A Micro-In-Macro Gastroretentive System for the Delivery of Narrow-Absorption Window Drugs.

A micro-in-macro gastroretentive and gastrofloatable drug delivery system (MGDDS), loaded with the model-drug ciprofloxacin, was developed in this study to address the limitations commonly experienced in narrow-absorption window (NAW) drug delivery. The MGDDS, which consists of microparticles loaded in a gastrofloatable macroparticle (gastrosphere) was designed to modify the release of ciprofloxacin, allowing for an increased drug absorption via the gastrointestinal tract. The prepared inner microparticles (1-4 µm) were formed by crosslinking chitosan (CHT) and Eudragit® RL 30D (EUD), with the outer gastrospheres prepared from alginate (ALG), pectin (PEC), poly(acrylic acid) (PAA) and poly(lactic-co-glycolic) acid (PLGA). An experimental design was utilized to optimize the prepared microparticles prior to Fourier Transition Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and in vitro drug release studies. Additionally, the in vivo analysis of the MGDDS, employing a Large White Pig model and molecular modeling of the ciprofloxacin-polymer interactions, were performed. The FTIR results determined that the crosslinking of the respective polymers in the microparticle and gastrosphere was achieved, with the SEM analysis detailing the size of the microparticles formed and the porous nature of the MGDDS, which is essential for drug release. The in vivo drug release analysis results further displayed a more controlled ciprofloxacin release profile over 24 h and a greater bioavailability for the MGDDS when compared to the marketed immediate-release ciprofloxacin product. Overall, the developed system successfully delivered ciprofloxacin in a control-release manner and enhanced its absorption, thereby displaying the potential of the system to be used in the delivery of other NAW drugs.

Ultra-Narrowband Near-Infrared Responsive J-Aggregates of Fused Quinoidal Tetracyanoindacenodithiophene.

Narrowband photoresponsive molecules are highly coveted in high-resolution imaging, sensing, and monochromatic photodetection, especially those extending into the near-infrared (NIR) spectral range. Here, a new class of J-aggregating materials based on quinoidal indacenodithiophenes (IDTs) that exhibit an ultra-narrowband (full width half maxima of 22 nm) NIR absorption peak centered at 770 nm is reported. The spectral width is readily tuned by the length of the solubilizing alkyl group, with longer chains resulting in significant spectral narrowing. The J-aggregate behavior is confirmed by a combination of excited state lifetime measurements and single-crystal X-ray diffraction measurements. Their utility as electron-transporting materials is demonstrated in both transistor and phototransistor devices, with the latter demonstrating good response at NIR wavelengths (780 nm) over a range of intensities.

[Effect of physicochemical properties on the pharmacokinetic parameters of the new representative of benzothiazinones antituberculosis drug macozinonе].

INTRODUCTION: Tuberculosis (TB) is one of the top ten causes of death worldwide. Improvement of the treatment options via development of new drugs and treatment regimens that would be more convenient for patients is one of key options of improving the effecacy of the TB prevention and careis. Since the creation of new treatment regimens by minimizing the number of the drugs used and reducing the duration of treatment is the most promising and correct direction, macozinone, a new candidate of the benzothiazinone series, can become the basis for development of new chemotherapy regimens for drug-resistant forms of TB including the combination of macozinone with the most effective modern anti-TB drugs. AIM: Comparative evaluation of the pharmacokinetic properties of macozinone capsules 80 mg and the new dosage form a dispersible tablet for preparation of oral solution. MATERIALS AND METHODS: Solubility of the substance macozinone in biorelevant media in vitro, permeability of macozinone in the test Caco-2 in vitro, as well as pharmacokinetics of macozinone in dogs in vivo were evaluated. RESULTS: The solubility assessment in biorelevant media showed that the average limit of macozinone substance dissolution in the pH 5.0 acetate buffer solution was from 6 to 9 mg/l, in FaSSIF medium (fasted) from 2.5 to 4 mg/l, and in FeSSIF medium (after meals) from 16.8 to 29 mg/l. It is established that the cell permeability of the pharmaceutical substance macozinone in the CACO-2 test system is on average 2.510-6cm/s in the forward direction from the apical to basolateral cell membrane, and 1.510-6cm/s in the reverse direction, which corresponds to low permeability. The main pharmacokinetic parameters of macozinone dispersable tablets 160 mg, after dosing with food and on an empty stomach, as well as capsules 80 mg, when administered on an empty stomach in vivo studies in dogs are presented. DISCUSSION: The specific physicochemical properties of macozinone, the problems of developing the new dosage form, as well as ways of solving some of them are presented. CONCLUSION: In the process of new dosage forms development, the existing chemical properties of the macozinone substance should be considered. One of the promising ways of increasing bioavailability and, consiquently, efficacy is development a fundamentally new drug form with modified release within the absorption window.

The Accordion Pill®: unique oral delivery to enhance pharmacokinetics and therapeutic benefit of challenging drugs.

