Design of fixed dose combination and physicochemical characterization of enteric-coated bilayer tablet with circadian rhythmic variations containing telmisartan and pravastatin sodium

Ternary Solid Dispersions: A Review of the Preparation, Characterization, Mechanism of Drug Release, and Physical Stability

The prevalence of active pharmaceutical ingredients (APIs) with low water solubility has experienced a significant increase in recent years. These APIs present challenges in formulation, particularly for oral dosage forms, despite their considerable therapeutic potential. Therefore, the improvement of solubility has become a major concern for pharmaceutical enterprises to increase the bioavailability of APIs. A promising formulation approach that can effectively improve the dissolution profile and the bioavailability of poorly water-soluble drugs is the utilization of amorphous systems. Numerous formulation methods have been developed to enhance poorly water-soluble drugs through amorphization systems, including co-amorphous formulations, amorphous solid dispersions (ASDs), and the use of mesoporous silica as a carrier. Furthermore, the successful enhancement of certain drugs with poor aqueous solubility through amorphization has led to their incorporation into various commercially available preparations, such as ASDs, where the crystalline structure of APIs is transformed into an amorphous state within a hydrophilic matrix. A novel approach, known as ternary solid dispersions (TSDs), has emerged to address the solubility and bioavailability challenges associated with amorphous drugs. Meanwhile, the introduction of a third component in the ASD and co-amorphous systems has demonstrated the potential to improve performance in terms of solubility, physical stability, and processability. This comprehensive review discusses the preparation and characterization of poorly water-soluble drugs in ternary solid dispersions and their mechanisms of drug release and physical stability.

Pharmaceutical Methods for Enhancing the Dissolution of Poorly Water-Soluble Drugs

Low water solubility is the main hindrance in the growth of pharmaceutical industry. Approximately 90% of newer molecules under investigation for drugs and 40% of novel drugs have been reported to have low water solubility. The key and thought-provoking task for the formulation scientists is the development of novel techniques to overcome the solubility-related issues of these drugs. The main intention of present review is to depict the conventional and novel strategies to overcome the solubility-related problems of Biopharmaceutical Classification System Class-II drugs. More than 100 articles published in the last 5 years were reviewed to have a look at the strategies used for solubility enhancement. pH modification, salt forms, amorphous forms, surfactant solubilization, cosolvency, solid dispersions, inclusion complexation, polymeric micelles, crystals, size reduction, nanonization, proliposomes, liposomes, solid lipid nanoparticles, microemulsions, and self-emulsifying drug delivery systems are the various techniques to yield better bioavailability of poorly soluble drugs. The selection of solubility enhancement technique is based on the dosage form and physiochemical characteristics of drug molecules.

Comprehensive Quality Evaluation for Medicinal and Edible Ziziphi Spinosae Semen before and after Rancidity Based on Traditional Sensory, Physicochemical Characteristics, and Volatile Compounds

To comprehensively evaluate the quality of medicinal and edible Ziziphi Spinosae Semen (ZSS, the dried ripe seeds of Ziziphus jujuba var. spinosa) before and after rancidity during storage, some indicators including traditional sensory properties, physicochemical characteristics, and volatile compounds were analyzed. As a result, compared with the normal samples, the rancid samples of ZSS produced a darker color, a bitter taste, and an irritating odor, increased moisture content, electrical conductivity, fatty oil content, and acid value, and decreased water- and alcohol-soluble extract contents and pH value. Among them, the acid value had significant difference (p < 0.01) from 3.90 of normal ZSS to 18.68 mg/g of rancid ZSS. A total of 39 volatile compounds were identified in samples, including 20 in normal ZSS and 38 compounds in rancid ZSS. Nineteen common compounds were identified in normal and rancid samples. Among them, the content of 10 compounds such as δ-limonene, (R,R)-2,3-butanediol, and (R,S)-2,3-butanediol was decreased but that of nine compounds such as acetic acid, n-octanoic acid, and n-nonanoic acid was increased in rancid ZSS. Nineteen unique compounds such as β-phellandrene, α-pinene, and 3-carene were detected and only one compound, δ-cadinene, was not detected in rancid ZSS. In addition, eight short-chain organic acids, acetic, propanoic, butanoic, pentanoic, hexanoic, heptanoic, octanoic, and nonanoic acids, were new products in rancid ZSS, and it was speculated that the production of a series of organic acids might be the material basis of irritating odor after normal ZSS became rancid. This is the first report that a series of short-chain organic acids have been found in a rancid substance. In conclusion, there was a significant difference between normal and rancid ZSS. These indicators could be used as an early warning for judging the rancidity phenomenon of medicinal and edible ZSS. In addition, this is the first comprehensive evaluation about the rancidity process of a medicinal and edible substance.

