Characterization of Taro (Colocasia esculenta) stolon polysaccharide and evaluation of its potential as a tablet binder in the formulation of matrix tablet

This investigation focuses on the extraction, characterization, and evaluation of taro (Colocasia esculenta) stolon polysaccharide (TSP) as a tablet binding agent, which is obtained from edible taro stolon. TSP was subjected to phytochemical screening and characterized by FTIR, DSC, TGA, DTA, XRD, particle size, polydispersity index, zeta potential, rheological behavior, and SEM. The tablets prepared with varying concentrations of TSP (2.5 %, 5 %, 7.5 %, and 10 % w/w) and diclofenac sodium (DS) were evaluated and compared with the same concentrations of gum acacia and PVP K-30. The presence of carbohydrates was confirmed by Molisch's test. The FTIR spectra established the compatibility of the drug with excipients. The SEM images revealed asymmetric and elongated particles of TSP powder. The hydration kinetics study showed matrix hydration and water penetration velocity within the range of 0.602-0.753 g/g and 0.112-0.189 cm/g.h, respectively. The tablets showed drug release of >75 % at 45 min. The release-exponent value above 0.89 indicated a super case II drug transport combining matrix erosion and diffusion. Optimum tablet hardness and very low friability, even at 2.5 % binder concentration, suggested the potential application of the novel TSP as a tablet binder in the formulation of the tablets.

Patient Acceptability and Preferences for Solid Oral Dosage Form Drug Product Attributes: A Scoping Review

Background

There is no consistent framework for patient-centric drug product design, despite the common understanding that drug product acceptability and preferences influence adherence and, therefore, drug product effectiveness. The aim of this review was to assess current understanding of patient acceptability and preferences for solid oral dosage form (SODF) drug product attributes, and the potential impact of these attributes on patient behaviors and outcomes.

Patients and Methods

A scoping review was conducted. Embase, Ovid MEDLINE®, and PubMed® were searched for full-text articles published between January 2013 and May 2023. Following screening and assessment against predefined inclusion criteria, data were analyzed thematically.

Results

Nineteen studies were included. Four overarching domains of drug product attributes were identified and summarized in a framework: appearance, swallowability, palatability, and handling. Each domain was informed by specific drug product attributes: texture, form, size, shape, color, marking, taste, mouthfeel, and smell. The most frequently studied domains were swallowability and appearance, while the most studied attributes were size, shape, and texture. Smell, marking, and mouthfeel were the least studied attributes. Texture intersected all domains, while form, shape, and size intersected appearance, swallowability, and handling. Swallowability and size appeared to be the key domain and attribute, respectively, to consider when designing drug products. Few studies explored the impact of drug product attributes on behaviors and outcomes.

Conclusion

While existing studies of drug product attributes have focused on appearance and swallowability, this review highlighted the importance of two less well-understood domains-palatability and handling-in understanding patients' acceptability and preferences for SODF drug products. The framework provides a tool to facilitate patient-centric design of drug products, organizing and categorizing physical drug product attributes into four overarching domains (appearance, swallowability, palatability, and handling), encouraging researchers to comprehensively assess the impact of drug product attributes on patient acceptability, preferences, and outcomes.

Apixaban and clopidogrel in a fixed-dose combination: Formulation and in vitro evaluation

Fixed-dose combination (FDC) products represent a novel, safe, and cost-effective formulation. Combined use of anticoagulant and antiplatelet medications is common among comorbid cardiovascular patients. This study aimed to formulate FDC tablets for Apixaban and Clopidogrel, as prophylaxis and treatment of thrombo-embolic events. FDC tablets were developed by combining small tablets of Immediate-Release Clopidogrel 75 mg and Extend-Release Apixaban 5 mg through direct compression and wet granulation. Particularly, Apixaban tablets were developed using design expert software, and various types and concentrations of polymers were entered. For Clopidogrel tablets, various diluents were used to develop the formulation. Then, the dissolution profile for each formula was studied. Finally, the optimized formulations were encapsulated within hard gelatin capsules. Apixaban formulation followed zero-order with super case Ⅱ transport mechanism as the dominant mechanism of drug release. The Apixaban drug release rate was affected by the type and concentration of the polymers in the formulation (P < 0.05). As the HPMC concentration was increased, Apixaban release was retarded. For, Clopidogrel, the formulated tablets with spray-dried lactose filler and sodium stearyl fumarate lubricant were found to be stable with good properties. In conclusion, the optimum formulation yielded Clopidogrel and extended-release Apixaban for 24 h with the desired in vitro drug dissolution.

Premix technologies for drug delivery: manufacturing, applications, and opportunities in regulatory filing

Active pharmaceutical ingredients (APIs) and excipients can be carefully combined in premix-based materials before being added to dosage forms, providing a flexible platform for the improvement of drug bioavailability, stability, and patient compliance. This is a promising and transformative approach in novel and generic product development, offering both the potential to overcome challenges in the delivery of complex APIs and viable solutions for bypassing patent hurdles in generic product filing. We discuss the different types of premixes; manufacturing technologies such as spray drying, hot melt extrusion, wet granulation, co-crystal, co-milling, co-precipitation; regulatory filing opportunities; and major bottlenecks in the use of premix materials in different aspects of pharmaceutical product development.

