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The concept of "one size fits all" followed by the conventional healthcare system has drawbacks in providing precise pharmacotherapy due to variation in the pharmacokinetics of different patients leading to serious consequences such as side effects. In this regard, digital-based three-dimensional printing (3DP), which refers to fabricating 3D printed pharmaceutical dosage forms with variable geometry in a layer-by-layer fashion, has become one of the most powerful and innovative tools in fabricating "personalized medicine" to cater to the need of therapeutic benefits for patients to the maximum extent. This is achieved due to the tremendous potential of 3DP in tailoring various drug delivery systems (DDS) in terms of size, shape, drug loading, and drug release. In addition, 3DP has a huge impact on special populations including pediatrics, geriatrics, and pregnant women with unique or frequently changing medical needs. The areas covered in the present article are as follows: (i) the difference between traditional and 3DP manufacturing tool, (ii) the basic processing steps involved in 3DP, (iii) common 3DP methods with their pros and cons, (iv) various DDS fabricated by 3DP till date with discussing few research studies in each class of DDS, (v) the drug loading principles into 3D printed dosage forms, and (vi) regulatory compliance.

Traditionally, the skin is considered as a protective barrier which acts as a highly impermeable region of the human body. But in recent times, it is recognized as a specialized organ that aids in the delivery of a wide range of drug molecules into the skin (intradermal drug delivery) and across the skin into systemic circulation (transdermal drug delivery, TDD). The bioavailability of a drug administered transdermally can be improved by several penetration enhancement techniques, which are broadly classified into chemical and physical techniques. Application of mentioned techniques together with efforts of various scientific and innovative companies had made TDD a multibillion dollar market and an average of 2.6 new transdermal drugs are being approved each year. Out of various techniques, the thermal ablation techniques involving chemicals, heating elements, lasers, and radiofrequency (RF) are proved to be more effective in terms of delivering the drug across the skin by disrupting the stratum corneum (SC). The reason behind it is that the thermal ablation technique resulted in improved bioavailability, quick treatment and fast recovery of the SC, and more importantly it does not cause any damage to underlying dermis layer. This review article mainly discussed about various thermal ablation techniques with commercial products and patents in each classes, and their safety aspects. This review also briefly presented anatomy of the skin, penetration pathways across the skin, and different generations of TDD. Graphical abstract.

The key objective of the current research was to fabricate and optimize Capecitabine (Cap)-loaded [poly(lactic-co-glycolic acid)] PLGA-based nanoparticles (NPs) by enabling quality by design (QbD) approach for enhancing antitumor activity by promising delivery of the drug at the colonic site. The current research was based on fabricating PLGA-based nanoparticles along with Eudragit S100 as enteric polymer employing solvent shifting method followed by optimization using QbD approach. This approach was found to be useful for understanding the multiple factors and their interaction influencing the product by utilizing Design of Experiment (DOE). Box-Behnken design (BBD) was adopted to achieve the required critical quality attributes (CQAs), i.e., minimizing particle size, maximizing entrapment efficiency, and minimizing PDI value. The optimized nanoparticles were lyophilized and characterized by FT-IR, DSC, TEM, DLS, MTT assay using HT-29 cell lines, and in vivo pharmacokinetic studies. The optimized PLGA-based nanoparticles were found to possess average particle size, PDI, zeta potential, and entrapment efficiency of 195 nm, 0.214, -6.65 mV, and 65%, respectively. TEM analysis revealed the spherical nature of nanoparticles. The FT-IR and DSC studies revealed no interaction. The bioavailability of Cap-loaded nanoparticles was found to be two fold increased than the pure drug, and also, it exhibited significantly more cytotoxic to tumor cells as compared to pure drug as confirmed by MTT assay. The optimized PLGA-based nanoparticles found to possess enhanced bioavailability and significantly more cytotoxic potential as compared to pure drug.

The main objective of the present investigation was to develop transdermal films of ondansetron HCl (OS) with polyvinyl alcohol (PVA) using Box-Behnken design and to optimize them employing Derringer’s optimization tool. Design-Expert software was used to investigate the effect of independent variables such as concentration (%, w/w) of glycerol and 1,8-cineole, and number of Freeze-Thaw cycle (F-T cycle) on the dependent variables viz. ultimate tensile strength (UTS) and flux. The F-T cycle followed by solvent casting method was employed to develop films. Universal tensile testing machine and Franz diffusion cell were used to measure tensile strength and flux, respectively. Quadratic model was found to be best fit model and the effect of concentration of glycerol and the number of F-T cycle significantly influences the tensile strength (p

Hydrogels are promising biomaterials because of their important qualities such as biocompatibility, biodegradability, hydrophilicity and non-toxicity. These qualities make hydrogels suitable for application in medical and pharmaceutical field. Recently, a tremendous growth of hydrogel application is seen, especially as gel and patch form, in transdermal drug delivery. This review mainly focuses on the types of hydrogels based on cross-linking and; secondly to describe the possible synthesis methods to design hydrogels for different pharmaceutical applications. The synthesis and chemistry of these hydrogels are discussed using specific pharmaceutical examples. The structure and water content in a typical hydrogel have also been discussed.

