An Update of Moisture Barrier Coating for Drug Delivery

Development and evaluation of innovative enteric-coated capsules for colon-specific delivery of hydrophilic biomaterials

OBJECTIVE

This research aims to design and evaluate an enteric-coated hard capsule dosage form for targeted delivery of biological materials, such as FMT (fecal microbiota transplant) or live microbes, to the distal parts of the GIT. The capsules are designed to be internally protected against destruction by hydrophilic filling during passage through the digestive tract.

METHODS

Hard gelatin capsules and DRcapsTMcapsules based on HPMC and gellan were used to encapsulate a hydrophilic body temperature-liquefying gelatin hydrogel with caffeine or insoluble iron oxide mixture. Different combinations of polymers were tested for the internal (ethylcellulose, Eudragit® E, and polyvinyl acetate) and external (Eudragit® S, Acryl-EZE®, and cellacefate) coating. The external protects against the acidic gastric environment, while the internal protects against the liquid hydrophilic filling during passage. Coated capsules were evaluated using standard disintegration and modified dissolution methods for delayed-release dosage forms.

RESULTS

Combining suitable internal (ethylcellulose 1.0 %) and external (Eudragit® S 20.0 %) coating of DRcapsTM capsules with the wiping and immersion method achieved colonic release times. While most coated capsules met the pharmaceutical requirements for delayed release, one combination stood out. Colonic times were indicated by the dissolution of soluble caffeine (during 120-720 min) measured by the dissolution method, and capsule rupture was indicated by the release of insoluble iron oxide (after 480 min) measured by the disintegration method. This promising result demonstrates the composition's suitability and potential to protect the content until it's released, inspiring hope for the future of colon-targeted delivery systems and its potential for the pharmaceutical and biomedical fields.

CONCLUSION

Innovative and easy capsule coatings offer significant potential for targeted drugs, especially FMT water suspension, to the GIT, preferably the colon. The administration method is robust and not considerably affected by the quantity of internal or external coatings. It can be performed in regular laboratories without specialized individual and personalized treatment equipment, making it a practical and feasible method for drug delivery.

Understanding the effect of plasticizers in film coat materials on the physical stability of amorphous solid dispersions

Amorphous solid dispersions (ASDs) have been extensively utilized to improve the bioavailability of drugs that have low aqueous solubility. The influence of different excipients on the conversion of amorphous drugs into their crystalline forms in ASDs has been extensively researched. However, there is limited knowledge examining the impact of film coating materials on the physical stability of oral tablet formulations containing ASDs. In this study, we demonstrate that plasticizers present in film coats can have a detrimental impact on the physical stability of ASDs. We systematically compared two frequently used plasticizers in film coats: triacetin and polyethylene glycol 3350 (PEG 3350). To gain mechanistic insights into the detrimental effects of plasticizers on the physical stability of ASDs, plasticizer leaching studies and physical stability studies of solvent-evaporated and spray-dried intermediates (SDI) using two BCS class II drugs were conducted. Triacetin was found to leach into the tablet core within one week when stressed at 40 °C/75 % RH, whereas no leaching was observed for PEG 3350, as discerned from spectroscopic studies. We also found that triacetin-containing ASDs exhibited greater amorphous to crystalline form conversion of the drug compared to PEG 3350-containing ASDs after stability testing. Moreover, the incorporation of triacetin into polymers was found to cause a significant depression of glass transition temperature and upon equilibration with moisture, a drop below room temperature. Overall, these observations underscore the importance of carefully selecting plasticizers to be present in film coatings when developing ASD pharmaceutical products.

Polyvinyl alcohol-based capsule shells manufactured by injection molding as ready-to-use moisture barriers for the development of delivery systems

In this work, feasibility of injection molding was demonstrated for manufacturing capsule shells. 600 µm-thick prototypes were successfully molded with pharmaceutical-grade low-viscosity polyvinyl alcohols (PVAs), possibly added with a range of different fillers. They showed reproducible weight and thickness (CV < 2 and 5, respectively), compliant behavior upon piercing (holes diameter analogous to the reference), tunable release performance (immediate and pulsatile), and moisture protection capability. To assess the latter, an on-line method relying on near infrared spectroscopy measurements was set-up and validated. Based on the data collected and considering the versatility IM would provide for product shape/thickness/composition, PVA-based molded shells could help widening the portfolio of ready-to-use capsules, representing an interesting alternative to those commercially available. Indeed, these capsules could be filled with various formulations, even those with stability issues, and intended either for oral administration or for pulmonary delivery via single-dose dry powder inhalers.

