of calcium alginate and chitosan-treated calcium alginate gel beads entrapping allyl isothiocyanate

Calcium alginate (CA), chitosan-coated calcium alginate (CCA-I), and chitosan–calcium alginate complex (CCA-II) gel beads, in which an oil-in-water emulsion containing allyl isothiocyanate (AITC) was entrapped, were prepared and characterized for efficient oral delivery of AITC. The AITC entrapment efficiency was 81% for CA gel beads, whereas about 30% lower values were determined for the chitosan-treated gel beads. Swelling studies showed that all the gel beads suddenly shrunk in simulated gastric fluid (pH 1.2). In simulated intestinal fluid (pH 7.4), CA and CCA-I gel beads rapidly disintegrated, whereas CCA-II gel beads highly swelled without degradation probably due to the strong chitosan–alginate complexation. Release studies revealed that most entrapped AITC was released during the shrinkage, degradation, or swelling of the gel beads, and the chitosan treatments, especially the chitosan–alginate complexation, were effective in suppressing the release. CCA-II gel beads showed the highest bead stability and AITC retention under simulated gastrointestinal pH conditions.     

Effect of formulation variables on preparation and evaluation of gelled self-emulsifying drug delivery system (SEDDS) of ketoprofen

The purpose of this study was to formulate a gelled self-emulsifying drug delivery system (SEDDS) containing ketoprofen as an intermediate in the development of sustained release solid dosage form. Captex 200 (an oil), Tween 80 (a surfactant), and Capmul MCM (a cosurfactant) were used to formulate SEDDS. Silicon dioxide was used as a gelling agent, which may aid in solidification and retardation of drug release. Effect of concentrations of cosurfactant and gelling agent on emulsification process and in vitro drug diffusion was studied using 3² factorial design. Multiple regression analysis data and response surfaces obtained showed that liquid crystal phase viscosity increased significantly with increasing amount of silicon dioxide, which in turn caused an increase in average droplet size of resultant emulsion and slower drug diffusion. Drug release from the formulation increased with increasing amount of cosurfactant.     

Development of Gelucire 43/01 Beads of Metformin Hydrochloride for Floating Delivery

The objective of this study was to prepare and characterize beads of Gelucire 43/01 for floating delivery of metformin hydrochloride (MH). The beads were evaluated for particle size, surface morphology, percent drug entrapment, percent yield, differential scanning calorimetry (DSC), in vitro floating ability, and in vitro drug release. Aging effect on storage was evaluated using hot stage microscopy (HSM), DSC, scanning electron microscopy, and in vitro floating ability. The formed beads were sufficiently hard and spherical in shape. Photomicrographs show that the surface was porous in nature. The average particle diameter of beads was found to be in the size range of 3.85 to 3.95 mm, and percent entrapment was 83.07% to 86.13%. The beads demonstrated favorable in vitro floating ability. The analysis of DSC thermograms revealed no physical interaction between the lipid and the drug in the prepared beads. Prepared formulations showed better controlled release behavior when compared with its conventional dosage form and comparable release profile with marketed sustained release product. HSM photomicrograph showed presence of some unmelted portion even at 43°C and completely melts on 51°C in aged sample. It was found that there was no significant effect on floating ability of aged beads since it remains floats up to 8 h study period. Thus, it is concluded that beads of Gelucire 43/01 could be serve as an effective carrier for highly water-soluble antihyperglycemic drugs like MH for the controlled delivery.     

Effect of hydroxypropyl methylcellulose and hydrogenated castor oil on naproxen release from sustained-release tablets

The effect of the concentration of hydrophilic (hydroxypropyl methylcellulose [HPMC]) and hydrophobic (hydrogenated castor oil [HCO]) products, fillers (lactose and dibasic calcium phosphate), and buffers (sodium bicarbonate, calcium carbonate, and sodium citrate) on naproxen release rate was studied. Matrix tablets were prepared by double compression, andIn vitro dissolution tests were performed. The dissolution results showed that an increased amount of HPMC or hydrogenated castor oil resulted in reduced drug release. The inclusion of buffers in the HPMC matrix tablets enhanced naproxen release. For HCO tablets, only sodium bicarbonate enhanced naproxen release. The presence of lactose on HPMC matrix tablets did not show a significantly different result from that obtained with the formulation containing dibasic calcium phosphate as a filler. However, for the tablets containing HCO, the presence of lactose significantly enhanced the naproxen release rate. The matrix-forming materials in this study were suitable for use in sustained-release tablets containing naproxen. The drug release can be modulated by adding suitable amounts of diluents and buffers.     