Effect of functional excipients on the dissolution and membrane permeation of furosemide formulated into multiple-unit pellet system (MUPS) tablets

The effect of functional excipients (i.e. chitosan, sodium lauryl sulphate, NaHCO₃, and CaCO₃) formulated in multiple-unit pellet system (MUPS) tablets has been investigated on the dissolution and permeability of furosemide, a BCS class IV compound. Spherical beads were produced and compressed into MUPS tablets. MUPS tablet formulations were evaluated for hardness, disintegration, mass variation, friability, and dissolution (pH 1.2, pH 4.6, and pH 7.4). Ex vivo permeability studies were conducted across excised pig tissues (pyloric antrum and duodenal region) on selected experimental MUPS tablet formulations. Histological analysis was conducted on the tissues after exposure to selected experimental MUPS tablet formulations. Dissolution results in the 0.1 M HCl (pH 1.2) showed the highest effect of the excipients on furosemide release. Dissolution parameters showed increased dissolution of furosemide for the MUPS tablet formulations containing functional excipients: a 4.5-10-fold increase in the AUC values, the %_max showed a 60-70% increase and up to a 19-fold increase in DRi was seen. Permeability results revealed a 2.5-fold higher cumulative percentage transport for selected formulations. The results proved that functional excipients incorporated into beads, compressed into MUPS tablet formulations increased furosemide release as well as permeation across excised intestinal tissues.

Active coating of immediate-release evogliptin tartrate to prepare fixed dose combination tablet with sustained-release metformin HCl

This study was aimed to develop a fixed dose combination (FDC) tablet containing a low dose of evogliptin tartrate (6.87 mg) for immediate release combined with a high dose (1000 mg) of sustained-release (SR) metformin HCl appropriate for once daily dosing the treatment of type 2 diabetes. To prepare the FDC tablets, an active coating was used in this study, whereby evogliptin tartrate film was layered on a matrix core tablet containing metformin HCl. To overcome the problem caused by a low-dose drug in combination with a relatively large matrix tablet containing high-dose drug, it was also aimed to confirm the formulation and coating operation for satisfactory content uniformity, and to describe the chemical stability during storage of the amorphous active coating layer formulation in relation to molecular mobility. Furthermore, the in vitro release and in vivo pharmacokinetic profiles of metformin HCl and evogliptin tartrate in the FDC active coating tablet were compared to those of the commercially marketed reference drugs, Diabex XR® (Daewoong, Seoul, Korea) containing metformin HCl and Suganon® (Donga ST, Seoul, Korea) containing evogliptin tartrate. In conclusion, the newly developed FDC active coating tablet in this study was confirmed to be bioequivalent to the reference marketed products in beagle dogs, with satisfactory content uniformity and stability.

Ternary solid dispersions: classification and formulation considerations

The number of active pharmaceutical compounds from the biopharmaceutical classification system (BCS) belonging to Class II and IV have significantly increased in recent years. These compounds have high therapeutic potential but are difficult to formulate as oral dosage forms due to their poor aqueous solubility. The solubility and bioavailability of these poorly water-soluble compounds can be increased by various formulation approaches, such as amorphous solid dispersions (ASD), salt formation, complexations, etc. Out of these techniques, the ASD approach, where compounds are converted into amorphous form and embedded in the hydrophilic matrix, have been successfully used in many marketed preparations. The recent advancement of this ASD approach is the design of ternary solid dispersions (TSD), where an additional component is added to further improve their performance in terms of solubility, stability, and processability. This review discusses the classification, mechanism of performance improvement, preparation techniques, and characterizations for TSD.

