Terahertz-spectroscopy for non-destructive determination of crystallinity of L-tartaric acid in smartFilms® and tablets made from paper

Curcumin- β-Cyclodextrin Molecular Inclusion Complex: A Water-Soluble Complex in Fast-dissolving Tablets for the Treatment ofNeurodegenerative Disorders

BACKGROUND

Orally disintegrating tablets (ODTs) have become an excellent choice for delivering drugs as their palatability is greatly improved. In this work, β-cyclodextrin has been used to improve the solubility of curcumin by encapsulating it into the hydrophobic cavity for the treatment of neurodegenerative disorders.

OBJECTIVES

The current study aimed to present the design, formulation, and optimisation of fastdissolving oral tablets of curcumin- β-cyclodextrin molecular inclusion complex using a 32-factorial design.

METHODS

The drug-excipient compatibility was studied by FTIR spectroscopy. The inclusion complex of curcumin-β-cyclodextrin was prepared using solvent casting and confirmed using XRD studies. Powder blends were evaluated for flow properties. Tablets prepared by direct compression were evaluated for post-compression parameters. Further, the effect of formulation variables, such as sodium starch glycolate (X1) and Neusilin® ULF2 (X2), on various responses, including disintegration time and dissolution at 2 hours, was studied using statistical models.

RESULTS

Post-compression parameters, i.e., hardness (4.4-5 kg/cm2), thickness (3.82-3.93 mm), weight variation (±7.5%), friability (< 1%), wetting time (51-85 seconds) and drug content (96.28- 99.32%) were all found to be within the permissible limits and the disintegration time of tablets with super-disintegrants ranged between 45-58 seconds. The in-vitro dissolution profile of tablets showed that higher SSG and Neuslin® ULF2 levels promoted drug release. For statistical analysis, the 2FI model was chosen. Optimised variables for formulation have been determined and validated with the experimental findings based on the significant desirability factor.

CONCLUSION

The current study reveals the validated curcumin-β-cyclodextrin inclusion complex fastdissolving tablets with SSG and Neusilin® ULF2 to be an ideal choice for effectively treating neurodegenerative disorders.

Terahertz Spectroscopy for Non-Destructive Solid-State Investigation of Norfloxacin in Paper Tablets after Wet Granulation

(1) Background: Amorphous drug systems are an intensively studied approach to overcome the insufficient bioavailability of poorly soluble drugs. Here, paper tablets were studied, which were made from cellulose-based paper matrices loaded with norfloxacin. Moreover, wet granulation was introduced as an additional processing step for improving the flowability of the solids, which is necessary when considering production on an industrial scale. (2) Methods: The possible impact of the wet granulation on the crystallinity of norfloxacin was studied by examining granulated and non-granulated samples. Crystallinity investigations were performed using X-ray powder diffraction (XRD) and terahertz time-domain spectroscopy (THz TDS). (3) Results: THz TDS allowed for a more straightforward crystallinity assessment than XRD. Moreover, using THz TDS, it was possible to detect minor changes in the crystallinity of the API after the granulation, whereas this was not possible with the XRD analysis. (4) Conclusions: THz TDS results indicate a partial crystallization of norfloxacin due to the wet granulation. Depending on the formulation, THz TDS can serve as a beneficial and advantageous tool to determine the crystallinity of an API.

Polyvinylpyrrolidone as co-inhibitor of crystallization of nifedipine in paper tablets

Techniques to maintain drugs amorphous that would otherwise crystallize is an extensively studied approach to enhance the dissolution characteristics of poorly soluble drugs. However, their performance is limited by the low physical stability of the amorphous phase which can lead to recrystallization which in turn results in decreased solubility and bioavailability of the drug. In this work, the crystallinity of nifedipine loaded into a cellulose-based paper matrix, so called smartFilms, was determined by terahertz time-domain spectroscopy. By adding polyvinylpyrrolidone as an extra carrier, the capability of smartFilms to transfer nifedipine into its amorphous state improved. Moreover, the performance of the formulation to inhibit recrystallization of the amorphous drug over a period of six months increased. For formulations containing up to 10 w% drug loading and additional polyvinylpyrrolidone (nifedipine/polyvinylpyrrolidone: 4:1 mass ratio), nifedipine was found to be completely amorphous after six months of storage.