The present investigation is focused on the development of transdermal film-forming gel (FFG) loaded with etoricoxib employing research surface methodology (RSM). Box-Behnken surface design method was used to develop experimental run using different concentrations of etoricoxib, hydroxypropyl methylcellulose (HPMC K100M), and eudragit RL100 as independent variables, and Derringer's optimization tool was employed to optimize best possible formulation. The dependent variables considered in this study were viscosity and drug permeation at 24 h (Q24, μg/cm2). Anti-inflammatory study was performed on Wistar albino rats for 8 h. Skin irritation studies and accelerated stability studies were performed for validated FFG formulations. Quadratic model was found to be best fit model (p < 0.0001) for both the responses. The influence of HPMC concentration on the viscosity was found to be highest whereas concentration of etoricoxib was maximum for Q24. The optimum composition of the FFG was observed to be 4% of etoricoxib, 1.1246% of HPMC, and 0.4% of eudragit. Above composition resulted in viscosity of 1549.5 mPa.s and maximum Q24 of 4639.11 μg/cm2 with desirability 0.918. The in vivo anti-inflammatory study demonstrated better sustained release effect (for 8 h) of optimized FFG compared to orally administered drug suspension. An average irritation score of 0.555 was observed on Draize scoring system. The validated FFG formulation was found to be stable for the 3 months in accelerated conditions. It can be concluded from the above investigations that the validated FFG formulation of etoricoxib is well tolerated and could provide sustained drug release for 8 h. Graphical abstract.

Even though the concept of three-dimensional printing (3DP) technology was evolved in 1970s, but its popularity in pharmaceutical field grows manifold during last decade due to the introduction of the first Food and Drug Administration (FDA) approved 3D printed drug product (Spritam®) into the market. Since then, there has been an immense focus on 3DP research not only in the biomedical field but also in pharmaceutical sector. This is due to potential advantages possessed by 3DP techniques including the customization of medicines with an adjusted dose for individuals, on-demand manufacturing, and the ability to fabricate complex geometries and sophisticated dosage forms, and cost-effectiveness. In this review, the concept and process of 3DP, different methods and techniques of 3DP, excipients, and drug characteristics requirement, quality defects, product quality characterization, and current trends of 3D regulation. It also focussed on the application of 3DP in pharmaceutical dosage form development.

The aim of the present investigation was to prepare and optimize suitable combination of polymers hydroxypropyl methylcellulose (HPMC) and pluronic ® F127 (PN F127) for the development of thermosensitive gel of Metoprolol succinate (MS) using central composite design (CCD). The effect of formulation factors (concentration of HPMC and PN F127) on responses such as cumulative percentage release (CPR) of MS, bioadhesive force (BF) and viscosity was measured statistically. Quadratic model was found to be best fit model among different models used in the study. The optimum conditions were found to be 0.92% of HPMC and 15% of PN F127. Under these conditions, the predicted CPR, BF and viscosity were found to be 84.94 μg/cm 2 , 41.56 gf and 48.94 Pa s, respectively. Ex vivo permeation of MS from optimized thermosensitive gel across abdominal skin of rat demonstrated highest flux (64.35 μg/cm 2 /h) for the gel formulation containing 1,8-cineole (5% w/w). The hypotensive activity was performed on normotensive rabbits and the results showed that the optimized formulation prolonged the activity up to 12 h. The above findings indicated that thermosensitive gel of MS for skin application exhibited strong potential against hypertension and expected to provide a better alternative to oral MS formulations.

In the present study, pluronic lecithin organogel (PLO) of diltiazem hydrochloride (DZH) was developed by taking different ratios of organic phase to aqueous phase (1:3, 1:4, and 1:5) with varying concentration of soya lecithin (20, 30, and 40 % w/w) in organic phase (isopropyl myristate, IPM) and pluronic (20, 25, and 30 % w/w) in aqueous phase, respectively, and characterized for in vitro parameters and ex vivo permeation study. The results of in vitro parameters were found to be within permissible limit and all the PLOs were physically stable at refrigeration and ambient temperature. The influence of phase ratio and different concentrations of soya lecithin on DZH release from the PLOs was found to be significant (p