Pharmaceutical Application of Tablet Film Coating

Tablet film coating is a common but critical process providing various functionalities to tablets, thereby meeting diverse clinical needs and increasing the value of oral solid dosage forms. Tablet film coating is a technology-driven process and the evolution of coated dosage forms relies on advancements in coating technology, equipment, analytical techniques, and coating materials. Although multiple coating techniques are developed for solvent-based or solvent-free coating processes, each method has advantages and disadvantages that may require continuous technical refinement. In the film coating process, intra- and inter-batch coating uniformity of tablets is critical to ensure the quality of the final product, especially for active film coating containing active pharmaceutical ingredients in the coating layer. In addition to experimental evaluation, computational modeling is also actively pursued to predict the influence of operation parameters on the quality of the final product and optimize process variables of tablet film coating. The concerted efforts of experiments and computational modeling can save time and cost in optimizing the tablet coating process. This review provides a brief overview of tablet film coating technology and modeling approaches with a focus on recent advancements in pharmaceutical applications.

Interfacial bonding in formulated bilayer tablets

To take full advantage of the drug delivery benefits offered by bilayer tablets, the common issue of weak interfacial bonding strength (IBS) with manufacturing must be overcome. This work seeks to characterize the effects of composition in individual layers and compaction pressure on the IBS. Mixtures of MCC and lactose in different ratios with and without HPMC were used where the first layer was compacted with two different pressures (20 and 100 MPa) followed by a second layer compaction pressure of 200 MPa. After identifying the failure mode as either at the interface or within a layer, the complex trends of bilayer tablet IBS as a function of MCC content were explained by considering the interplay between particle bonding strength and bonding area at the interface.

Investigation of Crystallization and Salt Formation of Poorly Water-Soluble Telmisartan for Enhanced Solubility

The crystal changes and salt formation of poorly water-soluble telmisartan (TEL) in various solvents were investigated for enhanced solubility, stability and crystallinity. Polymorphic behaviors of TEL were characterized by dispersing in distilled water, acetone, acetonitrile, DMSO, or ethanol using Method I: without heat and then dried under vacuum at room temperature; and Method II: with heat below boiling temperature, cooled at 5 °C, and then dried under vacuum at 40 °C. For salt formation (Method III), the following four powdered mixtures were prepared by dispersing in solution of hydrochloric acid (HCl) (pH 1.2), TEL/HCl; in simulated gastric fluid (pH 1.2 buffer), TEL/simulated gastric fluid (SGF); in intestinal fluid (pH 6.8 buffer), TEL/simulated intestinal fluid (SIF); or in NaOH (pH 6.8), TEL/NaOH, respectively, and then dried under a vacuum at room temperature. The structures of powdered mixtures were then studied using a field emission scanning electron microscope (FESEM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), FTIR, ¹H nuclear magnetic resonance (¹H-NMR), and LC⁻MS. The solubility of TEL in powdered forms was performed in pH 6.8, pH 1.2, and distilled water. No polymorphic behaviors of TEL were observed in various solvents as characterized by FESEM, DSC, PXRD, and FTIR. However, the structural changes of powdered mixtures obtained from Method III were observed due to the formation of salt form. Moreover, the solubility of salt form (TEL/HCl) was highly increased as compared with pure TEL. There were no significant changes of TEL/HCl compared with TEL in the content assay, PXRD, DSC, and FTIR during stressed storage conditions at 40 °C/75% relative humidity (RH) for 4 weeks under the closed package condition. Therefore, the present study suggests the new approach for the enhanced stability and solubility of a poorly water-soluble drug via salt form.

Chronotherapy for Hypertension

PURPOSE OF REVIEW

Given the emerging knowledge that circadian rhythmicity exists in every cell and all organ systems, there is increasing interest in the possible benefits of chronotherapy for many diseases. There is a well-documented 24-h pattern of blood pressure with a morning surge that may contribute to the observed morning increase in adverse cardiovascular events. Historically, antihypertensive therapy involves morning doses, usually aimed at reducing daytime blood pressure surges, but an absence of nocturnal dipping blood pressure is also associated with increased cardiovascular risk.

RECENT FINDINGS

To more effectively reduce nocturnal blood pressure and still counteract the morning surge in blood pressure, a number of studies have examined moving one or more antihypertensives from morning to bedtime dosing. More recently, such studies of chronotherapy have studied comorbid populations including obstructive sleep apnea, chronic kidney disease, or diabetes. Here, we summarize major findings from recent research in this area (2013-2017). In general, nighttime administration of antihypertensives improved overall 24-h blood pressure profiles regardless of disease comorbidity. However, inconsistencies between studies suggest a need for more prospective randomized controlled trials with sufficient statistical power. In addition, experimental studies to ascertain mechanisms by which chronotherapy is beneficial could aid drug design and guidelines for timed administration.