Human immunodeficiency virus (HIV) is still regarded as a global health problem, with 37.7 million people living with HIV (PLWH) at the end of 2020. However, antiretroviral therapy (ART) has advanced greatly in recent times, and is now extremely effective at reducing the viral load in the blood, which is how disease progression and treatment efficacy are often monitored. This has resulted in PLWH living longer lives, and developing more co-morbidities and a resultant increased pill burden. One such co-morbidity is that up to 50% of all PLWH will develop HIV-associated neurological degeneration (HAND), ranging from mild cognitive degeneration to fully manifested HIV-associated dementia. This is due to the presence of the blood-brain barrier (BBB), which prevents ART from reaching the brain in clinically useful quantities, resulting in a viral reservoir forming which contributes to the development of HAND. One method to bypass the BBB is via the nose-to-brain pathway, where formulations are administered intranasally and molecules are transported via trigeminal and olfactory nerve pathways directly to the brain. Using nanoparticles, and in particular nanocrystals (NCs), the delivery efficiency can possibly be enhanced by manipulating the drug formulations to possess specific particle characteristics. This pathway can also be accessed by a facial intradermal injection, although this involves hypodermic needles, which bring their own problems. Instead, microneedles (MNs) and microarray patches (MAPs) can be used to circumvent the problems caused by hypodermic needles and provide a patient friendly alternative for intradermal deposition of drug formulations. This thesis focuses on the delivery of rilpivirine (RPV) and cabotegravir (CAB) for the potential treatment of HAND via a MN-mediated facial intradermal delivery.