The aim of the present research was to optimize cryogel formulation of Diltiazem hydrochloride (DZ) with poly(vinyl alcohol) (PVA) and hydroxypropyl methylcellulose (HPMC) by utilizing response surface methodology followed by ex vivo permeation study on the optimized gel containing penetration enhancers. A 3-level factorial design was employed to formulate the experimental runs and to evaluate the effect of two independent variables such as the concentration of PVA and HPMC on characteristics of cryogel such as bioadhesive strength (BS) and in vitro drug release (dependent variables). Response surface plots such as contour and 3D plots were generated by the Design Expert® software to analyze the effect of independent variables on dependent variables. Fourier transform infrared spectroscopy studies confirmed the absence of interaction between DZ and polymers. Among various models generated by the software, quadratic model was found to be best fit for both the responses. Both the formulation factors influenced BS synergistically. However, the effect of HPMC concentration was more pronounced compared to concentration of PVA. But, an opposite effect shown by both the formulation factors on cumulative percentage of drug release (CPR) in 8 h. The optimized batch of cryogel of DZ selected by the software was having composition of 5 % of PVA and 2 % of HPMC. Penetration enhancers such as 1,8-cineole, d-limonene and carvone were incorporated into the optimized gel and permeation study was carried out using abdominal skin of rat. The study demonstrated a highest flux of 118 ± 5.81 µg/cm2/h in case of 1,8-cineole containing gel followed by carvone and d-limonene.

In the current study Indomethacin (IM) fast dissolving tablets (FDTs) were prepared by direct compression technique in order to enhance its dissolution rate. The tablets were formulated using two different approaches; super-disintegration and efferves-cence. A combination formulation of above approaches was also developed to further improve its properties. The super-disintegrants used in the formulae were sodium starch glycolate (Primogel), cross-povidone (Kollidon) and cross-carmellose (Ac-di-sol). Sodium bicarbonate and citric acid combination was employed as effervescent ingredients. The prepared powder mixtures of IM were subjected to evaluation of various pre-compression parameters and tablets were evaluated for weight variation, dimension, hardness, friability, drug content, disintegration, wetting time, uniformity of dispersion, in vitro drug release and stability studies. The FT-IR spectra shown there are no interaction between of IM with excipient. The results of pre-compression studies indicate acceptable flow property for all the powder mixtures. The data of weight variation, dimension, hardness, friability, uniformity of dispersion and drug content studies were within the official limits. The wetting time and disintegration time decreases considerably with the increase in super-disintegrants amount. By using the combination approach, the disintegration and wetting time further decreased. In vitro dissolution studies were carried out using phosphate buffer pH 6.8 as dissolution medium for 60min and observed that formulation IF9, among super-disintegration approach, released highest percentage (97.13±2.09) of IM. In vitro drug release was highest (98.54±2.89) at 60 min for formulation IF11, when all the formulations were taken into consideration. The stability study was performed on the promised formulation IF11 at 40±2 o C/ 75±5% RH for 3 months and the results indicated that there were no significant changes in aforesaid tablet properties.

The use of topical formulation is popular over the past decade due to extensive researches made in the field of transdermal drug delivery. As a result, an increasing number of drugs are being added to the list of therapeutic agents that can be delivered to systemic circulation through the skin. Commonly available dosage forms for the topical application are creams, ointments, gels, patches etc. The therapeutic benefits of the above topical formulations are limited due to barrier property of stratum corneum (SC). The use of chemical penetration enhancers (CPEs) is one of the long standing approach to overcome the barrier property of SC. Numerous class of novel compounds have been evaluated for penetration enhancement activity, including soft enhancement for percutaneous absorption (SEPA), for example, 2 N-nonyl-1,3- dioxolanes, N-acetyle prolinate esters (such as pentyl- and octyl-N-acetyle prolinate), alkyldiloxanes (e.g., 1-Alkyl-3-b-D glucopyranosyl-1,1,3,3-tetramethyl disiloxanes), transcarbam (such as 5-(dodecyloxycarbonyl) pentylammonium-5- (dodecyloxycarbonyl) pentylcarbamate), iminosulfurane (like N-hexyl,N-benzoyl-S,S-dimethylimino-sulfuranes), capsaicin derivatives (e.g., Nonivamide), cinnamene compounds (such as cinnamic acid, cinnamaldehyde etc), terpenes (like clove and basil oil) and synergestic combination of penetration enhancers (SCOPE). We briefly describe about the anatomy of skin. Potential mechanisms of action of above novel PEs along with adverse reactions associated with traditional PEs are also considered in this review.

Since the approval of first transdermal patch (Transderm Scop(®)) containing scopolamine in 1979, the improvement in systemic drug delivery through skin remains incremental. The traditional methods based on passive diffusion of drug molecules in to the skin are unable to deliver macromolecules, such as peptides, proteins, DNA and vaccines, due to the barrier properties of stratum corneum (SC). During the course of approximately 35 years, the focuses are not only to overcome the above barrier property of the skin but also the safety, accuracy and patient compliance aspect of the traditional methods. The former limitation can be overcome by altering the SC barrier function by different active methods such electrically assisted methods (sonophoresis, iontophoresis, electroporation, magnetophoresis, pressure waves, electron beam irradiation), SC abruption (microneedles, high-velocity jet) and SC removal (tape-stripping, suction, microdermabrasion, ablation). This review summarizes basic principles, mechanisms, advantages, limitations and recent development of above physical techniques along with skin anatomy and drug transport pathways across skin.