Trends in amorphous solid dispersion drug products approved by the U.S. Food and Drug Administration between 2012 and 2023

Forty-eight (48) drug products (DPs) containing amorphous solid dispersions (ASDs) have been approved by the U.S. Food and Drug Administration in the 12-year period between 2012 and 2023. These DPs comprise 36 unique amorphous drugs. Ten (10) therapeutic categories are represented, with most DPs containing antiviral and antineoplastic agents. The most common ASD polymers are copovidone (49%) and hypromellose acetate succinate (30%), while spray drying (54%) and hot melt extrusion (35%) are the most utilized manufacturing processes to prepare the ASD drug product intermediate (DPI). Tablet dosage forms are the most common, with several capsule products available. Line extensions of several DPs based on flexible oral solids and powders for oral suspension have been approved which provide patient-centric dosing to pediatric and other patient populations. The trends in the use of common excipients and film coating types are discussed. Eighteen (18) DPs are fixed-dose combinations, and some contain a mixture of amorphous and crystalline drugs. The DPs have dose/unit of amorphous drug ranging from <5 mg up to 300 mg, with the majority being ≤100 mg/unit. This review details several aspects of DPI and DP formulation and manufacturing of ASDs, as well as trends related to therapeutic category, dose, and patient-centricity.

Improving Inhalation Performance with Particle Agglomeration via Combining Mechanical Dry Coating and Ultrasonic Vibration

Agglomerate formulations for dry powder inhalation (DPI) formed with fine particles are versatile means for the highly efficient delivery of budesonide. However, uncontrolled agglomeration induces high deposition in the upper airway, causing local side effects due to high mechanical strength, worse deagglomeration, and poor fine-particle delivery. In the present study, fine lactose was mechanically dry-coated prior to particle agglomeration, and the agglomerates were then spheroidized via ultrasonic vibration to improve their aerosol performance. The results showed that the agglomerate produced with the surface-enriched hydrophobic magnesium stearate and ultrasonic vibration demonstrated improved aerosolization properties, benefiting from their lower mechanical strength, less interactive cohesive force, and improved fine powder dispersion behavior. After dispersion utilizing a Turbuhaler® with a pharmaceutical cascade impactor test, a fine particle fraction (FPF) of 71.1 ± 1.3% and an artificial throat deposition of 19.3 ± 0.4% were achieved, suggesting the potential to improve the therapeutic outcomes of budesonide with less localized infections of the mouth and pharynx.

Exploring the complexities of drug formulation selection, storage, and shelf-life for exploration spaceflight

Medications have been a part of space travel dating back to the Apollo missions. Currently, medical kits aboard the International Space Station (ISS) contain medications and supplies to treat a variety of possible medical events. As we prepare for more distant exploration missions to Mars and beyond, risk management planning for astronaut healthcare should include the assembly of a medication formulary that is comprehensive enough to prevent or treat anticipated medical events, remains safe and chemically stable, and retains sufficient potency to last for the duration of the mission. Emerging innovation and technologies in pharmaceutical development, delivery, quality maintenance, and validation offer promise for addressing these challenges. The present editorial will summarize the current state of knowledge regarding innovative formulary optimization strategies, pharmaceutical stability assessment techniques, and storage and packaging solutions that could enhance drug safety and efficacy for future exploration spaceflight missions.