Ontogenetic variation in chemical and physical characteristics of adaxial apple leaf surfaces

The reaction of plants to environmental factors often varies with developmental stage. It was hypothesized, that also the cuticle, the outer surface layer of plants is modified during ontogenesis. Apple plantlets, cv. Golden Delicious, were grown under controlled conditions avoiding biotic and abiotic stress factors. The cuticular wax surface of adaxial apple leaves was analyzed for its chemical composition as well as for its micromorphology and hydrophobicity just after unfolding of leaves ending in the seventh leaf insertion. The outer surface of apple leaves was formed by a thin amorphous layer of epicuticular waxes. Epidermal cells of young leaves exhibited a distinctive curvature of the periclinal cell walls resulting in an undulated surface of the cuticle including pronounced lamellae, with the highest density at the centre of cells. As epidermal cells expanded during ontogenesis, the upper surface showed only minor surface sculpturing and a decrease in lamellae. With increasing leaf age the hydrophobicity of adaxial leaf side decreased significantly indicated by a decrease in contact angle. Extracted from plants, the amount of apolar cuticular wax per area unit ranged from only 0.9 microgcm(-2) for the oldest studied leaf to 1.5 microgcm(-2) for the youngest studied leaf. Differences in the total amount of cuticular waxes per leaf were not significant for older leaves. For young leaves, triterpenes (ursolic acid and oleanolic acid), esters and alcohols were the main wax components. During ontogenesis, the proportion of triterpenes in total mass of apolar waxes decreased from 32% (leaf 1) to 13% (leaf 7); absolute amounts decreased by more than 50%. The proportion of wax alcohols and esters, and alkanes to a lesser degree, increased with leaf age, whereas the proportion of acids decreased. The epicuticular wax layer also contained alpha-tocopherol described for the first time to be present also in the epicuticular wax. The modifications in the chemical composition of cuticular waxes are discussed in relation to the varying physical characteristics of the cuticle during ontogenesis of apple leaves.     

Effect of a small molecule on diffusion and swelling properties of selected polysaccharide gel beads

The effect of a small molecule (e.g., sodium fluorescein, SF) on the swelling properties of and diffusion from calcium polysaccharide (alginate or pectin) gel beads was investigated. The gel beads were prepared by ionotropic gelation, soaked in different concentrations of SF solution, and then dried. The swelling behavior and release of SF from the dried beads were investigated. After soaking in SF, the beads swelled to sizes that depended on the initial concentration of SF. However, the size of the dried beads was independent of the SF concentration. The swelling of the beads occurred quite rapidly and reached a maximum within 2 h. Although most beads swelled to a size which was less than their original size of wet beads, some of them swelled much more than their original wet size. Higher concentration of SF and lower concentration of sodium alginate provided a greater increase in weight. The release profile of SF from dried gel beads in water consists of a burst or a very rapid release phase during the first 60 min followed by a much slower release phase. The similarity of the relative weight increase and release profiles of SF, suggests that swelling might contribute to release of SF, particularly during the burst phase.     

Novel Strategy to Fabricate Floating Drug Delivery System Based on Sublimation Technique

The present study aims to develop floating drug delivery system by sublimation of ammonium carbonate (AMC). The core tablets contain a model drug, hydrochlorothiazide, and various levels (i.e., 0–50% w/w) of AMC. The tablets were then coated with different amounts of the polyacrylate polymers (i.e., Eudragit® RL100, Eudragit® RS100, and the mixture of Eudragit® RL100 and Eudragit® RS100 at 1:1 ratio). The coated tablets were kept at ambient temperature (25°C) or cured at 70°C for 12 h before further investigation. The floating and drug release behaviors of the tablets were performed in simulated gastric fluid USP without pepsin at 37°C. The results showed that high amount of AMC induced the floating of the tablets. The coated tablets containing 40 and 50% AMC floated longer than 8 h with a time-to-float of about 3 min. The sublimation of AMC from the core tablets decreased the density of system, causing floating of the tablets. The tablets coated with Eudragit® RL100 floated at a faster rate than those of Eudragit® RS100. Even the coating level of polymer did not influence the time-to-float and floating time of coated tablets containing the same amount of AMC, the drug release from the tablets coated with higher coating level of polymer showed slower drug release. The results suggested that the sublimation technique using AMC is promising for the development of floating drug delivery system.     

