Development and evaluation of mucoadhesive buccal dosage forms of lidocaine hydrochloride by ex-vivo permeation studies

Current State of Minitablet Product Design: A Review

Interest in minitablets (MTs) has grown exponentially over the last 20 years and especially the last decade, as evidenced by the number of publications cited in Scopus and PubMed. MTs offer significant opportunities for personalized medicine, dose titration and flexible dosing, taste masking, and customizing drug delivery systems. Advances in specialized MT tooling, manufacturing, and characterization instrumentation have overcome many of the earlier development issues. Breakthrough MT swallowability, acceptability, and palatability research have challenged the long-standing idea that only liquids are acceptable dosage forms for infants and young children. MTs have been shown to be a highly acceptable dosage form for infants, small children, and geriatric patients who have difficulty swallowing. This review discusses the current state of MT applications, acceptability in pediatric and geriatric populations, medication adherence, manufacturing processes such as tableting and coating, running powder and tablet characterization, packaging and MT dispensing, and regulatory considerations.

Fabrication, optimization, and evaluation of lyophilized lacidipine-loaded fatty-based nanovesicles as orally fast disintegrating sponge delivery system

Lacidipine (LCD) is a potent antihypertensive agent. Fatty-based nanovesicles (FNVs) were designed to improve LCD low solubility and bioavailability. LCD-FNVs were formulated according to different proportions of cetyl alcohol, cremophor®RH40, and oleic acid adopting Box-Behnken Design. The optimized LCD-FNVs, composed of cetyl alcohol 48.4 mg, cremophor®RH40 120 mg, and oleic acid 40 mg, showed minimum vesicle size (124.8 nm), maximum entrapment efficiency % (91.04 %) and zeta potential (-36.3 mV). The optimized FNVs were then used to formulate the lyophilized orally fast-disintegrating sponge (LY-OFDS). The LY-OFDS had a very short disintegration time (58 sec), remarkably high % drug release (100 % after 15 mins), and increased the drug transbuccal permeation by over 9.5-fold compared to the drug suspension. In-vivo evaluation of antihypertensive activity in rats showed that the LY-OFDS reduced blood pressure immediately after 5 min and reached normal blood pressure 4.5-fold faster than the marketed oral tablets. In the In-vivo pharmacokinetic study in rabbits, the LY-OFDS showed 4.7-fold higher bioavailability compared with the marketed oral tablet. In conclusion, the LY-OFDS loaded with LCD-FNVs is a safe, and non-invasive approach that can deliver LCD effectively to the blood circulation via the buccal mucosa giving superior immediate capabilities of lowering high blood pressure and increasing the drug bioavailability.

Optimal delivery of poorly soluble drugs using electrospun nanofiber technology: Challenges, state of the art, and future directions

Poor aqueous solubility of both, existing drug molecules and those which are currently in the developmental stage, have posed a great challenge to pharmaceutical scientists because they often exhibit poor dissolution behavior and subsequent poor and erratic bioavailability. This has triggered extensive research to explore nanotechnology-based technology platforms for possible rescue. Recently, nanofibers have been exploited widely for diverse biomedical applications including for drug delivery. Electrospun nanofibers are capable of preserving the homogeneously loaded therapeutic agents in amorphous state potentialy impairing devitrification. The present review aims at providing an overview of the various key factors that affect the electrospinning process and characteristics of the nanofibers while fabrication of drug loaded nanofibers for poorly soluble drug candidates. The review explores various methodological advancements in the electrospinning process and set-ups for production scale-up. The various types of electrospun nanofibers (like simple matrix, core-sheath, Janus, and inclusion complex nanofibers) that have been exploited for the delivery of poorly soluble drugs are also critically assessed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Development of buccal film formulations and their mucoadhesive performance in biomimetic models

