Optimization and Evaluation of Gastroretentive Ranitidine HCl Microspheres by Using Factorial Design with Improved Bioavailability and Mucosal Integrity in Ulcer Model

Chitosan/hydroxypropylmethylcellulose based-mucoadhesive gastroretentive microparticles containing curcumin intended for the prevention of gastric ulcers

Gastric ulcer (GU) is a disease characterized by ulcerative lesions on the surface of the stomach mucosa caused mainly by health-related conditions, non-steroidal anti-inflammatory drugs (NSAIDs) use, and Helicobacter pylori infections. The treatment for this disease requires that the drug remains in contact with the site of action, however, the residence time of conventional dosage forms in this organ is limited due to gastric emptying. Curcumin (CUR) is a compound obtained from the rhizomes of the Curcuma longa plant and has been used in traditional Indian medicine for many centuries. However, its use is limited because it has low solubility in aqueous media. In addition, the treatment of gastric diseases requires the drug to remain in contact with the area, but the residence time of conventional dosage forms in this organ is limited. One strategy to overcome these limitations is the use of a gastroretentive and mucoadhesive delivery system. Therefore, this study aimed to develop polymeric chitosan and hydroxypropylmethylcellulose-based microparticles for the release of CUR and to evaluate their in vivo gastroprotective action. The microparticles had a spherical shape and size between 620 and 820 µm, and the encapsulation efficiency was over 50 %, with complete release of CUR after 24 h. Thermal analysis showed changes in the structure of the polymers and CUR, suggesting the establishment of new supramolecular interactions. Microparticles showed high bioadhesive forces to the mucin disc. This set of results, suggest that these systems are promising tools for the prevention of gastric lesions associated with the use of NSAIDs, with a gastroprotective index similar to that conferred by omeprazole.

Utilizing 4D Printing to Design Smart Gastroretentive, Esophageal, and Intravesical Drug Delivery Systems

The breakthrough of 3D printing in biomedical research has paved the way for the next evolutionary step referred to as four dimensional (4D) printing. This new concept utilizes the time as the fourth dimension in addition to the x, y, and z axes with the idea to change the configuration of a printed construct with time usually in response to an external stimulus. This can be attained through the incorporation of smart materials or through a preset smart design. The 4D printed constructs may be designed to exhibit expandability, flexibility, self-folding, self-repair or deformability. This review focuses on 4D printed devices for gastroretentive, esophageal, and intravesical delivery. The currently unmet needs and challenges for these application sites are tried to be defined and reported on published solution concepts involving 4D printing. In addition, other promising application sites that may similarly benefit from 4D printing approaches such as tracheal and intrauterine drug delivery are proposed.

A Full Factorial Design to Optimize Aminexil Nano Lipid Formulation to Improve Skin Permeation and Efficacy Against Alopecia

Aminexil (AMX) is considered to be one of the most widely used hair growth promoters. Nanostructured lipid carriers (NLC) are employed to increase the permeation of both lipophilic and hydrophilic drugs. Aminexil nanostructured lipid carrier (NLC) designed by pre-emulsion/ultrasonication method was utilized for alopecia treatment. For selecting optimum excipients, a solubility study was executed in liquid lipids, solid lipids, surfactants, and co-surfactants. A 2³ full factorial design was utilized for NLC optimization. Characterization of the developed formulas was performed. The penetration of the optimized formula across cuticle tissues was studied using confocal laser scanning microscopy (CLSM). AMX showed high solubility in glyceryl monostearate (GMS) and stearic acid, 28.87 ± 2.17 and 58.06 ± 2.227 mg/g, respectively. The results of physicochemical characterization showed that formula A7 was the optimized one. It is composed of GMS (solid lipid), oleic acid:garlic oil (1:1 v/v) (liquid lipid), and a surfactant/co-surfactant mixture (Cremophor EL/Transcutol HP). The particle size (PS) was 238.0 ± 2.13 nm, entrapment efficiency (EE) 100.535 ± 6.73%, and zeta potential (ZP) - 29.3 ± 0.93 mv. Ex vivo permeation study demonstrates the potential of AMX-NLC (formula A7) as a delivery system for AMX. The CLSM highly proved AMX-loaded NLC penetration through the skin. The histological study clearly demonstrated that AMX-loaded NLC promoted hair growth more effectively than the market product in chemotherapy-induced alopecia rats. The acquired findings revealed that targeting of AMX-loaded NLC into hair follicles was improved.

