Mucoadhesion

Current innovation in pharmaceuticals determine the merits of mucoadhesive drug delivery system is particularly relevant than oral control release, for getting local systematic drugs distribution in GIT for a prolong period of time at a predetermined rate. The demerits relative with the oral drug delivery system is the extensive presystemic metabolism, degrade in acidic medium as a result insufficient absorption of the drugs. However parental drug delivery system may beat the downside related with oral drug delivery system but parental drug delivery system has significant expense, least patient compliance and supervision is required. By the buccal drug delivery system the medication are directly pass via into systemic circulation, easy administration without pain, brief enzymatic activity, less hepatic metabolism and excessive bioavailability. This review article is an outline of buccal dosage form, mechanism of mucoadhesion, in-vitro and in-vivo mucoadhesion testing technique.

Mucoadhesive drug delivery systems interact with the mucus layer covering the mucosal epithelial surface, and mucin molecules and increase the residence time of the dosage form at the site of absorption. The drugs which have local action or those which have maximum absorption in gastrointestinal tract (GIT) require increased duration of stay in GIT. Thus, mucoadhesive dosage forms are advantageous in increasing the drug plasma concentrations and also therapeutic activity. In this regard, this review covers the areas of mechanisms, polymers used in mucoadhesion, factors influencing the mucoadhesive and also various mucoadhesive dosage forms. Keywords: Mucoadhesion, theories, mucoadhesive dosage forms.  

The present study includes the Formulation and Evaluation of Mucoadhesive Buccal Patch of Timolol Maleate for this study work timolol maleate selected as model drug and using either ionic polymers (SCMC) or non-ionic polymers (carbopol, HPMC).The fabricated patches were prepared by solvent casting method.  The mean thicknesses of the buccal patch formulations were 0.34 – 0.43 mm. Moisture uptake of transdermal patches were found to be 2.94-4.13.which prevents the patches from microbial growth and bulkiness. As amount of PVP increased in every polymer blend, tensile strength and elongation at break were increased. Addition of PVP predominantly decreased the swelling characteristics of the buccal patches, except for SCMC. The drug content of the prepared bioadhesive buccal patches were found in the range of 91.4 - 98.54 %.Bioadhesive strength of buccal patches in following order SCMC >Carbopol>HPMC. The release of Timolol maleate from HPMC patches was slower than SCMC and CP 934.As PVP concentration increased, dissolution rate increases among all polymers. For determination of λmax the solution of the timolol maleate was subjected to ultraviolet scanning in the rage 200 to 400 nm. The λmax was found to be at 294 nm .The pH of formulations was found to be 6.8 - 7.5 which is within the limit of semisolid specifications. The folding endurance of BP formulations was found to be 296 – 325.The results indicated that all formulations were flexible and soft. Bioadhesive buccal patches containing SCMC, HPMC and Carbopol showed a zero order drug release.

Buccal administration of drugs provides a convenient route of administration for both systemic and local drug actions. However, the preferred site for retentive oral transmucosal delivery systems and for sustained- and controlled-release delivery devices is the buccal mucosa, mainly because of the differences in permeability characteristics between the two regions and the buccal mucosa’s expanse of smooth and relatively immobile mucosa. The buccal mucosa offers excellent possibilities for the (long-term) delivery of suitable drugs, especially for metabolically unstable drugs, such as peptides. In the development of these buccal drug delivery systems, mucoadhesion of the device is a key element. Mucoadhesive polymers have been utilized in many different dosage forms in efforts to achieve systemic delivery of drugs through the buccal mucosa. Buccoadhesive drug delivery is relatively new drug delivery strategy; in this traditional polymers are replaced by novel bioadhesive polymers such as thiomers & lectins etc. to overcome limitation of traditional polymer.

Medication activities might be enhanced by creating new medication conveyance frameworks; one such detailing being a mucoadhesive framework. These frameworks stay in close contact with the absorption tissue, the mucous layer, discharging the medication at the activity site prompting expanded bioavailability for both local and systemic impacts. Throughout the last few decades, the application of mucoadhesive polymers in nasal medication conveyance frameworks has picked up enthusiasm among pharmaceutical researchers as a method for advertising dose structure residence time in the nasal cavity and in addition for enhancing closeness of contact with absorptive membrane of the natural framework. Also, the upgraded paracellular absorption after the swelling of the mucoadhesive polymers on the nasal layers gives a critical path to the assimilation of the macromolecules through the nasal cavity. This review explained a few parts of mucoadhesion identified with the nasal medication conveyance framework. On the first check, the theories of the attachment of mucoadhesive polymers to the mucosa epithelium are described. Also, the attributes and application of a few generally utilized mucoadhesive polymers as a part of nasal medication conveyance are introduced. The mucoadhesive polymers have gigantic potential for the conveyance of therapeutic macromolecules, qualities, and immunizations through the nasal cavity with upgraded bioavailability.