When developing buccal films for oromucosal drug administration, adhesion is essential to ensure sufficient time for permeation of the active ingredient(s) through the oral mucosa and avoid the detachment and subsequent swallowing of the film. In this study, biomimetic materials were evaluated as a replacement for buccal mucosa in mucoadhesion testing and potential adhesives were compared regarding their suitability to increase the adhesion of hypromellose-based oromucosal films. Gelatin gels, as possible biomimetics, failed to mimic the buccal mucosa. Furthermore, esophageal tissue lead to a wider variance of adhesion data despite showing a good correlation with buccal tissue. A synthetic copolymer hydrogel based on hydroxyethylmethacrylate (HEMA) and N-acryloyl glucosamine (AGA) was able to mimic the buccal mucosa in these tests and reduced the variation in the data compared to animal tissue. Adding polyacrylic acid and polyvinylpyrrolidone to the film formulations at a concentration of 5% w/w approximately doubled the maximum detachment force and work of adhesion. Sodium alginate enhanced the adhesive properties moderately but adding chitosan did not significantly increase mucoadhesion. Polyvinylpyrrolidone and polyacrylic acid are rated as strong adhesion enhancers for buccal films and the HEMA/AGA hydrogel is considered as a suitable alternative for animal mucosa in mucoadhesion testing.

Micellar buccal film for safe and effective control of seizures: Preparation, in vitro characterization, ex vivo permeation studies and in vivo assessment

The current research article focused on formulating an easily applied, water-based buccal film loaded with the antiepileptic drug, lamotrigine (LTG). The designed film can be comfortably administered by epileptic patients to ensure a controllable therapeutic efficacy against seizures. The solubility of LTG in water was significantly improved by micellar solubilization. Upon testing several surfactants, three of them (Synperonic PE/P84, Brij L23, and Brij 78) achieved maximum possible solubility for LTG and were characterized for their micellar size, cloud point, and % transmittance. Selected micellar systems were incorporated within a buccal film prepared using solvent casting method based on either gelatin or polyvinylpyrrolidone (3%w/v) with 1.5%w/v propylene glycol as a plasticizer. Different micellar films were characterized for their physicochemical characteristics, swelling index, folding endurance, drug content uniformity, and in vitro LTG release. From the tested formulations, one formulation; LTG-BF1 (in which Brij 78 was used for the micellar solubilization and gelatin as the matrix former), was selected as the optimum and extensively studied for mucoadhesion, ex vivo permeation studies by Franz diffusion cells and confocal laser scanning microscopy. Results showed superior enhanced permeation of micellar film. LTG-BF1 was evaluated for the in vivo performance using rats. Status epilepticus was induced in rats by injecting Pentylenetetrazol (PTZ) i.p. at an initial dose of 30 mg/kg, followed by 10 mg/kg every10 min till 60 min. A group of rats receiving the designed buccal formulation (20 mg/kg) was compared with a group receiving the same dose of the oral market product and the normal control and PTZ groups. Rats receiving LTG-BF1 recorded reduced seizure scores at all stages, longer latency time, and higher threshold PTZ dose compared to PTZ and market product groups. In addition, LTG-BF1 reduced brain concentrations of TNF-α and TGF-β with an elevation of EAAT2 and GABA brain contents compared to PTZ and market product groups and ameliorated neuronal damage. In conclusion, LTG-loaded buccal micellar film proved a superior antiepileptic effect in PTZ induced acute epileptic model.

Development and optimization of tibezonium iodide and lignocaine hydrochloride containing novel mucoadhesive buccal tablets: A pharmacokinetic investigation among healthy humans

OBJECTIVE

It is clinically important to deliver sustained-release mucoadhesive dosage of local anesthetic and antimicrobial agent for pain control. The current study aimed to develop and evaluate chitosan (CHI) based buccal mucoadhesive delivery for local release of tibezonium iodide (TBN) and lignocaine hydrochloride (LGN).

METHODS

Direct compression technique was employed, aided by other mucoadhesive polymers like hydroxypropylmethylcellulose (HPMC) and sodium alginate (SA) and evaluated for physicochemical and in vivo character.