Formulation Strategies to Improve the Stability and Handling of Oral Solid Dosage Forms of Highly Hygroscopic Pharmaceuticals and Nutraceuticals

Highly hygroscopic pharmaceutical and nutraceutical solids are prone to significant changes in their physicochemical properties due to chemical degradation and/or solid-state transition, resulting in adverse effects on their therapeutic performances and shelf life. Moisture absorption also leads to excessive wetting of the solids, causing their difficult handling during manufacturing. In this review, four formulation strategies that have been employed to tackle hygroscopicity issues in oral solid dosage forms of pharmaceuticals/nutraceuticals were discussed. The four strategies are (1) film coating, (2) encapsulation by spray drying or coacervation, (3) co-processing with excipients, and (4) crystal engineering by co-crystallization. Film coating and encapsulation work by acting as barriers between the hygroscopic active ingredients in the core and the environment, whereas co-processing with excipients works mainly by adding excipients that deflect moisture away from the active ingredients. Co-crystallization works by altering the crystal packing arrangements by introducing stabilizing co-formers. For hygroscopic pharmaceuticals, coating and co-crystallization are the most commonly employed strategies, whereas coating and encapsulation are popular for hygroscopic nutraceuticals (e.g., medicinal herbs, protein hydrolysates). Encapsulation is rarely applied on hygroscopic pharmaceuticals, just as co-crystallization is rarely used for hygroscopic nutraceuticals. Therefore, there is potential for improved hygroscopicity reduction by exploring beyond the traditionally used strategy.

Flame Retardant Coatings: Additives, Binders, and Fillers

This review provides an intensive overview of flame retardant coating systems. The occurrence of flame due to thermal degradation of the polymer substrate as a result of overheating is one of the major concerns. Hence, coating is the best solution to this problem as it prevents the substrate from igniting the flame. In this review, the descriptions of several classifications of coating and their relation to thermal degradation and flammability were discussed. The details of flame retardants and flame retardant coatings in terms of principles, types, mechanisms, and properties were explained as well. This overview imparted the importance of intumescent flame retardant coatings in preventing the spread of flame via the formation of a multicellular charred layer. Thus, the intended intumescence can reduce the risk of flame from inherently flammable materials used to maintain a high standard of living.

An Integrative QbD Approach for the Development and Optimization of Controlled Release Compressed Coated Formulation of Water-Soluble Drugs

Controlled release dosage forms maintain regulated pharmacokinetic profile of drug substance within its therapeutic window by ensuring constant plasma concentrations. Controlled release formulations not only increase the therapeutic efficacy of drug substances but also reduce their dose-related side effects. Present investigation was conducted to develop, optimize, and validate compressed coated controlled release tablet formulation for highly water-soluble drug substances which have no rate-controlling factor towards its release from dosage form. Drug dispersed waxy core tablet, press coated within the swellable hydrophilic polymeric barrier layer, was developed and optimized via quality by design approach (QbD) using Box-Behnken design. The optimized formulation was characterized and validated using in vitro quality control parameters. Attributes identified under SUPAC guidelines, such as drug release rates at 30 min, 6 h, and 12 h, were considered as the critical quality attributes (CQAs) that significantly affected efficiency of the compressed coated controlled release tablets. CQAs screened using risk assessment and Pareto chart analyses were used for optimizing controlled release dosage form. Findings revealed that tablets containing drug to wax ratio of 1:1, hydrophilic swellable polymer concentration of 200 mg, and prepared using compression pressure of 6.5 kg/cm² exhibited the highest desirability indices in terms of controlling the release rate of drug substance. Optimized formulation was also evaluated for swelling rate, erosion rate, and other post-compression parameters, including release kinetics. Fickian diffusion-based zero-order controlled release of BCS class I drug substance was achieved through the developed dosage form.

Data-Enriched Edible Pharmaceuticals (DEEP) with Bespoke Design, Dose and Drug Release

