Can Continuous Manufacturing of Topical Semisolids by Hot Melt Extrusion Soon Be a Reality?

For more than five decades, pharmaceutical manufacturers have been relying heavily on batch manufacturing that is a sequential, multistep, laborious, and time-consuming process. However, late advances in manufacturing technologies have prompted manufacturers to consider continuous manufacturing (CM) is a feasible manufacturing process that encompasses fewer steps and is less tedious and quick. Global regulatory agencies are taking a proactive role to facilitate pharmaceutical industries to adopt CM that assures product quality by employing robust manufacturing technologies encountering fewer interruptions, thereby substantially reducing product failures and recalls. However, adopting innovative CM is known to pose technical and regulatory challenges. Hot melt extrusion (HME) is one such state-of-the-art enabling technology that facilitates CM of diverse pharmaceutical dosage forms, including topical semisolids. Efforts have been made to continuously manufacture semisolids by HME integrating the principles of Quality by Design (QbD) and Quality Risk Management (QRM) and deploying Process Analytical Technologies (PAT) tools. Attempts have been made to systematically elucidate the effect of critical material attributes (CMA) and critical process parameters (CPP) on product critical quality attributes (CQA) and Quality Target Product Profiles (QTPP) deploying PAT tools. The article critically reviews the feasibility of one of the enabling technologies such as HME in CM of topical semisolids. The review highlights the benefits of the CM process and challenges ahead to implement the technology to topical semisolids. Once the CM of semisolids adopting melt extrusion integrated with PAT tools becomes a reality, the process can be extended to manufacture sterile semisolids that usually involve more critical processing steps.

Polymer coated polymeric microneedles for intravitreal delivery of dexamethasone

The polymer coated polymeric (PCP) microneedles (MNs) is a novel approach for controlled delivery of drugs (without allowing release of the excipients) to the target site. PCP MNs was explored as an approach to deliver the drug intravitreally to minimize the risks associated with conventional intravitreal injections. The core MNs was fabricated with polyvinyl pyrrolidone K30 (PVP K30) and coating was with Eudragit E100. Preformulation studies revealed that the films prepared using Eudragit E 100 exhibited excellent integrity in the physiological medium after prolonged exposure. FTIR studies were performed to investigate the possible interaction between the API and the polymer. The PCP MNs fabricated with different drug loads (dexamethasone sodium phosphate) were subjected to in vitro drug release studies. The drug release from uncoated MNs was instantaneous and complete. On the other hand, a controlled release profile was observed in case of PCP MNs. Likewise, even in the ex vivo porcine eye model, the drug release was gradual into the vitreous humor in case of PCP MNs. The uncoated microneedles released all the drug instantaneously where the PCP MNs retarded the release up to 3 h.

Continuous Manufacturing of Oil in Water (O/W) Emulgel by Extrusion Process

Pharmaceutical industries and drug regulatory agencies are inclining towards continuous manufacturing due to better control over the processing conditions and in view to improve product quality. In the present work, continuous manufacturing of O/W emulgel by melt extrusion process was explored using lidocaine as an active pharmaceutical ingredient. Emulgel was characterized for pH, water activity, globule size distribution, and in vitro release rate. Additionally, effect of temperature (25°C and 60°C) and screw speed (100, 300, and 600 rpm) on the globule size and in vitro release rate was studied. Results indicated that at a given temperature, emulgel prepared under screw speed of 300 rpm resulted in products with smaller globules and faster drug release.

Sublimation of Drugs from the Site of Application of Topical Products

The objective of the project was to investigate the plausibility of active pharmaceutical ingredients (APIs) to undergo sublimation from topical application following evaporation of solvent. Topical formulations with different APIs were subjected to a sublimation screening test. The APIs in the selected topical products were found to undergo sublimation to a different extent. The salicylic acid topical product was found to undergo a significant loss due to sublimation. The extent of sublimation of salicylic acid was significantly greater at skin temperature compared to room temperature. When the APIs were subjected to the sublimation screening test in their neat form at 32 ± 1 °C, the natural log of the rate of sublimation decreased linearly with the standard enthalpy of sublimation of compound (R² = 0.89). The formulation composition was found to have a significant impact on the extent of sublimation of the representative API, salicylic acid. The sublimation of APIs from the topical product was found to affect the mass balance studies in the case of the salicylic acid ointment. Furthermore, the results of the human studies agreed with the in vitro experimental results demonstrating the plausibility of loss of API due to sublimation from the site of application.