RESULTS

Fourier transform infrared spectral analysis (FTIR), powdered X-ray diffraction (XRPD), and differential scanning calorimetry (DSC) absence of physical interaction between ingredients. The physical parameters complied with USP specifications for all formulations. Optimum swellability (551.9%) was offered from formulation TL15, containing 30% SA. Highest ex vivo mucoadhesive strength (24.79 g) and time (18.39 h) was found with TL8. Formulation TL8 also exhibited maximum in vivo residence time (11.37 h). Almost complete drug release at 6 h was possessed by formulation TL5 (HPMC and CHI, 20% each) for TBN (99.98%) and LGN (99.06%). The optimized formulation TL5 exhibited dosage stability up to 6 months at 75% relative humidity and retained drug contents. TL5 was well tolerated by the volunteers with no inflammation, pain or irritation found. Almost 73% of volunteers reported an increase in salivary secretion. The first-order salivary C_max of TBN and LGN were found as 16.02 and 7.80 µg/mL within 4 h, respectively.

CONCLUSION

Therefore, the sustained release mucoadhesive dosage form of TBN and LGN can be an effective and alternative option to conventional delivery.

Predictivity of Standardized and Controlled Permeation Studies: Ex vivo - In vitro - In vivo Correlation for Sublingual Absorption of Propranolol

In preclinical drug development, ex vivo and in vitro permeability studies are a decisive element for specifying subsequent development steps. In this context, reliability, physiological alignment and appropriate in vivo correlation are mandatory for predictivity regarding drug absorption. Especially in oromucosal drug delivery, these prerequisites are not adequately met, which hinders its progressive development and results in the continuous need for animal experiments. To address current limitations, an innovative, standardized, and controlled ex vivo permeation model was applied. It is based on Kerski diffusion cells embedded in automated sampling and coupled to mass spectrometric quantification under physiologically relevant conditions. This study aimed to evaluate the predictivity of the developed model using porcine mucosa (ex vivo) in relation to data of sublingual propranolol absorption (in vivo). In addition, the usefulness of biomimetic barriers (in vitro) as a replacement for porcine mucosa was investigated. Therefore, solubility and permeability studies considering microenvironmental conditions were conducted and achieved good predictivity (R²=0.997) for pH-dependent permeability. A multiple level C correlation (R²≥0.860) between obtained permeability and reported pharmacokinetic animal data (AUC, C_max) was revealed. Furthermore, a point-to-point correlation was demonstrated for several sublingual formulations. The successful IVIVC confirms the standardized ex vivo model as a viable alternative to animal testing for estimating the in vivo absorption behavior of oromucosal pharmaceuticals.

Exploring the transmucosal permeability of cyclobenzaprine: A comparative preformulation by standardized and controlled ex vivo and in vitro permeation studies

As part of early drug development, preformulation studies are used to comprehensively explore the properties of new drugs. In particular, this includes the biopharmaceutical characterization and evaluation of impacting factors (e.g. excipients, microenvironmental conditions etc.) by permeation studies. To overcome the limitations of current studies, a novel standardized ex vivo procedure using esophageal mucosa as surrogate has been established successfully and applied to preformulation studies for oromucosal delivery of cyclobenzaprine hydrochloride, a tricyclic muscle relaxant with potential for psychopharmacotherapeutic use. By using the standardized ex vivo permeation process, a twofold enhancement of permeability (0.98 ± 0.16 to 1.96 ± 0.10 * 10^-5 cm/s) was observed by adjustment and controlling of microenvironmental pH, empowering a targeted and effective development of sublingual formulations. Predictivity and suitability were superior compared to in vitro experiments using artificial biomimetic membranes, revealing a determination coefficient (R²) of 0.995 vs. 0.322 concerning pH-dependent permeability of cyclobenzaprine. In addition, diffusion properties were extensively examined (e.g. influence of mucosal thicknesses, tissue freezing etc.). The alignment of the study design regarding physiologically/clinically relevant conditions resulted in ex vivo data that allowed for the estimation of plasma AUC levels in the extend of reported in vivo ranges.