Analysis of environmental biodegradability of cellulose-based pharmaceutical excipients in aqueous media

Pharmaceutical cellulosic polymers will inevitably reach natural water systems if they are not removed after entering wastewater. Biodegradation of organic chemicals in sewage or in the aquatic environment is an important removal mechanism. In this study, we investigated the environmental biodegradation of 14 cellulose derivatives commonly utilized as pharmaceutical excipients using three different test systems that are based on the closed bottle test (OECD 301D) and the manometric respirometry test (OECD 301F). For the different cellulose derivatives tested, we observed varying degrees of biodegradation ranging from 0 to 20.4 % chemical oxygen demand (COD). However, none met the criteria for classification as 'readily biodegradable'. In addition, 10 out of 14 cellulose derivatives and/or their possible transformation products formed during the experiments, may exhibit possible toxic inhibitory effects on the inoculum. This includes one or several derivatives of hydroxy propyl methyl cellulose, hydroxy propyl cellulose, methyl cellulose, ethyl cellulose, and hydroxy ethyl cellulose. Based on the results obtained, we have developed a graded classification score ('traffic light system') for excipient biodegradation. This could help streamline the assessment and classification of cellulose derivatives concerning risk of persistence and potential adverse environmental effects, thereby assisting in the prioritization of more favorable compounds. In the long term, however, excipients should be designed from the very beginning to be biodegradable and mineralizable in the environment ('benign by design').

Solubility-enabling formulations for oral delivery of lipophilic drugs: considering the solubility-permeability interplay for accelerated formulation development

INTRODUCTION

Tackling low water solubility of drug candidates is a major challenge in today's pharmaceutics/biopharmaceutics, especially by means of modern solubility-enabling formulations. However, drug absorption from these formulations oftentimes remains unchanged or even decreases, despite substantial solubility enhancement.

AREAS COVERED

In this article, we overview the simultaneous effects of the formulation on the solubility and the apparent permeability of the drug, and analyze the contribution of this solubility-permeability interplay to the success/failure of the formulation to increase the overall absorption and bioavailability. Three different patterns of interplay were identified: (1) solubility-permeability tradeoff in which every solubility gain comes with a price of concomitant permeability loss; (2) an advantageous interplay pattern in which the permeability remains unchanged alongside the solubility gain; and (3) an optimal interplay pattern in which the formulation increases both the solubility and the permeability. Passive vs. active intestinal permeability considerations in the context of the solubility-permeability interplay are also thoroughly discussed.

EXPERT OPINION

The solubility-permeability interplay pattern of a given formulation has a critical effect on its overall success/failure, and hence, taking into account both parameters in solubility-enabling formulation development is prudent and highly recommended.

Promising strategies for improving oral bioavailability of poor water-soluble drugs

INTRODUCTION

Oral administration of poorly water-soluble drugs (PWSDs) is generally related to low bioavailability, leading to high drug doses, multiple side effects, and low patient compliance. Thus, different strategies have been developed to increase drug solubility and dissolution in the gastrointestinal tract, opening new venues for these drugs.

AREAS COVERED

This review outlines the current challenges in PWSD formulation development and the strategies to overcome the oral barriers and increase their solubility and bioavailability. Conventional strategies include altering crystalline and molecular structures and modifying oral solid dosage forms. In contrast, novel strategies comprise micro- and nanostructured systems. Recent representative studies involving how these strategies have improved the oral bioavailability of PWSDs were also reviewed and reported.

EXPERT OPINION

New approaches to enhance PWSD bioavailability have sought to improve water solubility and dissolution rates, drug protection by overcoming biological barriers, and increased absorption. Still, only a handful of studies have focused on quantifying the increase in bioavailability. Improving the oral bioavailability of PWSDs remains an exciting unexplored field of research and has become an important issue for successfully developing pharmaceutical products.

Differences in in vivo absorption of flavone glycosides, flavone aglycones and terpene lactones under different dosage forms and physiological conditions

ETHNOPHARMACOLOGICAL RELEVANCE

Ginkgo biloba L. extract (GBE) oral preparations have been used for many years in the prevention and treatment of cardiovascular and cerebrovascular diseases, and the main active ingredients are flavonoids and terpene lactones. Among them, the oral absorption of the prototype components of flavonoid glycosides into the blood needs to be further clarified, and the differences in the oral absorption of different components in GBE by different dosage forms and physiological conditions are not clear yet.

AIM OF THE STUDY

To clarify the oral absorption of the prototype flavonoid glycosides in vivo, and to further explore the differences in the oral absorption of various active compounds under different oral dosage forms and dietary conditions.

MATERIALS AND METHODS

Firstly, the target compounds were selected based on the characteristic chromatogram of GBE and literature. Then, the content differences of three different oral GBE preparations were studied, and their pharmacokinetics (PK) were compared. Finally, the PK differences of the preparations with better oral absorption under different dietary conditions were studied.

RESULTS

Five flavonoid glycosides, three aglycones and four terpene lactones were selected as the research objects. The content determination results of GBE tablets, guttate pills and tinctures showed that the content of several components especially flavonoid glycosides in the tincture was higher than that of the other two preparations. After oral administration of these three preparations, the PK study showed different results from previous studies. The PK behavior of flavonoid glycosides was also determined at the same time as flavonoid glycosides and terpene lactones. and the bioavailability of flavonoid glycosides in the tincture was higher than that of the other two preparations. PK results of fasting and non-fasting showed that taking GBE tincture on an empty stomach increased the absorption of various compounds, especially flavonoid glycosides. However, due to the existence of food residues in the gastrointestinal tract, the oral bioavailability of flavonoid glycosides was significantly improved.

CONCLUSIONS

This study discussed the differences in the content and oral absorption of active compounds in different oral preparations of GBE, clarified the in vivo absorption of flavonoid glycosides prototype, as well as the influence of diet on the PK of active compounds, which has certain guiding significance for the clinical application of GBE oral preparations.

Optimization and In Vitro Characterization of Telmisartan Loaded Sodium Alginate Beads and Its In Vivo Efficacy Investigation in Hypertensive Induced Animal Model

BACKGROUND

Antihypertensive drug telmisartan (TEL) belongs to BCS class II, which is characterized by low water solubility and, consequently, low oral bioavailability. Gastroretentive systems may overcome the problems associated with low solubility of TEL and incomplete absorption by localizing the drug release in the stomach. The purpose of this study was to prepare TEL-loaded, oil-entrapped, floating alginate beads with the intent of enhancing the oral bioavailability of TEL for the treatment of hypertension.