Accordion Pill® (AP) is a novel gastric-retention oral delivery platform based on folded multilayer films (Intec Pharma, Jerusalem, Israel). Phase II clinical trials have evaluated gastric retention and pharmacokinetics (PK) of AP in healthy volunteers and efficacy and safety of AP containing carbidopa and levodopa (AP-CD/LD) in patients with Parkinson's disease (PD). AP was retained in the stomach for approximately 8 h, without special meal requirements. AP-CD/LD demonstrated improved absorption, more stable levodopa exposure and improved ON time compared with immediate-release CD/LD in advanced PD patients. AP provides a novel treatment platform for improving PK and efficacy for drugs with narrow absorption windows or poor solubility. Furthermore, AP allows multiple drug release profiles in a single capsule and can provide fixed-dose combinations.

Current State and Future Perspectives on Gastroretentive Drug Delivery Systems.

In recent years, many attempts have been made to enhance the drug bioavailability and therapeutic effectiveness of oral dosage forms. In this context, various gastroretentive drug delivery systems (GRDDS) have been used to improve the therapeutic efficacy of drugs that have a narrow absorption window, are unstable at alkaline pH, are soluble in acidic conditions, and are active locally in the stomach. In this review, we discuss the physiological state of the stomach and various factors that affect GRDDS. Recently applied gastrointestinal technologies such as expandable, superporous hydrogel; bio/mucoadhesive, magnetic, ion-exchange resin; and low- and high-density-systems have also been examined along with their merits and demerits. The significance of in vitro and in vivo evaluation parameters of various GRDDS is summarized along with their applications. Moreover, future perspectives on this technology are discussed to minimize the gastric emptying rate in both the fasted and fed states. Overall, this review may inform and guide formulation scientists in designing the GRDDS.

Overview on gastroretentive drug delivery systems for improving drug bioavailability.

In recent decades, many efforts have been made in order to improve drug bioavailability after oral administration. Gastroretentive drug delivery systems are a good example; they emerged to enhance the bioavailability and effectiveness of drugs with a narrow absorption window in the upper gastrointestinal tract and/or to promote local activity in the stomach and duodenum. Several strategies are used to increase the gastric residence time, namely bioadhesive or mucoadhesive systems, expandable systems, high-density systems, floating systems, superporous hydrogels and magnetic systems. The present review highlights some of the drugs that can benefit from gastroretentive strategies, such as the factors that influence gastric retention time and the mechanism of action of gastroretentive systems, as well as their classification into single and multiple unit systems.

Statistical Design of Experiments on Fabrication of Bilayer Tablet of Narrow Absorption Window Drug: Development and In vitro characterisation.

The current study involves the fabrication of oral bioadhesive bilayer matrices of narrow absorption window drug baclofen and the optimisation of their in vitro drug release and characterisation. Statistical design of experiments, a computer-aided optimisation technique, was used to identify critical factors, their interactions and ideal process conditions that accomplish the targeted response(s). A central composite design was employed to systematically optimise the drug delivery containing a polymer, filler and compression force. The values of ratio of different grades of hydroxypropyl methylcellulose, microcrystalline cellulose and compression force were varied to be fitted in design. Drug release at 1 h (Q1), 4 h (Q4), 8 h (Q8), 12 h (Q12), and hardness were taken as responses. Tablets were prepared by direct compression methods. The compressed tablets were evaluated for their hardness, weight variation, friability, content uniformity and diameter. Counter plots were drawn and optimum formulation was selected by desirability function. The formulations were checked for their ex vivo mucoadhesion. The experimental value of Q1, Q4, Q8, Q12 and hardness for check-point batch was found to be 31.64, 45.82, 73.27, 98.95% and 4.4 kg/cm(2), respectively. The release profile indicates Highuchi kinetics (Fickian transport) mechanism. The results of the statistical analysis of the data demonstrated significant interactions amongst the formulation variables, and the desirability function was demonstrated to be a powerful tool to predict the optimal formulation for the bilayer tablet.

Development of a Novel Floating In-situ Gelling System for Stomach Specific Drug Delivery of the Narrow Absorption Window Drug Baclofen.

The present study deals with development of a floating in-situ gel of the narrow absorption window drug baclofen. Sodium alginate-based in-situ gelling systems were prepared by dissolving various concentrations of sodium alginate in deionized water, to which varying concentrations of drug and calcium bicarbonate were added. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used to check the presence of any interaction between the drug and the excipients. A 3(2) full factorial design was used for optimization. The concentrations of sodium alginate (X1) and calcium bicarbonate (X2) were selected as the independent variables. The amount of the drug released after 1 h (Q1) and 10 h (Q10) and the viscosity of the solution were selected as the dependent variables. The gels were studied for their viscosity, in-vitro buoyancy and drug release. Contour plots were drawn for each dependent variable and check-point batches were prepared in order to get desirable release profiles. The drug release profiles were fitted into different kinetic models. The floating lag time and floating time found to be 2 min and 12 h respectively. A decreasing trend in drug release was observed with increasing concentrations of CaCO3. The computed values of Q1 and Q10 for the check-point batch were 25% and 86% respectively, compared to the experimental values of 27.1% and 88.34%. The similarity factor (f 2) for the check-point batch being 80.25 showed that the two dissolution profiles were similar. The drug release from the in-situ gel follows the Higuchi model, which indicates a diffusion-controlled release. A stomach specific in-situ gel of baclofen could be prepared using floating mechanism to increase the residence time of the drug in stomach and thereby increase the absorption.