Development and Evaluation of Solid Dispersion-Based Sublingual Films of Nisoldipine

Nisoldipine (NIS) is a calcium channel blocker that exhibits poor bioavailability (~5%) due to low aqueous solubility and presystemic metabolism in the gut wall. In this context, the present work aimed to develop NIS solid dispersion (NISSD)-based sublingual films using solvent casting technique to improve the dissolution. Phase solubility studies indicated that Soluplus® was the most effective carrier for improving the aqueous solubility of NIS. NISSDs were initially developed using the solvent evaporation method. Fourier transform infrared spectrometric studies were found to display the characteristic vibrational bands related to C=O stretching and N-H deformation in NISSDs, proving the chemical integrity of the drug in NISSDs. Subsequently, bioadhesive sublingual films of NISSDs were formulated using solvent casting method, using hydroxypropyl methyl cellulose (HPMC) E5, E15, and hydroxy ethyl cellulose (HEC EF) as hydrophilic polymers and polyethylene glycol 400 (PEG 400) as plasticizer. The incorporation of NISSDs was found to produce clear films that displayed uniform content. The sublingual film of NISSDs composed of HPMC E5 (2% w/v), was found to display the least thickness (0.29 ± 0.02 mm), the highest folding endurance (168.66 ± 4.50 times), and good bioadhesion strength (12.73 ± 0.503 g/cm2). This film was found to rapidly disintegrate (28.66 ± 3.05 sec) and display near-complete drug release (94.24 ± 1.22) in 30 min. Incorporating NISSDs into rapidly bioadhesive sublingual films considerably improves drug dissolution. Overall, these research outcomes underscored the potential of rapidly dissolving bioadhesive sublingual films to evade gut metabolism and resolve the bioavailability issues associated with oral administration of NIS.

Formulation, characterization, optimization, and in-vivo performance of febuxostat self-nano-emulsifying system loaded sublingual films

Febuxostat (FXS) is a potent antigout drug with poor water solubility and relative high first-pass effect leading to moderate oral bioavailability (<49%). This study aimed to increase FXS solubility and bioavailability by optimizing sublingual fast-dissolving films (SFs) containing a selected FXS self-nano-emulsifying system (s-SNES) previously prepared by our team. The s-SNES was loaded into SFs by solvent casting technique. A full factorial design (3²) was applied to study the effects of polymer and plasticizer types on mechanical characteristics and the dissolution profile of FXS from the SFs. Numerical optimization was performed to select the SF having highest desirability according to predetermined characteristics. The optimized SF (O-SF) contained 1 g of s-SNES, polyvinylpyrrolidone K30 (6%w/v), polyethylene glycol 300 (20%w/w of polymer wt.), and Avicel PH101 (0.5%w/v). O-SF showed good permeation of FXS through sheep sublingual tissue. Storage of O-SF for three months showed no significant change in the FXS dissolution profile. In-vivo performance of O-SF in rabbits was compared to that of oral marketed tablets (Staturic^® 80 mg). A cross-over design was applied and pharmacokinetic parameters were calculated after ensuring absence of sequence effect. Statistical analysis revealed better performance for O-SF with significantly higher C_max, AUC_0–24, AUC_0–∞, apparent t_1/2 together with lower t_max, and apparent k_el than marketed tablets. Relative bioavailability of O-SF compared to the marketed tablet was found to be 240.6%. This confirms the achievement of the study aims of improving dissolution rate and bioavailability of FXS using a patient-wise convenient formula.

Development of Salbutamol Sulphate Sublingual Films in Pullulan Matrix for Enhanced Bioavailability & Clinical Efficacy

BACKGROUND

Salbutamol sulphate (SS) is a model short-acting β2-adrenergic receptor agonist used for the relief of bronchospasm having poor bioavailability (50%) due to its extensive first-pass effect.

OBJECTIVE

Formulation of SS as fast dissolving sublingual films (FDSFs) using a biocompatible and biodegradable Pullulan polymer to bypass its metabolism in liver and offers a fast relieve of asthma.

METHOD

Films were prepared by solvent casting technique adopting 32 factorial design to study the effect of two independent variables namely; polymer type (HPMC E5, Pullulan, and L-HPC) and polymer to Maltodextrin ratio (3:0, 3:1 or 5:1). Films physicomechanical properties, disintegration time and in-vitro dissolution of the prepared formulations were evaluated.

RESULTS

Formula F3 containing Pullulan with Maltodextrin in a ratio 3:1 has the least disintegration time (26±2.6 seconds) and the highest dissolution rate (100%±0.5%) after four minutes. Pharmacokinetic study of the optimum formula F3 in healthy human volunteers revealed a shorter tmax (0.75±0.25 hour) compared to Ventolin® tablet 2 mg (2.1±0.37 hour). Clinical evaluation of F3 in 14 male asthmatic patients using ZAN Spirometry showed clinical improvement in lung function parameters when compared with Ventolin® tablets.

CONCLUSION

FDSFs significantly improved the bioavailability of SS and resulted in dramatic improvement in its clinical efficacy.

Fast Dissolving Sublingual Films of Ondansetron Hydrochloride: Effect of Additives on in vitro Drug Release and Mucosal Permeation

Ondansetron hydrochloride, a 5 HT3 antagonist is a powerful antiemetic drug which has oral bioavailability of 60% due to hepatic first pass metabolism and has a short half-life of 5 h. To overcome the above draw back, the present study was carried out to formulate and evaluate fast dissolving films of ondansetron hydrochloride for sublingual administration. The films were prepared from polymers such as polyvinylalcohol, polyvinyl pyrrolidone, Carbopol 934P in different ratios by solvent casting method. Propylene glycol or PEG 400 as plasticizers and mannitol or sodium saccharin as sweeteners were also included. The IR spectral studies showed no interaction between drug and polymer or with other additives. Satisfactory results were obtained when subjected to physico-chemical tests such as uniformity of weight, thickness, surface pH, folding endurance, uniformity of drug content, swelling index, bioadhesive strength, and tensile strength. Films were also subjected to in vitro drug release studies by using USP dissolution apparatus. Ex vivo drug permeation studies were carried out using porcine membrane model. In vitro release studies indicated 81–96% release within 7 min and 66–80% within 7 min during ex vivo studies. Drug permeation of 66–77% was observed through porcine mucosa within 40 min. Higher percentage of drug release was observed from films containing the sweeteners. The stability studies conducted for a period of 8 weeks showed no appreciable change in drug content, surface pH, and in vitro drug release.