Formulation of cyclodextrin inclusion complex-based orally disintegrating tablet of eslicarbazepine acetate for improved oral bioavailability

Formulation development, characterization, and evaluation of bedaquiline fumarate - Soluplus® - solid dispersion

Bedaquiline fumarate (BQF) is classified as a BCS class II drug and has poor water solubility and dissolution rate, which ultimately compromises bioavailability. The objective of this study is to improve the biopharmaceutical properties of BQF through a solid dispersion system by using Soluplus®. Two solid dispersion systems were prepared i.e. binary solid dispersion (BSD) and ternary solid dispersion (TSD) where 14.31-fold and 20.43-fold increase in solubility of BQF was observed with BSD and TSD in comparison to BQF. In our previous research work, we explored the BSD and TSD of BQF with a crystalline polymer, poloxamer 188, which showed an increment in the solubility of BQF. In the current research, amorphous Soluplus® polymer was selected to formulate BSD and TSD with BQF and showed higher solubility than poloxamer 188. The various solid and liquid state characterization results confirmed the presence of an amorphous form of BQF inside solid dispersion. The Fourier transform infrared spectroscopy showed no chemical interactions between BQF and polymer. The cellular uptake results demonstrated higher uptake in Caco-2 cell lines. Pharmacokinetic studies showed enhanced solubility and bioavailability of TSDs. Hence, the present research shows a promising formulation strategy for enhancing the biopharmaceutical performance of BQF by increasing its solubility.

Pharmacokinetics and pharmacodynamics of cyclodextrin-based oral drug delivery formulations for disease therapy

Oral drug administration has become the most common and preferred mode of disease treatment due to its good medication adherence and convenience. For orally administered drugs, the safety, efficacy, and targeting ability requirements have grown as disease treatment research advances. It is difficult to obtain prominent efficacy of traditional drugs simply via oral administration. Numerous studies have demonstrated that cyclodextrins (CDs) can improve the clinical applications of certain orally administered drugs by enhancing their water solubility and masking undesirable odors. Additionally, deeper studies have discovered that CDs can influence disease treatment by altering the drug pharmacokinetics (PK) or pharmacodynamics (PD). This review highlights recent research progress on the PK and PD effects of CD-based oral drug delivery in disease therapy. Firstly, the review describes the characteristics of current drug delivery modes in oral administration. Besides, we minutely summarized the different CD-containing drugs, focusing on the impact of CD-based alterations in PK or PD of orally administered drugs in treating diseases. Finally, we deeply discussed current challenges and future opportunities with regard to PK and PD of CD-based oral drug delivery formulations.

Evaluating physiochemical properties of FDA-approved orally administered drugs

INTRODUCTION

Analyses of orally administered FDA-approved drugs from 1990 to 1993 enabled the identification of a set of physiochemical properties known as Lipinski's Rule of Five (Ro5). The original Ro5 and extended versions still remain the reference criteria for drug development programs. Since many bioactive compounds do not conform to the Ro5, we validated the relevance of and adherence to these rulesets in a contemporary cohort of FDA-approved drugs.

AREAS COVERED

The authors noted that a significant proportion of FDA-approved orally administered parent compounds from 2011 to 2022 deviate from the original Ro5 criteria (~38%) or the Ro5 with extensions (~53%). They then evaluated if a contemporary Ro5 criteria (cRo5) could be devised to better predict oral bioavailability. Furthermore, they discuss many case studies showcasing the need for and benefit of increasing the size of certain compounds and cover several evolving strategies for improving oral bioavailability.

EXPERT OPINION

Despite many revisions to the Ro5, the authors find that no single proposed physiochemical rule has universal concordance with absolute oral bioavailability. Innovations in drug delivery and formulation have dramatically expanded the range of physicochemical properties and the chemical diversity for oral administration.

Development of α-Cyclodextrin-Based Orally Disintegrating Tablets for 4-Phenylbutyrate

Despite major improvements brought about by the introduction of taste-masked formulations of 4-phenylbutyrate (PB), poor compliance remains a significant drawback to treatment for some pediatric and dysphagic patients with urea cycle disorders (UCDs). This study reports on the development of a cyclodextrin (CD)-based orally disintegrating tablet (ODT) formulation for PB as an alternative to existing formulations. This is based on previous reports of the PB taste-masking potential of CDs and the suitability of ODTs for improving compliance in pediatric and dysphagic populations. In preliminary studies, the interactions of PB with α and βCD in the solid state were characterized using X-ray diffraction, scanning electron microscopy, dissolution, and accelerated stability studies. Based on these studies, lyophilized PB-CD solid systems were formulated into ODTs after wet granulation. Evaluation of the ODTs showed that they had adequate physical characteristics, including hardness and friability and good storage stability. Notably, the developed αCD-based ODT for PB had a disintegration time of 28 s and achieved a slightly acidic and agreeable pH (≈5.5) in solution, which is suitable for effective PB-CD complexation and taste masking. The developed formulation could be helpful as an alternative to existing PB formulations, especially for pediatric and dysphagic UCD patients.