Luliconazole loaded lyotropic liquid crystalline nanoparticles for topical delivery: QbD driven optimization, in-vitro characterization and dermatokinetic assessment

Fungal infections are an important cause of morbidity and pose a serious health concern especially in immunocompromised patients. Luliconazole (LUL) is a topical imidazole antifungal drug with a broad spectrum of activity. To overcome the limitations of conventional dosage forms, LUL loaded lyotropic liquid crystalline nanoparticles (LCNP) were formulated and characterized using a three-factor, five-level Central Composite Design of Response Surface Methodology. LUL loaded LCNP showed particle size of 181 ± 12.3 nm with an entrapment efficiency of 91.49 ± 1.61 %. The LUL-LCNP dispersion in-vitro drug release showed extended release up to 54 h. Ex-vivo skin permeation studies revealed transdermal flux value (J) of LUL-LCNP gel (7.582 μg/h/cm²) 2 folds higher compared to marketed cream (3.3706 μg/h/cm²). The retention of LUL in the stratum corneum was ∼1.5 folds higher and ∼2 folds higher in the epidermis and other deeper layers in comparison to the marketed cream. The total amount of drug penetrated (AUC_0-∞) with LCNP formulation was 4.7 folds higher in epidermis and 6.5 folds higher in dermis than marketed cream. The study's findings vouch that LCNP can be a promising and effective carrier system for the delivery of antifungal drugs with enhanced skin permeation.

Development, validation and standardization of oromucosal ex-vivo permeation studies for implementation in quality-controlled environments

Tissue-based ex-vivo studies on the oromucosal permeability of drugs are often insufficiently adapted to physiological and clinical conditions, which limits their predictivity. Moreover, the scientific community demands for the standardization of ex-vivo studies, since conceptual limitations (e.g. low sensitivity of analytical methods, insufficient monitoring, different designs) restrict the wide implementation in preclinical drug development. Therefore, an innovative ex-vivo permeation process consisting of novel Kerski diffusion cell coupled to fully automated sampling and sample preparation with LC-MS/MS quantification was developed and standardized. Novel assays for routine examination of tissue integrity and viability were developed and embedded in a comprehensive analytical control system. The high level of standardization and automation reduced the differences of between-run to within-run precision to ≤ 0.27 % CV. Successful validation proved a broad calibration range of 0.93-952.38 ng/mL of the model drug cyclobenzaprine with guideline-compliant relative errors from -7.9-12.6 % (between-run accuracy). Consequently, the method allowed the physiological-clinical alignment of the study conditions to therapeutic doses and the short residence time of intraoral drugs (sampling times 1-60 min). Applicability was demonstrated by assessing the oromucosal permeability for different sublingual cyclobenzaprine hydrochloride formulations representing the excipient selection as a common aspect during galenic development. Thereby, expressive evaluation of the dosage forms was achieved resulting in an improved permeation by replacing croscarmellose into polyvinylpyrrolidone (cumulative amount of 42.6 vs. 112.6 μg/cm²). Thus, the automated permeation process ensured lean, standardized and reproducible assessment of oromucosal permeability within quality-controlled academic and regulatory environments. Simultaneously, the improved ex-vivo predictivity through physiological-clinical adjustments facilitates the reduction of costly in-vivo studies.

Freeze-Dried Matrices for Buccal Administration of Propranolol in Children: Physico-Chemical and Functional Characterization

Buccal matrices represent a widely accepted dosage form permitting a convenient, easy, reliable drug administration and reducing administration errors. The aim of this study was the development of mucoadhesive buccal matrices for propranolol administration in children. Matrices were obtained by freeze-drying of drug loaded polymeric solutions based on gum tragacanth (GT), pectin (PEC), hydroxypropylmethylcellulose (HPMC), sodium hyaluronate (HA), gelatin (GEL), chitosan (CH) or a mixture of CH and HPMC (CH/HPMC). Matrices were characterized for drug solid state, morphology, water-uptake, mucoadhesion ability, in vitro drug release and permeation through porcine epithelium. The most promising formulations were tested for in vitro biocompatibility in human dental pulp fibroblasts. The preparative method and the polymeric composition influenced the drug solid state, as a complete amorphization as well as different polymorphic forms were observed. GEL and PEC guaranteed a fast and complete drug release due to their rapid dissolution, while for the other matrices the release was influenced by drug diffusion through the viscous gelled matrix. Moreover, matrices based on CH and CH/HPMC showed the best mucoadhesive properties, favoured the drug permeation, in virtue of CH ability to interfere with the lipid organization of biological membrane, and were characterized by a good biocompatibility profile.