Data-enriched edible pharmaceuticals (DEEP) is an approach to obtain personalized medicine, in terms of flexible and precise drug doses, while at the same time containing data, embedded in quick response (QR) codes at a single dosage unit level. The aim of this study was to fabricate DEEP with a patient-tailored dose, modify drug release and design to meet patients' preferences. It also aimed to investigate physical stability in terms of the readability of QR code patterns of DEEP during storage. Cannabinoids, namely, cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC), were used as the model active pharmaceutical ingredients (APIs). Three different substrates and two colorants for the ink were tested for their suitability to fabricate DEEP by desktop inkjet printing. Flexible doses and customizable designs of DEEP were obtained by manipulating the digital design of the QR code, particularly, by exploring different pattern types, embedded images and the physical size of the QR code pattern. Modification of the release of both APIs from DEEP was achieved by applying a hydroxypropyl cellulose (HPC) polymer coating. The appearance and readability of uncoated and polymer-coated DEEP did not change on storage in cold and dry conditions; however, the HPC polymer layer was insufficient in preserving the readability of the QR code pattern in the extreme storage condition (40 °C and 75% relative humidity). To sum up, the DEEP concept provides opportunities for the personalization of medicines, considering also patients' preferences.

Lipid-Polymeric Films: Composition, Production and Applications in Wound Healing and Skin Repair

The use of lipids in the composition of polymeric-based films for topical administration of bioactive ingredients is a recent research topic; while few products are commercially available, films containing lipids represent a strategic area for the development of new products. Some lipids are usually used in polymeric-based film formulations due to their plasticizing action, with a view to improving the mechanical properties of these films. On the other hand, many lipids have healing, antimicrobial, anti-inflammatory, anti-aging properties, among others, that make them even more interesting for application in the medical-pharmaceutical field. This manuscript discusses the production methods of these films both on a laboratory and at industrial scales, the properties of the developed biopolymers, and their advantages for the development of dermatologic and cosmetic products.

Sounding out stability of enteric coated dosage forms using Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS)

Stability testing is essential in the pharmaceutical industry to determine product shelf- life and the conditions under which drug products should be stored. Stability testing involves a complex set of procedures, considerable cost, time, and scientific expertise to build quality, efficacy and safety in a drug formulation. This paper highlights a new complementary approach to stability testing called Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS). BARDS measurements are based on reproducible changes in the compressibility of a solvent during dissolution. It is monitored acoustically via associated changes in the frequency of induced acoustic resonances. This study presents a novel approach to track the change of various drug formulations to determine the formulation's stability. Pellets, tablet and multiple-unit pellet system (MUPS) formulations were investigated to examine the effect of polymer coating and formulation core degradation over time. In combination with minimal usage of Ultra Violet - Visible Spectroscopy, BARDS can effectively track these changes. The technique offers a rapid approach to characterizing pharmaceutical formulations. BARDS can enable rapid development of solid drug formulation dissolution and disintegration testing as an In-Process Control test and drug stability analysis. The data show that a solid oral dose formulation has an intrinsic acoustic signature specific to the method of manufacture, excipient composition and elapsed time since the production of a product. BARDS data are also indicative of which aspect of a formulation may be unstable, whether a coating, sub-coating or core. It is potentially a time-efficient, cost-effective and greener approach to testing coating stability, disintegration and overall formulation stability.

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.

Evaluation of Experimental Multi-Particulate Polymer-Coated Drug Delivery Systems with Meloxicam

The objectives of this study are the development and evaluation of modified release multi-particulate drug delivery systems containing a BCS class II drug (meloxicam), formulated as polymer-coated pellets. Inert seeds containing microcrystalline cellulose, lactose monohydrate, and polyvinylpyrrolidone were prepared by extrusion-spheronization. The obtained cores were loaded with meloxicam using the drug layering technique, by spray coating in a fluidized bed with a liquid dispersion of the drug. The resulting drug pellets were film-coated with various polymers (Acryl-EZE® 93O, Eudragit® RS 30-D as well as experimental composite obtained by adding Methocel™ E5 Premium LV as pore forming agent to the extended release polymer Eudragit® RS 30-D). All experimental systems were evaluated by scanning electron microscopy and in vitro release testing, in an attempt to investigate the characteristics of the film coatings and their influence on drug release from the multi-particulate systems. The in vitro release study was performed in two stages, using two media with pH values corresponding to the gastric and intestinal environment (HCl 0.1N, pH = 1.2 for the first two hours of the test and phosphate buffer 50 mM, pH 6.8 for the next 4 h). The in vitro release data have highlighted the impact of the formulation factors on the drug release.