METHODS

For the formulation and optimization of seventeen formulations of TEL-loaded oil-entrapped floating alginate beads, a central composite design was utilized. The concentration of sodium alginate (X1), the concentration of cross-linker (X2), and the concentration of sesame oil (X3) served as independent variables, whereas the entrapment efficiency (Y1), in vitro buoyancy (Y2), and drug release Q6h (Y3) served as dependent variables. Using the emulsion gelation method and calcium chloride as the cross-linking agent, different formulations of TEL alginate beads were produced. All formulations were evaluated for their entrapment efficiency percentage, in vitro buoyancy, and in vitro drug release. The optimal formulation of TEL alginate beads was prepared with and without oil and evaluated for entrapment efficiency percentage, in vitro buoyancy, swelling ratio, average size, and in vitro drug release. Using scanning electron microscopes, the surface morphology was determined. Using IR spectroscopy, the compatibility between the ingredients was determined. In vivo evaluation of the optimized formulation in comparison to the free TEL was done in hypertension-induced rats, and the systolic blood pressure and all pharmacokinetic parameters were measured.

RESULTS

The prepared beads exhibited a high entrapment efficiency percentage, in vitro buoyancy, and prolonged drug release. TEL was compatible with other ingredients, as approved by IR spectroscopy. The prepared TEL beads were spherical, as shown by the SEM. The relative bioavailability of TEL-loaded oil-entrapped beads was 222.52%, which was higher than that of the pure TEL suspension. The prepared TEL beads formulation exhibited a higher antihypertensive effect for a prolonged time compared to pure TEL suspension.

CONCLUSIONS

It can be concluded that this innovative delivery method of TEL-loaded oil-entrapped beads is a promising tool for enhancing drug solubility and, thus, oral bioavailability and therapeutic efficacy, resulting in enhanced patient compliance. Furthermore, the in vivo study confirmed the formulation's extended anti-hypertensive activity in animal models.

Evolution of pediatric pharmaceutical forms for treatment of Hansen's disease (leprosy)

INTRODUCTION

Leprosy is a neglected, infectious, granulomatous and chronic disease caused by the pathological agent Mycobacterium leprae. The course of the disease is more aggressive in patients under 15 years of age, but the current treatment offered worldwide consists of solid forms, by the combination of antibiotics such as rifampicin, clofazimine and dapsone. This represents results in lack of adherence in pediatric patients and drug therapy failure, although numerous formulations and technologies have already been developed.

AREA COVERED

This study aims to analyze the technological evolution of the pharmaceutical treatment of leprosy, aimed at children. A review of patents around the world was conducted to look for technical and clinical aspects of formulations and devices.

EXPERT OPINION

Innovative formulations for pediatric patients were classified according to the routes of administration as oral, inhalable, injectable and transdermal. The formulations were organized as alternatives for pediatric therapy, taking into account the physicochemical aspects of drugs and the physiological aspects of pediatric patients. Among the difficulties for the patented formulations to reach the market, of special note is the low stability of the physicochemical characteristics of the drugs. Optimization of formulations would favor the pediatric treatment of leprosy, aiming at therapeutic success.

A Combined Rheological and Thermomechanical Analysis Approach for the Assessment of Pharmaceutical Polymer Blends

The viscoelastic nature of polymeric formulations utilised in drug products imparts unique thermomechanical attributes during manufacturing and over the shelf life of the product. Nevertheless, it adds to the challenge of understanding the precise mechanistic behaviour of the product at the microscopic and macroscopic level during each step of the process. Current thermomechanical and rheological characterisation techniques are limited to assessing polymer performance to a single phase and are especially hindered when the polymers are undergoing thermomechanical transitions. Since pharmaceutical processing can occur at these transition conditions, this study successfully proposes a thermomechanical characterisation approach combining both mechanical and rheological data to construct a comprehensive profiling of polymeric materials spanning both glassy and rubbery phases. This approach has been used in this study to assess the mechanical and rheological behaviour of heterogenous polymer blends of hydroxypropyl cellulose (HPC) and hydroxypropyl methylcellulose (HPMC) over a shearing rate range of 0.1–100 s−1 and a temperature range of 30–200 °C. The results indicate that HPC and HPMC do not appear to interact when mixing and that their mixture exhibits the mechanistic properties of the two individual polymers in accordance with their ratio in the mixture. The ability to characterise the behaviour of the polymers and their mixtures before, throughout, and after the glassy to rubbery phase transition by application of the combined techniques provides a unique insight towards a quality-by-design approach to this and other polymer-based solid dosage forms, designed with the potential to accelerate their formulation process through obviating the need for multiple formulation trials.

Characterization of Boswellia rivae Engl Resin as a Potential Use for Pharmaceutical Excipient

