Formulation, Characterization, and In Vitro Evaluation of Transdermal Patches for Inhibiting Crystallization of Mefenamic Acid

Fabrication and Synthesis of Thiococlchicoside Loaded Matrix Type Transdermal Patch

BACKGROUND

The goal of this work was to synthesize and fabricate matrix type transdermal patches based on a combination of polymers (Eudragit L100, HPMC and PVP K30), plasticizer and crosslinking agents (propylene glycol and triethyl citrate) and adhesives (Dura Tak 87-6908) to increase Thiocolchicoside (THC) absorption via topical route. This method allows avoidance of first-pass metabolism along with a consistent and extended duration of therapeutic activity.

METHODS

Fabrication and casting of polymeric solutions containing THC was done either in petri plates or through lab coater to get transdermal patches. Finally, the formulated patches were studied for their physicochemical and biological evaluation using scanning electron microscopy, FTIR, DSC, XRD and ex-vivo permeation studies using pig ear skin.

RESULTS

FTIR studies confirm that the THC characteristics peaks (carbonyl (Amide I) at 1525.5 cm-1, C=O stretching (tropane ring) at 1664.4 cm-1, Amide II band (N-H stretching) at 3325.9 cm-1, thioether band at 2360.7 cm-1, and OH group stretching band at 3400.2 cm-1) are still present in the polymer mixture even after formulation as a transdermal patch, indicating compatibility among all excipients. While on the other hand, DSC studies confirm endothermic peaks for all the polymers along with THC with the highest enthalpy of 65.979 J/g, which is an indicator of sharp endothermic peak at 198°C, leading to the melting of THC. The percentage drug content and percentage moisture uptake of all the formulation was found in the range of 96 ± 2.04 to 98.56 ± 1.34% and 4.13 ± 1.16 to 8.23 ± 0.90%, respectively. Drug release and release kinetics studies confirm that it is dependent on the composition of individual formulation.

CONCLUSION

All these findings support the possibility of using suitable polymeric composition, as well as proper formulation and manufacturing circumstances, to create a one-of-a-kind technology platform for transdermal drug administration.

Hydroxypropyl Methylcellulose Bioadhesive Hydrogels for Topical Application and Sustained Drug Release: The Effect of Polyvinylpyrrolidone on the Physicomechanical Properties of Hydrogel

Hydrogels are homogeneous three-dimensional polymeric networks capable of holding large amounts of water and are widely used in topical formulations. Herein, the physicomechanical, rheological, bioadhesive, and drug-release properties of hydrogels containing hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) were examined, and the intermolecular interactions between the polymers were explored. A three-level factorial design was used to form HPMC-PVP binary hydrogels. The physicomechanical properties of the binary hydrogels alongside the homopolymeric HPMC hydrogels were characterized using a texture analyzer. Rheological properties of the gels were studied using a cone and plate rheometer. The bioadhesiveness of selected binary hydrogels was tested on porcine skin. Hydrophilic benzophenone-4 was loaded into both homopolymeric and binary gels, and drug-release profiles were investigated over 24 h at 33 °C. Fourier transform infrared spectroscopy (FTIR) was used to understand the inter-molecular drug-gel interactions. Factorial design analysis supported the dominant role of the HPMC in determining the gel properties, rather than the PVP, with the effect of both polymer concentrations being non-linear. The addition of PVP to the HPMC gels improved adhesiveness without significantly affecting other properties such as hardness, shear-thinning feature, and viscosity, thereby improving bioadhesiveness for sustained skin retention without negatively impacting cosmetic acceptability or ease of use. The release of benzophenone-4 in the HPMC hydrogels followed zero-order kinetics, with benzophenone-4 release being significantly retarded by the presence of PVP, likely due to intermolecular interactions between the drug and the PVP polymer, as confirmed by the FTIR. The HPMC-PVP binary hydrogels demonstrate strong bioadhesiveness resulting from the addition of PVP with desirable shear-thinning properties that allow the formulation to have extended skin-retention times. The developed HPMC-PVP binary hydrogel is a promising sustained-release platform for topical drug delivery.