Evaluation of berberine nanoparticles as a strategy to modulate acetylcholinesterase activity

Researchers have concentrated efforts in the search for natural-based reversible inhibitors for cholinesterase enzymes as they may play a key role in the treatment of degenerative diseases. Diverse plant alkaloids can inhibit the action of acetylcholinesterase and, among them, berberine is a promising bioactive. However, berberine has poor water solubility and low bioavailability, which makes it difficult to use in treatment. The solid dispersion technique can improve the water affinity of hydrophobic substances, but berberine solid dispersions have not been extensively studied. Safety testing is also essential to ensure that the berberine-loaded solid dispersions are safe for use. This study investigated the effectiveness of berberine-loaded solid dispersions (SD) as inhibitors of acetylcholinesterase enzyme (AChE). Docking simulation was used to investigate the influence of berberine on AChE, and in vitro assays were conducted to confirm the enzymatic kinetics of AChE in the presence of berberine. Berberine SD also showed improved cytotoxic effects on tumoral cells when dispersed in aqueous media. In vivo assays using Allium cepa were implemented, and no cytotoxicity/genotoxicity was found for the berberine solid dispersion. These results suggest that berberine SD could be a significant step towards safe nanostructures for use in the treatment of neurodegenerative diseases.

Cyclodextrin: A prospective nanocarrier for the delivery of antibacterial agents against bacteria that are resistant to antibiotics

Supramolecular chemistry introduces us to the macrocyclic host cyclodextrin, which has a hydrophobic cavity. The hydrophobic cavity has a higher affinity for hydrophobic guest molecules and forms host-guest complexation with non-covalent interaction. Three significant cyclodextrin kinds are α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin. The most often utilized is β-cyclodextrin (β-CD). An effective weapon against bacteria that are resistant to antibiotics is cyclodextrin. Several different kinds of cyclodextrin nanocarriers (β-CD, HP-β-CD, Meth-β-CD, cationic CD, sugar-grafted CD) are utilized to enhance the solubility, stability, dissolution, absorption, bioavailability, and permeability of the antibiotics. Cyclodextrin also improves the effectiveness of antibiotics, antimicrobial peptides, metallic nanoparticles, and photodynamic therapy (PDT). Again, cyclodextrin nanocarriers offer slow-release properties for sustained-release formulations where steady-state plasma antibiotic concentration is needed for an extended time. A novel strategy to combat bacterial resistance is a stimulus (pH, ROS)-responsive antibiotics released from cyclodextrin carrier. Once again, cyclodextrin traps autoinducer (AI), a crucial part of bacterial quorum sensing, and reduces virulence factors, including biofilm formation. Cyclodextrin helps to minimize MIC in particular bacterial strains, keep antibiotic concentrations above MIC in the infection site and minimize the possibility of antibiotic and biofilm resistance. Sessile bacteria trapped in biofilms are more resistant to antibiotic therapy than bacteria in a planktonic form. Cyclodextrin also involves delivering antibiotics to biofilm and resistant bacteria to combat bacterial resistance.

Melting point depression for enhanced dissolution rate of eslicarbazepine acetate

BACKGROUND

Eslicarbazepine acetate (ESL) is antiepileptic agent which is approved for use as single therapy or in combination with other drugs. However, it suffers from poor oral bioavailability. Modulation of drug crystallinity can be utilized as an approach for enhancing drug dissolution.

OBJECTIVE

Accordingly, the aim of this study was to investigate possible eutectic system formation between eslicarbazepine with either tartaric acid or citric acid.

METHODOLOGY

Eslicarbazepine acetate was subjected to wet co-grinding with tartaric acid or citric acid at different molar ratios. The prepared formulations were assessed using Fourier-transform infrared (FTIR), X-ray powder diffraction (XRPD), differential scanning calorimetry in addition to dissolution studies.