Gastroretentive Sustained-Release Tablets Combined with a Solid Self-Micro-Emulsifying Drug Delivery System Adsorbed onto Fujicalin®

Gastroretentive drug delivery systems (GRDDS) get retained in the stomach for a long time, thus facilitating the absorption of drugs in the upper gastrointestinal tract. However, drugs that are difficult to dissolve or unstable in an acidic environment are not suitable for GRDDS. The current study designs GRDDS combined with a self-micro-emulsifying drug delivery system (SMEDDS) for drugs with solubility or stability problems in the stomach. The model drug fenofibrate was formulated into the optimized liquid SMEDDS composed of 50 w/w% Capryol^® PGMC, 40 w/w% Kolliphor^® RH40, and 10 w/w% Transcutol^® HP and solidified through adsorption on several porous adsorbents. In a dissolution medium at pH 1.2, the powdered SMEDDS using Fujicalin^® dissolved quickly and achieved higher drug dissolution than other adsorbents. Based on these results, a gastroretentive bilayer tablet consisting of a drug release layer and a swelling layer was designed. The drug release layer was formulated with the powdered SMEDDS and hydroxypropyl methylcellulose (HPMC) as a release modifier. HPMC was also added to the swelling layer as a water-swellable polymer. The dissolution rate depended on the viscosity of the HPMC in the drug release layer. The time for 90% drug release was extended from 3.7 to 12.0 h by increasing the viscosity grade of HPMC from 0.1 to 100 K. Moreover, the tablet swelled and maintained a size comparable to a human pylorus diameter or more for at least 24 h. This GRDDS could apply to a broader range of drug candidates.

Cellulosic Polymers for Enhancing Drug Bioavailability in Ocular Drug Delivery Systems

One of the major impediments to drug development is low aqueous solubility and thus poor bioavailability, which leads to insufficient clinical utility. Around 70–80% of drugs in the discovery pipeline are suffering from poor aqueous solubility and poor bioavailability, which is a major challenge when one has to develop an ocular drug delivery system. The outer lipid layer, pre-corneal, dynamic, and static ocular barriers limit drug availability to the targeted ocular tissues. Biopharmaceutical Classification System (BCS) class II drugs with adequate permeability and limited or no aqueous solubility have been extensively studied for various polymer-based solubility enhancement approaches. The hydrophilic nature of cellulosic polymers and their tunable properties make them the polymers of choice in various solubility-enhancement techniques. This review focuses on various cellulose derivatives, specifically, their role, current status and novel modified cellulosic polymers for enhancing the bioavailability of BCS class II drugs in ocular drug delivery systems.

Gastroretentive Technologies in Tandem with Controlled-Release Strategies: A Potent Answer to Oral Drug Bioavailability and Patient Compliance Implications

There have been many efforts to improve oral drug bioavailability and therapeutic efficacy and patient compliance. A variety of controlled-release oral delivery systems have been developed to meet these needs. Gastroretentive drug delivery technologies have the potential to achieve retention of the dosage form in the upper gastrointestinal tract (GIT) that can be sufficient to ensure complete solubilisation of the drugs in the stomach fluids, followed by subsequent absorption in the stomach or proximal small intestine. This can be beneficial for drugs that have an “absorption window” or are absorbed to a different extent in various segments of the GIT. Therefore, gastroretentive technologies in tandem with controlled-release strategies could enhance both the therapeutic efficacy of many drugs and improve patient compliance through a reduction in dosing frequency. The paper reviews different gastroretentive drug delivery technologies and controlled-release strategies that can be combined and summarises examples of formulations currently in clinical development and commercially available gastroretentive controlled-release products. The different parameters that need to be considered and monitored during formulation development for these pharmaceutical applications are highlighted.

Formulation, optimization and characterization of allantoin-loaded chitosan nanoparticles to alleviate ethanol-induced gastric ulcer: in-vitro and in-vivo studies

