Oral drug delivery in personalized medicine: Unmet needs and novel approaches

Permeation studies through porcine small intestine of furosemide solutions for personalised paediatric administration

Personalized medicine is a challenging research area in paediatric drug design since no suitable pharmaceutical forms are currently available. Furosemide is an anthranilic acid derivative used in paediatric practice to treat cardiac and pulmonary disorders in premature infants and neonates. However, it is not commercialized in suitable dosage forms for paediatrics. Elaborating new paediatric formulations when no commercial forms are available is a common practice in pharmacy laboratories; amongst these, oral liquid formulations are the most common. We developed two extemporaneous paediatric oral solutions of furosemide (pure powder). The characterization and stability study were also performed. Parameters such as organoleptic characteristics, rheology, pH, content of active substance, and microbial stability were evaluated at three temperatures for two months. Evaluation of all these parameters showed that both solutions were stable for 60 days at 4 and 25 °C. Moreover, ex vivo studies were performed to evaluate the permeation behaviour of developed solutions through porcine small intestine to evaluate the potential paediatric biological parameters influencing the bioavailability and efficacy. A validated spectrofluorometric method was also used for this purpose. Our results guarantee a correct dosification, administration and potential efficacy of furosemide when is formulated in liquid oral forms for the treatment of cardiac and pulmonary disorders in children.

Formulating SLMs as oral pulsatile system for potential delivery of melatonin to pediatric population

The formulation development of melatonin (MLT) for infants and children with neurodevelopmental difficulties was fully investigated. This population have a higher prevalence of sleep disorders and present special challenges for drug administration and swallowing. To solve these issues, solid lipid microparticles (SLMs) were designed to obtain an oral flexible dosage form constituted by GRAS excipients and a free flow pulsatile delivery system for MLT, able to maintain its release through 8h. Three groups of SLMs were produced by spray congealing and characterized as regards particle size, morphology, flowability, solid state, drug content and release behavior. The SLMs manipulation with milk and yogurt and the MLT stability in these foods were also investigated. Microparticles with different excipient composition were selected to obtain a pulsatile release pattern over 8h. The final delivery platform displayed a prompt release from group I SLMs together with a lag phase of groups II and III SLMs, followed by a repeated MLT release from group II and a prolonged MLT release related to the last group. Finally, MLT was compatible and stable in milk and yogurt suggesting that microparticles sprinkled into food is acceptable for MLT administration to children unable to swallow capsules or tablets.

Design and physicochemical stability studies of paediatric oral formulations of sildenafil

Personalized medicine is a challenging research area in paediatric treatments. Elaborating new paediatric formulations when no commercial forms are available is a common practice in pharmacy laboratories; among these, oral liquid formulations are the most common. But due to the lack of specialized equipment, frequently studies to assure the efficiency and safety of the final medicine cannot be carried out. Thus the purpose of this work was the development, characterization and stability evaluation of two oral formulations of sildenafil for the treatment of neonatal persistent pulmonary hypertension. After the establishment of a standard operating procedure (SOP) and elaboration, the physicochemical stability parameters appearance, pH, particle size, rheological behaviour and drug content of formulations were evaluated at three different temperatures for 90 days. Equally, prediction of long term stability, as well as, microbiological stability was performed. Formulations resulted in a suspension and a solution slightly coloured exhibiting fruity odour. Formulation I (suspension) exhibited the best physicochemical properties including Newtonian behaviour and uniformity of API content above 90% to assure an exact dosification process.

Behavior of printable formulations of loperamide and caffeine on different substrates--effect of print density in inkjet printing

The primary goal of the current work was to study the applicability of precision inkjet printing in fabrication of personalized doses of active pharmaceutical ingredients (APIs). Loperamide hydrochloride (LOP) and caffeine (CAF) were used as model compounds. Different doses of the drugs in a single dosage unit were produced, using a drop-on-demand inkjet printer by varying printing parameters such as the distance between jetted droplets (drop spacing) and the physical dimensions of the printed dosage forms. The behavior of the formulated printable inks for both APIs was investigated on the model substrates, using different analytical tools. The obtained results showed that printed LOP did not recrystallize on any substrates studied, whereas at least partial recrystallization of printed CAF was observed on all carrier surfaces. Flexible doses of both APIs were easily obtained by adjusting the drop spacing of the depositing inks, and the results were relevant with regards to the theoretical content. Adapting the dose by varying physical dimensions of single dosage units was less successful than the approach in which drop spacing was altered. In conclusion, controlled printing technology, by means of adjusting the distance between jetted droplets, offers a means to fabricate dosage forms with individualized doses.

Subcutaneous administration of nano- and microsuspensions of poorly soluble compounds to rats

The aim of the present study was to evaluate and interpret the pharmacokinetic profiles of two compounds after subcutaneous (s.c.) administration. The compounds have similar physicochemical properties, but are a base (BA99) and an acid (AC88), respectively. The compounds were administered as nano- (5 and 500 µmol/kg) and microsuspensions (5 µmol/kg) s.c. to Sprague-Dawley rats. At the low dose, the exposure was higher for both compounds administered as nanocrystals compared to microparticles. The high dose of the compounds resulted in even higher exposure, but not in a dose-linear manner. The differences in exposure between nano- and microparticles were mainly ascribed to higher dissolution rate and improved solubility for smaller particles. In addition to differences in exposure, there were also differences in the elimination pattern. After s.c. injection of 5 µmol/kg of BA99 as nano- and microsuspensions, the elimination profile was similar as observed earlier after oral administration. However, after injection of the higher dose of BA99 and all formulations of AC88, an extended elimination profile was observed, forming a maintained plateau under the investigated time-period. Essentially, constant plasma levels were caused by a balanced equilibrium between total body clearance of the drug and supply rate of drug from the formulations.