RESULTS

The characterization techniques confirmed eutectic system formation with tartaric and citric acid with the optimum molar ratio for eutexia being 1:1 for both substances. Development of eutectic systems significantly enhanced the dissolution rate of ESL. Increasing the ratio of tartaric acid higher than the optimum ratio for eutexia resulted in additional increase in drug dissolution rate. This suggested the impact of pH modification on drug dissolution rate. The enhanced dissolution rate in case of the formulations containing ESL and citric acid was accredited to combined effect of eutaxia and pH modulation. These explanations were proven from investigating the dissolution rate of the physical mixtures which were inferior in their dissolution rate compared with the prepared formulations.

CONCLUSION

co-processing of ESL with either citric acid or tartaric acid resulted in hastened dissolution rate which was accredited to combined effect of eutexia with pH modification.

Puzzle Out Machine Learning Model-Explaining Disintegration Process in ODTs

Tablets are the most common dosage form of pharmaceutical products. While tablets represent the majority of marketed pharmaceutical products, there remain a significant number of patients who find it difficult to swallow conventional tablets. Such difficulties lead to reduced patient compliance. Orally disintegrating tablets (ODT), sometimes called oral dispersible tablets, are the dosage form of choice for patients with swallowing difficulties. ODTs are defined as a solid dosage form for rapid disintegration prior to swallowing. The disintegration time, therefore, is one of the most important and optimizable critical quality attributes (CQAs) for ODTs. Current strategies to optimize ODT disintegration times are based on a conventional trial-and-error method whereby a small number of samples are used as proxies for the compliance of whole batches. We present an alternative machine learning approach to optimize the disintegration time based on a wide variety of machine learning (ML) models through the H2O AutoML platform. ML models are presented with inputs from a database originally presented by Han et al., which was enhanced and curated to include chemical descriptors representing active pharmaceutical ingredient (API) characteristics. A deep learning model with a 10-fold cross-validation NRMSE of 8.1% and an R² of 0.84 was obtained. The critical parameters influencing the disintegration of the directly compressed ODTs were ascertained using the SHAP method to explain ML model predictions. A reusable, open-source tool, the ODT calculator, is now available at Heroku platform.

A review of emerging technologies enabling improved solid oral dosage form manufacturing and processing

Tablets are the most widely utilized solid oral dosage forms because of the advantages of self-administration, stability, ease of handling, transportation, and good patient compliance. Over time, extensive advances have been made in tableting technology. This review aims to provide an insight about the advances in tablet excipients, manufacturing, analytical techniques and deployment of Quality by Design (QbD). Various excipients offering novel functionalities such as solubility enhancement, super-disintegration, taste masking and drug release modifications have been developed. Furthermore, co-processed multifunctional ready-to-use excipients, particularly for tablet dosage forms, have benefitted manufacturing with shorter processing times. Advances in granulation methods, including moist, thermal adhesion, steam, melt, freeze, foam, reverse wet and pneumatic dry granulation, have been proposed to improve product and process performance. Furthermore, methods for particle engineering including hot melt extrusion, extrusion-spheronization, injection molding, spray drying / congealing, co-precipitation and nanotechnology-based approaches have been employed to produce robust tablet formulations. A wide range of tableting technologies including rapidly disintegrating, matrix, tablet-in-tablet, tablet-in-capsule, multilayer tablets and multiparticulate systems have been developed to achieve customized formulation performance. In addition to conventional invasive characterization methods, novel techniques based on laser, tomography, fluorescence, spectroscopy and acoustic approaches have been developed to assess the physical-mechanical attributes of tablet formulations in a non- or minimally invasive manner. Conventional UV-Visible spectroscopy method has been improved (e.g. fiber-optic probes and UV imaging-based approaches) to efficiently record the dissolution profile of tablet formulations. Numerous modifications in tableting presses have also been made to aid machine product changeover, cleaning, and enhance efficiency and productivity. Various process analytical technologies have been employed to track the formulation properties and critical process parameters. These advances will contribute to a strategy for robust tablet dosage forms with excellent performance attributes.

Maraviroc Oral Disintegration Tablet: Analytical Design of Experiments (DoE) for Assessment and Comparison of In-Vitro Dissolution Profiles

Background:

The bioavailability of a drug in a solid oral dose depends on its release from the drug product and its balance in dissolution. Compared with a reference drug, the newly developed formulation needs to establish bioequivalence by comparing the dissolution profile.

Objective:

To compare dissolution profiles of a newly developed maraviroc oral disintegration tablet and the reference Axentri® tablet. The current research was designed to establish and validate an integral analytical consistency by Quality by Design (QbD) approach to quantify maraviroc from dissolution samples using the RP-HPLC method.