Formulation of Controlled-Release Baclofen Matrix Tablets II: Influence of Some Hydrophobic Excipients on the Release Rate and In Vitro Evaluation

The aim of this study was to investigate the influence of polymer level and type of some hydrophobic polymers, including hydrogenated castor oil (HCO); Eudragit RS100 (E-RS100); Eudragit L100 (E-L100), and some fillers namely mannitol [soluble filler], Dibasic calcium phosphate dihydrate (Emcompress) and anhydrous dibasic calcium phosphate [insoluble fillers] on the release rate and mechanism of baclofen from matrix tablets prepared by a hot-melt granulation process (wax tablets) and wet granulation process (E-RS100 and E-L100 tablets). Statistically significant differences were found among the drug release profile from different classes of polymeric matrices. Higher polymeric content (40%) in the matrix decreased the release rate of drug because of increased tortuosity and decreased porosity. At lower polymeric level (20%), the rate and extent of drug release was elevated. HCO was found to cause the strongest retardation of drug. On the other hand, replacement of Emcompress or anhydrous dibasic calcium phosphate for mannitol significantly retarded the release rate of baclofen, except for E-L100 (pH-dependent polymer). Emcompress surface alkalinity and in-situ increase in pH of the matrix microenvironment enhanced the dissolution and erosion of these matrix tablets. The release kinetics was found to be governed by the type and content of the excipients (polymer or filler). The prepared tablets showed no significant change in drug release rate when stored at ambient room conditions for 6 months.     

Development of cloxacillin loaded multiple-unit alginate-based floating system by emulsion-gelation method

This work investigates the development, optimization and in vitro evaluation of liquid paraffin-entrapped multiple-unit alginate-based floating system containing cloxacillin by emulsion-gelation method for gastro retentive delivery. The effect of process variables like drug to polymer ratio by weight, and liquid paraffin to water ratio by volume on various physicochemical properties in case of liquid paraffin-entrapped calcium alginate beads containing cloxacillin applicable to drug entrapment efficiency, density and drug release was optimized using 3² factorial design and analyzed using response surface methodology. The observed (actual values) responses were coincided well with the predicted values, given by the optimization technique. The optimized beads showed drug entrapment efficiency of 64.63 ± 0.78%, density of 0.90 ± 0.05 g/cm³, and drug release of 56.72 ± 0.85% in simulated gastric fluid (pH 1.2) after 8 h with floating lag time of 8.45 min and floated well over 12 h in simulated gastric fluid (pH 1.2). The average size of all dried beads ranged from 1.73 ± 0.04 to 1.97 ± 0.08 mm. The beads were characterized by SEM and FTIR for surface morphology and excipients-drug interaction analysis, respectively. All these beads showed prolonged sustained release of cloxacillin over 8 h in simulated gastric fluid (pH 1.2). The cloxacillin release profile from liquid paraffin beads followed Korsmeyer-Peppas model over a period of 8 h with anomalous (non-Fickian) diffusion mechanism for drug release.     

甘蓝型油菜叶表皮蜡质组分及结构与菌核病抗性关系

本试验选用6个抗病性不同的甘蓝型油莱品种,研究其叶表皮蜡质组成及结构与菌核病抗性的关系。结果表明,抗病品种在去除叶表皮蜡质后病情指数显著增加;感病品种无显著变化。不同抗性品种（系）间除酯类组分含量无显著差异外,其余蜡质组分含量差异显著。相关分析表明,蜡质组分中酯类含量与病情指数呈显著负相关关系,醇类、酮类含量与病情指数呈显著正相关,其余组分和蜡质总量与病情指数无显著相关关系。抗性品种叶表皮蜡质中烷类及酯类所占比重较高,而易感品种酮类比重较高。扫描电镜结果显示,抗病品种（系）的蜡质晶体主要为颗粒状、杆状、丝状;而感病品种（系）的蜡质晶体中不规则片状晶体所占比例较大。这些结果说明油菜叶表皮蜡质的组分及结构可能是抗病品种抵抗和延迟病原菌侵入的机制之一。     