Pharmaceutical excipients derived from natural sources like resins are nowadays meritoriously used in the formulation of drugs. Resins of natural origin have many advantages over chemically synthesized substances; they are safer, nontoxic, less expensive, biodegradable, and widely available. To our knowledge, resins from plants have been not sufficiently explored for application in pharmaceutical formulations. Thus, in the present study, a resin isolated from Boswellia rivae Engl was characterized for its potential use as a pharmaceutical excipient. Method. The resin was extracted from the oleo gum resin of Boswellia rivae Engl, which involved the removal of volatile oils, gum, and Boswellic acid contents. The dried resin powder was then characterized for its micromeritic properties, heavy metal contents, moisture content, moisture absorption power, pH, solubility, swelling property, and acute toxicity profile. Moreover, the crystal nature and the chemical functionality of the resin were evaluated by using X-ray diffraction and Fourier transform infrared spectrometry, respectively. Results. The yield of the neutral resin was 13.17%, and the powder was pale yellow and had irregular surfaces. The resin was freely soluble in organic solvents but almost insoluble in water. The moisture content of the dried extract was 2.5% while its moisture absorption capacity was 2.5%, 4%, and 5.47% at 40%, 60%, and 75% RH, respectively. Besides, the maximum swelling capacities of the resin observed were 40%, 37%, and 30% at 350C, 300C, and 250C, respectively. The bulk powder exhibited a 1.21 Hausner ratio, 36.497 angles of repose, and 17.03% Carr's index, indicating the fair flowability of the powder. Heavy metals such as zinc, chromium, and cobalt were detected at a low level while elements like copper, manganese, lead, and cadmium were absent. The X-ray diffraction study revealed that the crystallinity index of the powder was 42.7% with a crystal size of 994.5A. The Boswellia resin could be safe in mice up to 3 g/kg of their body weight. In conclusion, the physicochemical properties of the resin powder investigated reveal its potential application as pharmaceutical additives in the formulation of modified release solid dosages forms like tablets and microcapsules.

The effect of chitosan/TiO2/hyaluronic acid subphase on the behaviour of 1,2-dioleoyl-sn-glycero-3-phosphocholine membrane

The main aim of the study was to determine the effect of two polysaccharides: chitosan (Ch) and hyaluronic acid (HA), and/or titanium dioxide (TiO₂) on the structure and behaviour of the 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) membrane. To achieve this goal the surface pressure as a function of the area per molecule (π-A) isotherm for the phospholipid monolayer was recorded. The shape of the π-A isotherms and compression-decompression cycles, as well as the compression modulus values, were analysed in terms of biocompatibility. Besides, morphology and thickness of the phospholipid layers obtained by means of Brewster angle microscope at different π, were determined. The obtained results show that both polysaccharides Ch, HA, as well inorganic TiO₂ affect slightly the structure of the DOPC monolayer but do not disrupt it. Their presence brings no typical arrangements of both the polar heads and tails of DOPC molecules at the interface.

Toxicity of the polymeric excipients in geriatric polypharmacy

Geriatric polypharmacy is already a complicated issue in pharmacotherapy as multiple biological and pharmaceutical factors are involved. Given the fact that the geriatric population, in general, takes more than five medications for multiple diseases and most likely takes several supplements, there is a hidden issue with the types and amounts of the pharmaceutical inactive ingredients (polymers in particular) as they, as well as their impurities, may build up in an ill-performing body beyond their safety levels. In this commentary, we impart on biological factors, the importance of polymers, and the types and amounts of the impurities within each polymeric excipient that can potentially lead to severe pharmacological and biological impacts. Given the complex safety and toxicity issues in polypharmacy, we may need to revisit the safety standards and regulations on the inactive materials that are widely used in geriatric medications.

Improving Anticancer Activity of Chrysin using Tumor Microenvironment pH-Responsive and Self-Assembled Nanoparticles

Chrysin is a natural bioactive compound with potential biological activities. However, unfavorable physicochemical properties of native chrysin make it difficult to achieve good therapeutic efficacies. In this study, poly(ethylene) glycol (PEG₄₀₀₀)-conjugated chrysin nanoparticles were prepared. The PEG₄₀₀₀ was conjugated to chrysin through cis-aconityl and succinoyl linkers to achieve tumor microenvironment-specific drug release from PEGylated nanoparticles. The conjugation of PEG and chrysin via succinoyl (PCNP-1) and cis-aconityl (PCNP-2) linkers was confirmed by the ¹H NMR and FTIR analysis. The nanoparticles were characterized by DLS, TEM, XRD, and DSC analysis. Comparatively, PCNP-2 showed a better drug release profile and higher anticancer activity against human breast cancer cells than chrysin or PCNP-1. The apoptosis studies and colony formation inhibition assay revealed that the PCNP-2 induced more apoptosis and more greatly controlled the growth of human breast cancer cells than pure chrysin. Thus, the use of PCNPs may help to overcome the issues of chrysin and could be a better therapeutic approach.

Bioanalytical Methods and Strategic Perspectives Addressing the Rising Complexity of Novel Bioconjugates and Delivery Routes for Biotherapeutics

In recent years, an increase in the discovery and development of biotherapeutics employing new modalities, such as bioconjugates or novel routes of delivery, has created bioanalytical challenges. The inherent complexity of conjugated molecular structures means that quantification of the bioconjugate and its multiple components is critical for preclinical/clinical studies to inform drug discovery and development. Moreover, bioconjugates involve additional multifactorial complexity because of the potential for in vivo catabolism and biotransformation, which may require thorough investigations in multiple biological matrices. Furthermore, excipients that enhance absorption are frequently evaluated and employed for the development of oral and inhaled biotherapeutics. Risk-benefit assessments are required for novel or existing excipients that utilize dosages above previously approved levels. Bioanalytical methods that can measure both excipients and potential drug metabolites in biological matrices are highly relevant to these emerging bioanalysis challenges. We discuss the bioanalytical strategies for analyzing bioconjugates such as antibody-drug conjugates and antibody-oligonucleotide conjugates and review recent advances in bioanalytical methods for the quantification and characterization of novel bioconjugates. We also discuss bioanalytical considerations for both biotherapeutics and excipients through novel administration routes and review analyses in various biological matrices, from the extensively studied serum or plasma to tissue biopsy in the context of preclinical and clinical studies from both technical and regulatory perspectives.

Amorphous Solid Dispersions: Utilization and Challenges in Preclinical Drug Development within AstraZeneca

The poor aqueous solubility of many active pharmaceutical ingredients (APIs) dominates much of the early drug development portfolio and poses a major challenge in pharmaceutical development. Polymer-based amorphous solid dispersions (ASDs) are becoming increasingly common and offer a promising formulation strategy to tackle the solubility and oral absorption issues of these APIs. This review discusses the design, manufacture, and utilisation of ASD formulations in preclinical drug development, with a key focus on the pre-formulation assessments and workflows employed at AstraZeneca.