Tablets Made from Paper—An Industrially Feasible Approach

Many orally administrated drugs exhibit poor bioavailability due to their limited solubility. The smartFilm technology is an innovative approach to improve the drug aqueous solubility, where the drug is embedded within the matrix of cellulose-based paper in an amorphous state, hence increasing its solubility. Despite its proven effectiveness, smartFilms, i.e., pieces of paper, exhibit limited flowability and are not easy to swallow, and thus oral administration is not convenient. In addition, there is a lack of knowledge of their mechanical behavior under compression. This study aimed to transform unloaded smartFilms, i.e., paper, into a flowable physical form and investigated its mechanical behavior when compressed. Granules made of paper were prepared via wet granulation and were compressed into tablets. The influence of using different amounts and forms of sucrose, as a binder, on the pharmaceutical properties of the produced granules and tablets was studied and the most suitable composition was identified by using instrumented die experiments. For this, the Poisson’s ratio and Young’s modulus were determined for different compaction force levels and the deformation behavior was estimated with the Heckel mathematical model. All granule batches showed good flowability with angle of repose values between 25–35°. Granule batches with ≤30% dry sucrose content produced tablets that fulfilled the European Pharmacopeia requirements, and the compaction behavior of the granules was found to be comparable to the behavior of classical binders and compression enhancers. Paper can be transferred into granules. These granules can be used as suitable intermediate products for the production of tablets made of paper in large, industrial scale.

SmartFilm Tablets for Improved Oral Delivery of Poorly Soluble Drugs

(1) Background: Numerous oral drugs exhibit limited bioavailability due to their poor solubility and poor intestinal permeability. The smartFilm technology is an innovative approach that improves the drug aqueous solubility via incorporating the drug in an amorphous state into a cellulose-based matrix, i.e., paper. smartFilms can be transformed into a free-flowing physical form (i.e., paper granules) that can be compressed into tablets with optimum physico-chemical and pharmaceutical properties. The aim of this study was to investigate if smartFilm tablets are suitable for improved oral delivery of poorly water-soluble drugs. (2) Methods: Curcumin is a poorly soluble drug with low intestinal permeability and was used for the production of curcumin-loaded smartFilms. The curcumin-loaded smartFilms were transferred into smartFilm granules which were then compressed into curcumin-loaded smartFilm tablets. The tablets were characterized regarding their physico-chemical and pharmaceutical properties, and the intestinal permeability of curcumin was determined with the ex vivo porcine intestinal model. The ex vivo intestinal permeability of curcumin from the smartFilm tablets was compared to a physical mixture of curcumin and paper and to a classical and to an innovative commercial product, respectively. (3) Results: The produced curcumin-loaded smartFilm tablets fulfilled the European Pharmacopoeia requirements, incorporated curcumin in amorphous state within the cellulose matrix and exhibited an enhanced dissolution rate. The ex vivo intestinal permeation data were shown to correlate to the in vitro dissolution data. The ex vivo intestinal permeation of curcumin from the smartFilm tablets was about two-fold higher when compared to the physical mixture and the classical commercial product. No differences in the ex vivo bioavailability were found between the smartFilm tablets and the innovative commercial product. (4) Conclusions: smartFilm tablets are a cost-effective and industrially feasible formulation approach for the formulation of poorly water-soluble drugs, i.e., BCS class II and IV drugs.

Non-destructive crystallinity assessment of indomethacin in tablets made from smartFilms® using terahertz time-domain spectroscopy

We use terahertz (THz) time-domain spectroscopy (TDS) to assess the crystalline state of indomethacin (IM) when loaded in smartFilms®. We found that smartFilms favour the amorphous IM (A-IM) for low loading concentrations. For higher concentrations, IM recrystallizes in its \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha$$\end{document}α- crystalline form and the amount of A-IM in the smartFilms reduces. Both, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha$$\end{document}α- and A-IM are preferred over the more common \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\gamma$$\end{document}γ- crystalline form, as they exhibit better water solubility, which can increase the oral bioavailability of the drug.