Artemisia arborescens L essential oil loaded beads: Preparation and characterization

The purpose of this work was to prepare sodium alginate beads as a device for the controlled release of essential oil for oral administration as an antiviral agent. Different formulations were prepared with sodium alginate as a natural polymer and calcium chloride or glutaraldehyde as a cross-linking agent. Loading capacities of between 86% and 100% were obtained in freshly prepared beads by changing exposure time to the cross-linking agent. Drying of the calcium alginate beads caused only a slight decrease in the loading efficiency. The surface morphology of the different bead formulations were studied using scanning electron microscopy (SEM). Stability studies over a 3-month period showed that glutaraldehyde reacted with some components ofArtemisia arborescens L essential oil, changing its composition. Calcium alginate beads showed an in vitro controlled release of the essential oil for the investigated 24 hours, while the use of glutaraldehyde as a cross-linking agent was found not appropriate because of the interactions with azulene derivatives and the low degree of matrix cross-linkage. Published: August 24, 2007     

Changes in leaf cuticular waxes of sesame (Sesamum indicum L.) plants exposed to water deficit

Sesame (Sesamum indicum L.) is one of the most important oilseed crops, having seeds and oil that are highly valued as a traditional health food. The objective of this study was to evaluate leaf cuticular wax constituents across a diverse selection of sesame cultivars, and the responses of these waxes to drought-induced wilting. Water-deficit was imposed on 18 sesame cultivars by withholding irrigation for 15d during the post-flowering stage, and the effect on seed yield and leaf waxes compared with a well-watered control. Leaf cuticular waxes were dominated by alkanes (59% of total wax), with aldehydes being the next-most abundant class. Compared to well-irrigated plants, drought treatment caused an increase in wax amount on most cultivars, with only three cultivars having a notable reduction. When expressed as an average across all cultivars, drought treatment caused a 30% increase in total wax amount, with a 34% increase in total alkanes, a 13% increase in aldehydes, and a 28% increase in the total of unknowns. In all cultivars, the major alkane constituents were the C27, C29, C31, C33, and C35 homologs, whereas the major aldehydes were the C30, C32, and C34 homologs, and drought exposure had only minor effects on the chain length distribution within these and other wax classes. Drought treatments caused a large decrease in seed yield per plant, but did not affect the mean weight of individual seeds, showing that sesame responds to post-flowering drought by reducing seed numbers, but not seed size. Seed yield was inversely correlated with the total wax amount (-0.466*), indicating that drought induction of leaf wax deposition does not contribute directly to seed set. Further studies are needed to elucidate the ecological role for induction of the alkane metabolic pathway by drought in regulating sesame plant survival and seed development in water-limiting environments.     

Oxycellulose Beads with Drug Exhibiting pH-Dependent Solubility

The aim of this study was to develop novel hydrogel-based beads and characterize their potential to deliver and release a drug exhibiting pH-dependent solubility into distal parts of gastrointestinal (GI) tract. Oxycellulose beads containing diclofenac sodium as a model drug were prepared by the ionotropic external gelation technique using calcium chloride solution as the cross-linking medium. Resulting beads were characterized in terms of particle shape and size, encapsulation efficacy, swelling ability and in vitro drug release. Also, potential drug–polymer interactions were evaluated using Fourier transform infrared spectroscopy. The particle size was found to be 0.92–0.96 mm for inactive (oxycellulose only) and 1.47–1.60 mm for active (oxycellulose–diclofenac sodium) beads, respectively. In all cases, the sphericity factor was between 0.70 and 0.81 with higher values observed for samples containing higher polymer and drug concentrations. The swelling of inactive beads was found to be strongly influenced by the pH and composition (i.e. Na⁺ concentration) of the selected media (simulated gastric fluid vs. phosphate buffer pH 6.8). The encapsulation efficiency of the prepared particles ranged from 58% to 65%. Results of dissolution tests showed that the drug loading inside of the particles influenced the rate of its release. In general, prepared particles were able to release the drug within 12–16 h after a lag time of 4 h. Fickian diffusion was found as the predominant drug release mechanism. Thus, this novel particulate system showed a good potential to deliver drugs specifically to the distal parts of the human GI tract.