Journal of Pharmaceutical and Biopharmaceutical Research

Since the invention of bioactive glass 50 years ago, it has become a versatile material used in healthcare in a variety of applications and compositions.  Bioactive glass has shown superior capabilities of drug delivery compared to traditional carriers. For example, time-released medications are less likely to reach toxic levels, while delivering a specific, therapeutic dose to a localized area. The objective of this paper is to investigate the properties and effectiveness of mesoporous bioglass (MBG) as a drug delivery carrier. A literature review of various polymer coated 45S5 Bioglass^® loaded with vancomycin was analyzed to determine their drug release response. Since MBG continues to be a preferred carrier with numerous combinations; size, coating, doped with ions, medications, and other physical conditions, there is a need to understand more fully their effectiveness. For a given loading efficiency of 5-15% the burst release % for day 1 remained 15-30% for given surface area, pore volume and pore size of 3.5 to 5 nm. The mechanical properties summarized in this paper are compared with the drug release kinetics. In general, for a given fracture toughness and compressive strength, the ratio of Young’s modulus to bending strength around 250 determined poor apatite mineralization resulting in slow release. As this ratio increased the apatite mineralization and dissolution rate increased. Doping MBG with ions enhanced the drug efficacy to treat a particular condition, for example, silver. Polymer coated MBG exhibited slower dissolution rate than uncoated MBG. Dissolution time increased with the drug loading rate, drying time of the coating, multi-layer coats of drug and polymer for the drug studied in this paper to more than 50%.

The most critical component of the TDDS is the adhesive, which is responsible for the safety, efficacy and quality of the patch. For drug delivery to successfully occur, the patch must adhere to the surface of the contact area. If a patch has inadequate adhesion, it is likely to fall off before the entire delivery period has been satisfied, leading to risks for the patient and others who may encounter the patch. Despite the critical concerns associated with the adhesive properties of the patches, the adhesion quality and failure mechanisms have not been fully studied. If certain molecules encounter the adhesive, it may cause irreversible altering of its chemical composition, which could render it unsuitable for transdermal applications. In many cases of TDDS failure, sweat is believed to be a culprit responsible for causing adhesive failure. The goal of this project is to investigate the chemical composition of the adhesive layer of a transdermal patch. The patch sample is a Sandoz Estradiol Transdermal System manufactured by Noven Pharmaceuticals, Inc., designed to deliver 0.1mg per day and contains 1.56mg of Estradiol USP, the active ingredient. By analyzing the chemical composition of a patch that has not been worn, versus a patch that has been worn, it may be possible to determine the chemical interaction that causes adhesive failure. Fourier Transform Infra-Red (FTIR) Spectroscopy (OPUS FTIR Spectrometer) was performed on an unused estradiol TDDS patch immediately after opening, and again after 24 hours in ambient air to investigate the potential for oxidation. The IR Spectrum was then analyzed, and the peaks were reviewed. The IR Spectra for the sample left out for 24 hours indicated lengthened peaks corresponding to C=O, C-O, and O-H, a decreased transmittance, and a wider bandwidth in those regions. Based on these results, it can be determined that oxidation does occur on a patch sample that is exposed to ambient air. In future works, additional patch samples will be collected and used for an extensive IR and UV analysis. By comparing the IR and UV Spectrum graphs of “used” patches that did not fail, with “failed” patches, it may be possible to identify a cause for premature patch failure related to sweat interactions.

Nanoparticle formulation is a recently developed drug delivery technology with enhanced targeting potential. Nanoparticles encapsulate the drug of choice and delivers it to the target via a targeting molecules (ex. antigen) located on the nanoparticle surface. Nanoparticles can even be targeted to deeply penetrating tissue and can be modeled to deliver drugs through the blood brain barrier. These advancements are providing better disease targeting such as to cancer and Alzheimer’s. Various polymers can be manufactured into nanoparticles. The polymers examined in this paper are polycaprolactone (PCL), poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA), and poly(glycolic acid) (PGA). The purpose of this study is to analyze the mechanical properties of these polymers to establish drug delivery trends and model pharmacokinetics and biotransport. We found that, in general, as the melting point, elastic modulus and tensile strength increases, the degradation rate also increases. PLA composite material may be an ideal polymer for drug delivery due to its good control of degradation.

Drug delivery with nanoparticulate carriers is a new and upcoming research area that is making major changes within the pharmaceutical industry.  Nanoparticulate carriers are discussed, particularly, engineered nanoparticulate carriers used as drug delivery systems for targeted delivery. Nanoparticulate carriers that are used for drug delivery systems include polymers, micelles, dendrimers, liposomes, ceramics, metals, and various forms of biological materials.  The properties of these nanoparticulate carriers are very advantageous for targeted drug delivery and result in efficient drug accumulation at the targeted area of interest, reduced drug toxicity, reduced systemic side effects, and more efficient use of the drug overall.  Nanoparticlulate carriers are effective in passing various biological impediments and have a relatively high cellular uptake compared to that of microparticulate carriers, which allows for the drug agent to reach a targeted cell or tissue.  The use of nanoparticulate carriers for drug delivery results in a prolonged and sustained release of the drug which ultimately reduces the cost and amount of doses that need to be administered to the patient.  Currently, there is extensive research of nanoparticles as drug delivery carriers for challenging disease treatment cases such as cancer, HIV, and diabetes.