Development and evaluation of transdermal delivery system of tranylcypromine for the treatment of depression

Tranylcypromine (logP = 1.34, MW = 133.19 g/mol) is a monoamine oxidase inhibitor used in treating major depressive disorder and is available only as oral tablets. Transdermal delivery of tranylcypromine minimizes hepatic and gastrointestinal side effects associated with oral dosing and prevents systemic side effects improving patient compliance. A two-day suspension-based transdermal delivery method was developed in this study, and the delivery of tranylcypromine across dermatomed porcine ear skin was evaluated. Different penetration enhancers were screened, namely, isopropyl myristate, oleyl alcohol, oleic acid, and a combination of oleic acid and oleyl alcohol. Isopropyl myristate was chosen as the penetration enhancer, and suspension-based transdermal patches were formulated with acrylate and polyisobutylene pressure-sensitive adhesives by the solvent evaporation method. The release liner and backing membrane were chosen, and the drying time for each patch was optimized. The optimized patches were characterized for their adhesive properties, drying time, peel test, shear strength, and uniformity in drug content. In vitro permeation studies were performed on dermatomed porcine ear skin using vertical static Franz diffusion cells, and the receptor samples were collected at predetermined time points for 48 h. The samples were analyzed in a validated UPLC method. Acrylate-based suspension patch delivered a significantly higher amount of drug (712 ± 21.46 μg/cm²) as compared to passive delivery from drug dissolved in propylene glycol (461.49 ± 75.55 μg/cm²), reaching the two-day therapeutic target. However, the PIB-based suspension patch delivered 559.25 ± 12.37 μg/cm² of tranylcypromine across the skin but did not reach the required target.

Microscopic and Spectroscopic Imaging and Thermal Analysis of Acrylates, Silicones and Active Pharmaceutical Ingredients in Adhesive Transdermal Patches

Dermal or transdermal patches are increasingly becoming a noteworthy alternative as carriers for active pharmaceutical ingredients (APIs), which makes their detailed physicochemical evaluation essential for pharmaceutical development. This paper demonstrates mid-infrared (FTIR) and Raman spectroscopy with complementary microscopic methods (SEM, optical and confocal Raman microscopy) and differential scanning calorimetry (DSC) as tools for the identification of the state of model API (testosterone TST, cytisine CYT or indomethacin IND) in selected adhesive matrices. Among the employed spectroscopic techniques, FTIR and Raman may be used not only as standard methods for API identification in the matrix, but also as a means of distinguishing commercially available polymeric materials of a similar chemical structures. A novel approach for the preparation of adhesive polymers for the FTIR analysis was introduced. In silicone matrices, all three APIs were suspended, whereas in the case of the acrylic PSA, Raman microscopy confirmed that only IND was dissolved in all three acrylic matrices, and the dissolved fraction of the CYT differed depending on the matrix type. Moreover, the recrystallization of TST was observed in one of the acrylates. Interestingly, a DSC analysis of the acrylic patches did not confirm the presence of the API even if the microscopic images showed suspended particles.

Assessment of nano lipid carrier loaded transdermal patch of rizatriptan benzoate

BACKGROUND

Migraine is a neurological disorder and is accompanied by different painful episodes. Hence the maintenance of a steady-state concentration of drug can be beneficial for the patients suffering with migraine. The present investigation focuses on the development of nano lipid carriers (NLCs) loaded transdermal patch of rizatriptan benzoate to sustain the effect of the drug for the enhancement of therapeutic effects.