Allantoin (ALL) is a phytochemical possessing an impressive array of biological activities. Nonetheless, developing a nanostructured delivery system targeted to augment the gastric antiulcerogenic activity of ALL has not been so far investigated. Consequently, in this survey, ALL-loaded chitosan/sodium tripolyphosphate nanoparticles (ALL-loaded CS/STPP NPs) were prepared by ionotropic gelation technique and thoroughly characterized. A full 24 factorial design was adopted using four independently controlled parameters (ICPs). Comprehensive characterization, in vitro evaluations as well as antiulcerogenic activity study against ethanol-induced gastric ulcer in rats of the optimized NPs formula were conducted. The optimized NPs formula, (CS (1.5% w/v), STPP (0.3% w/v), CS:STPP volume ratio (5:1), ALL amount (13 mg)), was the most convenient one with drug content of 6.26 mg, drug entrapment efficiency % of 48.12%, particle size of 508.3 nm, polydispersity index 0.29 and ζ-potential of + 35.70 mV. It displayed a sustained in vitro release profile and mucoadhesive strength of 45.55%. ALL-loaded CS/STPP NPs (F-9) provoked remarkable antiulcerogenic activity against ethanol-induced gastric ulceration in rats, which was accentuated by histopathological, immunohistochemical (IHC) and biochemical studies. In conclusion, the prepared ALL-loaded CS/STPP NPs could be presented to the phytomedicine field as an auspicious oral delivery system for gastric ulceration management.

Oral administration of natural polyphenol-loaded natural polysaccharide-cloaked lipidic nanocarriers to improve efficacy against small-cell lung cancer

Oral administration shows good tolerance in patients. Botanic anticancer drugs without serious side effects have attracted increased attention worldwide. However, oral delivery of natural anticancer drugs faces great challenges due to low solubility, gastrointestinal side effects, first-pass effects, and P-glycoprotein efflux. Here, we loaded the natural polyphenol curcumin (Cc) into natural polysaccharide-cloaked lipidic nanocarriers (Cc@CLNs) to improve the efficacy in small-cell lung cancer (SCLC) associated with oral administration. Compared to other nanoformulations, Cc@CLNs have advantages of simple operation, easy scale-up, low cost, and high safety. Cc@CLNs improve bioavailability by inducing synergistic effects (efficient cell membrane penetration, inherent muco-adhesiveness, resistance to pepsin and trypsin degradation, promoted dissolution, enhanced epithelia/M cellular uptake and inhibition of efflux transporters) and countering the tendency of nanocarriers to aggregate and fuse, which limit lipid-based nanosystems. In this study, we first evaluated the oral bioavailability of Cc@CLNs in rats and their efficacy in H446 tumor-bearing mice. The oral bioavailability increased by 8.94-fold, and the tumor growth inhibition rate doubled compared to that achieved with free Cc. We investigated the action of Cc against SCLC stem cells, and Cc@CLNs greatly enhanced this action. The expression of CD133 and ABCG2 in the Cc@CLNs group decreased by 38.05% and 32.57%, respectively, compared to the respective expression levels in the control.

Modulation of the Release of a Non-Interacting Low Solubility Drug from Chitosan Pellets Using Different Pellet Size, Composition and Numerical Optimization

Two size classes of piroxicam (PXC) pellets (mini (380–550 μm) and conventional (700–1200 μm)) were prepared using extrusion/spheronization and medium viscosity chitosan (CHS). Mixture experimental design and numerical optimization were applied to distinguish formulations producing high sphericity pellets with fast or extended release. High CHS content required greater wetting liquid volume for pellet formation and the diameter decreased linearly with volume. Sphericity increased with CHS for low-to-medium drug content. Application of PXRD showed that the drug was a mixture of form II and I. Crystallinity decreased due to processing and was significant at 5% drug content. Raman spectroscopy showed no interactions. At pH 1.2, the dissolved CHS increased ‘apparent’ drug solubility up to 0.24 mg/mL while, at pH 5.6, the suspended CHS increased ‘apparent’ solubility to 0.16 mg/mL. Release at pH 1.2 was fast for formulations with intermediate CHS and drug levels. At pH 5.6, conventional pellets showed incomplete release while mini pellets with a CHS/drug ratio ≥2 and up to 21.25% drug, showed an extended release that was completed within 8 h. Numerical optimization provided optimal formulations for fast release at pH 1.2 with drug levels up to 40% as well as for extended release formulations with drug levels of 5% and 10%. The Weibull model described the release kinetics indicating complex or combined release (parameter ‘b’ > 0.75) for release at pH 1.2, and normal diffusion for the mini pellets at pH 5.6 (‘b’ from 0.63 to 0.73). The above results were attributed mainly to the different pellet sizes and the extensive dissolution/erosion of the gel matrix was observed at pH 1.2 but not at pH 5.6.

Preparation and evaluation of gastro-floating hollow adhesive microspheres of carbomer/ethyl cellulose encapsulating dipyridamole

Gastro-floating hollow adhesive microspheres of Carbomer/ethyl cellulose encapsulating dipyridamole were fabricated and evaluated in vitro and in vivo.