Methods:

Maraviroc was formulated into an orally disintegrating tablet using a direct compression technique at different concentrations of sodium starch glycolate as super disintegrants and talc and magnesium stearate as glidants. The dissolution test in 0.1N HCl was performed according to standard procedures to predict bioequivalence. The results of dissolution tests were analyzed using the QbD Box Behnken Design multivariate RP-HPLC method.

Results:

The optimized formulation (F2) was selected as it showed 90% drug release in 5 min and a disintegration time of 22 sec with dissolution profiles to the marketed reference to meet the FDA requirements of f2 similarity factor statistics. The integrated analytical QbD method was statistically analyzed by ANOVA, counter-plot, and 3D response surface plots, which demonstrated that the model is statistically significant. The developed method was validated as per ICH guidelines Q2 (R1).

Conclusion :

In conclusion, maraviroc oral disintegrating tablets have been well prepared, and superior statement consistency is established by the implementation of the QbD analytical method for orally disintegrating tablet excellence and adoption.

Binding parameters and molecular dynamics of β-lactoglobulin-vanillic acid complexation as a function of pH - part B: Neutral pH

Interactions between the dimeric form of β-lactoglobulin and vanillic acid were investigated at pH 7.2, using a variety of spectroscopic techniques and molecular dynamics (MD) simulations. FTIR and CD studies showed alterations in the secondary structure of the protein upon its interaction with the ligand. Fluorescence measurements indicated that the dimeric complex with the phenolic acid produced a large dissociation constant (K_D) compared to the monomeric counterpart at acidic pH (part A of this series). Stoichiometry of 1:1 was identified for the β-lactoglobulin-vanillic acid complex by Job plot analysis at neutral pH suggesting two ligand molecules can participate in binding with the dimer. Molecular docking and MD simulations suggested that the top-ranked binding sites of the ligand were located at the entrance of each β-barrel structure of the dimer. These simulations also allowed identification of the contribution of water molecules, in the form of protein-water-ligand bridging interactions, to the complexes.

Binding parameters and molecular dynamics of β-lactoglobulin-vanillic acid complexation as a function of pH - Part A: Acidic pH

Protein-phenolic compound interactions are commonly investigated with inappropriate linear equations for the analysis of binding strength and stoichiometry. This work utilises more appropriate protocols for the investigation of molecular interactions between vanillic acid and β-lactoglobulin at pH 2.4, where the protein predominately exists as a monomer. Non-linear binding and Job plot analysis were conducted on fluorescence data to effectively determine the interaction's dissociation constant (K_D, 2.93 × 10^-5 M) and stoichiometry (1:1). Furthermore, spectroscopic techniques revealed statistically significant alterations to the conformational characteristics of β-lactoglobulin upon complexation. Molecular dynamics (MD) simulations support a 1:1 interaction stoichiometry and reveal that the stabilisation of vanillic acid was dynamic in nature but mainly supported by four π-alkyl interactions and one hydrogen bond, located within the β-barrel of the monomer. Water molecules, which are generally not accounted for in MD simulation analysis, were shown to be an important factor in the ligand stabilization via bridging interactions.

Development and optimisation of simulated salivary fluid for biorelevant oral cavity dissolution

Drug release within the oral cavity can be of paramount importance for formulations that are designed for specific purposes such as taste-masking, faster onset of therapeutic action, localization of treatment or avoidance of first-pass metabolism. Preclinical methods for assessment of dissolution in the oral cavity are necessary for design and development of these formulation but currently there is no consensus on what variables should be defined to achieve biorelevance in these tests. In this study, biorelevant simulated salivary fluids (SSFs) that can be uniformly applied for oral cavity dissolution testing were developed. Unstimulated saliva (US) SSF and stimulated saliva (SS) SSF were separately developed since the two states significantly differ. Physicochemical properties including pH, buffer capacity, surface tension and viscosity were assessed during development and optimised to mimic human saliva (HS). In order to account for the salivary proteins in HS, use of bovine submaxillary mucin (BSM) and porcine gastric mucin (PGM) in SSFs was evaluated. Following optimisation of the SSFs, biorelevance of the developed SSFs to HS was assessed by their comparative physicochemical properties as well as dissolution profiles of three diverse model compounds (sildenafil citrate, efavirenz, and caffeine) which showed comparable profiles between the SSFs and HS. This work addresses the lack of uniformed biorelevant dissolution media for oral cavity dissolution studies and provides a basis for standardised dissolution tests that provide consistency and harmonisation in future oral cavity dissolution studies. We envisage that this will have a positive impact on the development of new medicines that require functionality in the oral cavity.

