For systemic drug delivery, the buccal region offers an attractive route of drug administration. Salbutamol sulfate is a short-acting β2-adrenergic receptor agonist used for the relief of bronchospasm in conditions such as asthma and chronic obstructive pulmonary disease. It's oral bioavailability is ∼40% due to extensive first pass metabolism. Salbutamol sulfate patches were prepared using Eudragit L-100, HPMC, PVA and Carbopol 934 in various proportions and combinations using PEG-400/PG as plasticizers. Patches were laminated on one side with a water impermeable backing layer for unidirectional drug release. The thickness of medicated patches were ranged between 0.23 ± 0.008 and 0.59 ± 0.007 mm and mass varied between 65.23 ± 3.3 and 117.92 ± 4.2 mg. Patches showed an increase in mass and swelling index with PEG-400 when compared with PG. The surface-pH of patches ranged between 6 and 7. Formulations E7 (7.5 mL Eudragit L-100, 15 mL HPMC K4M, 7.5 mL PVA and 2 mL PEG-400), E12 (7.5 mL Eudragit L-100, 7.5 mL PVA, 15 mL Carbopol and 2 mL PEG-400), F7 (7.5 mL Eudragit L-100, 15 mL HPMC K4M, 7.5 mL PVA and 2 mL PG), and F12 (7.5 mL Eudragit L-100, 7.5 mL PVA, 15 mL Carbopol and 2 mL PG) showed high folding endurance. Residence time of the tested patches ranged between 101 and 110 min. The maximum in vitro release was found to be 99.93% over a period of 120 min for formulation F12. Data of in vitro release from patches were fitted to different kinetic models such as Higuchi and Korsmeyer-Peppas models to explain the release profile. Formulations E7 and F7 were best fitted to the non-Fickian, where as formulations E12 and F12 showed Fickian/anomalous drug release. Stability studies indicated that there was no change in the chemical and physical characteristics during the test period.

Development and characterization of mucoadhesive patches of salbutamol sulfate for unidirectional buccal drug delivery: Buccal patches of salbutamol sulfate were prepared using five different water soluble polymers in various proportions and combinations using PEG-400/PG as plasticizers. A 3² full factorial design was used to design the experiments for each polymer combination. Patches were laminated on one side with a water impermeable backing layer for unidirectional drug release. The thickness of medicated patches ranged between 0.2 and 0.4 mm and showed an increase in mass whenever PEG-400 was used as plasticizer. The surface pH of all patches approached neutral. Eight formulations which had shown high folding endurance (> 300) were selected for evaluation. Patches prepared with PEG-400 showed a high swelling index. The residence time of the tested patches ranged between 105 and 130 min. Formulations A10, A32, B10 and B32 fitted the Higuchi model best, whereas formulations A19 and B19 showed super case II transport drug release. Stability studies indicated that there was no change in the chemical and physical characteristics during the test period of 6 months.

The objective of the present work was to formulate and evaluate mucoadhesive in situ nasal gels of loratadine. This drug delivery system may overcome the first-pass metabolism and subsequently improve the bioavailability of the drug. A total of 16 formulations of in situ nasal gels were prepared using different polymeric ratios of hydroxypropyl methylcellulose (HPMC K-100) and xanthan gum. All formulations had a clear appearance in the sol form, with gelling temperature of the nasal gels ranging between 33.1 ± 0.43 and 34.8 ± 0.82 °C. The gelling time of all the formulations varied from 4.0 ± 0.21 to 11.3 ± 0.22 s; the drug content was >95%. The pH of the formulations ranged between 5.6 ± 0.004 and 6.0 ± 0.003, i.e. no mucosal irritation is expected as the pH was in the acceptable range. Mucoadhesive strength was adequate (3010.89 ± 1.21-6678.89 ± 0.45 dyne/cm2) to provide prolonged adhesion. In vitro drug release studies showed that the prepared formulations could release the drug for up to 10 h with all of them following Higuchi kinetics. The accelerated stability studies indicated that the gels were stable over the six months test period. The DSC and XRD analysis revealed that there was no drug-polymer interaction. From these findings it can be concluded that in situ nasal gels may be potential drug delivery systems for loratadine to overcome first-pass metabolism and thereby to improve the bioavailability.