Quantification of atovaquone from amorphous solid dispersion formulation using HPLC: An in vitro and ex vivo investigation

Atovaquone (ATQ) is a poorly soluble drug. Therefore, formulating ATQ into its supersaturated state through solid dispersion for bioavailability enhancement can be of great value. However, due to fast crystallising properties of ATQ, the quantification of ATQ in a supersaturated solid dispersion system can be complicated. Therefore, in pursuit of accurate quantification of such sample, a simple HPLC analytical method utilising a C₁₈ column (250 × 4.6 mm ID, 5 μm) for the quantitation of ATQ has been developed and validated. Atovaquone elution using the proposed method demonstrated a retention time around 7.6 min with good linearity (R² > 0.999). The system suitability is also detailed with the tailing factor at 1.365 ± 0.002. The addition of solubilising agent as sample treatment step aided in ensuring the accurate quantitation of the fast crystallising ATQ. The developed HPLC quantitation method has been successfully employed in the analysis of ATQ from solid dispersion samples in in vitro dissolution as well as ex vivo permeation studies for formulation development.

Manufacturing and characterisation of a novel composite dosage form for buccal drug administration

The potential of alternative routes of application compared to the traditional oral route is constantly growing. Especially in transmucosal applications for the oral cavity, easy accessibility is an attractive feature with many new opportunities. The combination of a minitablet and a buccal mucoadhesive carrier film has been shown to enable safe and accurate drug administration compared to semi-solid formulations currently available on the market. In order to investigate these so-called composite dosage forms in more detail, two different manufacturing methods were compared within this study to investigate the resulting properties. The formulation development of the minitablets containing lidocaine, complying with the compendial requirements, resulted in immediate release using both manufacturing methods (more than 80% lidocaine release after 3-4 min using direct incorporation, 7-8 min by the gluing method). Differences in morphology and drug migration behaviour could be observed. The directly incorporated minitablets revealed a twofold higher drug migration (1.5 mm) into the mucoadhesive shielding film within two weeks compared to the glued minitablets (0.8 mm). These findings enable a further optimization of the formulation depending on the duration of the application and the feasibility for the addressed patient population.

Fabrication of Mucoadhesive Buccal Films for Local Administration of Ketoprofen and Lidocaine Hydrochloride by Combining Fused Deposition Modeling and Inkjet Printing

In the area of developing oromucosal drug delivery systems, mucoadhesive buccal films are the most promising formulations for either systemic or local drug delivery. The current study presents the fabrication of buccal films, by combining fused deposition modeling (FDM) and inkjet printing. Hydroxypropyl methylcellulose-based films were fabricated via FDM, containing the non-steroidal anti-inflammatory drug ketoprofen. Unidirectional release properties were achieved, by incorporating an ethyl cellulose-based backing layer. The local anesthetic lidocaine hydrochloride, combined with the permeation enhancer l-menthol, was deposited onto the film by inkjet printing. Physicochemical analysis showed alterations in the characteristics of the films, and the mucoadhesive and mechanical properties were effectively modified, due to the ink deposition on the substrates. The in vitro release data of the active pharmaceutical compounds, as well as the permeation profiles across ex vivo porcine buccal mucosa and filter-grown TR146 cells of human buccal origin, were associated with the presence of the permeation enhancer and the backing layer. The lack of any toxicity of the fabricated films was demonstrated by the MTT viability assay. This proof-of-concept study provides an alternative formulation approach of mucoadhesive buccal films, intended for the treatment of local oromucosal diseases or systemic drug delivery.