Studies on the pH-dependent solubility of various grades of calcium phosphate-based pharmaceutical excipients

Calcium phosphate-based pharmaceutical excipients, including calcium hydrogen phosphate anhydrous and dihydrate, calcium hydroxide phosphate have been well established in pharmaceutical technology for a very long time. Nowadays, they are of increasing interest to the pharmaceutical industry because, in addition to their advanced functional properties, they offer beneficial biocompatible and biodegradable properties. Yet, there is limited availability of embracing information regarding the solubility of these popular excipients, especially in variable pH conditions, reflecting those of the gastrointestinal tract (GIT). The study has shown that the solubility of calcium phosphates as well as their dissolution rate decreases significantly with increasing pH of dissolution fluids. The highest solubility was observed for dibasic calcium phosphate dihydrate, the lowest for tribasic calcium phosphate. This article provides also a comparison of various calcium phosphate types originating from different manufacturers, which may prove to be useful and help formulation scientists to design new medicinal products.

Quick and Simultaneous Analysis of Dissolved Active Pharmaceutical Ingredients and Formulation Excipients from the Dissolution Test Utilizing UHPLC and Charged Aerosol Detector

The objective of the study is to develop a quick and simultaneous analysis system for the dissolution of the active pharmaceutical ingredient (API) and the formulation excipient in samples from the dissolution test by UHPLC using the charged aerosol and PDA detectors. The combination of two columns for size-exclusion chromatography (SEC) and the equipment of the charged aerosol detector allowed the quick determination of various water-soluble polymers. Three model sustained-release tablets, each containing a different API of different water solubility (propranolol (soluble), ranitidine (very soluble), and cilostazol (practically insoluble)), were prepared from polyethylene oxide (PEO) matrix to verify the applicability and utility of the analysis system. The dissolution of propranolol was the same as that of PEO, indicating that the diffusion rate of propranolol was consistent with the erosion rate of the PEO and that the dissolution of PRO was based on diffusion. Ranitidine was released faster than PEO, suggesting that ranitidine was diffused through the gel layer of PEO early upon contact with the dissolution medium and before PEO gel erosion. Cilostazol was released slower as compared to PEO, indicating that cilostazol dissolution was based on the polymer's erosion. These results suggested that the analysis system developed in this study is a precise and valid tool to study the dissolution behavior of both APIs and excipients. Optimization of the SEC column for the appropriate separation of APIs and excipients makes the analysis system more efficient and convenient to study the drug release mechanisms and to design formulations.

The Influence of Omeprazole on the Dissolution Processes of pH-Dependent Magnetic Tablets Assessed by Pharmacomagnetography

Pharmacomagnetography involves the simultaneous assessment of solid dosage forms (SDFs) in the human gastrointestinal (GI) tract and the drug plasmatic concentration, using a biomagnetic technique and pharmacokinetics analysis. This multi-instrumental approach helps the evaluation, as GI variables can interfere with the drug delivery processes. This study aimed to employ pharmacomagnetography to evaluate the influence of omeprazole on the drug release and absorption of metronidazole administered orally in magnetic-coated tablets. Magnetic-coated tablets, coated with Eudragit^® E-100 (E100) and containing 100 mg of metronidazole, were produced. For the in vivo experiments, 12 volunteers participated in the two phases of the study (placebo and omeprazole) on different days to assess the bioavailability of metronidazole. The results indicated a shift as the pH of the solution increased and a delay in the dissolution of metronidazole, showing that the pH increase interferes with the release processes of tablets coated with E100. Our study reinforced the advantages of pharmacomagnetography as a tool to perform a multi-instrumental correlation analysis of the disintegration process and the bioavailability of drugs.

A Comprehensive Review on Pellets as a Dosage Form in Pharmaceuticals

Oral route of administration is widely accepted and desired because of its versatility, convenience, and, most importantly, patient compliance. Multiparticulate systems like granules and pellets are more advantageous when compared to single-unit dosage forms, as they are capable of distributing the drug more evenly in the gastrointestinal tract. The current paper focuses on pellets, the merits and demerits associated, various pelletization techniques, and their characterization. It also focuses on how pellets can be employed for drug delivery is controlled and sustained release formulations. It gives a complete emphasis on the drug and excipients that can be used in pellet formation, the marketed formulations, and the research pertaining to pellets.

Effect of Pharmaceutical Excipients on Intestinal Absorption of Metformin via Organic Cation-Selective Transporters

Growing evidence has shown that some pharmaceutical excipients can act on drug transporters. The present study was aimed at investigating the effects of 13 commonly used excipients on the intestinal absorption of metformin (MTF) and the underlying mechanisms using Caco-2 cells and an ex vivo mouse non-everted gut sac model. First, the uptake of MTF in Caco-2 cells was markedly inhibited by nonionic excipients including Solutol HS 15, polysorbate 20, polysorbate 40, polysorbate 60, polysorbate 80, and crospovidone. Second, transport profile studies showed that MTF was taken up via multiple cation-selective transporters, among which a novel pyrilamine-sensitive proton-coupled organic cation (H⁺/OC⁺) antiporter played a key role. Third, Solutol HS 15, polysorbate 40, and polysorbate 60 showed cis-inhibitory effects on the uptake of either pyrilamine (prototypical substrate of the pyrilamine-sensitive H⁺/OC⁺ antiporter) or 1-methyl-4-phenylpyridinium (substrate of traditional cation-selective transporters including OCTs, MATEs, PMAT, SERT, and THTR-2), indicating that their suppression on MTF uptake is due to the synergistic inhibition toward multiple influx transporters. Finally, the pH-dependent mouse intestinal absorption of MTF was significantly decreased by Solutol HS 15, polysorbate 20, polysorbate 40, polysorbate 60, polysorbate 80, and pyrilamine. In conclusion, this study revealed that a novel transport process mediated by the pyrilamine-sensitive H⁺/OC⁺ antiporter contributes to the intestinal absorption of MTF in conjunction with the traditional cation-selective transporters. Mechanistic understanding of the interaction of excipients with cation-selective transporters can improve the formulation design and clinical application of cationic drugs.