The objective of present study was to prepare and evaluate Zaltoprofen (ZLT) enteric coated oral mucoadhesive sustained release (SR) tablet in order to improve its GI residence time and improve its bioavailability by using natural biopolymers like xanthan gum and semisynthetic polymer HPMC for its safe use in rheumatoid arthritis, osteoarthritis, ankylosing spondylitis condition. The sustained release polymers, hydroxypropyl methylcellulose (HPMC) of different viscosities and xanthan gum evaluated in different proportions as a major matrix material. Drug-polymer compatibility studies by FTIR and DSC gave confirmation about their purity and showed no interaction physically between drug and selected polymers. ZLT matrix tablets were prepared by wet granulation.  The effect of polymer concentration on the drug release profile and in-vitro bioadhesion of the matrix tablets was studied. A 32 full factorial design was utilized in the optimizing the levels of HPMC and Xanthan gum. Concentration of HPMC K4M and the concentration of xanthan gum per tablet were used as the independent variables.  The dependent variables were the bioadhesive strength, percent drug dissolved at 2, 6 and 10 hours. The data obtained were fit to a model and polynomial equations were generated. Response surface graph was generated based on these equations. Formulation composition with desired release characteristics and bioadhesive strength were found to be predictive using this model. The optimized factorial batch was further given the coating of Opadry® enteric (94 series) polymer in order to avoid GI disturbances. The Z-22 tablets were kept for stability study at 40°C ±2°C and 75% ± 5% RH for a period of 6 months according to ICH guidelines. The formulation was found to be stable after 6 months of study. The pharmacokinetic parameters Cmax, Tmax, Mean Residence Time (MRT) and Area under Curve (AUC) of developed SR tablet were found to be improved with significant difference (p

There are various approaches for the delivery of therapeutic substance to the target site in a controlled release fashion. One such approach is using microspheres as carriers for drugs or active pharmaceutical compound. However, the success of this drug delivery system is limited due to their short residence time at the site of absorption. Mucoadhesive microspheres can be tailored to adhere to any mucosal tissue including those found in stomach, thus offering the possibilities of localized as well as systemic controlled release of drugs. This article presents the  advantages of Mucoadhesive microsphere, mechanism, theories involved in mucoadhesion, factor that affect the mucoadhesion, polymer in Mucoadhesive drug delivery system, methodology of preparation of Mucoadhesive microsphere, method of evaluation and their applications in drug delivery. Mucoadhesive drug delivery systems promises several advantages that arise from localization at a given target site, prolonged residence time at the site of drug absorption and an intensified contact with the mucosa increasing the drug concentration gradient.

Perindopril is an angiotensin converting enzyme inhibitor. The bioavailability of Perindopril following oral administration is 20 % due to high hepatic first pass metabolism. When administered orally, frequent dosing is needed due to its short biological half-life (0.8 to 1hr). sobuccal patches are one of the better option for perindopril administration. 9 Formulations were prepared using 32 full factorial designs by solvent-casting technique to explore the effects of sodium alginate and carbopol 934 (as independent variables) on drug release, mucoadhesive strength and retention time (as dependent variables). The prepared buccal patches were also evaluated for, weight uniformity, patch thickness, folding endurance, surface pH, swelling studies, % moisture content,% drug content, tensile strength, drug release studies, mucoadhesive strength, retention time. The ex-vivo permeation studies were carried out across excised sheep buccal mucosa using modified Franz diffusion cell. Patches exhibited drug release in the range of 70.37to 96.62% in 8 hrs. Drug release from patches followed zero order and higuchi release model and the mechanism of the drug release was due to swelling and erosion of hydrophilic polymers. The formulation was optimized with desirable drug release, mucoadhesive strength and retention time by applying computer software Design Expert 8.0.7.1. Ex-vivo drug release values for the cumulative amount of the drug permeated across the sheep buccal mucosa from optimized formulation was 76.76%. The experimented values were in good agreement with expected values for the optimized formulation which demonstrate the feasibility of the model in the development of buccal patches.

As a site for drug delivery the oral cavity offers advantages over the conventional gastrointestinal route and the parenteral and other alternative routes of drug administration. It provides direct entry into the systemic circulation thereby avoiding the hepatic first pass effect. Verapamil HCl belongs to a drug group of calcium channel antagonists. The oral absorption of the drug from these forms is 90% but its bioavailability approaches only 10–20%, due to a extensive first-pass effect. Here attempt is made to extract mucilage and use as gelling and mucoadhesive agent. The yield of natural mucoadhesive fenugreek extract was 28-29 percent. Fenugreek mucilage shows synergistic effect with xanthan gum and provide higher viscosity. Fenugreek is used with xanthan gum in the selected ratio of 2.5:1. Different parameters were evaluated like % yield of fenugreek, viscosity, gel strength, mucoadhesive study, in-vitro diffusion study, ex-vivo permeation study and differential scanning calorimetry. The mucosal permeation of drug from the formulation was evaluated using Franz diffusion cell, goat buccal mucosa as semi-permeable membrane. The amount of the drug released was determined by evaluating drug diffused through the membrane by using UV- spectrophotometry. The verapamil HCl release was sustained up to 6 hrs by optimizing concentration of fenugreek and xanthan gum.

  Advancement in science and technology has leds to an evolution of controlled drug delivery as one of the important facets of novel drug delivery with an aim of designing therapeutically efficient dosage forms.  With this insight an attempt was made in designing an oral patch system developed with an inspiration to mimic transdermal drug delivery system. The hypothesis involved development of a compressed patch system for achieving steady therapeutic levels of a model antiprotozoal antibiotic Metronidazole. The patch system comprises of a poorly permeable layer, a mucoadhesive layer containing drug-loaded microspheres and a backing layer. The drug content of microspheres was found to be 50% with an average particle size of 100m. Individual layers of patch system were evaluated for folding endurance, flexibility, thickness and mucoadhesion test. Finally compressed patch system was folded and encapsulated into hard gelatin capsule, then subjected for in-vitro dissolution test in phosphate buffer and also for in-vitro diffusion across cellophane membrane and rat intestine. Drug-excipient compatibility studies revealed no interaction. The stability data further assured the stability of formulations. Thus formulations seem to match mostly gastro retentive category of sustained release forms through bio-adhesion approach concluding an easier, controlled and safer means of oral administration. Key words: Mucoadhesion, compressed patch system, gastro retentive device.