Design of a novel bilayered gastric mucoadhesive system for localized and unidirectional release of lamotrigine

Physicochemical Characterization and Evaluation of Ficus vasta Gum as a Binder in Tablet Formulation

Binders are ingredients used in tablet granulation process for tablet cohesiveness which confirms that the tablet remains intact after compression. Natural gums have been employed as disintegrants, emulsifying agents, suspending agents, and binders in tablets. Even though Ficus vasta gum is claimed as a possible pharmaceutical excipient by some phytochemical studies, literature is scanty on its efficacy as a tablet binder. The purpose of this study was to isolate, characterize, and comparatively evaluate Ficus vasta gum as a potential binder in tablet formulation. Gum was extracted from Ficus vasta tree, characterized for physicochemical properties, and applied as a binder in paracetamol granule and tablet formulation. Granules were prepared using 4%, 6%, 8%, and 10% w/w concentration of the gum and standard binders (polyvinylpyrrolidone K-30 and Starch@1500) by wet granulation. The formulated tablets were then evaluated for tablet quality parameters, and comparison between the test and standard binders was done by ANOVA. The dried crude gum yielded 50.63% (w/w) of a brownish yellow purified gum. The angle of repose, Carr's index, and the Hausner ratio all complied with the pharmacopoeial recommendations. The gum is compatible with the model drug, paracetamol. The paracetamol granules prepared with Ficus gum binder demonstrated an optimum size range and size distribution with substantial flow and compressibility properties. Ficus gum binder demonstrated significantly higher disintegration time and strength properties than that of similar concentrations of Starch@1500 but lower than polyvinylpyrrolidone (p < 0.05). Ficus gum has better binding properties than starch but lower than polyvinylpyrrolidone. Hence, Ficus vasta gum can be used as an alternative tablet binder in tablet manufacturing.

Exorbitant Drug Loading of Metformin and Sitagliptin in Mucoadhesive Buccal Tablet: In Vitro and In Vivo Characterization in Healthy Volunteers

The aim of the proposed study is to develop a mucoadhesive buccal delivery system for the sustained delivery of metformin (MET) and sitagliptin (SIT) against diabetes mellitus (DM) with improved bioavailability. Polymeric blend of Carbopol® 940 (CP), agarose (AG) or polyvinylpyrrolidone K30 (PVP) as mucoadhesive agents in formulations (R1-R15) were compressed via the direct compression technique. Tablets were characterized for solid state studies, physicochemical and in vivo mucoadhesion studies in healthy volunteers. Outcomes did not reveal any unusual peak or interaction between the drugs and polymers in the physical mixture through Fourier Transform Infrared Spectroscopy (FTIR) and DSC analysis. The mucoadhesive blend of CP and PVP was superior compared to other blends. The formulation R4 revealed exorbitant loading of drugs with complete drug release for 6 h with ex vivo mucoadhesive strength and time of 26.99 g and 8.1 h, respectively. It was further scrutinized to evaluate it as an optimized formulation where it was found to be stable for up to 6 months. The formulation R4 depicted Korsmeyer-Peppas model and first-order mode of release correspondingly for SIT and MET. Moreover, it showed hemocompatibility, biocompatibility and stability with non-significant changes in the dissolution profile. Overall, the CP blend with PVP was found appropriate to yield the desired release coupled with the optimized mucoadhesive properties of the buccal tablets, ensuring sufficient pharmaceutical stability.

Investigation of the Absorption of Nanosized lamotrigine Containing Nasal Powder via the Nasal Cavity

Nasal drug delivery has become a popular research field in the last years. This is not surprising since the nose possesses unique anatomical and physical properties. Via the nasal mucosa local, systemic, and directly central nerve systemic (CNS) effect is achievable. Powders have favorable physicochemical properties over liquid formulations. Lamotrigine (LAM) is an antiepileptic agent with a relatively mild side effect spectrum, but only available in tablet form on market. Reducing the particle size to the nano range can affect the bioavailability of pharmaceutical products. The aim of this article was to continue the work started, compare the in vitro properties of a nanonized lamotrigine containing nasal powder (nanoLAMpowder) and its physical mixture (PM) that were prepared by dry milling. Moreover, to study their trans-epithelial absorption to reach the blood and target the brain by axonal transport. Due to the dry milling technique, the particle size of LAM, their surface and also their structure changed that led to higher in vitro dissolution and permeability rate. The results of the in vivo tests showed that the axonal transport of the drug was assumable by both intranasal formulations because the drug was present in the brain within a really short time, but the LAM from the nanoLAMpowder liberated even faster.