Polymer-Coated Polymeric (PCP) Microneedles for Controlled Dermal Delivery of 5-Fluorouracil

Polymeric microneedles were prepared with Polyvinyl Pyrrolidone (PVP) K-30 using the mold casting technique. The core microneedles were coated with Eudragit E-100 by dip and spin method. The amount of 5-fluorouracil (FU) loaded in the core microneedles was 604 ± 35.4 µg. The coating thickness was 24.12 ± 1.12 µm. The objective was to deliver the 5-FU gradually in a controlled release manner at the target site in the sub-stratum corneum layer. This approach is anticipated to improve the safety and efficacy of topical melanoma treatment. The release of the drug was prolonged for up to 3 h from the polymer-coated polymeric (PCP) microneedles. The entire amount was found to release within 15 min in uncoated MNs. Likewise, the permeation of the drug from the uncoated microneedles was rapid, whereas the PCP microneedles were able to prolong the permeation up to 420 min. The PCP microneedles were subjected to stability studies at 25°C ± 2°C/60%RH, and 40°C ± 2°C/75%RH condition for 3 months. The formulations were found intact, and the release rate was not significantly different form the fresh formulation. The drug content was found to meet the acceptability criteria as well (98.12 ± 1.8% and 97.8 ± 2.1% at 25 and 40°C respectively after 3 months). Overall, this study demonstrated the feasibility of fabrication of PCP microneedles using Eudragit E100 for intraregional controlled delivery of drugs.

Polymer Coated Polymeric (PCP) Microneedles for Controlled Delivery of Drugs (Dermal and Intravitreal)

Microneedles are used to deliver drugs topically across the skin and mucous membranes. Dissolvable microneedles are made using soluble polymers, which disintegrates in the tissue and release the entire payload instantaneously including the polymer construct. Often, a slow release of drug into the tissue is desirable to overcome the severity of side effects at the site of administration as well as systemic adverse effects. In addition, controlled release of active pharmaceutical ingredient (API) only (not the excipients) is safe and effective particularly when the drug delivery is intended to sensitive organs like the eye. In this project, the feasibility of fabricating polymer coated polymeric (PCP) microneedles to achieve a gradual release of only the active ingredient from the device was investigated. The potential application of such PCP microneedles in the dermal and intravitreal drug delivery was also explored using animal tissue models. The PCP microneedles were found to be intact even after prolonged contact with the release medium. The time at which 50% (T50%) of dextran (10 K) was released in case of microneedles prepared using 20% of core polymer (PVP-K30) was about 15 min versus less than 5 min in the case of uncoated microneedles. Whereas when the core polymer concentration was increased to 50%, the T50% was increased to 90 min. The rate of release depended on the polymer molecular weight grade. The rate of drug release was not influenced by the total amount of concentration of dextran. The PCP microneedles of lidocaine hydrochloride could constantly release the drug for up to 9 h in the skin tissue. Likewise, the PCP microneedles infused voriconazole, intravitreally for 6 h.

Polymer Coated Polymeric (PCP) microneedles for sampling of drugs and biomarkers from tissues

The polymer coated polymeric (PCP) microneedles were fabricated using PVP K30 in the core and ethyl cellulose in the coating. The PCP microneedles do not disintegrate in the tissue upon insertion and rather stays intact and allows diffusion of drugs and analytes across the membrane both inward and outward. In this project the potential use of PCP microneedles for sampling analytes from the dermal tissue was explored. The amount of analyte sampled depended on the concentration in the tissue, physicochemical properties of the analyte and duration of insertion of the array in the tissue. Further, an advanced type of PCP microneedle array was fabricated by entrapping absorbent beads in the core microneedles. The adsorbent enabled the PCP microneedles to recover significantly higher amount of analyte from the tissue.