Development and characterization of orodispersible film containing cefixime trihydrate

Patients suffering from dysphagia have trouble in swallowing conventional oral dosage forms and there is also risk of choking, which may cause patient noncompliance. This study aimed to develop an orodispersible film (ODF) containing cefixime trihydrate (CFX) to cope with the above-mentioned problems as well as to enhance water solubility and masking the bitter taste of the drug. The freeze-drying and kneading methods were used for the formation of inclusion complexes. The physicochemical evaluation revealed that T7 was the best film for the incorporation of pure drug and inclusion complexes. Films were further characterized for physical and mechanical properties. Drug content, dissolving time of the film and drug release tests were performed. In vivo taste and disintegration time studies were also conducted in healthy human volunteers. FTIR spectra of the individual ingredients and prepared formulations have confirmed the chemical compatibilities of the ingredients. The solubility of CFX was increased by complexation with β-CD and optimized freeze-dried inclusion complex (FD1) was selected for the formation of ODF. C4 was selected as an optimized film for the delivery of CFX as this film has released 95.52% drug at the end of 10 min. Dissolution kinetics of FD1 showed that it followed zero-order kinetics while drug release from films, exhibits first-order kinetics; however, both showed non-Fickian transport. In vivo taste evaluation revealed that taste was masked by inclusion complexation with β-CD. However, selected ingredients and employed methodology enabled to formulate film, capable of delivering taste-masked CFX with improved solubility and better patient compliance.

Development of metformin hydrochloride loaded dissolving tablets with novel carboxymethylcellulose/poly-l-lysine/TPP complex

Natural polymers like polysaccharides, polypeptides and their derivatives are broadly applied in drug delivery due to excellent biocompatibility and biodegradability. In this study, the dissolving tablets, formed with carboxymethylcellulose/poly-l-lysine/tripolyphosphate (CMC/PLL/TPP) complex, were prepared using metformin hydrochloride (MetHCl) as model drug. Confocal laser scanning microscopy observation manifested that FITC-labeled PLL interacted with CMC and formed a uniform interior microstructure. Scanning electron microscope images showed the drug-loaded tablets had well-formed shapes with smooth surfaces. MetHCl embedded interior the microstructures of the tablets and represented in a crystal form. Thermo-gravimetric analysis and differential scanning calorimetry indicated that the drug-loaded tablets had stable thermal properties with less moisture content (3.52%). Fourier transform infrared spectrometer confirmed that the CMC/PLL/TPP complex was fabricated via the electrostatic interactions between -NH₃⁺, -COO^- and -[P₂O₅⁴-]^- groups. The drug-loaded tablets had a high drug loading efficiency of 85.76% and drug encapsulation efficiency of 81.47%, and a shorter wetting time of 2.16 min in SSF (pH 6.8) and lower swelling ratio of 233.34%. The drug loaded in the samples could be released completely within 10 min in simulated saliva fluid (SSF pH 6.8), indicating a rapid drug release and dissolving profile in the environment, which could be developed for dissolving tablets.

Development of Pediatric Orodispersible Tablets Based on Efavirenz as a New Therapeutic Alternative

BACKGROUND

Efavirenz is the most used medication in the treatment of Acquired Immunodeficiency Syndrome (AIDS). The limited number of pediatric antiretroviral formulations approved by regulatory agencies is the most significant obstacle to adequate and efficient pharmacotherapy for this group of patients. The efavirenz has excellent therapeutic potential, but has low aqueous solubility/bioavailability.

METHODS

To minimize these limitations, multicomponent systems with β-cyclodextrin and polyvinylpyrrolidone K-30 were obtained. Due to the limited number of pediatric antiretroviral formulations, the development of a pediatric orodispersible tablet is an alternative that is thought easy to administer, since it disintegrates rapidly in the oral cavity. The multicomponent systems were obtained by the method of kneading and characterized by solubility test, X-ray diffraction, differential scanning calorimetry and infrared absorption spectroscopy by Fourier transform. The orodispersible tablets were prepared by direct compression. The quality control of hardness, friability, disintegration, and dissolution was performed. The influence of the components of the formulation on the characteristics of the tablets was evaluated through a 22 factorial design added with three central points, to compare the effect of the dependent variables on the responses.