Co-processing of small molecule excipients with polymers to improve functionality

INTRODUCTION

Polymers have various applications such as binder, film coating agent, stabilizer, drug release modification, and as primary packaging materials. Recently, they have been explored in co-processing technique to improve the functionality of small molecule excipients (SMEs). Co-processing is a concept wherein two or more excipients interact at sub-particle level to provide synergy in functionality and minimize drawbacks of individual excipients.

AREA COVERED

The present review highlights the application of co-processing to improve the functionality of SMEs using polymers; physicochemical and mechanical properties of polymers for co-processing; advantages of co-processed excipients for different applications; functionality enhancement of co-processed excipients; novel concepts/methods for co-processing; mechanistic insights on co-processing and commercial products available in the market.

EXPERT OPINION

Most of the SMEs do not possess optimal multifunctional properties like flow, compressibility, compactibility, and disintegration ability, required to compensate for poorly compactable drugs. Some of these drawbacks can be overcome by co-processing of SMEs with polymers. For example, co-processing of a brittle SME and plastic material (polymer) can provide a synergistic effect and result in the generation of single entity multi-functional excipient. Besides, novel co-processed excipients generated using combinations of SMEs and polymers can also generate intellectual property rights.

Adequate formulation approach for oral chemotherapy: Etoposide solubility, permeability, and overall bioavailability from cosolvent- vs. vitamin E TPGS-based delivery systems

Injectable-to-oral conversions for anticancer drugs represent an important trend. The goal of this research was to investigate the suitability of formulation approaches for anticancer oral drug delivery, aiming to reveal mechanistic insights that may guide oral chemotherapy development. TPGS vs. PEG-400 were studied as oral formulations for the anticancer drug etoposide, accounting for drug solubility, biorelevant dissolution, permeability, solubility-permeability interplay, and overall bioavailability. Increased etoposide solubility was demonstrated with both excipients. Biorelevant dissolution revealed that TPGS or PEG-400, but not aqueous suspension, allowed complete dissolution of the entire drug dose. Both TPGS and PEG-400 resulted in decreased in-vitro etoposide permeability across artificial membrane, i.e. solubility-permeability tradeoff. While PEG-400 resulted in the same solubility-permeability tradeoff also in-vivo, TPGS showed the opposite trend: the in-vivo permeability of etoposide was markedly increased in the presence of TPGS. This increased permeability was similar to the drug permeability under P-gp inhibition. Rat PK study demonstrated significantly higher etoposide bioavailability from TPGS vs. PEG-400 or suspension (AUC of 72, 41, and 26 µg·min/mL, respectively). All in all, TPGS-based delivery system allows overcoming the solubility-permeability tradeoff, increasing systemic etoposide exposure. Since poor solubility and strong efflux are common to many anticancer agents, this work can aid in the development of better oral delivery approach for chemotherapeutic drugs.

Prolonged Delivery of Apomorphine Through the Buccal Mucosa, Towards a Noninvasive Sustained Administration Method in Parkinson's Disease: In Vivo Investigations in Pigs

In the current work, prolonged systemic delivery of apomorphine via buccal mucosa was shown to be a promising treatment for Parkinson's disease as a substitute for clinically utilized subcutaneous infusions. Due to extensive 'first-pass' metabolism, apomorphine is administered parenterally to bypass liver metabolism. Drawbacks of parenteral administration cause low patient compliance and adherence to treatment. On the other hand, while also bypassing the liver, delivery through buccal mucosa has a superior safety profile, is less costly, lacks pain and discomfort, and possesses excellent accessibility, overall augmenting patient compliance. Current in vivo study in pigs showed: (1) steady plateau levels of apomorphine in plasma were obtained 30 min following administration and remained constant for 8 h until a delivery device was removed, (2) bioavailability of apomorphine was 55%-80% as opposed to <2% peroral and (3) simulation of the pharmacokinetic profile obtained in pigs predicted therapeutically relevant levels of apomorphine in human. Furthermore, antipyrine was incorporated as a permeation marker to enable mechanistic investigation of apomorphine release from the delivery device and its permeation through the buccal mucosa. In addition, limitations of an Ussing diffusion chamber as an ex vivo research tool were also discussed.

The solubility, permeability and the dose as key factors in formulation development for oral lipophilic drugs: Maximizing the bioavailability of carbamazepine with a cosolvent-based formulation

The purpose of this research was to investigate drug dose, solubility, permeability, and their interplay, as key factors in oral formulation development for lipophilic drugs. A PEG400-based formulation was studied for five doses of the lipophilic drug carbamazepine, accounting for biorelevant dissolution of the dose in the GIT, and in-vivo bioavailability in rats. With the three lower doses (10, 25 and 50 mg/kg), complete in-vitro dissolution was achieved and maintained throughout the experiment with this formulation, while significant precipitation was obtained with higher doses (100 and 200 mg/kg). Likewise, the studied formulation allowed complete bioavailability in-vivo with the three lower doses, while the same formulation allowed only 76% and 42% bioavailability for the 100 and 200 mg/kg doses, respectively. There was good correlation between the in-vitro and in-vivo results. In conclusion, this work demonstrates that the dose is a crucial factor in formulation development; while a given formulation may be optimal for a certain drug dose, it may no longer be optimal for higher doses of the same drug. Hence, the solubility, the permeability, and their interplay, have to be considered in light of the drug dose intended to be administered in order to achieve successful oral formulation development.