Chronological Delivery of Antihypertensive Drugs in Bilayered Core-in-Cup Buccoadhesive Tablets: In Vitro and In Vivo Evaluation

Hypertension shows circadian blood pressure rhythms (day-night pattern) that urge the delivery of antihypertensive drugs at the right time in the desired levels. Thus, a bilayered core-in-cup buccoadhesive tablet was formulated that immediately releases olmesartan, to give a burst effect, and controls azelnidipine release, to prolong its therapeutic effect. The main challenge was the poor bioavailability of azelnidipine due to its poor aqueous solubility and first-pass effect. Hence, liquisolid compact buccoadhesive tablets were prepared to enhance solubility, dissolution profiles, and bypass the oral route. Two factorial designs were conducted to study the type and concentration effect of the mucoadhesive polymers on the dissolution and mucoadhesion of olmesartan and azelnidipine. Characterization studies were conducted regarding drug content, surface pH, water uptake, mucoadhesive strength, in vitro release, and ex vivo permeability. The core-in-cup olmesartan/azelnidipine buccoadhesive tablet showed similar release profile to the statistically optimized formulae of each drug. In vitro dissolution study showed enhanced release of azelnidipine than the directly compressed tablets, to comply with the regulatory standards of controlled release systems. In vivo pharmacokinetic study of olmesartan and azelnidipine conducted on human volunteers against Rezaltas® 10/8 mg tablet showed percentage relative bioavailability of 106.12 and 470.82%, respectively. Graphical Abstract.

Functional nanocarrier for drug and gene delivery via local administration in mucosal tissues

Local administration has many advantages for treating diseases. However, the surface mucus layer becomes a major obstacle that easily traps and fast removes local administrated drugs and genes in mucosal tissues. Fortunately, the rapidly developing nanocarriers with special physical and chemical properties may help to refine the treatment of mucosal tissues via delivering drugs and genes to the target tissue, and prolong the drug action time. Therefore, this review focuses on the strategies to apply different nanocarriers for drug-delivery in mucosal tissues, including mucoadhesive and mucus-penetrating types. Delivering drugs and genes to anatomical sites with high mucus turnover becomes more feasible and effective, and maintains sufficient local drug concentration to improve treatment efficacy.

Preliminary study of nanonized lamotrigine containing products for nasal powder formulation

The nasal delivery of drugs offers a great alternative route to avoid adverse events and to increase patient compliance due to its advantageous properties. Besides nasal application, topical, systemic and central effects are also available. Nasal powders (NPs) have better adhesion due to the additive polymers that may be, eg, gelling or good wettability agents; thus, their bioavailability is better compared to the liquid formulations. Using nanoparticles, innovative and more efficient products can be achieved, which may lead to the improvement of different therapies. The aim of this study was to produce NP formulations containing lamotrigine (LAM) as interactive physical mixtures and nanosized LAM-based formulations. After risk assessment of the preliminary tests, the micrometric properties (particle size and morphology) and the structural properties (differential scanning calorimetry [DSC], X-ray powder diffraction [XRPD]) were investigated; thereafter, physicochemical properties (solubility, polarity) and in vitro dissolution and diffusion profiles were also examined. These product samples showed an appropriate particle size ranging 10–25 µm, while the particle size of LAM in the products was between 120 and 230 nm and the dissolved amount of drug was >60% after 5 minutes in these cases.

Polymeric micelles, a promising drug delivery system to enhance bioavailability of poorly water-soluble drugs

Oral administration is the most commonly used and readily accepted form of drug delivery; however, it is find that many drugs are difficult to attain enough bioavailability when administered via this route. Polymeric micelles (PMs) can overcome some limitations of the oral delivery acting as carriers able to enhance drug absorption, by providing (1) protection of the loaded drug from the harsh environment of the GI tract, (2) release of the drug in a controlled manner at target sites, (3) prolongation of the residence time in the gut by mucoadhesion, and (4) inhibition of efflux pumps to improve the drug accumulation. To explain the mechanisms for enhancement of oral bioavailability, we discussed the special stability of PMs, the controlled release properties of pH-sensitive PMs, the prolongation of residence time with mucoadhesive PMs, and the P-gp inhibitors commonly used in PMs, respectively. The primary purpose of this paper is to illustrate the potential of PMs for delivery of poorly water-soluble drugs with bioavailability being well maintained.