METHOD

Stearic acid and peanut oil were used to make the NLCs. A central composite design was employed to observe the effect of formulation factors like solid lipid ratio, phase volume ratio, and concentration of surfactants on the formation of nanoparticles. The effects were evaluated for the responses like particle size and entrapment of the drug in the nanocarriers. The optimized formulation was subjected to compatibility, thermal, surface characteristics, and surface morphology studies. The optimized formulation was dispersed in HPMC 15CPS and PVP K30 polymer matrix and the transdermal patch was evaluated for its mechanical properties, drug release study, and skin irritation study.

RESULTS

The experimental design was suitable to produce nanosized stable lipid carriers of the drug with high drug entrapment. The drug and excipients were found to be compatible. The thermal and surface characteristics study proved the high loading of drug in the nanoparticles. The surface morphology study showed the formation of irregular-shaped NLCs. The transdermal patch had good mechanical properties. The ex vivo study of the formulated patch showed a sustained release of the drug over 24h. No skin irritation was reported from the transdermal patch.

CONCLUSION

Therefore, it can be concluded that the nanoparticles loaded transdermal patch of rizatriptan benzoate can be promising in controlling the divergent phases of migraine.

Transdermal Glipizide Delivery System Based on Chitosan-Coated Deformable Liposomes: Development, Ex Vivo, and In Vivo Studies

The current study aimed to develop and evaluate a sustained-release transdermal Glipizide (GLP) film to overcome its oral administration problems. Chitosan (CS)-coated deformable liposomes (DLs) were utilized to enhance the drug transdermal delivery. The formulations were characterized in terms of particle size, zeta potential, entrapment efficiency (EE%), vesicle deformability, morphology, stability, and in vitro release. Transdermal films of chosen formulations were prepared by the solvent casting technique, and an ex vivo study throughout rat skin was also performed. Moreover, a pharmacokinetics (PK) study was carried out and blood glucose levels were estimated. All the liposomes were in the nanometer range and a high EE% was obtained from DLs compared to conventional liposomes (CL). The prepared formulations showed a high stability and the DLs exhibited a high deformability compared to CL. The in vitro release study confirmed the sustained release of GLP from both CL and DL and a more pronounced sustained release of GLP was detected after coating with CS. Moreover, GLP was shown to efficiently permeate through the rat skin from transdermal films by an ex vivo permeation test. The transdermal films showed a promising PK profile in the rat as compared with oral GLP. Most importantly, GLP-CS-DL1 demonstrated a higher hypoglycemic effect, confirming the possibility of systemic action by the local topical delivery of GLP.

[Detection and Analysis of Drug Crystals in Medical Transdermal Patches by Using X-ray Diffraction Measurement]

The crystallization of active pharmaceutical ingredients (APIs) in matrix-type transdermal patches has implications for the rate of drug absorption through the skin and patch adhesion strength. Therefore, the presence or absence and the degree of API crystallinity must be controlled to guarantee the quality of patches. In this study, the utility of laboratory-level X-ray diffractometers for the detection and analysis of crystalline APIs in transdermal patches was investigated using medical patches of tulobuterol and isosorbide dinitrate. Several matrix-type patches employ a controlled drug delivery system containing intentionally crystallized API. Both benchtop and high-resolution laboratory X-ray diffractometers can detect several characteristic peaks of the APIs in these patches even if the patches are wrapped in an outer bag, although a benchtop model provides peak heights one-seventh to one-fifth that of a high-resolution instrument. An isosorbide dinitrate patch containing an unintentionally crystallized spot was wrapped in an outer bag, followed by measurements using both X-ray diffractometers. For both instruments, several isosorbide dinitrate-derived peaks were detected only at the crystallized spot, although the signal-to-noise ratio was poorer for the benchtop model. These results show that a high-resolution X-ray diffractometer is advantageous for high-detection sensitivity and offers a high degree of freedom of the measurement position on the sample. It was concluded that a laboratory-level high-resolution X-ray diffractometer can be used to examine the crystalline state of APIs in patches inside an unopened outer bag.