A novel micro-photogrammetric instrument for visualizing in 3D small objects applied to the quantitative study of the dissolution behavior of a pharmaceutical dosage form

The work presented here proposes an innovative approach to 3D chemical mapping of solid formulations by microphotogrammetry. We present details of a novel microphotogrammetry apparatus and the first results for the application of photogrammetry to the dissolution analysis of solid pharmaceutical dosage forms. Unlike other forms of optical imaging, microphotogrammetry allows a true 3D model to be constructed that includes direct observation of the sides of the sample rather than only top-down topographic imaging. Volume and structural changes are assessed quantitatively and related to chemical analysis by high performance liquid chromatography. The recently introduced method of chemical identification by dissolution analysis, or chemical imaging by dissolution analysis, is employed for the first time to obtain tomographic images of the dissolution process.

Lignin and Cellulose Blends as Pharmaceutical Excipient for Tablet Manufacturing via Direct Compression

Extensive efforts are being made to find alternative uses for lignin (LIG). In the present work the use of this biopolymer as excipient to prepare tablets was studied. For this purpose, LIG was combined with microcrystalline cellulose (MCC) and used as excipients to prepare directly compressed tablets containing a model drug, tetracycline (TC). The excipients contained different concentrations of LIG: 100%, 75%, 50%, 25% and 0% (w/w). Two different compression forces were used (two and five tonnes). When formulations were prepared using LIG as the only excipient, tablets were formed, but they showed lower densities and crushing strength than the ones obtained with only MCC or LIG/MCC blends. Moreover, tablets prepared using five tonnes of compression force showed TC releases ranging from 40% to 70% of the drug loading. On the other hand, the tablets prepared using two tonnes of compression force showed a faster and more efficient TC release, between 60% and 90%. The presence of LIG in the tablets modified significantly the release profile and the maximum amount of TC released. Finally, a DPPH (2,2-diphenyl-1-picrylhydrozyl) assay was performed to confirm that the presence of LIG provided antioxidant properties to the formulations. Accordingly, LIG has potential as a pharmaceutical excipient.

Tablet Scoring: Current Practice, Fundamentals, and Knowledge Gaps

Oral solid dosage formulations and/or tablets have remained the preferred route of administration by both patients and health care practitioners. Oral tablets are easy to administer, they are non-invasive and cause less risk adversity. Because of the lack of commercially available tablet dose options, tablets are being split or partitioned by users. Tablet scoring refers to the breakage of a tablet to attain a desired efficacy dose and is an emerging concept in the pharmaceutical industry. The primary reason for the tablet scoring practice is to adjust the dose: dose tapering or dose titrating. Other reasons for tablet partitioning are to facilitate dose administration, particularly among the pediatric and the geriatric patient population, and to mitigating the high cost of prescription drugs. The scope of this review is to: (1) evaluate the advantages and inconveniences associated with tablet scoring/portioning, and (2) identify factors in the formulation and the manufacturing of tablets that influence tablet splitting. Whereas tablet partitioning has been a common practice, there is a lack of understanding regarding the fundamentals underpinning the performance of tablets with respect to splitting. Several factors can influence tablet partitioning: tablet size, shape, and thickness. A requirement has recently been set by the European Pharmacopoeia and the U.S. Food and Drug Administration for the uniformity of mass of subdivided tablets. For breaking ease, an in-vivo reference test and a routinely applicable in-vitro test need to be established.

Polymer-Coated Gold Nanospheres Do Not Impair the Innate Immune Function of Human B Lymphocytes in Vitro

Gold nanoparticles (GNPs) are intended for use within a variety of biomedical applications due to their physicochemical properties. Although, in general, biocompatibility of GNPs with immune cells such as macrophages and dendritic cells is well established, the impact of GNPs on B lymphocyte immune function remains to be determined. Since B lymphocytes play an important role in health and disease, the suitability of GNPs as a B cell-targeting tool is of high relevance. Thus, we provide information on the interactions of GNPs with B lymphocytes. Herein, we exposed freshly isolated human B lymphocytes to a set of well-characterized and biomedically relevant GNPs with distinct surface (polyethylene glycol (PEG), PEG/poly(vinyl alcohol) (PEG/PVA)) and shape (spheres, rods) characteristics. Polymer-coated GNPs poorly interacted with B lymphocytes, in contrast to uncoated GNPs. Importantly, none of the GNPs significantly affected cell viability, even at the highest concentration of 20 μg/mL over a 24 h suspension exposure period. Furthermore, none of the nanosphere formulations affected the expression of activation markers (CD69, CD86, MHC II) of the naive B lymphocytes, nor did they cause an increase in the secretion of pro-inflammatory cytokines ( i.e. , IL-6, IL-1β). However, the absence of polymer coating on the sphere GNPs and the rod shape caused a decrease in IL-6 cytokine production by activated B lymphocytes, suggesting a functional impairment. With these findings, the present study contributes imperative knowledge toward the safe-by-design approaches being conducted to benefit the development of nanomaterials, specifically those as theranostic tools.