RESULTS

An increase in drug solubility was observed, with a decrease in crystallinity. Besides that, an excellent dissolution profile presented with more than 83% of the drug's content dissolved in less than 15 minutes. Satisfactory disintegration time and friability were observed.

CONCLUSION

It was observed that reduced concentrations of mannitol decreased the hardness and disintegration time of the formulations. The orodispersible tablet composed of efavirenz: β- cyclodextrin: polyvinylpyrrolidone, favors greater absorption and bioavailability. It has several advantages for pediatric patients, as the dosage form disintegrates quickly in the mouth and does not require water for administration, thereby improving patient compliance with the treatment.

The Role of Functional Excipients in Solid Oral Dosage Forms to Overcome Poor Drug Dissolution and Bioavailability

Many active pharmaceutical ingredients (APIs) exhibit poor solubility and low dissolution rates in aqueous environments such as the luminal fluids of the gastrointestinal tract. The oral bioavailability of these compounds is usually very low as a result of their poor solubility properties. In order to improve the bioavailability of these poorly soluble drugs, formulation strategies have been applied as a means to improve their aqueous solubility and dissolution rates. With respect to formulation approaches, excipients can be incorporated in the formulation to assist in the dissolution process of the drug, or specialized dosage forms can be formulated that improve dissolution rate through various mechanisms. This paper provides an overview of selected excipients (e.g., alkalinizing agents, surfactants and sugars) that can be used in formulations to increase the dissolution rate as well as specialized dosage forms such as self-emulsifying delivery systems and formulation techniques such as inclusion complexes and solid dispersions. These formulation approaches are discussed with available examples with specific reference to positive outcomes in terms of drug solubility and bioavailability enhancement.

Optimized furosemide taste masked orally disintegrating tablets

Optimized orally disintegrating tablets (ODTs) containing furosemide (FUR) were prepared by direct compression method. Two factors, three levels (3²) full factorial design was used to optimize the effect of taste masking agent (Eudragit E100; X1) and superdisintegarant; croscarmellose sodium (CCS; X2) on tablet properties. A composite was prepared by mixing ethanolic solution of FUR and Eudragit E100 with mannitol prior to mixing with other tablet ingredients. The prepared ODTs were characterized for their FUR content, hardness, friability and wetting time. The optimized ODT formulation (F1) was evaluated in term of palatability parameters and the in vivo disintegration. The manufactured ODTs were complying with the pharmacopeia guidelines regarding hardness, friability, weight variation and content. Eudragit E100 had a very slightly enhancing effect on tablets disintegration. However, the effects of both Eudragit E100 (X1) and CCS (X2) on ODTs disintegration time (Y1) were insignificant (p > 0.05). Moreover, X1 exhibited antagonistic effect on the dissolution after 5 and 30 min (D5 and D30, respectively), but only its effect on D30 is significant (p = 0.0004). Furthermore, the optimized ODTs formula showed good to acceptable taste in term of palatability, and in vivo disintegration time of this formula was about 10 s.

Nimodipine Ophthalmic Formulations for Management of Glaucoma

PURPOSE

Preparation and evaluation of topical ophthalmic formulations containing nimodipine-CD complexes prepared using HP-β-CD, SBE-β-CD and M-β-CD for the management of glaucoma.

METHODS

Nimodipine-CD complexes were prepared using a freeze-drying method. Two different molar ratios (NMD:CD) were used for each cyclodextrin. The inclusion complexes were characterized using DSC, FTIR, yield (%), drug content and in vitro release characteristics. NMD-CD complexes incorporated into chitosan eye drops and a temperature-triggered in situ gelling system were evaluated for their pH, viscosity and in vitro release characteristics. We determined the intraocular pressure (IOP) lowering effect of NMD-hydroxypropylmethylcellulose (HPMC) eye drops through a single dose response design using C57BL/6J mice. The minimum effective concentration (MEC) of nimodipine was further applied to mice that vary in the parental allele of Cacna1s, the drug target of nimodipine. Cytotoxicity was also evaluated.

RESULTS

Our ophthalmic formulations possessed pH and viscosity values that are compatible with the eye. In vitro release of nimodipine was significantly increased from chitosan eye drops containing NMD-CD complexes compared to uncomplexed drug. Administration of nimodipine can lower IOP significantly after a single drop of drug HPMC suspension. The IOP-lowering response of the MEC (0.6%) was significantly influenced by the parental allele of Cacna1s.

CONCLUSIONS

Nimodipine can be used as a promising topical drug for management of glaucoma through ocular delivery.