The purpose of the study is to develop and assess mucoadhesive in situ nasal gel formulations of loratadine and chlorpheniramine maleate to advance the bioavailability of the drug as compared to its conventional dosage forms. The influence of various permeation enhancers, such as EDTA (0.2% w/v), sodium taurocholate (0.5% w/v), oleic acid (5% w/v), and Pluronic F 127 (10% w/v), on the nasal absorption of loratadine and chlorpheniramine from in situ nasal gels containing different polymeric combinations, such as hydroxypropyl methylcellulose, Carbopol 934, sodium carboxymethylcellulose, and chitosan, is studied. Among these permeation enhancers, sodium taurocholate, Pluronic F127 and oleic acid produced a noticeable increase in the loratadine in situ nasal gel flux compared with in situ nasal gels without permeation enhancer. However, EDTA increased the flux slightly, and in most cases, the increase was insignificant. However, in the case of chlorpheniramine maleate in situ nasal gels, the permeation enhancer oleic acid only showed a noticeable increase in flux. Sodium taurocholate and oleic acid seems to be a better and efficient enhancer, enhancing the flux > 5-fold compared with in situ nasal gels without permeation enhancer in loratadine in situ nasal gels. Pluronic F127 also showed a better permeation, increasing the effect by >2-fold in loratadine in situ nasal gels. In chlorpheniramine maleate in situ nasal gels with EDTA, sodium taurocholate and Pluronic F127 were equally effective, enhancing chlorpheniramine maleate permeation. Oleic acid has a better effect as permeation enhancer in chlorpheniramine maleate in situ nasal gels and showed a maximum permeation enhancement of >2-fold.

Abstract: Mucoadhesive buccal patches of Salbutamol Sulphate were prepared using five different polymers (polyvinyl pyrrolidone [PVP]), polyvinyl alcohol [PVA], water soluble chitosan [CHWS], acid soluble chitosan [CHAS], hydroxypropyl methyl cellulose [HPMC]) in various proportions and combinations (CHWS/PVP/HPMC, CHWS/PVA/HPMC, CHAS/PVP/HPMC, and CHAS/PVA/HPMC). A 32 full factorial design was used to design the experiments. A total of 72 patches were prepared. Thickness of the patches ranged between 0.3±0.003 and 0.6±0.009 mm. Mass of the patches were in the range of 68.12±4.6 to 95.52±5.0 mg. Patches showed increased mass whenever PEG -400 was used as plasticizer. The surface pH of patches were acidic to neutral (pH 4-pH 7). Patches showed satisfactory drug loading efficiency (85% to 97%). Eight formulations (C9, C18, C27, C36, D9, D18, D27 and D36)-which showed high folding endurance- were selected for further characterization. Patches with PEG -400 showed higher swelling index when compared to PG. The residence time of the patches ranged between 115 min and 120 min. Formulation C18 showed the maximum in vitro drug release of 101.4 % over a period of 120 min. Formulations D36 and C36 were best fitted to Higuchi model. The remaining formulations were best fitted to the Korsmeyer-Peppas model. Drug permeation was fast and showed the similar profile as that of the in vitro drug release. Patches were stable, during and at the end of the accelerated stability study.

The purpose of this work was to study the effect of various permeation enhancers on the permeation of salbutamol sulphate (SS) buccal patches through buccal mucosa in order to improve the bioavailability by avoiding the first pass metabolism in the liver and possibly in the gut wall and also achieve a better therapeutic effect. The influence of various permeation enhancers, such as dimethyl sulfoxide (DMSO), linoleic acid (LA), isopropyl myristate (IPM) and oleic acid (OA) on the buccal absorption of SS from buccal patches containing different polymeric combinations such as hydroxypropyl methyl cellulose (HPMC), carbopol, polyvinyl alcohol (PVA), polyvinyl pyrollidone (PVP), sodium carboxymethyl cellulose (NaCMC), acid and water soluble chitosan (CHAS and CHWS) and Eudragit-L100 (EU-L100) was investigated. OA was the most efficient permeation enhancer increasing the flux greater than 8-fold compared with patches without permeation enhancer in HPMC based buccal patches when PEG-400 was used as the plasticizer. LA also exhibited a better permeation enhancing effect of over 4-fold in PVA and HPMC based buccal patches. In PVA based patches, both OA and LA were almost equally effective in improving the SS permeation irrespective of the plasticizer used. DMSO was more effective as a permeation enhancer in HPMC based patches when PG was the plasticizer. IPM showed maximum permeation enhancement of greater than 2-fold when PG was the plasticizer in HPMC based buccal patches.