Methacrylate-Copolymer Eudragit EPO as a Solubility-Enabling Excipient for Anionic Drugs: Investigation of Drug Solubility, Intestinal Permeability, and Their Interplay

The purpose of this work was to investigate the use of the dimethylaminoethyl methacrylate-copolymer Eudragit EPO (EPO) in oral solubility-enabling formulations for anionic lipophilic drugs, aiming to guide optional formulation design and maximize oral bioavailability. We have studied the solubility, the permeability, and their interplay, using the low-solubility nonsteroidal anti-inflammatory drug mefenamic acid as a model drug. Then, we studied the biorelevant solubility enhancement of mefenamic acid from EPO-based formulations throughout the gastrointestinal tract (GIT), using the pH-dilution dissolution method. EPO allowed a profound and linear solubility increase of mefenamic acid, from 10 μg/mL without EPO to 9.41 mg/mL in the presence of 7.5% EPO (∼940-fold; 37 °C); however, a concomitant decrease of the drug permeability was obtained, both in vitro and in vivo in rats, indicating a solubility-permeability trade-off. In the absence of an excipient, the unstirred water layer (UWL) adjacent to the GI membrane was found to hinder the permeability of the drug, accounting for this UWL effect and revealing that the true membrane permeability allowed good prediction of the solubility-permeability trade-off as a function of EPO level using a direct relationship between the increased solubility afforded by a given EPO level and the consequent decreased permeability. Biorelevant dissolution studies revealed that EPO levels of 0.05 and 0.1% were insufficient to dissolve mefenamic acid dose during the entire dissolution time course, whereas 0.5 and 1% EPO allowed complete solubility with no drug precipitation. In conclusion, EPO may serve as a potent solubility-enabling excipient for BCS class II/IV acidic drugs; however, it should be used carefully. It is prudent to use the minimal EPO amounts just sufficient to dissolve the drug dose throughout the GIT and not more than that. Excess amounts of EPO provide no solubility gain and cause further permeability loss, jeopardizing the overall success of the formulation. This work may help the formulator to hit the optimal solubility-permeability balance, maximizing the oral bioavailability afforded by the formulation.

Ampholytic and Polyelectrolytic Starch as Matrices for Controlled Drug Delivery

The potential of the polyampholytic and polyelectrolytic starch compounds as excipients for drug controlled release was investigated using various tracers differing in terms of solubility and permeability. Ampholytic trimethylaminecarboxymethylstarch (TMACMS) simultaneously carrying trimethylaminehydroxypropyl (TMA) cationic groups and carboxymethyl (CM) anionic groups was obtained in one-step synthesis in aqueous media. Trimethylaminestarch (TMAS) and carboxymethylstarch (CMS) powders were also synthesized separately and then homogenized at equal proportions in liquid phase for co-processing by spray drying (SD) to obtain polyelectrolytic complexes TMAS-CMS (SD). Similarly, equal amounts of TMAS and CMS powders were dry mixed (DM) to obtain TMAS:CMS (DM). Monolithic tablets were obtained by direct compression of excipient/API mixes with 60% or 80% drug loads. The in vitro dissolution tests showed that ampholytic (TMACMS) and co-processed TMAS-CMS (SD) with selected tracers (one from each class of Biopharmaceutical Classification System (BCS)), were able to control the release even at very high loading (80%). The presence of opposite charges located at adequate distances may impact the polymeric chain organisation, their self-assembling, and implicitly the control of drug release. In conclusion, irrespective of preparation procedure, ampholytic and polyelectrolytic starch materials exhibited similar behaviours. Electrostatic interactions generated polymeric matrices conferring good mechanical features of tablets even at high drug loading.

Gellan Gum/Laponite Beads for the Modified Release of Drugs: Experimental and Modeling Study of Gastrointestinal Release

In this study, gellan gum (GG), a natural polysaccharide, was used to fabricate spherical porous beads suitable as sustained drug delivery systems for oral administration. GG was cross-linked with calcium ions to prepare polymeric beads. Rheological studies and preliminary experiments of beads preparation allowed to identify the GG and the CaCl2 concentrations suitable for obtaining stable and spherical particles. GG beads were formed, through ionotropic gelation technique, with and without the presence of the synthetic clay laponite. The resultant beads were analyzed for dimensions (before and after freeze-drying), morphological aspects and ability to swell in different media miming biological fluids, namely SGF (Simulated Gastric Fluid, HCl 0.1 M) and SIF (Simulated Intestinal Fluid, phosphate buffer, 0.044 M, pH 7.4). The swelling degree was lower in SGF than in SIF and further reduced in the presence of laponite. The GG and GG-layered silicate composite beads were loaded with two model drugs having different molecular weight, namely theophylline and cyanocobalamin (vitamin B12) and subjected to in-vitro release studies in SGF and SIF. The presence of laponite in the bead formulation increased the drug entrapment efficiency and slowed-down the release kinetics of both drugs in the gastric environment. A moving-boundary swelling model with "diffuse" glassy-rubbery interface was proposed in order to describe the swelling behavior of porous freeze-dried beads. Consistently with the swelling model adopted, two moving-boundary drug release models were developed to interpret release data from highly porous beads of different drugs: drug molecules, e.g., theophylline, that exhibit a typical Fickian behavior of release curves and drugs, such as vitamin B12, whose release curves are affected by the physical/chemical interaction of the drug with the polymer/clay complex. Theoretical results support the experimental observations, thus confirming that laponite may be an effective additive for fabricating sustained drug delivery systems.

Methods to Assess Mixing of Pharmaceutical Powders

The pharmaceutical manufacturing process consists of several steps, each of which must be monitored and controlled to ensure quality standards are met. The level of blending has an impact on the final product quality; therefore, it is important to be able to monitor blending progress and identify an end-point. Currently, the pharmaceutical industry assesses blend content and uniformity through the extraction of samples using thief probes followed by analytical methods, such as spectroscopy, to determine the sample composition. The development of process analytical technologies (PAT) can improve product monitoring with the aim of increasing efficiency, product quality and consistency, and creating a better understanding of the manufacturing process. Ideally, these are inline methods to remove issues related to extractive sampling and allow direct monitoring of the system using various sensors. Many technologies have been investigated, including spectroscopic techniques such as near-infrared spectroscopy, velocimetric techniques that may use tracers, tomographic techniques, and acoustic emissions monitoring. While some techniques have demonstrated potential, many have significant disadvantages including the need for equipment modification, specific requirements of the material, expensive equipment, extensive analysis, the location of the probes may be critical and/or invasive, and lastly, the technique may only be applicable to the development phase. Both the advantages and disadvantages of the technologies should be considered in application to a specific system.