Pharmaceutical assessment of polyvinylpyrrolidone (PVP): As excipient from conventional to controlled delivery systems with a spotlight on COVID-19 inhibition

Polyvinylpyrrolidone (PVP) is a water-soluble polymer obtained by polymerization of monomer N-vinylpyrrolidone. PVP is an inert, non-toxic, temperature-resistant, pH-stable, biocompatible, biodegradable polymer that helps to encapsulate and cater both hydrophilic and lipophilic drugs. These advantages enable PVP a versatile excipient in the formulation development of broad conventional to novel controlled delivery systems. PVP has tunable properties and can be used as a brace component for gene delivery, orthopedic implants, and tissue engineering applications. Based on different molecular weights and modified forms, PVP can lead to exceptional beneficial features with varying chemical properties. Graft copolymerization and other techniques assist PVP to conjugate with poorly soluble drugs that can inflate bioavailability and even introduces the desired swelling tract for their control or sustained release. The present review provides chemistry, mechanical, physicochemical properties, evaluation parameters, dewy preparation methods of PVP derivatives intended for designing conventional to controlled systems for drug, gene, and cosmetic delivery. The past and growing interest in PVP establishes it as a promising polymer to enhance the trait and performance of current generation pharmaceutical dosage forms. Furthermore, the scrutiny explores existing patents, marketed products, new and futuristic approaches of PVP that have been identified and scope for future development, characterization, and its use. The exploration spotlights the importance and role of PVP in the design of Povidone-iodine (PVP-I) and clinical trials to assess therapeutic efficacy against the COVID-19 in the current pandemic scenario.

Sustained acoustic medicine; sonophoresis for nonsteroidal anti-inflammatory drug delivery in arthritis

Background: Arthritis pain is primarily managed by nonsteroidal anti-inflammatory drugs (NSAIDs), such as diclofenac. Topical diclofenac gel is limited in efficacy due to its limited penetration through the skin. This study investigates the use of a multihour, wearable, localized, sonophoresis transdermal drug delivery device for the penetration enhancement of diclofenac through the skin. Materials & methods: A commercially available, sustained acoustic medicine (sam®) ultrasound device providing 4 h, 1.3 W, 132 mW/cm2, 3 MHz ultrasound treatment was evaluated for increasing the drug delivery of diclofenac gel through a human skin model and was compared with standard of care topical control diclofenac gel. Results: Sonophoresis of the diclofenac gel for 4 h increases diclofenac delivery by 3.8× (p < 0.01), and penetration by 32% (p < 0.01). Conclusion: Sustained acoustic medicine can be used as a transdermal drug-delivery device for nonsteroidal anti-inflammatory drugs.

In vitro and in vivo characterization of domperidone-loaded fast dissolving buccal films

The delivery of drugs via fast dissolving films is an effective alternative for drugs with low bioavailability when administered by other routes. This is the case of domperidone (DMP) an anti-emetic drug with low water solubility and vulnerable to extensive first-pass effect. To overcome these limitations, in this work, we designed and produced fast dissolving muco-adhesive buccal films of domperidone using varying amount polyvinylpyrrolidone (PVP K-90) using the solvent casting method. Films loaded with more than 10% of drug were not homogenous and opaque as indicated by white patches of drug in the film matrix. Formulation of DMP in the film form resulted in conversion of the drug from crystalline state to the semi-crystalline state as indicated by X-ray powder diffraction analysis. Moreover, about 40% of drug loaded within the films was released during the first five minutes compared to only about only 6.5% of pure drug in drug dissolution assays in vitro. In vivo pharmacokinetics analysis revealed that the DMP-loaded film had higher maximum plasma concentration (C_max) and shorter time to reach C_max (T_max) than a commercially available tablet formulation. In conclusion, the produced DMP buccal film formulation showed high absorption rate, rapid onset of action, and improved bioavailability compared with the conventional tablet. Our findings may support the development of novel dosage forms for the transmucosal delivery of DMP for convenient, rapid, and effective treatment of nausea and vomiting.