Individual oral therapy with immediate release and effervescent formulations delivered by the solid dosage pen

New devices enabling freely selectable dosing of solid oral medications are urgently needed for personalized medicine. One approach is the use of the recently published Solid Dosage Pen, allowing flexible dosing of tablet-like sustained release slices from drug loaded extruded strands. Slices were suitable for oral single dosed application. The aim of the present study was the development of immediate release dosage forms for applications of the device, especially for young children. Using two model drugs, two different concepts were investigated and evaluated. Effervescent formulations were manufactured by an organic wet-extrusion process and immediate release formulations by a melt-extrusion process. Dissolution experiments were performed for both formulations to ensure the immediate release behavior. Extruded strands were individually dosed by the Solid Dosage Pen. Various doses of the two formulations were analyzed regarding uniformity of mass and content according to pharmacopoeial specifications. Proof of concept was demonstrated in both approaches as results comply with the regulatory requirements. Furthermore, storing stress tests were performed and drug formulations were characterized after storing. The results show that suitable packaging material has been selected and storage stability is probable.

Individualized, discrete event, simulations provide insight into inter- and intra-subject variability of extended-release, drug products

OBJECTIVE

Develop and validate particular, concrete, and abstract yet plausible in silico mechanistic explanations for large intra- and interindividual variability observed for eleven bioequivalence study participants. Do so in the face of considerable uncertainty about mechanisms.

METHODS

We constructed an object-oriented, discrete event model called subject (we use small caps to distinguish computational objects from their biological counterparts). It maps abstractly to a dissolution test system and study subject to whom product was administered orally. A subject comprises four interconnected grid spaces and event mechanisms that map to different physiological features and processes. Drugs move within and between spaces. We followed an established, Iterative Refinement Protocol. Individualized mechanisms were made sufficiently complicated to achieve prespecified Similarity Criteria, but no more so. Within subjects, the dissolution space is linked to both a product-subject Interaction Space and the GI tract. The GI tract and Interaction Space connect to plasma, from which drug is eliminated.

RESULTS

We discovered parameterizations that enabled the eleven subject simulation results to achieve the most stringent Similarity Criteria. Simulated profiles closely resembled those with normal, odd, and double peaks. We observed important subject-by-formulation interactions within subjects.

CONCLUSION

We hypothesize that there were interactions within bioequivalence study participants corresponding to the subject-by-formulation interactions within subjects. Further progress requires methods to transition currently abstract subject mechanisms iteratively and parsimoniously to be more physiologically realistic. As that objective is achieved, the approach presented is expected to become beneficial to drug development (e.g., controlled release) and to a reduction in the number of subjects needed per study plus faster regulatory review.

Design of a pediatric oral formulation with a low proportion of hydrochlorothiazide

It is a normal pediatric practice in community and hospital pharmacies to prepare a new drug formulation when no commercial forms of it are available. Any dose or stability control is usually done for these types of compounding formulations due to the effort which means to develop these types of tests in pharmacies. We have studied five different hydrochlorothiazide oral formulations prepared with traditional compounding techniques in pharmacies to treat heart failure and edemas in babies. A Standard Operating Procedure (SOP) was done for every suspension. After the strictly monitoring of the SOP, every suspension was subjected to quality control tests (pH, particle size, viscosity, dose content and stability). There is only one studied formulation that guarantees the correct dose administering and stability after 3 weeks stored at 5 °C and light protected. Both, the percentage of wetting agent and the viscosity of the suspensor vehicle in this formulation make the correct dose administering possible after the formulation is shaken.

Orally disintegrating mini-tablets (ODMTs)--a novel solid oral dosage form for paediatric use

The new European regulations on paediatric medicines and recent WHO recommendations have induced an increased need for research into novel child-appropriate dosage forms. The aim of this study was the development of orally disintegrating mini-tablets (ODMTs) as a suitable dosage form for paediatric patients. The suitability of five commercially available ready-to-use tableting excipients, Ludiflash, Parteck ODT, Pearlitol Flash, Pharmaburst 500 and Prosolv ODT, to be directly compressed into mini-tablets, with 2 mm in diameter, was examined. All of the excipients are based on co-processed mannitol. Drug-free ODMTs and ODMTs with a child-appropriate dose of hydrochlorothiazide were investigated. ODMTs could be produced with all investigated excipients. ODMTs with a sufficient crushing strength >7 N and a low friability <1% could be obtained, as well as ODMTs with a short simulated wetting test-time <5 s. ODMTs made of Ludiflash showed the best results with crushing strengths from 7.8 N up to 11.8 N and excellent simulated wetting test-times from 3.1 s to 5.0 s. For each excipient, ODMTs with accordance to the pharmacopoeial specification content uniformity could be obtained. The promising results indicate that orally disintegrating mini-tablets may serve as a novel platform technology for paediatrics in future.